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Sample records for 1h 31p 77se

  1. 4 T Actively detuneable double-tuned 1H/31P head volume coil and four-channel 31P phased array for human brain spectroscopy.

    PubMed

    Avdievich, N I; Hetherington, H P

    2007-06-01

    Typically 31P in vivo magnetic resonance spectroscopic studies are limited by SNR considerations. Although phased arrays can improve the SNR; to date 31P phased arrays for high-field systems have not been combined with 31P volume transmit coils. Additionally, to provide anatomical reference for the 31P studies, without removal of the coil or patient from the magnet, double-tuning (31P/1H) of the volume coil is required. In this work we describe a series of methods for active detuning and decoupling enabling use of phased arrays with double-tuned volume coils. To demonstrate these principles we have built and characterized an actively detuneable 31P/1H TEM volume transmit/four-channel 31P phased array for 4 T magnetic resonance spectroscopic imaging (MRSI) of the human brain. The coil can be used either in volume-transmit/array-receive mode or in TEM transmit/receive mode with the array detuned. Threefold SNR improvement was obtained at the periphery of the brain using the phased array as compared to the volume coil. PMID:17379554

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

    SciTech Connect

    Nakada, T.; Kwee, I.L.; Suzuki, N.; Houkin, K. )

    1989-11-01

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

  3. Direct and simultaneous quantification of ATP, ADP and AMP by (1)H and (31)P Nuclear Magnetic Resonance spectroscopy.

    PubMed

    Lian, Yakun; Jiang, Hua; Feng, Jinzhou; Wang, Xiaoyan; Hou, Xiandeng; Deng, Pengchi

    2016-04-01

    ATP, ADP and AMP are energy substances with vital biological significance. Based on the structural differences, a simple, rapid and comprehensive method has been established by (1)H and (31)P Nuclear Magnetic Resonance ((1)H-NMR and (31)P-NMR) spectroscopies. Sodium 3-(trimethylsilyl) propionate-2,2,3,3-d4 (TMSP) and anhydrous disodium hydrogen phosphate (Na2HPO4) were selected as internal standards for (1)H-NMR and (31)P-NMR, respectively. Those three compounds and corresponding internal standards can be easily distinguished both by (1)H-NMR and (31)P-NMR. In addition, they all have perfect linearity in a certain range: 0.1-100mM for (1)H-NMR and 1-75mM for (31)P-NMR. To validate the precision of this method, mixed samples of different concentrations were measured. Recovery experiments were conducted in serum (91-113% by (1)H-NMR and 89-113% by (31)P-NMR). PMID:26838434

  4. Compatibility of Superparamagnetic Iron Oxide Nanoparticle Labeling for 1H MRI Cell Tracking with 31P MRS for Bioenergetic Measurements

    PubMed Central

    Zhang, Zhuoli; Hancock, Brynne; Leen, Stephanie; Ramaswamy, Sharan; Sollott, Steven J.; Boheler, Kenneth R.; Juhaszova, Magdalena; Lakatta, Edward G.; Spencer, Richard G.; Fishbein, Kenneth W.

    2011-01-01

    Labeling of cells with superparamagnetic iron oxide nanoparticles permits cell tracking by 1H MRI while 31P MRS allows non-invasive evaluation of cellular bioenergetics. We evaluated the compatibility of these two techniques by obtaining 31P NMR spectra of iron-labeled and unlabeled immobilized C2C12 myoblast cells in vitro. Broadened but usable 31P spectra were obtained, and peak area ratios of resonances corresponding to intracellular metabolites showed no significant differences between labeled and unlabeled cell populations. We conclude that 31P NMR spectra can be obtained from cells labeled with sufficient iron to permit visualization by 1H imaging protocols and that these spectra have sufficient quality to be used in assessing metabolic status. This result introduces the possibility of using localized 31P MRS to evaluate the viability of iron-labeled therapeutic cells as well as surrounding host tissue in vivo. PMID:20853523

  5. Solid-State Quantitative (1)H and (31)P MRI of Cortical Bone in Humans.

    PubMed

    Seifert, Alan C; Wehrli, Felix W

    2016-06-01

    Magnetic resonance imaging (MRI) plays a pivotal role for assessment of the musculoskeletal system. It is currently the clinical modality of choice for evaluation of soft tissues including cartilage, ligaments, tendons, muscle, and bone marrow. By comparison, the study of calcified tissue by MRI is still in its infancy. In this article, we review the potential of the modality for assessment of cortical bone properties known to be affected in degenerative bone disease, with focus on parameters related to matrix and mineral densities, and porosity, by means of emerging solid-state (1)H and (31)P MRI techniques. In contrast to soft tissues, the MRI signal in calcified tissues has very short lifetime, on the order of 100 μs to a few milliseconds, demanding customized imaging approaches that allow capture of the signal almost immediately after excitation. The technologies described are suited for quantitatively imaging human cortical bone in specimens as well as in vivo in patients on standard clinical imagers, yielding either concentrations in absolute units when measured against a reference standard, or more simply, in the form of surrogate biomarkers. The two major water fractions in cortical bone are those of collagen-bound and pore water occurring at an approximately 3:1 ratio. Collagen-bound water density provides a direct quantitative measure of osteoid density. While at an earlier stage of development, quantification of mineral phosphorus by (31)P MRI yields mineral density and, together with knowledge of matrix density, should allow quantification of the degree of bone mineralization. PMID:27048472

  6. 31P MRSI and 1H MRS at 7 T: initial results in human breast cancer.

    PubMed

    Klomp, Dennis W J; van de Bank, Bart L; Raaijmakers, Alexander; Korteweg, Mies A; Possanzini, Cecilia; Boer, Vincent O; van de Berg, Cornelius A T; van de Bosch, Maurice A A J; Luijten, Peter R

    2011-12-01

    This study demonstrates the feasibility of the noninvasive determination of important biomarkers of human (breast) tumor metabolism using high-field (7-T) MRI and MRS. (31) P MRSI at this field strength was used to provide a direct method for the in vivo detection and quantification of endogenous biomarkers. These encompass phospholipid metabolism, phosphate energy metabolism and intracellular pH. A double-tuned, dual-element transceiver was designed with focused radiofrequency fields for unilateral breast imaging and spectroscopy tuned for optimized sensitivity at 7 T. T(1) -weighted three-dimensional MRI and (1) H MRS were applied for the localization and quantification of total choline compounds. (31) P MRSI was obtained within 20 min per subject and mapped in three dimensions over the breast with pixel volumes of 10 mL. The feasibility of monitoring in vivo metabolism was demonstrated in two patients with breast cancer during neoadjuvant chemotherapy, validated by ex vivo high-resolution magic angle spinning NMR and compared with data from an age-matched healthy volunteer. Concentrations of total choline down to 0.4 mM could be detected in the human breast in vivo. Levels of adenosine and other nucleoside triphosphates, inorganic phosphate, phosphocholine, phosphoethanolamine and their glycerol diesters detected in glandular tissue, as well as in tumor, were mapped over the entire breast. Altered levels of these compounds were observed in patients compared with an age-matched healthy volunteer; modulation of these levels occurred in breast tumors during neoadjuvant chemotherapy. To our knowledge, this is the first comprehensive MRI and MRS study in patients with breast cancer, which reveals detailed information on the morphology and phospholipid metabolism from volumes as small as 10 mL. This endogenous metabolic information may provide a new method for the noninvasive assessment of prognostic and predictive biomarkers in breast cancer treatment. PMID

  7. Bone Mineral 31P and Matrix-Bound Water Densities Measured by Solid-State 1H and 31P MRI

    PubMed Central

    Seifert, Alan C.; Li, Cheng; Rajapakse, Chamith S.; Bashoor- Zadeh, Mahdieh; Bhagat, Yusuf A.; Wright, Alexander C.; Zemel, Babette S.; Zavaliangos, Antonios; Wehrli, Felix W.

    2014-01-01

    Bone is a composite material consisting of mineral and hydrated collagen fractions. MRI of bone is challenging due to extremely short transverse relaxation times, but solid-state imaging sequences exist that can acquire the short-lived signal from bone tissue. Previous work to quantify bone density via MRI used powerful experimental scanners. This work seeks to establish the feasibility of MRI-based measurement on clinical scanners of bone mineral and collagen-bound water densities, the latter as a surrogate of matrix density, and to examine the associations of these parameters with porosity and donors’ age. Mineral and matrix-bound water images of reference phantoms and cortical bone from 16 human donors, ages 27-97 years, were acquired by zero-echo-time 31P and 1H MRI on whole body 7T and 3T scanners, respectively. Images were corrected for relaxation and RF inhomogeneity to obtain density maps. Cortical porosity was measured by micro-CT, and apparent mineral density by pQCT. MRI-derived densities were compared to x-ray-based measurements by least-squares regression. Mean bone mineral 31P density was 6.74±1.22 mol/L (corresponding to 1129±204 mg/cc mineral), and mean bound water 1H density was 31.3±4.2 mol/L (corresponding to 28.3±3.7 %v/v). Both 31P and bound water (BW) densities were correlated negatively with porosity (31P: R2 = 0.32, p < 0.005; BW: R2 = 0.63, p < 0.0005) and age (31P: R2 = 0.39, p < 0.05; BW: R2 = 0.70, p < 0.0001), and positively with pQCT density (31P: R2 = 0.46, p < 0.05; BW: R2 = 0.50, p < 0.005). In contrast, the bone mineralization ratio (expressed here as the ratio of 31P density to bound water density), which is proportional to true bone mineralization, was found to be uncorrelated with porosity, age, or pQCT density. This work establishes the feasibility of image-based quantification of bone mineral and bound water densities using clinical hardware. PMID:24846186

  8. A practical guide for the setup of a 1H-31P-13C double cross-polarization (DCP) experiment.

    PubMed

    Ciesielski, Wlodzimierz; Kassassir, Hassan; Potrzebowski, Marek J

    2011-01-01

    O-phospho-L-threonine is a convenient sample to setup a (1)H-(31)P-(13)C double cross-polarization (DCP) Hartmann-Hahn match. The (1)H-(31)P-(13)C technique is extremely sensitive to the rate of the sample spinning. Both zero-quantum (ZQ) and double-quantum (DQ) cross-polarization operate at an average spinning rate (6-7 kHz). At higher spinning rates (10 kHz), the DQCP mechanism dominates and leads to a reduction of signal intensity, in particular for lower (31)P RF field strength. The application of two shape pulses during the second cross-polarization greatly improves the signal to noise ratio allowing the recording of better quality spectra. (31)P-(13)C spectrally induced filtering in combination with cross-polarization (SPECIFIC-CP) experiments can be carried out under ZQCP and DQCP conditions if careful attention is paid to the choice of RF field amplitudes and carriers Ω. Application of 1D and 2D (1)H-(31)P-(13)C experiments is demonstrated on model samples; disodium ATP hydrate and O-phospho-L-tyrosine. PMID:21440422

  9. Proton 1H- and Phosphorus 31P-MR spectroscopy (MRS) in asymptomatic HIV-positive patients

    PubMed Central

    Schuettfort, Gundolf; Hattingen, Elke; Pilatus, Ulrich; Stephan, Christoph; Wolf, Timo; Goepel, Siri; Haberl, Annette; Blasel, Stella; Zanella, Freidhelm; Brodt, Hans-Reinhard; Bickel, Markus

    2014-01-01

    Introduction HIV infection is accompanied by a variety of neurological disorders. Depression of cell-mediated immunity is followed by the development of central nervous system opportunistic infections/tumours, and frequently by the occurrence of the AIDS dementia complex (ADC). However, the pathophysiology of the emergence of neuro-AIDS is still unknown. Despite the development of cognitive impairments, the early diagnosis, objectification and quantification of the existence and extent of this impairment during infection are difficult to recognize in each individual case. To support the early diagnosis of ADC, there is a need for additional, non-invasive diagnostic methods. In this study, it is of interest to answer the clinically relevant question of whether magnetic resonance spectroscopy can detect changes in the cerebral metabolism of asymptomatic HIV-positive patients and is possibly suitable for the early diagnosis and prevention of HIV encephalopathy. Methods A group of 13 asymptomatic, HIV-positive patients with combined antiretroviral therapy (cART) and 13 healthy controls were examined with 2D 1H-MRS and 3D 31P-MRS at 3T. The patients were treated with cART for at least 12 months. Changes in the absolute concentrations of phosphorylated metabolites (ATP), N-acetyl-aspartate, creatine, myo-Isonitol, glutamate/glutamine and choline-containing compounds were compared with that of control subjects. Results Asymptomatic HIV-positive patients had significantly lower N-acetyl-aspartate in the white matter in a frontal and parietal target region. The other evaluated metabolites in the 1H MRS showed no significant difference between the HIV-positive patients and healthy controls. The 31P-MRS detected significant elevated values regarding the choline-containing compounds PEth, GPE and PCho. Conclusions This spectroscopic study revealed a significantly lower N-acetyl-aspartate in the white matter in a frontal and parietal cerebral target region in asymptomatic, HIV

  10. Determination of glucan phosphorylation using heteronuclear 1H, 13C double and 1H, 13C, 31P triple-resonance NMR spectra.

    PubMed

    Schmieder, Peter; Nitschke, Felix; Steup, Martin; Mallow, Keven; Specker, Edgar

    2013-10-01

    Phosphorylation and dephosphorylation of starch and glycogen are important for their physicochemical properties and also their physiological functions. It is therefore desirable to reliably determine the phosphorylation sites. Heteronuclear multidimensional NMR-spectroscopy is in principle a straightforward analytical approach even for complex carbohydrate molecules. With heterogeneous samples from natural sources, however, the task becomes more difficult because a full assignment of the resonances of the carbohydrates is impossible to obtain. Here, we show that the combination of heteronuclear (1) H,(13) C and (1) H,(13) C,(31) P techniques and information derived from spectra of a set of reference compounds can lead to an unambiguous determination of the phosphorylation sites even in heterogeneous samples. PMID:23913630

  11. An efficient 1H/31P double-resonance solid-state NMR probe that utilizes a scroll coil

    PubMed Central

    Grant, Christopher V.; Sit, Siu-Ling; De Angelis, Anna A.; Khuong, Kelli S.; Wu, Chin H.; Plesniak, Leigh A.; Opella, Stanley J.

    2007-01-01

    The construction and performance of a scroll coil double-resonance probe for solid-state NMR on stationary samples is described. The advantages of the scroll coil at the high resonance frequencies of 1H and 31P include: high efficiency, minimal perturbations of tuning by a wide range of samples, minimal RF sample heating of high dielectric samples of biopolymers in aqueous solution, and excellent RF homogeneity. The incorporation of a cable tie cinch for mechanical stability of the scroll coil is described. Experimental results obtained on a Hunter Killer Peptide 1 (HKP1) interacting with phospholipid bilayers of varying lipid composition demonstrate the capabilities of this probe on lossy aqueous samples. PMID:17719813

  12. An efficient (1)H/(31)P double-resonance solid-state NMR probe that utilizes a scroll coil.

    PubMed

    Grant, Christopher V; Sit, Siu-Ling; De Angelis, Anna A; Khuong, Kelli S; Wu, Chin H; Plesniak, Leigh A; Opella, Stanley J

    2007-10-01

    The construction and performance of a scroll coil double-resonance probe for solid-state NMR on stationary samples is described. The advantages of the scroll coil at the high resonance frequencies of (1)H and (31)P include: high efficiency, minimal perturbations of tuning by a wide range of samples, minimal RF sample heating of high dielectric samples of biopolymers in aqueous solution, and excellent RF homogeneity. The incorporation of a cable tie cinch for mechanical stability of the scroll coil is described. Experimental results obtained on a Hunter Killer Peptide 1 (HKP1) interacting with phospholipid bilayers of varying lipid composition demonstrate the capabilities of this probe on lossy aqueous samples. PMID:17719813

  13. Study of stereospecificity of 1H, 13C, 15N and 77Se shielding constants in the configurational isomers of the selenophene-2-carbaldehyde azine by NMR spectroscopy and MP2-GIAO calculations.

    PubMed

    Afonin, Andrei V; Pavlov, Dmitry V; Albanov, Alexander I; Levanova, Ekaterina P; Levkovskaya, Galina G

    2011-11-01

    In the (1)H and (13)C NMR spectra of selenophene-2-carbaldehyde azine, the (1)H-5, (13)C-3 and (13)C-5 signals of the selenophene ring are shifted to higher frequencies, whereas those of the (1)H-1, (13)C-1, (13)C-2 and (13)C-4 are shifted to lower frequencies on going from the EE to ZZ isomer or from the E moiety to the Z moiety of EZ isomer. The (15)N chemical shift is significantly larger in the EE isomer relative to the ZZ isomer and in the E moiety relative to the Z moiety of EZ isomer. A very pronounced difference (60-65 mg/g) between the (77)Se resonance positions is revealed in the studied azine isomers, the (77)Se peak being shifted to higher frequencies in the ZZ isomer and in the Z moiety of EZ isomer. The trends in the changes of the measured chemical shifts are reasonably reproduced by the GIAO calculations at the MP2 level of the (1)H, (13)C, (15)N and (77)Se shielding constants in the energy-favorable conformation with the syn orientation of both selenophene rings relative to the C = N groups. The NBO analysis suggests that such an arrangement of the selenophene rings may take place because of a higher energy of some intramolecular interactions. PMID:22002712

  14. Dynamic interleaved 1H/31P STEAM MRS at 3 Tesla using a pneumatic force-controlled plantar flexion exercise rig

    PubMed Central

    Meyerspeer, M.; Krššák, M.; Kemp, G.J.; Roden, M.; Moser, E.

    2016-01-01

    1 Objective To develop a measurement method for interleaved acquisition of 1H and 31P STEAM localised spectra of exercising human calf muscle. 2 Materials and Methods A nonmagnetic exercise rig with a pneumatic piston and sensors for force and pedal angle was constructed to enable plantar flexion measured in the 3 Tesla MR scanner, which holds the dual tuned (1H,31P) surface coil used for signal transmission and reception. 3 Results 31P spectra acquired in interleaved mode benefit from higher SNR (factor of 1.34± 0.06 for PCr) compared to standard acquisition due to the Nuclear Overhauser effect (NOE) and substantial PCr/Pi changes during exercise can be observed in 31P spectra. 1H spectral quality is equal to that in single mode experiments and allows Cr2 changes to be monitored. 4 Conclusion The feasibility of dynamic interleaved localised 1H and 31P spectroscopy during plantar flexion exercise has been demonstrated using a custom-built pneumatic system for muscle activation. This opens the possibility of studying the dynamics of metabolism with multi nuclear MRS in a single run. PMID:16320091

  15. Mapping hypoxia-induced bioenergetic rearrangements and metabolic signaling by 18O-assisted 31P NMR and 1H NMR spectroscopy.

    PubMed

    Pucar, Darko; Dzeja, Petras P; Bast, Peter; Gumina, Richard J; Drahl, Carmen; Lim, Lynette; Juranic, Nenad; Macura, Slobodan; Terzic, Andre

    2004-01-01

    Brief hypoxia or ischemia perturbs energy metabolism inducing paradoxically a stress-tolerant state, yet metabolic signals that trigger cytoprotection remain poorly understood. To evaluate bioenergetic rearrangements, control and hypoxic hearts were analyzed with 18O-assisted 31P NMR and 1H NMR spectroscopy. The 18O-induced isotope shift in the 31P NMR spectrum of CrP, betaADP and betaATP was used to quantify phosphotransfer fluxes through creatine kinase and adenylate kinase. This analysis was supplemented with determination of energetically relevant metabolites in the phosphomonoester (PME) region of 31P NMR spectra, and in both aromatic and aliphatic regions of 1H NMR spectra. In control conditions, creatine kinase was the major phosphotransfer pathway processing high-energy phosphoryls between sites of ATP consumption and ATP production. In hypoxia, creatine kinase flux was dramatically reduced with a compensatory increase in adenylate kinase flux, which supported heart energetics by regenerating and transferring beta- and gamma-phosphoryls of ATP. Activation of adenylate kinase led to a build-up of AMP, IMP and adenosine, molecules involved in cardioprotective signaling. 31P and 1H NMR spectral analysis further revealed NADH and H+ scavenging by alpha-glycerophosphate dehydrogenase (alphaGPDH) and lactate dehydrogenase contributing to maintained glycolysis under hypoxia. Hypoxia-induced accumulation of alpha-glycerophosphate and nucleoside 5'-monophosphates, through alphaGPDH and adenylate kinase reactions, respectively, was mapped within the increased PME signal in the 31P NMR spectrum. Thus, 18O-assisted 31P NMR combined with 1H NMR provide a powerful approach in capturing rearrangements in cardiac bioenergetics, and associated metabolic signaling that underlie the cardiac adaptive response to stress. PMID:14977188

  16. Structural characterization of chemical warfare agent degradation products in decontamination solutions with proton band-selective (1)H-(31)P NMR spectroscopy.

    PubMed

    Koskela, Harri; Hakala, Ullastiina; Vanninen, Paula

    2010-06-15

    Decontamination solutions, which are usually composed of strong alkaline chemicals, are used for efficient detoxification of chemical warfare agents (CWAs). The analysis of CWA degradation products directly in decontamination solutions is challenging due to the nature of the matrix. Furthermore, occasionally an unforeseen degradation pathway can result in degradation products which could be eluded to in standard analyses. Here, we present the results of the application of proton band-selective (1)H-(31)P NMR spectroscopy, i.e., band-selective 1D (1)H-(31)P heteronuclear single quantum coherence (HSQC) and band-selective 2D (1)H-(31)P HSQC-total correlation spectroscopy (TOCSY), for ester side chain characterization of organophosphorus nerve agent degradation products in decontamination solutions. The viability of the approach is demonstrated with a test mixture of typical degradation products of nerve agents sarin, soman, and VX. The proton band-selective (1)H-(31)P NMR spectroscopy is also applied in characterization of unusual degradation products of VX in GDS 2000 solution. PMID:20507069

  17. 13C and 31P chemical shielding tensors of a single crystal of dipotassium α- D-glucose-1-phosphate dihydrate. An application of a 13C-{ 1H, 31P} triple-resonance technique

    NASA Astrophysics Data System (ADS)

    McDowell, C. A.; Naito, A.; Sastry, D. L.; Takegoshi, K.

    The 13C NMR spectra of a single crystal of dipotassium α- D-glucose-l-phosphate dehydrate for different orientations in the external magnetic field, were recorded by using 1H and 31P double nuclear decoupling. To overcome difficulties encountered because of the high 13C RF power required to achieve the Hartmann-Hahn condition, a new cross-polarization method (K. Takegoshi and C. A. McDowell, J. Magn. Reson.67, 356 (1986)) was used. The directions of the most shielded principal value of the 13C chemical shielding tensors for the C2-C6 carbon nuclei in the glucose group were along the CO bond, and that for the CI carbon nucleus made an angle of 42† with the C1-O5 bond direction in the O1-C1-O5 plane. The 31P chemical shielding tensors are axially symmetric and the direction of the least shielded principal value is almost parallel to the P-O1(R) bond, which is the longest among the four PO bonds in the phosphate moiety.

  18. Outcome-related metabolomic patterns from 1H/31P NMR after mild hypothermia treatments of oxygen–glucose deprivation in a neonatal brain slice model of asphyxia

    PubMed Central

    Liu, Jia; Litt, Lawrence; Segal, Mark R; Kelly, Mark J S; Yoshihara, Hikari A I; James, Thomas L

    2011-01-01

    Human clinical trials using 72 hours of mild hypothermia (32°C–34°C) after neonatal asphyxia have found substantially improved neurologic outcomes. As temperature changes differently modulate numerous metabolite fluxes and concentrations, we hypothesized that 1H/31P nuclear magnetic resonance (NMR) spectroscopy of intracellular metabolites can distinguish different insults, treatments, and recovery stages. Three groups of superfused neonatal rat brain slices underwent 45 minutes oxygen–glucose deprivation (OGD) and then were: treated for 3 hours with mild hypothermia (32°C) that began with OGD, or similarly treated with hypothermia after a 15-minute delay, or not treated (normothermic control group, 37°C). Hypothermia was followed by 3 hours of normothermic recovery. Slices collected at different predetermined times were processed, respectively, for 14.1 Tesla NMR analysis, enzyme-linked immunosorbent assay (ELISA) cell-death quantification, and superoxide production. Forty-nine NMR-observable metabolites underwent a multivariate analysis. Separated clustering in scores plots was found for treatment and outcome groups. Final ATP (adenosine triphosphate) levels, severely decreased at normothermia, were restored equally by immediate and delayed hypothermia. Cell death was decreased by immediate hypothermia, but was equally substantially greater with normothermia and delayed hypothermia. Potentially important biomarkers in the 1H spectra included PCr-1H (phosphocreatine in the 1H spectrum), ATP-1H (adenosine triphosphate in the 1H spectrum), and ADP-1H (adenosine diphosphate in the 1H spectrum). The findings suggest a potential role for metabolomic monitoring during therapeutic hypothermia. PMID:20717124

  19. Outcome-related metabolomic patterns from 1H/31P NMR after mild hypothermia treatments of oxygen-glucose deprivation in a neonatal brain slice model of asphyxia.

    PubMed

    Liu, Jia; Litt, Lawrence; Segal, Mark R; Kelly, Mark J S; Yoshihara, Hikari A I; James, Thomas L

    2011-02-01

    Human clinical trials using 72 hours of mild hypothermia (32°C-34°C) after neonatal asphyxia have found substantially improved neurologic outcomes. As temperature changes differently modulate numerous metabolite fluxes and concentrations, we hypothesized that (1)H/(31)P nuclear magnetic resonance (NMR) spectroscopy of intracellular metabolites can distinguish different insults, treatments, and recovery stages. Three groups of superfused neonatal rat brain slices underwent 45 minutes oxygen-glucose deprivation (OGD) and then were: treated for 3 hours with mild hypothermia (32°C) that began with OGD, or similarly treated with hypothermia after a 15-minute delay, or not treated (normothermic control group, 37°C). Hypothermia was followed by 3 hours of normothermic recovery. Slices collected at different predetermined times were processed, respectively, for 14.1 Tesla NMR analysis, enzyme-linked immunosorbent assay (ELISA) cell-death quantification, and superoxide production. Forty-nine NMR-observable metabolites underwent a multivariate analysis. Separated clustering in scores plots was found for treatment and outcome groups. Final ATP (adenosine triphosphate) levels, severely decreased at normothermia, were restored equally by immediate and delayed hypothermia. Cell death was decreased by immediate hypothermia, but was equally substantially greater with normothermia and delayed hypothermia. Potentially important biomarkers in the (1)H spectra included PCr-(1)H (phosphocreatine in the (1)H spectrum), ATP-(1)H (adenosine triphosphate in the (1)H spectrum), and ADP-(1)H (adenosine diphosphate in the (1)H spectrum). The findings suggest a potential role for metabolomic monitoring during therapeutic hypothermia. PMID:20717124

  20. In vivo (1)H MRS and (31)P MRSI of the response to cyclocreatine in transgenic mouse liver expressing creatine kinase.

    PubMed

    Cui, Min-Hui; Jayalakshmi, Kamaiah; Liu, Laibin; Guha, Chandan; Branch, Craig A

    2015-12-01

    Hepatocyte transplantation has been explored as a therapeutic alternative to liver transplantation, but a means to monitor the success of the procedure is lacking. Published findings support the use of in vivo (31)P MRSI of creatine kinase (CK)-expressing hepatocytes to monitor proliferation of implanted hepatocytes. Phosphocreatine tissue level depends upon creatine (Cr) input to the CK enzyme reaction, but Cr measurement by (1)H MRS suffers from low signal-to-noise ratio (SNR). We examine the possibility of using the Cr analog cyclocreatine (CCr, a substrate for CK), which is quickly phosphorylated to phosphocyclocreatine (PCCr), as a higher SNR alternative to Cr. (1)H MRS and (31)P MRSI were employed to measure the effect of incremental supplementation of CCr upon PCCr, γ-ATP, pH and Pi /ATP in the liver of transgenic mice expressing the BB isoform of CK (CKBB) in hepatocytes. Water supplementation with 0.1% CCr led to a peak total PCCr level of 17.15 ± 1.07 mmol/kg wet weight by 6 weeks, while adding 1.0% CCr led to a stable PCCr liver level of 18.12 ± 3.91 mmol/kg by the fourth day of feeding. PCCr was positively correlated with CCr, and ATP concentration and pH declined with increasing PCCr. Feeding with 1% CCr in water induced an apparent saturated level of PCCr, suggesting that CCr quantization may not be necessary for quantifying expression of CK in mice. These findings support the possibility of using (31)P MRS to noninvasively monitor hepatocyte transplant success with CK-expressing hepatocytes. PMID:26451872

  1. sup 1 H and sup 31 P nuclear magnetic resonance and kinetic studies of the active site structure of chloroplast CF sub 1 ATP synthase

    SciTech Connect

    Devlin, C.C.; Grisham, C.M. )

    1990-07-03

    The interaction of nucleotides and nucleotide analogues and their complexes with Mn{sup 2+} bound to both the latent and dithiothreitol-activated CF{sub 1} ATP synthase has been examined by means of steady-state kinetics, water proton relaxation rate (PRR) measurements, and {sup 1}H and {sup 31}P nuclear relaxation measurements. Titration of both the latent and activated Mn{sup 2+}-CF{sub 1} complexes with ATP, ADP, P{sub i}, Co(NH{sub 3}){sub 4}ATP, Co(NH{sub 3}){sub 4}ADP, and Co(NH{sub 3}){sub 4}AMPPCP leads to increases in the water relaxation enhancement, consistent with enhanced metal binding and a high ternary complex enhancement. Steady-state kinetic studies are consistent with competitive inhibition of CF{sub 1} by Co(NH{sub 3}){sub 4}AMPPCP with respect to CaATP. {sup 1}H and {sup 31}P nuclear relaxation measurements in solutions of CF{sub 1} and Co(NH{sub 3}){sub 4}AMPPCP were used to determine the conformation of the bound substrate analogue and the arrangement with respect to this structure of high- and low-affinity sites for Mn{sup 2+}. The bound nucleotide analogue adopts a bent conformation, with the low-affinity sites for Mn{sup 2+}. The bound nucleotide analogue adopts a bent conformation, with the low-affinity Mn{sup 2+} site situated between the adenine and triphosphate moieties and the high-affinity metal site located on the far side of the triphosphate chain. The low-affinity metal forms a distorted inner-sphere complex with the {beta}-P and {gamma}-P of the substrate. The distances from Mn{sup 2+} to the triphosphate chain are too large for first coordination sphere complexes but are appropriate for second-sphere complexes involving, for example, intervening hydrogen-bonded water molecules or residues from the protein.

  2. Singlet-triplet separations measured by [sup 31]P[l brace][sup 1]H[r brace] NMR: Applications to quadruply bonded dimolybdenum and ditungsten complexes

    SciTech Connect

    Cotton, F.A.; Eglin, J.L.; Bo Hong; James, C.A. )

    1993-05-12

    A series of quadruply bonded dimolybdenum and ditungsten compounds M[sub 2]X[sub 4](PP)[sub 2] (M = Mo, W; PP = bidentate phosphine ligands; X = Cl, Br, I) with internal rotational angles [chi] varying from 0.0 to 69.4[degrees] have been studied. Their [sup 31]P[l brace][sup 1]H[r brace] NMR spectra are characterized by their temperature-dependent shifts and line widths that broaden with increasing temperature. A nonlinear, least-squares fit of this temperature dependence of the paramagnetic shifts for their NMR signals allows the evaluation of the singlet-triplet energy separation ([minus]2J), the diamagnetic shift (H[sub dia]), and the electron-nucleus hyperfine coupling constant (A). The singlet-triplet energy separations for all the compounds investigated are found to be in the range 1200-3000 cm[sup [minus]1]. It is now clearly established that the ground state remains [sup 1]A[sub 1g] ([delta][sup 2]) even at [chi] = 45[degrees], where [sup 3]A[sub 2u] ([delta][delta]*) lies 1230 cm[sup [minus]1] above it. The [delta]-bond energy and electronic [delta]-barrier can also be experimentally estimated as 13.8[+-]0.5 kcal mol[sup [minus]1] and 10.3[+-]0.5 kcal mol[sup [minus]1], respectively. 32 refs., 3 figs., 1 tab.

  3. Modeling sickle cell vasoocculsion in the rat leg: Quantification of trapped sickle cells and correlation with sup 31 P metabolic and sup 1 H magnetic resonance imaging changes

    SciTech Connect

    Fabry, M.E.; Rajanayagam, V.; Fine, E.; Holland, S.; Gore, J.C.; Nagel, R.L.; Kaul, D.K. )

    1989-05-01

    The authors have developed an animal model to elucidate the acute effects of perfusion abnormalities on muscle metabolism induced by different density-defined classes of erythrocytes isolated from sickle cell anemia patients. Technetium-99m ({sup 99m}Tc)-labeled, saline-washed normal (AA), homozygous sickle (SS), or high-density SS (SS4) erythrocytes were injected into the femoral artery of the rat and quantitative {sup 99m}Tc imaging, {sup 31}P magnetic resonance spectroscopy by surface coil at 2 teslas, and {sup 1}H magnetic resonance imaging at 0.15 tesla were performed. Between 5 and 25 {mu}l of SS4 cells was trapped in the microcirculation of the thigh. In contrast, fewer SS discocytes (SS2) or AA cells were trapped. After injection of SS4 cells an initial increase in inorganic phosphate was observed in the region of the thigh served by the femoral artery, intracellular pH decreased, and subsequently the proton relaxation time T{sub 1} reached a broad maximum at 18-28 hr. When T{sub 1} obtained at this time was plotted against the volume of cells trapped, an increase of T{sub 1} over the control value of 411 {plus minus} 48 msec was found that was proportional to the number of cells trapped. They conclude that the densest SS cells are most effective at producing vasoocclusion. The extent of the change detected by {sup 1}H magnetic resonance imaging is dependent on the amount of cells trapped in the microcirculation and the magnitude of the initial increase of inorganic phosphate.

  4. Bevacizumab impairs oxidative energy metabolism and shows antitumoral effects in recurrent glioblastomas: a 31P/1H MRSI and quantitative magnetic resonance imaging study.

    PubMed

    Hattingen, Elke; Jurcoane, Alina; Bähr, Oliver; Rieger, Johannes; Magerkurth, Jörg; Anti, Sandra; Steinbach, Joachim P; Pilatus, Ulrich

    2011-12-01

    Bevacizumab shows unprecedented rates of response in recurrent glioblastomas (GBM), but the detailed mechanisms are still unclear. We employed in vivo magnetic resonance spectroscopic imaging (MRSI) and quantitative magnetic resonance imaging to investigate whether bevacizumab alters oxygen and energy metabolism and whether this effect has antitumoral activity in recurrent GBM. (31)P and (1)H MRSI, apparent diffusion coefficient (ADC), and high-resolution T2 and T2' mapping (indirect marker of oxygen extraction) were investigated in 16 patients with recurrent GBM at 3 Tesla before and 1.5-2 months after initiation of therapy with bevacizumab. Changes of metabolite concentrations and of the quantitative values in the tumor and normal appearing brain tissue were calculated. The Wilcoxon signed-ranks test was used to evaluate differences for tumor/edema versus control as well as changes before versus after commencement of therapy. Survival analyses were performed for significant parameters. Tumor T2', pH, ADC, and T2 decreased significantly in patients responding to bevacizumab therapy (n = 10). Patients with at least 25% T2' decrease during treatment showed longer progression-free and overall survival durations. Levels of high-energy metabolites were lower at baseline; these persisted under therapy. Glycerophosphoethanolamine as catabolic phospholipid metabolite increased in responders. The MRSI data support the hypothesis that bevacizumab induces relative tumor hypoxia (T2' decrease) and affects energy homeostasis in recurrent GBM, suggesting that bevacizumab impairs vascular function. The antiangiogenic effect of bevacizumab is predictive of better outcome and seems to induce antitumoral activity in the responding GBMs. PMID:21890539

  5. 31P and 1H MRS of DB-1 Melanoma Xenografts: Lonidamine Selectively Decreases Tumor Intracellular pH and Energy Status and Sensitizes Tumors to Melphalan

    PubMed Central

    Nath, Kavindra; Nelson, David S.; Ho, Andrew; Lee, Seung-Cheol; Darpolor, Moses M.; Pickup, Stephen; Zhou, Rong; Heitjan, Daniel F.; Leeper, Dennis B.; Glickson, Jerry D.

    2012-01-01

    In vivo 31P MRS demonstrates that human melanoma xenografts in immunosuppressed mice treated with lonidamine (LND, 100 mg/kg, i.p.) exhibit a decrease in intracellular pH (pHi) from 6.90 ± 0.05 to 6.33 ± 0.10 (p < 0.001), a slight decrease in extracellular pH (pHe) from 7.00 ± 0.04 to 6.80 ± 0.07 (p > 0.05), and a monotonic decline in bioenergetics (NTP/Pi) by 66.8 ± 5.7% (p < 0.001) relative to the baseline level. Both bioenergetics and pHi decreases were sustained for at least 3 hr following LND treatment. Liver exhibited a transient intracellular acidification by 0.2 ± 0.1 pH units (p > 0.05) at 20 min post-LND with no significant change in pHe and a small transient decrease in bioenergetics, 32.9 ± 10.6 % (p > 0.05), at 40 min post-LND. No changes in pHi or ATP/Pi were detected in the brain (pHi, bioenergetics; p > 0.1) or skeletal muscle (pHi, pHe, bioenergetics; p > 0.1) for at least 120 min post-LND. Steady-state tumor lactate monitored by 1H MRS with a selective multiquantum pulse sequence with Hadamard localization increased ~3-fold (p = 0.009). Treatment with LND increased systemic melanoma response to melphalan (LPAM; 7.5 mg/kg, i.v.) producing a growth delay of 19.9 ± 2.0 d (tumor doubling time = 6.15 ± 0.31d, log10 cell-kill = 0.975 ± 0.110, cell-kill = 89.4 ± 2.2%) compared to LND alone of 1.1 ± 0.1 d and LPAM alone of 4.0 ± 0.0 d. The study demonstrates that the effects of LND on tumor pHi and bioenergetics may sensitize melanoma to pH-dependent therapeutics such as chemotherapy with alkylating agents or hyperthermia. PMID:22745015

  6. Hepatic lipid profiling of deer mice fed ethanol using {sup 1}H and {sup 31}P NMR spectroscopy: A dose-dependent subchronic study

    SciTech Connect

    Fernando, Harshica; Bhopale, Kamlesh K.; Boor, Paul J.; Ansari, G.A. Shakeel; Kaphalia, Bhupendra S.

    2012-11-01

    Chronic alcohol abuse is a 2nd major cause of liver disease resulting in significant morbidity and mortality. Alcoholic liver disease (ALD) is characterized by a wide spectrum of pathologies starting from fat accumulation (steatosis) in early reversible stage to inflammation with or without fibrosis and cirrhosis in later irreversible stages. Previously, we reported significant steatosis in the livers of hepatic alcohol dehydrogenase (ADH)-deficient (ADH{sup −}) vs. hepatic ADH-normal (ADH{sup +}) deer mice fed 4% ethanol daily for 2 months [Bhopale et al., 2006, Alcohol 39, 179–188]. However, ADH{sup −} deer mice fed 4% ethanol also showed a significant mortality. Therefore, a dose-dependent study was conducted to understand the mechanism and identify lipid(s) involved in the development of ethanol-induced fatty liver. ADH{sup −} and ADH{sup +} deer mice fed 1, 2 or 3.5% ethanol daily for 2 months and fatty infiltration in the livers were evaluated by histology and by measuring dry weights of extracted lipids. Lipid metabolomic changes in extracted lipids were determined by proton ({sup 1}H) and {sup 31}phosphorus ({sup 31}P) nuclear magnetic resonance (NMR) spectroscopy. The NMR data was analyzed by hierarchical clustering (HC) and principle component analysis (PCA) for pattern recognition. Extensive vacuolization by histology and significantly increased dry weights of total lipids found only in the livers of ADH{sup −} deer mice fed 3.5% ethanol vs. pair-fed controls suggest a dose-dependent formation of fatty liver in ADH{sup −} deer mouse model. Analysis of NMR data of ADH{sup −} deer mice fed 3.5% ethanol vs. pair-fed controls shows increases for total cholesterol, esterified cholesterol, fatty acid methyl esters (FAMEs), triacylglycerides and unsaturation, and decreases for free cholesterol, phospholipids and allylic and diallylic protons. Certain classes of neutral lipids (cholesterol esters, fatty acyl chain (-COCH{sub 2}-) and FAMEs) were

  7. New adamantane-like mercury-chalcogen cages. Synthetic and multinuclear (/sup 31/P, /sup 77/Se, /sup 199/Hg) NMR study of ((. mu. -ER)/sub 6/(HgL)/sub 4/)/sup 2 +/ (E = S or Se; L = tertiary phosphine or arsine) and related species with mixed ligands

    SciTech Connect

    Dean, P.A.W.; Vittal, J.J.; Trattner, M.H.

    1987-12-16

    Reaction between HgL/sub 2/(ClO/sub 4/)/sub 2/, Hg(ER)/sub 2/, and L in a 1:3:2 ratio produces the isolable salts ((..mu..-ER)/sub 6/(HgL)/sub 4/)(ClO/sub 4/)/sub 2/ (L = PPh/sub 3/, ER = SePh, SPh, SMe, or SEt; L = AsPh/sub 3/, ER = SPh; L = PEt/sub 3/, ER = SePh or SPh). Multinuclear (/sup 31/P, /sup 77/Se, /sup 199/Hg) NMR was used to demonstrate the adamantanoid structure of the cations in these salts as well as in those with L = PPh/sub 3/ and ER = S-n-Pr, S-n-Bu, or S-n-C/sub 5/H/sub 11/, which were studied in situ. To confirm that the new cations contain the hitherto unobserved (..mu..-ER)/sub 6/Hg/sub 4/ core, several series of clusters with mixed ligands were investigated (as ClO/sub 4//sup -/ salts) by the multinuclear NMR technique also. The systems ((..mu..-ER)/sub 6/(HgL)/sub 4/)/sup 2 +/-((..mu..-ER)/sub 6/(HgL')/sub 4/)/sup 2 +/ (ER = SePh, L = PPh/sub 3/, L' = PEt/sub 3/; ER = SPh, L = PPh/sub 3/, L' = PEt/sub 3/ or AsPh/sub 3/) give the series ((..mu..-ER)/sub 6/(HgL)/sub 4-n/(HgL')/sub n/)/sup 2 +/ (n = 0-4). The related species ((..mu..-SPh)/sub 6/(HgPPh/sub 3/)/sub 4-n/(HgSbPh/sub 3/)/sub n/)/sup 2 +/ (n = 0-2 and possibly 3) were produced from Hg(PPhh/sub 3/)/sub 2/(ClO/sub 4/)/sub 2/, Hg(SPh)/sub 2/, and SbPh/sub 3/. From the notably rich /sup 31/P and /sup 199/Hg NMR spectra of the system ((..mu..-SPh)/sub 6/(HgPPh/sub 3/)/sub 4/)/sup 2 +/-((..mu..-SePh)/sub 6/(HgPPh/sub 3/)/sub 4/)/sup 2 +/ it was possible to demonstrate the existence of every possible mixed-chalcogen core in the series ((..mu..-SPh)/sub 6-m/(..mu..-SePh)/sub m/(HgPPh/sub 3/)/sub 4/)/sup 2 +/ (m = 0-6). The new (..mu..-SR)/sub 6/Hg/sub 4/ cages are possible models for the proposed Hg/sub 4/(Cys)/sub 11/ cluster in Hg/sub 7/-metallothionein. 46 references, 3 figures, 2 tables.

  8. Interaction Study of an Amorphous Solid Dispersion of Cyclosporin A in Poly-Alpha-Cyclodextrin with Model Membranes by 1H-, 2H-, 31P-NMR and Electron Spin Resonance

    PubMed Central

    Debouzy, Jean-Claude; Bourbon, Fréderic; Lahiani-Skiba, Malika; Skiba, Mohamed

    2014-01-01

    The properties of an amorphous solid dispersion of cyclosporine A (ASD) prepared with the copolymer alpha cyclodextrin (POLYA) and cyclosporine A (CYSP) were investigated by 1H-NMR in solution and its membrane interactions were studied by 1H-NMR in small unilamellar vesicles and by 31P 2H NMR in phospholipidic dispersions of DMPC (dimyristoylphosphatidylcholine) in comparison with those of POLYA and CYSP alone. 1H-NMR chemical shift variations showed that CYSP really interacts with POLYA, with possible adduct formation, dispersion in the solid matrix of the POLYA, and also complex formation. A coarse approach to the latter mechanism was tested using the continuous variations method, indicating an apparent 1 : 1 stoichiometry. Calculations gave an apparent association constant of log Ka = 4.5. A study of the interactions with phospholipidic dispersions of DMPC showed that only limited interactions occurred at the polar head group level (31P). Conversely, by comparison with the expected chain rigidification induced by CYSP, POLYA induced an increase in the fluidity of the layer while ASD formation led to these effects almost being overcome at 298 K. At higher temperature, while the effect of CYSP seems to vanish, a resulting global increase in chain fluidity was found in the presence of ASD. PMID:24883210

  9. sup 31 P and sup 1 H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

    SciTech Connect

    Jarori, G.K.; Ray, B.D.; Rao, B.D.N. )

    1989-11-28

    The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of {sup 31}P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the {delta} protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of {sup 31}P relaxation rates in E-MnADP and E-MnATP yields activation energies ({Delta}E) in the range 6-10 kcal/mol. Thus, the {sup 31}P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and {Delta}E values in the range 1-2 kcal/mol; i.e., these rates depend upon {sup 31}P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 {angstrom}, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the {sup 1}H spin-lattice relaxation rate of the {delta} protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective {tau}{sub C} of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate ({tau}{sub S1}) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the {delta} protons was 10.9 {plus minus} 0.3 {angstrom}.

  10. 1H and 31P NMR and HPLC studies of mouse L1210 leukemia cell extracts: the effect of Au(I) and Cu(I) diphosphine complexes on the cell metabolism.

    PubMed

    Berners-Price, S J; Sant, M E; Christopherson, R I; Kuchel, P W

    1991-03-01

    The effect of the antitumor complex [Au(dppe)2]Cl (where dppe is Ph2P(CH2)2PPh2) on the overall metabolism of cultured mouse L1210 leukemia cells was investigated by comparing 1H and 31P NMR spectra of perchloric acid extracts of cells incubated for 1 h in the presence and absence of 2 microM [Au(dppe)2]Cl. There were marked (ca. two-fold) increases in the levels of lactate and almost all detectable amino acids suggesting a drug-induced increase in the rate of glycolysis and inhibition of protein synthesis. The levels of taurine and phosphorylcholine were significantly decreased and 31P NMR spectra revealed a depletion of nucleoside triphosphates (NTP). The effect on nucleotide metabolism was investigated further by separating purine and pyrimidine nucleotides and precursors by anion-exchange HPLC. NTP levels were depleted by ca. 70-90% and there was a ca. three- to four-fold increase in nucleoside di- and monophosphates. The effect is postulated to be the result of uncoupling of mitochondrial oxidative phosphorylation. The Cu(I) complex [Cu(Ph2PCH = CHPPh2)2]Cl produced a similar effect on the cellular metabolism but was more potent. The water-soluble complex [Cu(Ph2P(CH2)PEt2)2]Cl caused the accumulation of cellular amino acids at a concentration that did not significantly deplete ATP levels. PMID:2062226

  11. New adamantane-like mercury-chalcogen cages. 2. Synthetic and multinuclear ( sup 31 P, sup 77 Se, sup 125 Te, sup 199 Hg) magnetic resonance study of tellurolate-bridged mercury(III) clusters ((. mu. -TeR) sub 6 (HgPR prime sub 3 ) sub 4 ) sup 2+ and ((. mu. -TeR) sub 6 (Hg)(HgPR prime sub 3 ) sub 3 ) sup 2+ and related species with mixed-bridging chalcogenates

    SciTech Connect

    Dean, P.A.W.; Manivannan, V.; Vittal, J.J. )

    1989-06-14

    The salts (({mu}-TePh){sub 6}(HgPR{prime}{sub 3}){sub 3}(Hg))(ClO{sub 4}){sub 2} (R{prime} = Ph, 4-C{sub 6}H{sub 4}Me, 4-C{sub 6}H{sub 4}Cl) are preparable from Hg(TePh){sub 2}, Mg(PR{prime}{sub 3}){sub 2}(ClO{sub 4}){sub 2}, and PR{prime}P{sub 3} in a 3:1:1 ratio in CH{sub 2}Cl{sub 2} or CHCl{sub 3}. The new cations have been characterized in CH{sub 2}Cl{sub 2} and DMF by multinuclear ({sup 31}P, {sup 125}Te, {sup 199}Hg) magnetic resonance and shown to be of adamantanoid structure with novel tellurolate bridging. These spectra provide clear evidence for preferential formation of one (R{prime} = Ph) or a mixture of both (R{prime} = 4-C{sub 6}H{sub 4}Cl, in DMF solution) of the two C{sub 3} isomers that are possible for adamantane-like ({mu}-TeR){sub 6}M{sub 4} as a result of inversion at the pyramidal Te atoms. Such preferential isomer formation has not been demonstrated previously for any adamantanoid chalcogenate-bridge ({mu}-ER){sub 6}M{sub 4} in solution. Isomer formation at various temperatures is reported. For the cations with R = Ph, the rate of inversion at Te varies with R{prime} in the order alkyl > 4-C{sub 6}H{sub 4}Me > Ph > 4-C{sub 6}H{sub 4}Cl. When R = Ph, R{prime} = 4-C{sub 6}H{sub 4}Me, NMR spectra ({sup 31}P, {sup 77}Se, {sup 125}Te, {sup 199}Hg) of mixtures of ((TeR){sub 6}(HgPR{prime}{sub 3}){sub 4}){sup 2+} and (({mu}-ER){sub 6}(HgPR{prime}{sub 3}){sub 4}){sup 2+} (E = S, Se) provide evidence for the formation of the mixed-chalcogen cores ({mu}-Te){sub 6-m}({mu}-E){sub m}Hg{sub 4}. 35 refs., 8 figs., 3 tabs.

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

    SciTech Connect

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

    1989-06-28

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

  13. Structural characterization of selenosubtilisin by sup 77 Se-NMR spectroscopy

    SciTech Connect

    House, K.L.; Dunlap, R.B.; Odom, J.D.; Wu, Z.P.; Hilvert. D. Research Inst. of Scripps Clinic, La Jolla, CA )

    1991-03-15

    Selenosubtilisin is an artificial enzyme containing an active site selenocysteine residue. In this environment the selenium atom is a valuable probe of structure-function relationships and also confers novel redox and hydrolytic properties to the original protease template. The authors have used {sup 77}Se NMR spectroscopy to characterize different oxidation states of {sup 77}Se isotopically enriched selenosubtilisin. The oxidized form of the enzyme exhibits a {sup 77}Se resonance at 1,189 ppm. This is in good agreement with the {sup 77}Se chemical shifts for model seleninic acids, confirming that the prosthetic group is in the seleninic acid oxidation state. On treatment of the oxidized enzyme with three equivalents of 3-carboxy-4-nitrobenzenethiol at pH 5.0, they observe the enzyme bound selenenyl sulfide at 388.5 ppm. This work demonstrates the utility of {sup 77}Se NMR spectroscopy for examining structure-function relationships of selenium containing proteins.

  14. Optimized (31)P MRS in the human brain at 7 T with a dedicated RF coil setup.

    PubMed

    van de Bank, Bart L; Orzada, Stephan; Smits, Frits; Lagemaat, Miriam W; Rodgers, Christopher T; Bitz, Andreas K; Scheenen, Tom W J

    2015-11-01

    The design and construction of a dedicated RF coil setup for human brain imaging ((1)H) and spectroscopy ((31)P) at ultra-high magnetic field strength (7 T) is presented. The setup is optimized for signal handling at the resonance frequencies for (1)H (297.2 MHz) and (31)P (120.3 MHz). It consists of an eight-channel (1)H transmit-receive head coil with multi-transmit capabilities, and an insertable, actively detunable (31)P birdcage (transmit-receive and transmit only), which can be combined with a seven-channel receive-only (31)P array. The setup enables anatomical imaging and (31)P studies without removal of the coil or the patient. By separating transmit and receive channels and by optimized addition of array signals with whitened singular value decomposition we can obtain a sevenfold increase in SNR of (31)P signals in the occipital lobe of the human brain compared with the birdcage alone. These signals can be further enhanced by 30 ± 9% using the nuclear Overhauser effect by B1-shimmed low-power irradiation of water protons. Together, these features enable acquisition of (31)P MRSI at high spatial resolutions (3.0 cm(3)  voxel) in the occipital lobe of the human brain in clinically acceptable scan times (~15 min). PMID:26492089

  15. Optimized 31P MRS in the human brain at 7 T with a dedicated RF coil setup

    PubMed Central

    van de Bank, Bart L.; Orzada, Stephan; Smits, Frits; Lagemaat, Miriam W.; Rodgers, Christopher T.; Bitz, Andreas K.

    2015-01-01

    The design and construction of a dedicated RF coil setup for human brain imaging (1H) and spectroscopy (31P) at ultra‐high magnetic field strength (7 T) is presented. The setup is optimized for signal handling at the resonance frequencies for 1H (297.2 MHz) and 31P (120.3 MHz). It consists of an eight‐channel 1H transmit–receive head coil with multi‐transmit capabilities, and an insertable, actively detunable 31P birdcage (transmit–receive and transmit only), which can be combined with a seven‐channel receive‐only 31P array. The setup enables anatomical imaging and 31P studies without removal of the coil or the patient. By separating transmit and receive channels and by optimized addition of array signals with whitened singular value decomposition we can obtain a sevenfold increase in SNR of 31P signals in the occipital lobe of the human brain compared with the birdcage alone. These signals can be further enhanced by 30 ± 9% using the nuclear Overhauser effect by B 1‐shimmed low‐power irradiation of water protons. Together, these features enable acquisition of 31P MRSI at high spatial resolutions (3.0 cm3 voxel) in the occipital lobe of the human brain in clinically acceptable scan times (~15 min). © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd. PMID:26492089

  16. MP2 calculation of (77) Se NMR chemical shifts taking into account relativistic corrections.

    PubMed

    Rusakov, Yury Yu; Rusakova, Irina L; Krivdin, Leonid B

    2015-07-01

    The main factors affecting the accuracy and computational cost of the Second-order Möller-Plesset perturbation theory (MP2) calculation of (77) Se NMR chemical shifts (methods and basis sets, relativistic corrections, and solvent effects) are addressed with a special emphasis on relativistic effects. For the latter, paramagnetic contribution (390-466 ppm) dominates over diamagnetic term (192-198 ppm) resulting in a total shielding relativistic correction of about 230-260 ppm (some 15% of the total values of selenium absolute shielding constants). Diamagnetic term is practically constant, while paramagnetic contribution spans over 70-80 ppm. In the (77) Se NMR chemical shifts scale, relativistic corrections are about 20-30 ppm (some 5% of the total values of selenium chemical shifts). Solvent effects evaluated within the polarizable continuum solvation model are of the same order of magnitude as relativistic corrections (about 5%). For the practical calculations of (77) Se NMR chemical shifts of the medium-sized organoselenium compounds, the most efficient computational protocols employing relativistic Dyall's basis sets and taking into account relativistic and solvent corrections are suggested. The best result is characterized by a mean absolute error of 17 ppm for the span of (77) Se NMR chemical shifts reaching 2500 ppm resulting in a mean absolute percentage error of 0.7%. PMID:25998325

  17. Determination of coordination modes and estimation of the 31P-31P distances in heterogeneous catalyst by solid state double quantum filtered 31P NMR spectroscopy.

    PubMed

    Zhang, Si-Yong; Wang, Mei-Tao; Liu, Qing-Hua; Hu, Bing-Wen; Chen, Qun; Li, He-Xing; Amoureux, Jean-Paul

    2011-04-01

    To overcome the separation difficulty of the palladium-based homogeneous catalyst, the palladium complex can be anchored on various supports such as silica. However, it is difficult to determine the amounts of the two coordination modes of the Pd nucleus, that is, Pd coordinates with one phosphorus atom and Pd coordinates with two phosphorus atoms. Here a (31)P double-quantum filtered (DQ-filtered) method in solid-state NMR is introduced for the palladium-based heterogenous catalyst system. With the DQ-filtered method, we can not only determine the amounts of the two different kinds of palladium coordination modes, we can also estimate the interatomic distance of two (31)P nuclei bonded to a palladium nucleus. With the help of this method, we can quickly estimate interatomic distances in our designed system and accurately re-design the palladium system to accommodate either one (31)P or two (31)P. PMID:21301702

  18. Ex vivo identification of atherosclerotic plaque calcification by a 31P solid-state magnetic resonance imaging technique.

    PubMed

    Hallock, Kevin J; Hamilton, James A

    2006-12-01

    Calcified tissue is a common component of atherosclerotic plaques, and occurs most often in mature plaques. The process of calcification is a poorly understood risk factor that may contribute to a plaque's vulnerability to sudden rupture. In this study a solid-state imaging sequence, termed single-point imaging (SPI), was used to observe calcification directly in ex vivo atherosclerotic plaques. Standards were used to validate the ability of (31)P SPI to detect and differentiate calcification from crystalline cholesterol, phospholipids, and other plaque components. After suitable experimental parameters were found, human carotid specimens obtained by endarterectomy were imaged ex vivo by (31)P solid-state imaging and standard (1)H methods. In contrast to (1)H imaging methods, (31)P imaging detected only the calcification in the plaque. PMID:17089379

  19. Surface coil localization of /sup 31/P NMR signals from orthotopic human kidney and liver

    SciTech Connect

    Jue, T.; Rothman, D.L.; Lohman, J.A.B.; Hughes, E.W.; Hanstock, C.C.; Shulman, R.G.

    1988-02-01

    By incorporating the hyperbolic secant inversion pulses with the image-selected in vivo spectroscopy localization technique and by applying a gradient-echo imaging method, the authors have selected only the /sup 31/P NMR signals from orthotopic human kidney and liver, using a single concentric /sup 1/H//sup 31/P surface coil. Corresponding to the experimental results on animal studies, the phosphocreatine signal is dramatically reduced in the localized spectra. The localization strategy also allows them to shim easily on the well-defined volume of interest and leads to high-resolution spectra that exhibit multiplet structure. The results indicate that they can obtain localized signals from deep small organs and point the way for other human metabolism studies.

  20. Nuclear-Overhauser-enhanced MR imaging of (31)P-containing metabolites: multipoint-Dixon vs. frequency-selective excitation.

    PubMed

    Rink, Kristian; Berger, Moritz C; Korzowski, Andreas; Breithaupt, Mathies; Biller, Armin; Bachert, Peter; Nagel, Armin M

    2015-12-01

    The purpose of this study is to develop nuclear-Overhauser-enhanced (NOE) [(1)H]-(31)P magnetic resonance imaging (MRI) based on 3D fully-balanced steady-state free precession (fbSSFP). Therefore, two implementations of a 3D fbSSFP sequence are compared using frequency-selective excitation (FreqSel) and multipoint-Dixon (MP-Dixon). (31)P-containing model solutions and four healthy volunteers were examined at field strengths of B0=3T and 7T. Maps of the distribution of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine 5´-triphosphate (ATP) in the human calf were obtained with an isotropic resolution of 1.5cm (1.0cm) in an acquisition time of 5min (10min). NOE-pulses had the highest impact on the PCr acquisitions enhancing the signal up to (82 ± 13) % at 3T and up to (37 ± 9) % at 7T. An estimation of the level of PCr in muscle tissue from [(1)H]-(31)P MRI data yielded a mean value of (33 ± 8) mM. In conclusion, direct [(1)H]-(31)P imaging using FreqSel as well as MP-Dixon is possible in clinically feasible acquisition times. FreqSel should be preferred for measurements where only a single metabolite resonance is considered. MP-Dixon performs better in terms of SNR if a larger spectral width is of interest. PMID:26248272

  1. Solid state 77Se NMR investigations on arsenic-selenium glasses and crystals

    NASA Astrophysics Data System (ADS)

    Bureau, Bruno; Troles, Johann; LeFloch, Marie; Smektala, Frédéric; Silly, Gilles; Lucas, Jacques

    2003-01-01

    Some resolved solid state 77Se NMR spectra are presented in the As xSe 1- x glass family at ambient temperature. They exhibit three different kinds of Se environments. A comparison with the parent crystalline phases permits to assign the lines to Se- Se-Se, Se- Se-As and As- Se-As Se atom neighborhoods. The measurements of the relative intensities of the lines prove the validity of the intermediate range order structural model known as the "chains crossing model" which is based on AsSe 3 pyramids homogeneously distributed among the divalent Se atoms network. In particular, any scenario involving a selenium clustering process is refuted.

  2. Human cardiac 31P magnetic resonance spectroscopy at 7 tesla

    PubMed Central

    Rodgers, Christopher T; Clarke, William T; Snyder, Carl; Vaughan, J Thomas; Neubauer, Stefan; Robson, Matthew D

    2014-01-01

    Purpose Phosphorus magnetic resonance spectroscopy (31P-MRS) affords unique insight into cardiac energetics but has a low intrinsic signal-to-noise ratio (SNR) in humans. Theory predicts an increased 31P-MRS SNR at 7T, offering exciting possibilities to better investigate cardiac metabolism. We therefore compare the performance of human cardiac 31P-MRS at 7T to 3T, and measure T1s for 31P metabolites at 7T. Methods Matched 31P-MRS data were acquired at 3T and 7T, on nine normal volunteers. A novel Look-Locker CSI acquisition and fitting approach was used to measure T1s on six normal volunteers. Results T1s in the heart at 7T were: phosphocreatine (PCr) 3.05 ± 0.41s, γ-ATP 1.82 ± 0.09s, α-ATP 1.39 ± 0.09s, β-ATP 1.02 ± 0.17s and 2,3-DPG (2,3-diphosphoglycerate) 3.05 ± 0.41s (N = 6). In the field comparison (N = 9), PCr SNR increased 2.8× at 7T relative to 3T, the Cramer-Ráo uncertainty (CRLB) in PCr concentration decreased 2.4×, the mean CRLB in PCr/ATP decreased 2.7× and the PCr/ATP SD decreased 2×. Conclusion Cardiac 31P-MRS at 7T has higher SNR and the spectra can be quantified more precisely than at 3T. Cardiac 31P T1s are shorter at 7T than at 3T. We predict that 7T will become the field strength of choice for cardiac 31P-MRS. Magn Reson Med 72:304–315, 2014. © 2013 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited. PMID:24006267

  3. 77Se nuclear magnetic resonance of topological insulator Bi2Se3

    NASA Astrophysics Data System (ADS)

    Georgieva, Nataliya M.; Rybicki, Damian; Guehne, Robin; Williams, Grant V. M.; Chong, Shen V.; Kadowaki, Kazuo; Garate, Ion; Haase, Jürgen

    2016-05-01

    Topological insulators constitute a new class of materials with an energy gap in the bulk and peculiar metallic states on the surface. We report on new features resulting from the bulk electronic structure, based on a comprehensive nuclear magnetic resonance (NMR) study of 77Se on Bi2Se3 and Cu0.15Bi2Se3 single crystals. First, we find two resonance lines and show that they originate from the two inequivalent Se lattice sites. Second, we observe unusual field-independent linewidths and attribute them to an unexpectedly strong internuclear coupling mediated by bulk electrons. In order to support this interpretation, we present a model calculation of the indirect internuclear coupling and show that the Bloembergen-Rowland coupling is much stronger than the Ruderman-Kittel-Kasuya-Yosida coupling. Our results call for a revision of earlier NMR studies and add information concerning the bulk electronic properties.

  4. Exploring new Routes for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with 31P NMR

    NASA Astrophysics Data System (ADS)

    Vestergren, Johan; Persson, Per; Sundman, Annelie; Ilstedt, Ulrik; Giesler, Reiner; Schleucher, Jürgen; Gröbner, Gerhard

    2014-05-01

    Phosphorus (P) is the primary growth-limiting nutrient in some of the world's biomes. Rock phosphate is a non-renewable resource and the major source of agricultural fertilizers. Predictions of P consumption indicate that rock phosphate mining may peak within 35 years, with severe impacts on worldwide food production1. Organic P compounds constitute a major fraction of soil P, but little is known about the dynamics and bioavailability of organic P species. Our aim is to develop new liquid and solid state 31P-NMR (nuclear magnetic resonance) techniques to identify P-species in water and soils; information required for correlating P speciation with plant and soil processes2, and eventually to improve P use. Soil organic P is frequently extracted using NaOH/EDTA, followed by characterization of the extract by solution 31P-NMR. However, the obtained NMR spectra usually have poor resolution due to line broadening caused by the presence of paramagnetic ions. Therefore, we successfully developed an approach to avoid paramagnetic line broadening by precipitation of metal sulfides. Sulfide precipitation dramatically reduces NMR line widths for soil extracts, without affecting P-composition. The resulting highly improved resolution allowed us to apply for the first time 2D 1H,31P-NMR methods to identify different P monoesters in spectral regions which are extremely crowded in 1D NMR spectra.3 By exploiting 2D 1H-31P NMR spectra of soil extracts we were able to unambiguously identify individual organic P species by combining 31P and 1H chemical shifts and coupling constants. This approach is even suitable for a structural characterization of unknown P-components and for tracing degradation pathways between diesters and monoesters3,4.Currently we apply our approach on boreal4 and tropical soils with focus on Burkina Faso. In addition we also monitor P-species in aqueos ecosystems. For this purpose stream water from the Krycklan catchment in northern Sweden5 has been used to

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

    PubMed

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

    2010-06-21

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

  6. Accurate calculation of (31)P NMR chemical shifts in polyoxometalates.

    PubMed

    Pascual-Borràs, Magda; López, Xavier; Poblet, Josep M

    2015-04-14

    We search for the best density functional theory strategy for the determination of (31)P nuclear magnetic resonance (NMR) chemical shifts, δ((31)P), in polyoxometalates. Among the variables governing the quality of the quantum modelling, we tackle herein the influence of the functional and the basis set. The spin-orbit and solvent effects were routinely included. To do so we analysed the family of structures α-[P2W18-xMxO62](n-) with M = Mo(VI), V(V) or Nb(V); [P2W17O62(M'R)](n-) with M' = Sn(IV), Ge(IV) and Ru(II) and [PW12-xMxO40](n-) with M = Pd(IV), Nb(V) and Ti(IV). The main results suggest that, to date, the best procedure for the accurate calculation of δ((31)P) in polyoxometalates is the combination of TZP/PBE//TZ2P/OPBE (for NMR//optimization step). The hybrid functionals (PBE0, B3LYP) tested herein were applied to the NMR step, besides being more CPU-consuming, do not outperform pure GGA functionals. Although previous studies on (183)W NMR suggested that the use of very large basis sets like QZ4P were needed for geometry optimization, the present results indicate that TZ2P suffices if the functional is optimal. Moreover, scaling corrections were applied to the results providing low mean absolute errors below 1 ppm for δ((31)P), which is a step forward in order to confirm or predict chemical shifts in polyoxometalates. Finally, via a simplified molecular model, we establish how the small variations in δ((31)P) arise from energy changes in the occupied and virtual orbitals of the PO4 group. PMID:25738630

  7. Combined (Super 31)P and (Super 1)H NMR Experiments in the Structural Elucidation of Polynuclear Thiolate Complexes

    ERIC Educational Resources Information Center

    Cerrada, Elena; Laguna, Mariano

    2005-01-01

    A facile synthesis of two gold(I) complexes with 1,2-benzenedithiolate ligand and two different bidentate phosphines are described. A detailed sequence of NMR experiments is suggested to determine the structure of the compounds.

  8. Superconductivity in (TMTSF)2ClO4 probed by ^77Se NMR

    NASA Astrophysics Data System (ADS)

    Shinagawa, J.; Kurosaki, Y.; Brown, S. E.; Jerome, D.; Christensen, J. B.; Bechgaard, K.

    2007-03-01

    Superconductivity in the Bechgaard salts (TMTSF)2X, with X=PF6, ClO4, survives well beyond the paramagnetic limit set by the transition temperature Tc 1K. As a result, it has been hypothesized that the spin pairing is triplet. We report on measurements of the ^77Se Knight shift and spin-lattice relaxation rate T1-1, conducted in situ with interlayer resistivity, deep within the superconducting state of (TMTSF)2ClO4. At fields H0 10kOe aligned along the a- and b'-axes, the Knight shift reveals a decrease in spin susceptibility χs that is likely consistent with singlet pairing. The field dependence of T1-1 at temperatures TTc exhibits a very sharply-defined increase at a field Hs 15kOe. For H0>Hs, T1-1 is close to the normal state value, even though Hc2Hs and Rzz=0 to within experimental uncertainty. We discuss the implications for interpreting the results as evidence for a crossover, or a phase transition within the superconducting state.

  9. Whole-body radiofrequency coil for (31) P MRSI at 7 T.

    PubMed

    Löring, J; van der Kemp, W J M; Almujayyaz, S; van Oorschot, J W M; Luijten, P R; Klomp, D W J

    2016-06-01

    Widespread use of ultrahigh-field (31) P MRSI in clinical studies is hindered by the limited field of view and non-uniform radiofrequency (RF) field obtained from surface transceivers. The non-uniform RF field necessitates the use of high specific absorption rate (SAR)-demanding adiabatic RF pulses, limiting the signal-to-noise ratio (SNR) per unit of time. Here, we demonstrate the feasibility of using a body-sized volume RF coil at 7 T, which enables uniform excitation and ultrafast power calibration by pick-up probes. The performance of the body coil is examined by bench tests, and phantom and in vivo measurements in a 7-T MRI scanner. The accuracy of power calibration with pick-up probes is analyzed at a clinical 3-T MR system with a close to identical (1) H body coil integrated at the MR system. Finally, we demonstrate high-quality three-dimensional (31) P MRSI of the human body at 7 T within 5 min of data acquisition that includes RF power calibration. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27037615

  10. Differential cross sections measurement of 31P(p,pγ1)31P reaction for PIGE applications

    NASA Astrophysics Data System (ADS)

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.

    2016-09-01

    Differential cross sections of proton induced gamma-ray emission from the 31P(p,pγ1)31P (Eγ = 1266 keV) nuclear reaction were measured in the proton energy range of 1886-3007 keV at the laboratory angle of 90°. For these measurements a thin Zn3P2 target evaporated onto a self-supporting C film was used. The gamma-rays and backscattered protons were detected simultaneously. An HPGe detector placed at an angle of 90° with respect to the beam direction was employed to collect gamma-rays while an ion implanted Si detector placed at a scattering angle of 165° was used to detect backscattered protons. Simultaneous collection of gamma-rays and RBS spectra is a great advantage of this approach which makes differential cross-section measurements independent on the collected beam charge. The obtained cross-sections were compared with the previously only measured data in the literature. The validity of the measured differential cross sections was verified through a thick target benchmarking experiment. The overall systematic uncertainty of cross section values was estimated to be better than ±9%.

  11. U1h Superstructure

    SciTech Connect

    Glen Sykes

    2000-11-01

    The U1H Shaft Project is a design build subcontract to supply the U. S. Department of Energy (DOE) a 1,045 ft. deep, 20 ft. diameter, concrete lined shaft for unspecified purposes. The subcontract awarded to Atkinson Construction by Bechtel Nevada to design and construct the shaft for the DOE has been split into phases with portions of the work being released as dictated by available funding. The first portion released included the design for the shaft, permanent hoist, headframe, and collar arrangement. The second release consisted of constructing the shaft collar to a depth of 110 ft., the service entry, utility trenches, and installation of the temporary sinking plant. The temporary sinking plant included the installation of the sinking headframe, the sinking hoist, two deck winches, the shaft form, the sinking work deck, and temporary utilities required to sink the shaft. Both the design and collar construction were completed on schedule. The third release consisted of excavating and lining the shaft to the station depth of approximately 950 feet. Work is currently proceeding on this production sinking phase. At a depth of approximately 600 feet, Atkinson has surpassed production expectation and is more than 3 months ahead of schedule. Atkinson has employed the use of a Bobcat 331 excavator as the primary means of excavation. the shaft is being excavated entirely in an alluvial deposit with varying degrees of calcium carbonate cementation. Several more work packages are expected to be released in the near future. The remaining work packages include, construction of the shaft station a depth of 975 ft. and construction of the shaft sump to a depth of 1,045 ft., installation of the loading pocket and station steel and equipment, installation of the shaft steel and guides, installation of the shaft utilities, and installation of the permanent headframe, hoist, collar utilities, and facilities.

  12. (77)Se chemical shift tensor of L-selenocystine: experimental NMR measurements and quantum chemical investigations of structural effects.

    PubMed

    Struppe, Jochem; Zhang, Yong; Rozovsky, Sharon

    2015-03-01

    The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine's specialized biological roles, it is of interest to examine their (77)Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state (77)Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information on selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on (77)Se L-selenocystine's chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10-20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of -180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. -90°, the energy costs to alter the dihedral angle in the range from -120° to -60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. (77)Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272 ± 30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3-9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results suggest

  13. 77Se Chemical Shift Tensor of L-selenocystine: Experimental NMR Measurements and Quantum Chemical Investigations of Structural Effects

    PubMed Central

    Struppe, Jochem; Zhang, Yong; Rozovsky, Sharon

    2015-01-01

    The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine’s specialized biological roles, it is of interest to examine their 77Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state 77Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information of selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on 77Se L-selenocystine’s chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10–20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of −180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. −90°, the energy costs to alter the dihedral angle in the range from −120° to −60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. 77Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272±30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3–9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results

  14. In vivo (31) P MRS assessment of intracellular NAD metabolites and NAD(+) /NADH redox state in human brain at 4 T.

    PubMed

    Lu, Ming; Zhu, Xiao-Hong; Chen, Wei

    2016-07-01

    NAD(+) and NADH play key roles in cellular respiration. Intracellular redox state defined by the NAD(+) /NADH ratio (RX) reflects the cellular metabolic and physiopathological status. By taking advantage of high/ultrahigh magnetic field strengths, we have recently established a novel in vivo (31) P MRS-based NAD assay for noninvasive and quantitative measurements of intracellular NAD concentrations and redox state in animal and human brains at 16.4 T, 9.4 T and 7 T. To explore its potential for clinical application, in this study we investigated the feasibility of assessing the NAD metabolism and redox state in human brain at a lower field of 4 T by incorporating the (1) H-decoupling technique with the in vivo (31) P NAD assay. The use of (1) H decoupling significantly narrowed the linewidths of NAD and α-ATP resonances, resulting in higher sensitivity and better spectral resolution as compared with the (1) H-coupled (31) P spectrum. These improvements made it possible to reliably quantify cerebral NAD concentrations and RX, consistent with previously reported results obtained from similar age human subjects at 7 T. In summary, this work demonstrates the capability and utility of the (1) H-decoupled (31) P MRS-based NAD assay at lower field strength; thus, it opens new opportunities for studying intracellular NAD metabolism and redox state in human brain at clinical settings. This conclusion is supported by the simulation results, indicating that similar performance and reliability as observed at 4T can be achieved at 3 T with the same signal-to-noise ratio. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27257783

  15. Kinetics of the in vivo31P 1H nuclear overhauser effect of the human-calf-muscle phosphocreatine resonance

    NASA Astrophysics Data System (ADS)

    Bachert, Peter; Bellemann, Matthias E.

    In 31P 1H double-resonance experiments in a 1.5 T whole-body MR system, we observed in vivo the truncated driven, transient, and steady-state 31P- 1H nuclear Overhauser effect of the phosphocreatine resonance in 31P MR spectra of human gastrocnemius muscle. Maximum signal enhancements of 0.52 ± 0.01, 0.20 ± 0.01, and 0.79 ± 0.02 were measured, respectively. Fitting the data with theoretical functions which solve the multispin Solomon equations for N protons (S spins) dipolar coupled to a 31P nucleus (I spin) yields cross-relaxation times {2}/{[Σ i=1-N σIS(i) ] } in the order of 20 s. In vivo experiments are feasible for studying relaxation mechanisms in coupled 31P 1H spin systems in intact tissue.

  16. Selenium Chain Length Distribution in GexSe100-x Glasses: Insights from (77)Se NMR Spectroscopy and Quantum Chemical Calculations.

    PubMed

    Kaseman, Derrick C; Oliveira, Karina Moreira; Palazzo, Teresa; Sen, Sabyasachi

    2016-05-19

    The statistics of selenium chain length distribution in GexSe100-x glasses with 5 ≤ x ≤ 20 are investigated using a combination of high-resolution, two-dimensional (77)Se nuclear magnetic resonance (NMR) spectroscopy and quantum chemical calculations. This combined approach allows for the distinction of various selenium chain environments on the basis of subtle but systematic effects of next-nearest neighbors of Se atoms in -Se-Se-Se- linkages on the (77)Se chemical shift tensor parameters. Simulation of the experimental (77)Se NMR spectral line shapes indicates that Se chain speciation in these chalcogenide glasses follows the Flory-Schulz distribution, originally developed for organic chain polymers. PMID:27129100

  17. Nematicity and in-plane anisotropy of superconductivity in β -FeSe detected by 77Se nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Baek, S.-H.; Efremov, D. V.; Ok, J. M.; Kim, J. S.; van den Brink, Jeroen; Büchner, B.

    2016-05-01

    The recent study of 77Se nuclear magnetic resonance (NMR) in a β -FeSe single crystal proposed that ferro-orbital order breaks the 90∘ C4 rotational symmetry, driving nematic ordering. Here, we report an NMR study of the impact of small strains generated by gluing on nematic state and spin fluctuations. We observe that the local strains strongly affect the nematic transition, considerably enhancing its onset temperature. On the contrary, no effect on low-energy spin fluctuations was found. Furthermore we investigate the interplay of the nematic phase and superconductivity. Our study demonstrates that the twinned nematic domains respond unequivalently to superconductivity, evidencing the twofold C2 symmetry of superconductivity in this material. The obtained results are well understood in terms of the proposed ferro-orbital order.

  18. Feasibility Evaluation of Detecting Hydroxymethylphosphine Oxide In Vivo by (31)P-MRS.

    PubMed

    Doblas, Sabrina; Pathuri, Gopal; Towner, Rheal A; Gali, Hariprasad

    2010-09-01

    Application of organophosphorus compounds in biomedicine is attractive because the (31)P nucleus is very amenable to study by nuclear magnetic resonance (NMR) techniques, particularly, by in vivo (31)P magnetic resonance spectroscopy ((31)P-MRS). The water-soluble organophosphorus compounds that are non-toxic, exhibit metabolic stability, and show a unique resonance peak in (31)P NMR spectroscopy, which could be ideal to be used as probes for (31)P-MRS. Here we evaluated the in vivo feasibility of potentially using a hydroxymethylphosphine oxide as a novel probe for (31)P-MRS studies using tris (hydroxymethyl) phosphine oxide (THPO) as an example. THPO was synthesized, injected in the normal CF1 mice, and (31)P spectra were acquired before and after injection with the coil located on the regions of interest. The NMR signal from the region of interest appeared within one minute of THPO injection. The compound was stable in vivo as no metabolites of THPO were observed. No toxicity was observed after THPO injection in mice. The peak concentrations of THPO in liver and kidney were reached within 15 min and 60 min respectively. THPO was excreted exclusively in urine without undergoing any metabolism indicating that it is very stable under in vivo conditions. These initial studies in normal CF1 mice clearly demonstrate that THPO possess the essential characteristics required for a potential MRS probe. Based on the current preliminary results, we suggest that HMPs, when incorporated into targeted drugs (peptides, proteins, antibodies, etc.), may serve as novel (31)P probes for monitoring the drug distribution in vivo by MRS. PMID:23675197

  19. U1h shaft project

    SciTech Connect

    Brian Briggs; R. G. Musick

    2000-06-30

    The U1h shaft project is a design/build subcontract to construct one 20 foot (ft) finished diameter shaft to a depth of 1,045 ft at the Nevada Test Site. Atkinson Construction was subcontracted by Bechtel Nevada to construct the U1h Shaft for the Department of Energy. The project consists of furnishing and installing the sinking plant, construction of the 1,045 ft of concrete lined shaft, development of a shaft station at a depth of 976 ft, and construction of a loading pocket at the station. The outfitting of the shaft and installation of a new hoist may be incorporated into the project at a later date. This paper should be of interest to those involved with the construction of relatively deep shafts and underground excavations.

  20. Skeletal muscle ATP turnover by 31P magnetic resonance spectroscopy during moderate and heavy bilateral knee extension

    PubMed Central

    Cannon, Daniel T; Bimson, William E; Hampson, Sophie A; Bowen, T Scott; Murgatroyd, Scott R; Marwood, Simon; Kemp, Graham J; Rossiter, Harry B

    2014-01-01

    During constant-power high-intensity exercise, the expected increase in oxygen uptake () is supplemented by a  slow component (), reflecting reduced work efficiency, predominantly within the locomotor muscles. The intracellular source of inefficiency is postulated to be an increase in the ATP cost of power production (an increase in P/W). To test this hypothesis, we measured intramuscular ATP turnover with 31P magnetic resonance spectroscopy (MRS) and whole-body during moderate (MOD) and heavy (HVY) bilateral knee-extension exercise in healthy participants (n = 14). Unlocalized 31P spectra were collected from the quadriceps throughout using a dual-tuned (1H and 31P) surface coil with a simple pulse-and-acquire sequence. Total ATP turnover rate (ATPtot) was estimated at exercise cessation from direct measurements of the dynamics of phosphocreatine (PCr) and proton handling. Between 3 and 8 min during MOD, there was no discernable (mean ± SD, 0.06 ± 0.12 l min−1) or change in [PCr] (30 ± 8 vs. 32 ± 7 mm) or ATPtot (24 ± 14 vs. 17 ± 14 mm min−1; each P = n.s.). During HVY, the was 0.37 ± 0.16 l min−1 (22 ± 8%), [PCr] decreased (19 ± 7 vs. 18 ± 7 mm, or 12 ± 15%; P < 0.05) and ATPtot increased (38 ± 16 vs. 44 ± 14 mm min−1, or 26 ± 30%; P < 0.05) between 3 and 8 min. However, the increase in ATPtot (ΔATPtot) was not correlated with the during HVY (r2 = 0.06; P = n.s.). This lack of relationship between ΔATPtot and , together with a steepening of the [PCr]– relationship in HVY, suggests that reduced work efficiency during heavy exercise arises from both contractile (P/W) and mitochondrial sources (the O2 cost of ATP resynthesis; P/O). PMID:25281731

  1. Skeletal muscle ATP turnover by 31P magnetic resonance spectroscopy during moderate and heavy bilateral knee extension.

    PubMed

    Cannon, Daniel T; Bimson, William E; Hampson, Sophie A; Bowen, T Scott; Murgatroyd, Scott R; Marwood, Simon; Kemp, Graham J; Rossiter, Harry B

    2014-12-01

    During constant-power high-intensity exercise, the expected increase in oxygen uptake (V̇O2) is supplemented by a V̇O2 slow component (V̇O2 sc ), reflecting reduced work efficiency, predominantly within the locomotor muscles. The intracellular source of inefficiency is postulated to be an increase in the ATP cost of power production (an increase in P/W). To test this hypothesis, we measured intramuscular ATP turnover with (31)P magnetic resonance spectroscopy (MRS) and whole-body V̇O2 during moderate (MOD) and heavy (HVY) bilateral knee-extension exercise in healthy participants (n = 14). Unlocalized (31)P spectra were collected from the quadriceps throughout using a dual-tuned ((1)H and (31)P) surface coil with a simple pulse-and-acquire sequence. Total ATP turnover rate (ATPtot) was estimated at exercise cessation from direct measurements of the dynamics of phosphocreatine (PCr) and proton handling. Between 3 and 8 min during MOD, there was no discernable V̇O2 sc (mean ± SD, 0.06 ± 0.12 l min(-1)) or change in [PCr] (30 ± 8 vs. 32 ± 7 mm) or ATPtot (24 ± 14 vs. 17 ± 14 mm min(-1); each P = n.s.). During HVY, the V̇O2 sc was 0.37 ± 0.16 l min(-1) (22 ± 8%), [PCr] decreased (19 ± 7 vs. 18 ± 7 mm, or 12 ± 15%; P < 0.05) and ATPtot increased (38 ± 16 vs. 44 ± 14 mm min(-1), or 26 ± 30%; P < 0.05) between 3 and 8 min. However, the increase in ATPtot (ΔATPtot) was not correlated with the V̇O2 sc during HVY (r(2) = 0.06; P = n.s.). This lack of relationship between ΔATPtot and V̇O2 sc , together with a steepening of the [PCr]-V̇O2 relationship in HVY, suggests that reduced work efficiency during heavy exercise arises from both contractile (P/W) and mitochondrial sources (the O2 cost of ATP resynthesis; P/O). PMID:25281731

  2. Advancement of 31P Magnetic Resonance Spectroscopy Using GRAPPA Reconstruction on a 3D Volume

    NASA Astrophysics Data System (ADS)

    Clevenger, Tony

    The overall objective of this research is to improve currently available metabolic imaging techniques for clinical use in monitoring and predicting treatment response to radiation therapy in liver cancer. Liver metabolism correlates with inflammatory and neoplastic liver diseases, which alter the intracellular concentration of phosphorus- 31 (31P) metabolites [1]. It is assumed that such metabolic changes occur prior to physical changes of the tissue. Therefore, information on regional changes of 31P metabolites in the liver, obtained by Magnetic Resonance Spectroscopic Imaging (MRSI) [1,2], can help in diagnosis and follow-up of various liver diseases. Specifically, there appears to be an immediate need of this technology for both the assessment of tumor response in patients with Hepatocellular Carcinoma (HCC) treated with Stereotactic Body Radiation Therapy (SBRT) [3--5], as well as assessment of radiation toxicity, which can result in worsening liver dysfunction [6]. Pilot data from our lab has shown that 31P MRSI has the potential to identify treatment response five months sooner than conventional methods [7], and to assess the biological response of liver tissue to radiation 24 hours post radiation therapy [8]. While this data is very promising, commonly occurring drawbacks for 31P MRSI are patient discomfort due to long scan times and prone positioning within the scanner, as well as reduced data quality due to patient motion and respiration. To further advance the full potential of 31P MRSI as a clinical diagnostic tool in the management of liver cancer, this PhD research project had the following aims: I) Reduce the long acquisition time of 3D 31P MRS by formulating and imple- menting an appropriate GRAPPA undersampling scheme and reconstruction on a clinical MRI scanner II) Testing and quantitative validation of GRAPPA reconstruction on 3D 31P MRSI on developmental phantoms and healthy volunteers At completion, this work should considerably advance 31P MRSI

  3. Combined MRI and 31P-MRS Investigations of the ACTA1(H40Y) Mouse Model of Nemaline Myopathy Show Impaired Muscle Function and Altered Energy Metabolism

    PubMed Central

    Gineste, Charlotte; Le Fur, Yann; Vilmen, Christophe; Le Troter, Arnaud; Pecchi, Emilie; Cozzone, Patrick J.; Hardeman, Edna C.; Bendahan, David; Gondin, Julien

    2013-01-01

    Nemaline myopathy (NM) is the most common disease entity among non-dystrophic skeletal muscle congenital diseases. Mutations in the skeletal muscle α-actin gene (ACTA1) account for ∼25% of all NM cases and are the most frequent cause of severe forms of NM. So far, the mechanisms underlying muscle weakness in NM patients remain unclear. Additionally, recent Magnetic Resonance Imaging (MRI) studies reported a progressive fatty infiltration of skeletal muscle with a specific muscle involvement in patients with ACTA1 mutations. We investigated strictly noninvasively the gastrocnemius muscle function of a mouse model carrying a mutation in the ACTA1 gene (H40Y). Skeletal muscle anatomy (hindlimb muscles and fat volumes) and energy metabolism were studied using MRI and 31Phosphorus magnetic resonance spectroscopy. Skeletal muscle contractile performance was investigated while applying a force-frequency protocol (from 1–150 Hz) and a fatigue protocol (80 stimuli at 40 Hz). H40Y mice showed a reduction of both absolute (−40%) and specific (−25%) maximal force production as compared to controls. Interestingly, muscle weakness was associated with an improved resistance to fatigue (+40%) and an increased energy cost. On the contrary, the force frequency relationship was not modified in H40Y mice and the extent of fatty infiltration was minor and not different from the WT group. We concluded that the H40Y mouse model does not reproduce human MRI findings but shows a severe muscle weakness which might be related to an alteration of intrinsic muscular properties. The increased energy cost in H40Y mice might be related to either an impaired mitochondrial function or an alteration at the cross-bridges level. Overall, we provided a unique set of anatomic, metabolic and functional biomarkers that might be relevant for monitoring the progression of NM disease but also for assessing the efficacy of potential therapeutic interventions at a preclinical level. PMID:23613869

  4. sup 31 P NMR analysis of coal moieties bearing -OH, -NH, and -SH functions

    SciTech Connect

    Verkade, J.G.

    1991-08-31

    NMR reagents for the speciation and quantitation of labile-hydrogen functional groups and sulfur groups in coal ligands have been synthesized and evaluated. These reagents, which contain the NMR-active nuclei {sup 31}p, {sup 119}Sn or {sup 195}pt, were designed to possess improved chemical shift resolution over reagents reported in the literature. Our efforts were successful in the case of the new {sup 31}p and {sup 119}Sn reagents we developed, but the {sup 195}pt work on sulfur groups was only partially successful in as much as the grant came to a close and was not renewed. Our success with {sup 31}P and {sup 119}Sn NMR reagents came to the attention of Amoco and they have recently expressed interest in further supporting that work. A further measure of the success of our efforts can be seen in the nine publications supported by this grant which are cited in the reference list.

  5. Monitoring changes of paramagnetically-shifted 31P signals in phospholipid vesicles

    NASA Astrophysics Data System (ADS)

    Joyce, Rebecca E.; Williams, Thomas L.; Serpell, Louise C.; Day, Iain J.

    2016-03-01

    Phospholipid vesicles are commonly used as biomimetics in the investigation of the interaction of various species with cell membranes. In this letter we present a 31P NMR investigation of a simple vesicle system using a paramagnetic shift reagent to probe the inner and outer layers of the lipid bilayer. Time-dependent changes in the 31P NMR signal are observed, which differ whether the paramagnetic species is inside or outside the vesicle, and on the choice of buffer solution used. An interpretation of these results is given in terms of the interaction of the paramagnetic shift reagent with the lipids.

  6. Structure and motion of phospholipids in human plasma lipoproteins. A sup 31 P NMR study

    SciTech Connect

    Fenske, D.B.; Chana, R.S.; Parmar, Y.I.; Treleaven, W.D.; Cushley, R.J. )

    1990-04-24

    The structure and motion of phospholipids in human plasma lipoproteins have been studied by using {sup 31}P NMR. Lateral diffusion coefficients, D{sub T}, obtained from the viscosity dependence of the {sup 31}P NMR line widths, were obtained for very low density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoproteins (HDL{sub 2}, HDL{sub 3}), and egg PC/TO microemulsions at 25{degree}C, for VLDL at 40{degree}C, and for LDL at 45{degree}C. In order to prove the orientation and/or order of the phospholipid head-group, estimates of the residual chemical shift anistropy, {Delta}{sigma}, have been obtained for all the lipoproteins and the microemulsions from the viscosity and field dependence for the {sup 31}P NMR line widths. These results suggest differences in the orientation and/or ordering of the head-group in the HDLs. The dynamic behavior of the phosphate moiety in LDL and HDL{sub 3} has been obtained from the temperature dependence of the {sup 31}P spin-lattice relaxation rates. Values of the correlation time for phosphate group reorientation and the activation energy for the motion are nearly identical in LDL and HDL{sub 3} and are similar to values obtained for phospholipid bilayers. This argues against long-lived protein-lipid interactions being the source of either the slow diffusion in LDL or the altered head-group orientation in the HDLs.

  7. Comparison of phosphorus forms in three extracts of dairy feces by solution 31P NMR analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using solution 31P NMR spectroscopy, we compared three extractants, deionized water, sodium acetate buffer (pH 5.0) with fresh sodium dithionite (NaAc-SD), and 0.25 M NaOH-0.05 M EDTA (NaOH-EDTA), for the profile of P compounds in two dairy fecal samples. Phosphorus extracted was 35% for water, and...

  8. Solid State FT-IR and (31)P NMR Spectral Features of Phosphate Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solid-state spectroscopic techniques, including Fourier transform infrared (FT-IR) and solid-state 31P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopies, are powerful tools for evaluating metal speciation and transformation mechanisms of P compounds in the environment. Studie...

  9. Functional group analysis in coal by sup 31 P NMR spectroscopy

    SciTech Connect

    Verkade, J.G.

    1989-05-01

    The purpose of this research is to determine the labile-hydrogen functional group composition of coal and coal-derived materials by the nmr spectroscopy of their derivatives made with reagents containing the nmr-active nuclei {sup 31}P, {sup 119}Sn, or {sup 205}Tl. 7 refs.

  10. Accuracy and precision of quantitative 31P-MRS measurements of human skeletal muscle mitochondrial function.

    PubMed

    Layec, Gwenael; Gifford, Jayson R; Trinity, Joel D; Hart, Corey R; Garten, Ryan S; Park, Song Y; Le Fur, Yann; Jeong, Eun-Kee; Richardson, Russell S

    2016-08-01

    Although theoretically sound, the accuracy and precision of (31)P-magnetic resonance spectroscopy ((31)P-MRS) approaches to quantitatively estimate mitochondrial capacity are not well documented. Therefore, employing four differing models of respiratory control [linear, kinetic, and multipoint adenosine diphosphate (ADP) and phosphorylation potential], this study sought to determine the accuracy and precision of (31)P-MRS assessments of peak mitochondrial adenosine-triphosphate (ATP) synthesis rate utilizing directly measured peak respiration (State 3) in permeabilized skeletal muscle fibers. In 23 subjects of different fitness levels, (31)P-MRS during a 24-s maximal isometric knee extension and high-resolution respirometry in muscle fibers from the vastus lateralis was performed. Although significantly correlated with State 3 respiration (r = 0.72), both the linear (45 ± 13 mM/min) and phosphorylation potential (47 ± 16 mM/min) models grossly overestimated the calculated in vitro peak ATP synthesis rate (P < 0.05). Of the ADP models, the kinetic model was well correlated with State 3 respiration (r = 0.72, P < 0.05), but moderately overestimated ATP synthesis rate (P < 0.05), while the multipoint model, although being somewhat less well correlated with State 3 respiration (r = 0.55, P < 0.05), most accurately reflected peak ATP synthesis rate. Of note, the PCr recovery time constant (τ), a qualitative index of mitochondrial capacity, exhibited the strongest correlation with State 3 respiration (r = 0.80, P < 0.05). Therefore, this study reveals that each of the (31)P-MRS data analyses, including PCr τ, exhibit precision in terms of mitochondrial capacity. As only the multipoint ADP model did not overstimate the peak skeletal muscle mitochondrial ATP synthesis, the multipoint ADP model is the only quantitative approach to exhibit both accuracy and precision. PMID:27302751

  11. CD and 31P NMR studies of tachykinin and MSH neuropeptides in SDS and DPC micelles

    NASA Astrophysics Data System (ADS)

    Schneider, Sydney C.; Brown, Taylor C.; Gonzalez, Javier D.; Levonyak, Nicholas S.; Rush, Lydia A.; Cremeens, Matthew E.

    2016-02-01

    Secondary structural characteristics of substance P (SP), neurokinin A (NKA), neurokinin B (NKB), α-melanocyte stimulating hormone peptide (α-MSH), γ1-MSH, γ2-MSH, and melittin were evaluated with circular dichroism in phosphite buffer, DPC micelles, and SDS micelles. CD spectral properties of γ1-MSH and γ2-MSH as well as 31P NMR of DPC micelles with all the peptides are reported for the first time. Although, a trend in the neuropeptide/micelle CD data appears to show increased α-helix content for the tachykinin peptides (SP, NKA, NKB) and increased β-sheet content for the MSH peptides (α-MSH, γ1-MSH, γ2-MSH) with increasing peptide charge, the lack of perturbed 31P NMR signals for all neuropeptides could suggest that the reported antimicrobial activity of SP and α-MSH might not be related to a membrane disruption mode of action.

  12. Excitation functions for actinides produced in the interactions of sup 31 P with sup 248 Cm

    SciTech Connect

    Leyba, J.D.; Henderson, R.A.; Hall, H.L.; Czerwinski, K.R.; Kadkhodayan, B.A.; Kreek, S.A.; Brady, E.K.; Gregorich, K.E.; Lee, D.M.; Nurmia, M.J.; Hoffman, D.C. Nuclear Science Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California )

    1991-11-01

    Excitation functions have been measured for the production of various isotopes of Bk, Cf, Es, and Fm from the interactions of 174- and 239-MeV {sup 31}P projectiles with {sup 248}Cm. The isotopic distributions were symmetric and displayed full widths at half maximum of 2.5, 2.5, and 2.25 mass units for Bk, Cf, and Fm, respectively. The maxima of the isotopic distributions occur for those reaction channels which involve the exchange of the fewest number of nucleons between the target and projectile for which the calculated excitation energy is a positive quantity. The maxima of the excitation functions occur at those projectile energies which are consistent with the calculated reaction barriers based upon a binary reaction mechanism. The effects of the odd proton in the {sup 31}P projectile on the final isotopic distributions are discussed.

  13. Erythrocytes in muscular dystrophy. Investigation with 31P nuclear magnetic resonance spectroscopy

    SciTech Connect

    Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

    1981-05-01

    Phosphorus 31 nuclear magnetic resonance (31P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual 31P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which lead to lower steady-state concentrations of the intracellular phosphates.

  14. Erythrocytes in muscular dystrophy. Investigation with /sup 31/P nuclear magnetic resonance spectroscopy

    SciTech Connect

    Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

    1981-05-01

    Phosphorus 31 nuclear magnetic resonance (/sup 31/P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual /sup 31/P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which leads to lower steady-state concentrations of the intracellular phosphates.

  15. Pyrolysis temperature affects phosphorus transformation in biochar: Chemical fractionation and (31)P NMR analysis.

    PubMed

    Xu, Gang; Zhang, You; Shao, Hongbo; Sun, Junna

    2016-11-01

    Phosphorus (P) recycling or reuse by pyrolyzing crop residue has recently elicited increased research interest. However, the effects of feedstock and pyrolysis conditions on P species have not been fully understood. Such knowledge is important in identifying the agronomic and environmental uses of biochar. Residues of three main Chinese agricultural crops and the biochars (produced at 300°C-600°C) derived from these crops were used to determine P transformations during pyrolysis. Hedley sequential fractionation and (31)P NMR analyses were used in the investigation. Our results showed that P transformation in biochar was significantly affected by pyrolysis temperature regardless of feedstock (Wheat straw, maize straw and peanut husk). Pyrolysis treatment transformed water soluble P into a labile (NaHCO3-Pi) or semi-labile pool (NaOH-Pi) and into a stable pool (Dil. HCl P and residual-P). At the same time, organic P was transformed into inorganic P fractions which was identified by the rapid decomposition of organic P detected with solution (31)P NMR. The P transformation during pyrolysis process suggested more stable P was formed at a higher pyrolysis temperature. This result was also evidenced by the presence of less soluble or stable P species, such as such as poly-P, crandallite (CaAl3(OH)5(PO4)2) and Wavellite (Al3(OH)3(PO4)2·5H2O), as detected by solid-state (31)P NMR in biochars formed at a higher pyrolysis temperature. Furthermore, a significant proportion of less soluble pyrophosphate was identified by solution (2%-35%) and solid-state (8%-53%) (31)P NMR, which was also responsible for the stable P forms at higher pyrolysis temperature although their solubility or stability requires further investigation. Results suggested that a relatively lower pyrolysis temperature retains P availability regardless of feedstock during pyrolysis process. PMID:27343937

  16. (77)Se nuclear spin-lattice relaxation in binary Ge-Se glasses: insights into floppy versus rigid behavior of structural units.

    PubMed

    Sen, Sabyasachi; Kaseman, Derrick C; Hung, Ivan; Gan, Zhehong

    2015-04-30

    The mechanism of (77)Se nuclear spin-lattice relaxation is investigated in binary Ge-Se glasses. The (77)Se nuclides in Se-Se-Se chain sites relax faster via dipolar coupling fluctuation compared to those in Ge-Se-Ge sites shared by GeSe4 tetrahedra that relax slower via the fluctuation of the chemical shift anisotropy. The relaxation rate for the Se-Se-Se sites decreases markedly with increasing magnetic field, whereas that for the Ge-Se-Ge sites displays no appreciable dependence on the magnetic field such that the extent of differential relaxation between the two Se environments becomes small at high fields on the order of 19.6 T. The corresponding dynamical correlation time is three orders of magnitude shorter (∼10(-9) s) for the Se-Se-Se sites, compared to that for the Ge-Se-Ge sites (∼10(-6) s). The large decoupling in the time scale between these Se environments provides direct experimental support to the commonly made assumption that the selenium chains are mechanically floppy, and the interconnected GeSe4 tetrahedra form the rigid elements in the selenide glass structure. PMID:25848959

  17. Evaluation of Phosphorus Characterization in Ileal Digesta, Manure, and Litter Samples: 31P-NMR vs. HPLC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using 31-Phosphorus Nuclear Magnetic Resosonance Spectroscopy (31P-NMR) to characterize phosphorus (P) in manures and litter has become prevalent in the area of nutrient management. To date, there has been no published work evaluating P quantification in manure/litter samples with 31P-NMR compared ...

  18. Evaluation of Phosphorus Characterization in Broiler Ileal Digesta, Manure, and Litter Samples: 31P-NMR vs. HPLC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using 31-Phosphorus Nuclear Magnetic Resosonance Spectroscopy (31P-NMR) to characterize phosphorus (P) in manures and litter has become prevalent in the area of nutrient management. To date, there has been no published work evaluating P quantification in manure/litter samples with 31P-NMR compared t...

  19. In vivo 31P-NMR spectroscopy of right ventricle in pigs.

    PubMed

    Schwartz, G G; Steinman, S K; Weiner, M W; Matson, G B

    1992-06-01

    The energy metabolism of the right ventricle (RV) in vivo has been largely unexplored. The goal of this study was to develop and implement techniques for in vivo 31P nuclear magnetic resonance (NMR) spectroscopy of the RV free wall. A two-turn, crossover-design elliptical surface coil was constructed to provide high sensitivity across the thin RV wall but minimal sensitivity in the blood-filled RV cavity. In 36 open-chest, anesthetized pigs, 31P spectroscopy of the RV free wall was performed with this coil at a field strength of 2 Tesla. Spectra were obtained from 800 acquisitions in 24 min with an average signal-to-noise ratio of 13.2 for phosphocreatine (PCr). The PCr-to-ATP (PCr/ATP) ratio of porcine RV was 1.42 +/- 0.05 (mean +/- SE), uncorrected for saturation at a repetition time of 1.8 s. With the use of literature values of the time constant of longitudinal relaxation (T1) to correct for partial saturation, the RV PCr/ATP was estimated to lie between 1.7 and 2.3. Decreased RV PCr/ATP was observed during RV ischemia and pressure overload. Thus in vivo 31P spectroscopy of the RV is readily accomplished with an appropriate surface coil and can provide new information about RV energy metabolism. PMID:1621852

  20. [sup 31]P NMR study of immobilized artificial membrane surfaces. Structure and dynamics of immobilized phospholipids

    SciTech Connect

    Qiu, X.; Pidgeon, C. )

    1993-11-25

    Chromatography surfaces were prepared by immobilizing a single-chain ether phospholipid at approximately a monolayer density on silica particles. The chromatography particles are denoted as [sup ether]IAM.PC[sup C10/C3], and they are stable to all solvents. The structure and dynamics of the interphase created by immobilizing phospholipids on silica particles were studied by [sup 31]P NMR methods. [sup ether]IAM.PC[sup C10/C3] spontaneously wets when suspended in both aqueous and organic solvents, and [sup 31]P NMR spectra were obtained in water, methanol, chloroform, acetonitrile, and acetone. [sup 31]P NMR spectra were subjected to line-shape analysis. From line-shape analysis, the correlation times for rapid internal motion ([tau]-PLL) and wobbling ([tau]-PRP) of the phospholipid headgroup were calculated for each solvent. Immobilized phospholipid headgroups comprising the IAM interfacial region undergo rapid reorientation similar to the case of the phospholipids forming liposome membranes with [tau]-PLL approximately 1 ns. Phospholipids in liposome membranes exhibit slower wobbling motion ([tau]-PRP approximately 1 ms) in the plane of the membrane. However, the immobilized phospholipids on [sup ether]IAM.PC[sup C10/C3] surfaces wobble with correlation times [tau]-PRP that depend on the solvent bathing the [sup ether]IAM.PC[sup C10/C3] surface. 41 refs., 9 figs., 2 tabs.

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

    PubMed

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

    2004-09-01

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

  2. /sup 31/P nuclear magnetic resonance measurements of intracellular pH in giant barnacle muscle

    SciTech Connect

    Hamm, J.R.; Yue, G.M.

    1987-01-01

    The accuracy of intracellular pH (pH/sub i/) measurements by /sup 31/P nuclear magnetic resonance (NMR) spectroscopy was examined in single muscle fibers from the giant barnacle, Balanus nubilis. The pH/sub i/ was derived from the chemical shifts of 2-deoxy-D-glucose-6-phosphate and inorganic phosphate. In fibers superfused with sea water at pH 7.7, pH/sub i/ = 7.30 +/- 0.02 at 20/sup 0/C. Experimentally induced pH/sub i/ changes were followed with a time resolution of 3 min. Intracellular alkalinization was induced by exposure to NH/sub 3/Cl and intracellular acidification followed when NH/sub 3/ was removed. Then acid extrusion was stimulated by exposure to bicarbonate containing sea water. In single muscle fibers /sup 31/P NMR results were in excellent agreement with microelectrode studies over the pH range of 6.5 to 8.0. The initial acid extrusion rate was 1.7 +/- 0.3 mmol x 1/sup -1/ x min/sup -1/ at pH/sub i/ 6.75. The authors results showed that /sup 31/P NMR is a reliable in vivo pH probe.

  3. 31P nuclear magnetic resonance measurements of intracellular pH in giant barnacle muscle.

    PubMed

    Hamm, J R; Yue, G M

    1987-01-01

    The accuracy of intracellular pH (pHi) measurements by 31P nuclear magnetic resonance (NMR) spectroscopy was examined in single muscle fibers from the giant barnacle, Balanus nubilis. The pHi was derived from the chemical shifts of 2-deoxy-D-glucose-6-phosphate and inorganic phosphate. In fibers superfused with sea water at pH 7.7, pHi = 7.30 +/- 0.02 at 20 degrees C. Experimentally induced pHi changes were followed with a time resolution of 3 min. Intracellular alkalinization was induced by exposure to NH4Cl and intracellular acidification followed when NH3 was removed. Then acid extrusion was stimulated by exposure to bicarbonate containing sea water. In single muscle fibers 31P NMR results were in excellent agreement with microelectrode studies over the pH range of 6.5 to 8.0. The initial acid extrusion rate was 1.7 +/- 0.3 mmol X l-1 X min-1 at pHi 6.75. Our results showed that 31P NMR is a reliable in vivo pH probe. PMID:3812665

  4. Prediction of 31P nuclear magnetic resonance chemical shifts for phosphines

    NASA Astrophysics Data System (ADS)

    Tong, Jianbo; Liu, Shuling; Zhang, Shengwan; Li, Shengshi Z.

    2007-07-01

    Quantitative relationships of the 31P NMR chemical shifts of the phosphorus atoms in 291 phosphines with the atomic ionicity index (INI) and stereoscopic effect parameters ( ɛα, ɛβ, ɛγ) were primarily investigated in this paper for modeling some fundamental quantitative structure-spectroscopy relationships (QSSR). The results indicated that the 31P NMR chemical shifts of phosphines can be described as the quantitative equation by multiple linear regression (MLR): δp (ppm) = -174.0197 - 2.6724 INI + 40.4755 ɛα + 15.1141 ɛβ - 3.1858 ɛγ, correlation coefficient R = 0.9479, root mean square error (rms) = 13.9, and cross-validated predictive correlation coefficient was found by using the leave-one-out procedure to be Q2 = 0.8919. Furthermore, through way of random sampling, the estimative stability and the predictive power of the proposed MLR model were examined by constructing data set randomly into both the internal training set and external test set of 261 and 30 compounds, respectively, and then the chemical shifts were estimated and predicted with the training correlation coefficient R = 0.9467 and rms = 13.4 and the external predicting correlation coefficient Qext = 0.9598 and rms = 10.8. A partial least square model was developed that produced R = 0.9466, Q = 0.9407 and Qext = 0.9599, respectively. Those good results provided a new, simple, accurate and efficient methodology for calculating 31P NMR chemical shifts of phosphines.

  5. sup 31 P NMR analysis of coal moieties bearing -OH, -NH, and -SH functions

    SciTech Connect

    Verkade, J.G.

    1991-01-01

    The purpose of this research is to develop a convenient, reliable and rapid NMR method for the determination of labile-hydrogen functional groups and organic sulfur compounds which are components of coal and coal-derived materials. For this purpose, the former functional groups, including water molecules, are derivatized with reagents containing NMR-active nuclei such as {sup 31}P or {sup 119}Sn, while sulfur groups are derivatized with {sup 195}Pt NMR tagging reagents. Knowledge of the heteroatom composition of coals is necessary for the development of increasingly sophisticated coal processing technologies.

  6. In Vivo 31P Echo-Planar Spectroscopic Imaging of Human Calf Muscle

    NASA Astrophysics Data System (ADS)

    Wilhelm, Thomas; Bachert, Peter

    2001-03-01

    Localized phosphorus-31 NMR spectra of human calf muscle in vivo were obtained by means of echo-planar spectroscopic imaging (EPSI) with a 1.5-T whole-body scanner. The technique permits the measurement of two-dimensional 31P SI data at a minimum acquisition time of 2.4 s (8×8 voxels, TR=300 ms). With 9.4 min measurement time (TR=1100 ms, 64 averages) and 25×25×40 mm spatial resolution in vivo the 31P NMR signal-to-noise ratio (S/N) of the phosphocreatine (PCr) resonance was about 45; the multiplets of nucleoside 5‧-triphosphates were resolved. Spectral quality permits quantitative assessment of the PCr signal in a measurement time that is shorter by a factor of 2 or more than the minimum measurement time feasible with chemical-shift imaging. In a functional EPSI study with a time resolution of 20.5 s on the calf muscle of volunteers, spectra showed a 40% decrease of the PCr signal intensity (at rest: S/N≅12) upon exertion of the muscle.

  7. 2D exchange 31P NMR spectroscopy of bacteriophage M13 and tobacco mosaic virus.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1995-01-01

    Two-dimensional (2D) exchange 31P nuclear magnetic resonance spectroscopy is used to study the slow overall motion of the rod-shaped viruses M13 and tobacco mosaic virus in concentrated gels. Even for short mixing times, observed diagonal spectra differ remarkably from projection spectra and one-dimensional spectra. Our model readily explains this to be a consequence of the T2e anisotropy caused by slow overall rotation of the viruses about their length axis. 2D exchange spectra recorded for 30% (w/w) tobacco mosaic virus with mixing times < 1 s do not show any off-diagonal broadening, indicating that its overall motion occurs in the sub-Hz frequency range. In contrast, the exchange spectra obtained for 30% M13 show significant off-diagonal intensity for mixing times of 0.01 s and higher. A log-gaussian distribution around 25 Hz of overall diffusion coefficients mainly spread between 1 and 10(3) Hz faithfully reproduces the 2D exchange spectra of 30% M13 recorded at various mixing times in a consistent way. A small but notable change in diagonal spectra at increasing mixing time is not well accounted for by our model and is probably caused by 31P spin diffusion. PMID:7756532

  8. Nuclear spin decoherence of neutral 31P donors in silicon: Effect of environmental 29Si nuclei

    NASA Astrophysics Data System (ADS)

    Petersen, Evan S.; Tyryshkin, A. M.; Morton, J. J. L.; Abe, E.; Tojo, S.; Itoh, K. M.; Thewalt, M. L. W.; Lyon, S. A.

    2016-04-01

    Spectral diffusion arising from 29Si nuclear spin flip-flops, known to be a primary source of electron spin decoherence in silicon, is also predicted to limit the coherence times of neutral donor nuclear spins in silicon. Here, the impact of this mechanism on 31P nuclear spin coherence is measured as a function of 29Si concentration using X -band pulsed electron nuclear double resonance. The 31P nuclear spin echo decays show that decoherence is controlled by 29Si flip-flops resulting in both fast (exponential) and slow (nonexponential) spectral diffusion processes. The decay times span a range from 100 ms in crystals containing 50% 29Si to 3 s in crystals containing 1% 29Si. These nuclear spin echo decay times for neutral donors are orders of magnitude longer than those reported for ionized donors in natural silicon. The electron spin of the neutral donors "protects" the donor nuclear spins by suppressing 29Si flip-flops within a "frozen core," as a result of the detuning of the 29Si spins caused by their hyperfine coupling to the electron spin.

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

    PubMed

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

    1988-02-01

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

  10. Hypophosphite ion as a 31P nuclear magnetic resonance probe of membrane potential in erythrocyte suspensions.

    PubMed Central

    Kirk, K; Kuchel, P W; Labotka, R J

    1988-01-01

    Hypophosphorus acid has a single pKa of 1.1 and at physiological pH values it is therefore present almost entirely as the univalent hypophosphite ion. When added to a red cell suspension the ion crosses the cell membrane rapidly, via the anion exchange protein, and the intra- and extracellular populations of the ion give rise to separate 31P NMR resonances. From a single 31P NMR spectrum it was possible to determine the relative amounts of hypophosphite in the intra- and extracellular compartments and thereby estimate the corresponding concentrations. The ratio of intracellular to extracellular hypophosphite concentration was independent of the total hypophosphite concentration for cells suspended in NaCl solutions and was independent of hematocrit. The hypophosphite distribution ratio increased as extracellular NaCl was replaced iso-osmotically with citrate or sucrose, through it remained very similar to the corresponding hydrogen ion distribution ratio. Incorporation of the hypophosphite distribution ratio into the Nernst equation yielded an estimate of the membrane potential. For cells suspended in NaCl solutions the estimated potential was consistently around -10 mV. PMID:3207824

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

    SciTech Connect

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

    1988-02-01

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

  12. The A31P missense mutation in cardiac myosin binding protein C alters protein structure but does not cause haploinsufficiency.

    PubMed

    van Dijk, Sabine J; Bezold Kooiker, Kristina; Mazzalupo, Stacy; Yang, Yuanzhang; Kostyukova, Alla S; Mustacich, Debbie J; Hoye, Elaine R; Stern, Joshua A; Kittleson, Mark D; Harris, Samantha P

    2016-07-01

    Mutations in MYBPC3, the gene encoding cardiac myosin binding protein C (cMyBP-C), are a major cause of hypertrophic cardiomyopathy (HCM). While most mutations encode premature stop codons, missense mutations causing single amino acid substitutions are also common. Here we investigated effects of a single proline for alanine substitution at amino acid 31 (A31P) in the C0 domain of cMyBP-C, which was identified as a natural cause of HCM in cats. Results using recombinant proteins showed that the mutation disrupted C0 structure, altered sensitivity to trypsin digestion, and reduced recognition by an antibody that preferentially recognizes N-terminal domains of cMyBP-C. Western blots detecting A31P cMyBP-C in myocardium of cats heterozygous for the mutation showed a reduced amount of A31P mutant protein relative to wild-type cMyBP-C, but the total amount of cMyBP-C was not different in myocardium from cats with or without the A31P mutation indicating altered rates of synthesis/degradation of A31P cMyBP-C. Also, the mutant A31P cMyBP-C was properly localized in cardiac sarcomeres. These results indicate that reduced protein expression (haploinsufficiency) cannot account for effects of the A31P cMyBP-C mutation and instead suggest that the A31P mutation causes HCM through a poison polypeptide mechanism that disrupts cMyBP-C or myocyte function. PMID:26777460

  13. Optical hyperpolarization and inductive readout of 31P donor nuclei in natural abundance single crystal 29Si

    NASA Astrophysics Data System (ADS)

    Alexander, Thomas; Haas, Holger; Deshpande, Rahul; Gumann, Patryk; Cory, David

    2016-05-01

    We optically polarize and inductively detect 31P donor nuclei in single crystal silicon at high magnetic fields (6 . 7T). Samples include both natural abundance 29Si and an isotopically purified 28Si sample. We observe dipolar order in the 29Si nuclear spins through a spin-locking measurement. This provides a means of characterizing spin transport in the vicinity of the 31P donors.

  14. Heteronuclear 19F-1H statistical total correlation spectroscopy as a tool in drug metabolism: study of flucloxacillin biotransformation.

    PubMed

    Keun, Hector C; Athersuch, Toby J; Beckonert, Olaf; Wang, Yulan; Saric, Jasmina; Shockcor, John P; Lindon, John C; Wilson, Ian D; Holmes, Elaine; Nicholson, Jeremy K

    2008-02-15

    We present a novel application of the heteronuclear statistical total correlation spectroscopy (HET-STOCSY) approach utilizing statistical correlation between one-dimensional 19F/1H NMR spectroscopic data sets collected in parallel to study drug metabolism. Parallel one-dimensional (1D) 800 MHz 1H and 753 MHz 19F{1H} spectra (n = 21) were obtained on urine samples collected from volunteers (n = 6) at various intervals up to 24 h after oral dosing with 500 mg of flucloxacillin. A variety of statistical relationships between and within the spectroscopic datasets were explored without significant loss of the typically high 1D spectral resolution, generating 1H-1H STOCSY plots, and novel 19F-1H HET-STOCSY, 19F-19F STOCSY, and 19F-edited 1H-1H STOCSY (X-STOCSY) spectroscopic maps, with a resolution of approximately 0.8 Hz/pt for both nuclei. The efficient statistical editing provided by these methods readily allowed the collection of drug metabolic data and assisted structure elucidation. This approach is of general applicability for studying the metabolism of other fluorine-containing drugs, including important anticancer agents such as 5-fluorouracil and flutamide, and is extendable to any drug metabolism study where there is a spin-active X-nucleus (e.g., 13C, 15N, 31P) label present. PMID:18211034

  15. Dynamic stereochemistry of erigeroside by measurement of 1H- 1H and 13C- 1H coupling constants

    NASA Astrophysics Data System (ADS)

    Tafazzoli, Mohsen; Ghiasi, Mina; Moridi, Mahdi

    2008-07-01

    Erigeroside was extracted from Satureja khuzistanica Jamzad (Marzeh Khuzistani in Persian, family of lamiaceae), and 1H, 13C, 13C{ 1H}, 1H- 1H COSY, HMQC and J-HMBC were obtained to identify this compound and determine a complete set of J-coupling constants ( 1JC-H, 2JC-H, 3JC-H and 3JH-H) values within the exocyclic hydroxymethyl group (CH 2OH) and anomeric center. In parallel, density functional theory (DFT) using B3LYP functional and split-valance 6-311++G** basis set has been used to optimized the structures and conformers of erigeroside. In all calculations solvent effects were considered using a polarized continuum (overlapping spheres) model (PCM). The dependencies of 1J, 2J and 3J involving 1H and 13C on the C 5'-C 6' ( ω), C 6'-O 6' ( θ) and C 1'-O 1' ( φ) torsion angles in erigeroside were computed using DFT method. Complete hyper surfaces for 1JC1',H1', 2JC5',H6'R, 2JC5',H6'S, 2JC6',H5', 3JC4',H6'R, 3JC4',H6'S and 2JH6'R-H5'S as well as 3JH5',H6'R were obtained and used to derive Karplus equations to correlate these couplings to ω, θ and φ. These calculated J-couplings are in agreement with experimental values. These results confirm the reliability of DFT calculated coupling constants in aqueous solution.

  16. 31P NMR Study of Filled Skutterudite CeOs4P12

    NASA Astrophysics Data System (ADS)

    Magishi, K.; Sugawara, H.; Saito, T.; Koyama, K.

    2012-12-01

    We report the results of the electrical resistivity ρ(T) and the 31P-NMR measurements on filled skutterudite CeOs4P12 in order to investigate the magnetic properties at low temperatures from a microscopic point of view. For the polycrystalline sample synthesized under high pressure (HP), ρ(T) increases with decreasing temperature. On the other hand, for the single crystal (SC), ρ(T) reveals a positive temperature dependence between room temperature and 200 K, and increases with decreasing temperature below 200 K. Also, 1/T1 obeys the activated temperature dependence 1/T1 propto exp(-Δ/kBT) above 160 K with an energy gap Δ/fB ~ 500 K and 540 K for the HP and the SC samples, which are slightly larger than that of a previous report.

  17. sup 31 P saturation transfer and phosphocreatine imaging in the monkey brain

    SciTech Connect

    Mora, B.; Narasimhan, P.T.; Ross, B.D. California Inst. of Tech., Pasadena ); Allman, J. ); Barker, P.B. )

    1991-10-01

    {sup 31}P magnetic resonance imaging with chemical-shift discrimination by selective excitation has been employed to determine the phosphocreatine (PCr) distribution in the brains of three juvenile macaque monkeys. PCr images were also obtained while saturating the resonance of the {gamma}-phosphate of ATP, which allowed the investigation of the chemical exchange between PCr and the {gamma}-phosphate of ATP catalyzed by creatine kinase. Superposition of the PCr images over the proton image of the same monkey brain revealed topological variations in the distribution of PCr and creatine kinase activity. PCr images were also obtained with and without visual stimulation. In two out of four experiments, an apparently localized decrease in PCr concentration was noted in visual cortex upon visual stimulation. This result is interpreted in terms of a possible role for the local ADP concentration in stimulating the accompanying metabolic response.

  18. Decomposition of adsorbed VX on activated carbons studied by {sup 31}P MAS NMR

    SciTech Connect

    Ishay Columbus; Daniel Waysbort; Liora Shmueli; Ido Nir; Doron Kaplan

    2006-06-15

    The fate of the persistent OP nerve agent O-ethyl S-(2-(diisopropylamino)ethyl) methylphosphonothioate (VX) on granular activated carbons that are used for gas filtration was studied by means of 31P magic angle spinning (MAS) NMR spectroscopy. Four types of activated carbon were used, including coal-based BPL. VX as vapor or liquid was adsorbed on carbon granules, and MAS NMR spectra were recorded periodically. The results show that at least 90% of the adsorbed VX decomposes within 20 days or less to the nontoxic ethyl methylphosphonic acid (EMPA) and bis(S-2-diisopropylaminoethane) ((DES){sub 2}). Decomposition occurred irrespective of the phase from which VX was loaded, the presence of metal impregnation on the carbon surface, and the water content of the carbon. Theoretical and practical aspects of the degradation are discussed. 17 refs., 6 figs., 3 tabs.

  19. Decomposition of adsorbed VX on activated carbons studied by 31P MAS NMR.

    PubMed

    Columbus, Ishay; Waysbort, Daniel; Shmueli, Liora; Nir, Ido; Kaplan, Doron

    2006-06-15

    The fate of the persistent OP nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) on granular activated carbons that are used for gas filtration was studied by means of 31P magic angle spinning (MAS) NMR spectroscopy. VX as vapor or liquid was adsorbed on carbon granules, and MAS NMR spectra were recorded periodically. The results show that at least 90% of the adsorbed VX decomposes within 20 days or less to the nontoxic ethyl methylphosphonic acid (EMPA) and bis(S-2-diisopropylaminoethane) {(DES)2}. Decomposition occurred irrespective of the phase from which VX was loaded, the presence of metal impregnation on the carbon surface, and the water content of the carbon. Theoretical and practical aspects of the degradation are discussed. PMID:16830567

  20. Detoxification of organophosphorus pesticides and nerve agents through RSDL: efficacy evaluation by (31)P NMR spectroscopy.

    PubMed

    Elsinghorst, Paul W; Worek, Franz; Koller, Marianne

    2015-03-01

    Intoxication by organophosphorus compounds, especially by pesticides, poses a considerable risk to the affected individual. Countermeasures involve both medical intervention by means of antidotes as well as external decontamination to reduce the risk of dermal absorption. One of the few decontamination options available is Reactive Skin Decontamination Lotion (RSDL), which was originally developed for military use. Here, we present a (31)P NMR spectroscopy based methodology to evaluate the detoxification efficacy of RSDL with respect to a series of organophosphorus pesticides and nerve agents. Kinetic analysis of the obtained NMR data provided degradation half-lives proving that RSDL is also reasonably effective against organophosphorus pesticides. Unexpected observations of different RSDL degradation patterns are presented in view of its reported oximate-catalyzed mechanism of action. PMID:25597861

  1. 31P magnetization transfer measurements of Pi→ATP flux in exercising human muscle

    PubMed Central

    Savage, David B.; Williams, Guy B.; Porter, David; Carpenter, T. Adrian; Brindle, Kevin M.; Kemp, Graham J.

    2016-01-01

    Fundamental criticisms have been made over the use of 31P magnetic resonance spectroscopy (MRS) magnetization transfer estimates of inorganic phosphate (Pi)→ATP flux (VPi-ATP) in human resting skeletal muscle for assessing mitochondrial function. Although the discrepancy in the magnitude of VPi-ATP is now acknowledged, little is known about its metabolic determinants. Here we use a novel protocol to measure VPi-ATP in human exercising muscle for the first time. Steady-state VPi-ATP was measured at rest and over a range of exercise intensities and compared with suprabasal oxidative ATP synthesis rates estimated from the initial rates of postexercise phosphocreatine resynthesis (VATP). We define a surplus Pi→ATP flux as the difference between VPi-ATP and VATP. The coupled reactions catalyzed by the glycolytic enzymes GAPDH and phosphoglycerate kinase (PGK) have been shown to catalyze measurable exchange between ATP and Pi in some systems and have been suggested to be responsible for this surplus flux. Surplus VPi-ATP did not change between rest and exercise, even though the concentrations of Pi and ADP, which are substrates for GAPDH and PGK, respectively, increased as expected. However, involvement of these enzymes is suggested by correlations between absolute and surplus Pi→ATP flux, both at rest and during exercise, and the intensity of the phosphomonoester peak in the 31P NMR spectrum. This peak includes contributions from sugar phosphates in the glycolytic pathway, and changes in its intensity may indicate changes in downstream glycolytic intermediates, including 3-phosphoglycerate, which has been shown to influence the exchange between ATP and Pi catalyzed by GAPDH and PGK. PMID:26744504

  2. Physiologic significance of the phosphorylation potential in isolated perfused rat hearts (31-P NMR)

    SciTech Connect

    Watters, T.; Wikman-Coffelt, J.; Wu, S.; Wendland, M.; James, T.; Sievers, R.; Botvinick, E.; Parmley, W.

    1986-03-05

    The authors assessed the metabolic and mechanical effects of changes in coronary perfusion pressure (CPP) and afterload (A) in isolated working apex-ejecting rat hearts perfused with Krebs-Henseleit solution containing an excess of O/sub 2/ and substrate. Log (phosphorylation potential) or log (ATP)/(ADP)x (Pi), designated (L), and log (PCR)/(Pi), designated (L*), were calculated from HPLC measurements after rapid freeze-clamping. Increasing CPP from 80-140 cm H/sub 2/O caused an increase in coronary flow (flow), developed pressure (DevP), O/sub 2/ consumption (VO/sub 2/), L, L*, and CO. L and L* were directly related to VO/sub 2/ and CO. Increasing A from 80-140 cm H/sub 2/O caused an increase in DevP and VO/sub 2/, but a decrease in L, L*, and CO. L and L* were inversely linearly related to VO/sub 2/ but were directly linearly related to CO. In both experiments, L and L* are directly related to CO, suggesting that determination of L* (which can be done with 31-P NMR spectroscopy) may be a useful non-invasive method for determining cardiac pump function curves. L and L* may be related to the Frank-Starling mechanism. In a separate experiment using 31-P NMR spectroscopy of isovolumic (left ventricular balloon) perfused rat hearts, increasing CPP caused a direct linear increase in flow, DevP, and L*, confirming the L* results reported above with CPP experiments using the rapid freeze-clamp technique.

  3. Physiologic significance of the phosphorylation potential in isolated perfused rat hearts (/sup 31/P NMR)

    SciTech Connect

    Watters, T.; Wikman-Coffelt, J.; Wu, S.; Wendland, M.; James, T.; Sievers, R.; Botvinick, E.; Parmley, W.

    1986-03-05

    The authors assessed the metabolic and mechanical effects of changes in coronary perfusion pressure (CPP) and afterload (A) in isolated working apex-ejecting rat hearts perfused with Krebs-Henseleit solution containing an excess of O/sub 2/ and substrate. Log(phosphorylation potential) or log (ATP)/(ADP)x (Pi), designated (L), and log (PCR)/(Pi), designated (L*), were calculated from HPLC measurements after rapid freeze-clamping. Increasing CPP from 80-140 cm H/sub 2/O caused an increase in coronary flow(flow), developed pressure(DevP), O/sub 2/ consumption (VO/sub 2/), L, L*, and CO. L and L* were directly related to VO/sub 2/ and CO. Increasing A from 80-140 cm H/sub 2/O caused an increase in DevP and VO/sub 2/, but a decrease in L, L*, and CO. L and L* were inversely linearly related to VO/sub 2/ but were directly linearly related to CO. In both experiments, L and L* are directly related to CO, suggesting that determination of L* (which can be done with /sup 31/P NMR spectroscopy) may be a useful non-invasive method for determining cardiac pump function curves. L and L* may be related to the Frank-Starling mechanism. In a separate experiment using /sup 31/P NMR spectroscopy of isovolumic (left ventricular balloon) perfused rat hearts, increasing CPP caused a direct linear increase in flow, DevP, and L*, confirming the L* results reported above with CPP experiments using the rapid freeze-clamp technique.

  4. Abnormal skeletal muscle oxidative capacity after lung transplantation by 31P-MRS.

    PubMed

    Evans, A B; Al-Himyary, A J; Hrovat, M I; Pappagianopoulos, P; Wain, J C; Ginns, L C; Systrom, D M

    1997-02-01

    Although lung transplantation improves exercise capacity by removal of a ventilatory limitation, recipients' postoperative maximum oxygen uptake (VO2max) remains markedly abnormal. To determine if abnormal skeletal muscle oxidative capacity contributes to this impaired aerobic capacity, nine lung transplant recipients and eight healthy volunteers performed incremental quadriceps exercise to exhaustion with simultaneous measurements of pulmonary gas exchange, minute ventilation, blood lactate, and quadriceps muscle pH and phosphorylation potential by 31P-magnetic resonance spectroscopy (31P-MRS). Five to 38 mo after lung transplantation, peak VO2 was decreased compared with that of normal control subjects (6.7 +/- 0.4 versus 12.3 +/- 1.0 ml/min/kg, p < 0.001), even after accounting for differences in age and lean body weight. Neither ventilation, arterial O2 saturation nor mild anemia could account for the decrease in aerobic capacity. Quadriceps muscle intracellular pH (pH(i)) was more acidic at rest (7.07 +/- 0.01 versus 7.12 +/- 0.01 units, p < 0.05) and fell during exercise from baseline values at a lower metabolic rate (282 +/- 21 versus 577 +/- 52 ml/min, p < 0.001). Regressions for pH(i) versus VO2, phosphocreatine/inorganic phosphate ratio (PCr/Pi) versus VO2, and blood lactate versus pH(i) were not different. Among transplant recipients, the metabolic rate at which pH(i) fell correlated closely with VO2max (r = 0.87, p < 0.01). The persistent decrease in VO2max after lung transplantation may be related to abnormalities of skeletal muscle oxidative capacity. PMID:9032203

  5. Composition of phosphorus in wetland soils determined by SMT and solution 31P-NMR analyses.

    PubMed

    Zhang, Wenqiang; Jin, Xin; Ding, Yuekui; Zhu, Xiaolei; Rong, Nan; Li, Jie; Shan, Baoqing

    2016-05-01

    In Eastern China, wetlands are common in the lower reaches of catchments or in coastal zones. Wetlands are at risk from eutrophication because of the large quantities of phosphorus (P) they receive from rivers. They are also decreasing in size. In this contribution, we present information about the composition of P in wetland soils, obtained using the Standards, Measurements, and Testing (SMT) protocol and (31)P-nuclear magnetic resonance (NMR) spectroscopy. Average P concentrations varied in the different wetland soils and, in four of the five wetlands sampled, exceeded 500 mg∙kg(-1). HCl-inorganic P (Pi) was the main Pi fraction in wetland soils. The percentage contribution of Pi (89.7 %) to total P was the highest in the Yangtze River estuary wetland. Six P components were detected by (31)P-NMR analysis. Mono-P was the main organic P (Po) in wetland soils. Orthophosphate (Ortho-P) was positively and negatively related to NaOH-Pi (R (2) = 0.957, p < 0.001) and HCl-Pi (R (2) = -0.689, p < 0.001), respectively. Orthophosphate monoesters (Mono-P) were positively related to Po (R (2) = 0.617, p < 0.001) and ortho-P (R (2) = 0.624, p < 0.001), respectively. The main Po component was Mono-P, and it may be mineralized to ortho-P under the frequently changing redox conditions in wetland soils. The information from this study will support the development of robust scientific and effective policy for P management in wetlands. PMID:26832861

  6. 77Se NMR Investigation of the KxFe2−ySe2 high-Tc Superconductor (Tc = 33 K)

    SciTech Connect

    Petrovic, C.; Torchetti, D.A. Fu, M.; Christensen, D.C.; Nelson, K.J.; Imai, T.; Lei, H.C.

    2011-03-18

    We report comprehensive {sup 77}Se NMR measurements on a single crystalline sample of the recently discovered FeSe-based high-temperature superconductor K{sub x}Fe{sub 2-y}Se{sub 2} (T{sub c} = 33 K) in a broad temperature range up to 290 K. Despite deviations from the stoichiometric KFe{sub 2}Se{sub 2} composition, we observed {sup 77}Se NMR line shapes as narrow as 4.5 kHz under a magnetic field applied along the crystal c axis, and found no evidence for co-existence of magnetic order with superconductivity. On the other hand, the {sup 77}Se NMR line shape splits into two peaks with equal intensities at all temperatures when we apply the magnetic field along the ab plane. This suggests that K vacancies may have a superstructure and that the local symmetry of the Se sites is lower than the tetragonal fourfold symmetry of the average structure. This effect might be a prerequisite for stabilizing the s{sub {+-}} symmetry of superconductivity in the absence of the hole bands at the Brillouin zone center. From the increase of NMR linewidth below T{sub c} induced by the Abrikosov lattice of superconducting vortices, we estimate the in-plane penetration depth {lambda}{sub ab} {approx} 290 nm and the carrier concentration n{sub e} {approx} 1 x 10{sup +21} cm{sup -3}. Our Knight shift {sup 77}K data indicate that the uniform spin susceptibility decreases progressively with temperature, in analogy with the case of FeSe (T{sub c} {approx} 9 K) as well as other FeAs high-T{sub c} systems. The strong suppression of {sup 77}K observed immediately below T{sub c} for all crystal orientations is consistent with a singlet pairing of Cooper pairs. We do not however observe the Hebel-Slichter coherence peak of the nuclear spin-lattice relaxation rate 1/T1 immediately below T{sub c}, expected for conventional BCS s-wave superconductors. In contrast with the case of FeSe, we do not observe evidence for an enhancement of low-frequency antiferromagnetic spin fluctuations near T{sub c

  7. Metabolic engineering applications of in vivo sup 31 P and sup 13 C NMR studies of Saccharomyces cerevisiae

    SciTech Connect

    Shanks, J.V.

    1989-01-01

    With intent to quantify NMR measurements as much as possible, analysis techniques of the in vivo {sup 31}P NMR spectrum are developed. A systematic procedure is formulated for estimating the relative intracellular concentrations of the sugar phosphates in S. cerevisiae from the {sup 31}P NMR spectrum. In addition, in vivo correlation of inorganic phosphate chemical shift with the chemical shifts of 3-phosphoglycerate, {beta}-fructose 1,6-diphosphate, fructose 6-phosphate, and glucose 6-phosphate are determined. Also, a method was developed for elucidation of the cytoplasmic and vacuolar components of inorganic phosphate in the {sup 31}P NMR spectrum of S. cerevisiae. An in vivo correlation relating the inorganic phosphate chemical shift of the vacuole with the chemical shift of the resonance for pyrophosphate and the terminal phosphate of polyphosphate (PP{sub 1}) is established. Transient measurements provided by {sup 31}P NMR are applied to reg1 mutant and standard strains. {sup 31}P and {sup 13}C NMR measurements are used to analyze the performance of recombinant strains in which the glucose phosphorylation step had been altered.

  8. Enhanced Y1H Assays for Arabidopis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcription regulation plays a key role in development and response to environment. To understand this mechanism, we need to know which transcription factor (TFs) would bind to which promoter, thus regulate their target gene expression. Yeast one-hybrid (Y1H) technique can be used to map this kind...

  9. Contraction and recovery of living muscles studied by 31p nuclear magnetic resonance

    PubMed Central

    Gadian, D. G.; Dawson, M. Joan; Wilkie, D. R.

    1977-01-01

    1. Phosphorus nuclear magnetic resonance (31P NMR) can be used to measure the concentrations of phosphorus-containing metabolites within living tissue. We have developed methods for maintaining muscles in physiological condition, stimulating them and recording tension while at the same time accumulating their 31P NMR spectra. Experiments were performed on frog sartorii and frog and toad gastrocnemii at 4° C. 2. The NMR signals from 31P (the naturally occurring phosphorus) is weak, and signal averaging is required. In order to follow the time course of reactions it is necessary to maintain the muscles in a steady state for many hours while they are undergoing repeated contractions. Signals were accumulated in separate computer bins according to time after initiation of contraction. By these means spectra were obtained which corresponded to the different intervals during the contraction and recovery cycle. 3. In the absence of stimulation, the spectra of frog sartorius muscles and of their extracts indicated concentrations of adenosine triphosphate (ATP), phosphoryl creatine (PCr), inorganic orthophosphate (Pi) and sugar phosphates (sugar P) which are in reasonable agreement with the values obtained by chemical analysis. 4. We have confirmed that unidentified resonances representing unknown compounds appear in the spectra of both frog and toad muscle; one of these is much larger in spectra from toad than from frog. We have found an additional small, unidentified resonance which appears to be specific to toad muscle. 5. Spectra accumulated during actual contractions (1 s tetani every 2 min) did not differ dramatically from those accumulated throughout the 2 min cycle of contraction and partial recovery. 6. Following 25 s tetanii, approximately 20% of the PCr had been hydrolysed; it was then rebuilt exponentially with a half-time of about 10 min. The increase in [Pi] immediately after contraction and the time course of its disappearance corresponded to the changes in

  10. {sup 31}P NMR analysis of coal moieties bearing -OH, -NH, and -SH functions. Final technical report

    SciTech Connect

    Verkade, J.G.

    1991-08-31

    NMR reagents for the speciation and quantitation of labile-hydrogen functional groups and sulfur groups in coal ligands have been synthesized and evaluated. These reagents, which contain the NMR-active nuclei {sup 31}p, {sup 119}Sn or {sup 195}pt, were designed to possess improved chemical shift resolution over reagents reported in the literature. Our efforts were successful in the case of the new {sup 31}p and {sup 119}Sn reagents we developed, but the {sup 195}pt work on sulfur groups was only partially successful in as much as the grant came to a close and was not renewed. Our success with {sup 31}P and {sup 119}Sn NMR reagents came to the attention of Amoco and they have recently expressed interest in further supporting that work. A further measure of the success of our efforts can be seen in the nine publications supported by this grant which are cited in the reference list.

  11. On Neglecting Chemical Exchange Effects When Correcting in Vivo 31P MRS Data for Partial Saturation

    NASA Astrophysics Data System (ADS)

    Ouwerkerk, Ronald; Bottomley, Paul A.

    2001-02-01

    Signal acquisition in most MRS experiments requires a correction for partial saturation that is commonly based on a single exponential model for T1 that ignores effects of chemical exchange. We evaluated the errors in 31P MRS measurements introduced by this approximation in two-, three-, and four-site chemical exchange models under a range of flip-angles and pulse sequence repetition times (TR) that provide near-optimum signal-to-noise ratio (SNR). In two-site exchange, such as the creatine-kinase reaction involving phosphocreatine (PCr) and γ-ATP in human skeletal and cardiac muscle, errors in saturation factors were determined for the progressive saturation method and the dual-angle method of measuring T1. The analysis shows that these errors are negligible for the progressive saturation method if the observed T1 is derived from a three-parameter fit of the data. When T1 is measured with the dual-angle method, errors in saturation factors are less than 5% for all conceivable values of the chemical exchange rate and flip-angles that deliver useful SNR per unit time over the range T1/5 ≤ TR ≤ 2T1. Errors are also less than 5% for three- and four-site exchange when TR ≥ T1*/2, the so-called "intrinsic" T1's of the metabolites. The effect of changing metabolite concentrations and chemical exchange rates on observed T1's and saturation corrections was also examined with a three-site chemical exchange model involving ATP, PCr, and inorganic phosphate in skeletal muscle undergoing up to 95% PCr depletion. Although the observed T1's were dependent on metabolite concentrations, errors in saturation corrections for TR = 2 s could be kept within 5% for all exchanging metabolites using a simple interpolation of two dual-angle T1 measurements performed at the start and end of the experiment. Thus, the single-exponential model appears to be reasonably accurate for correcting 31P MRS data for partial saturation in the presence of chemical exchange. Even in systems where

  12. A 13C{31P} REDOR NMR Investigation of the Role of Glutamic Acid Residues in Statherin-Hydroxyapatite Recognition

    PubMed Central

    Ndao, Moise; Ash, Jason T.; Breen, Nicholas F.; Goobes, Gil; Stayton, Patrick S.; Drobny, Gary P.

    2011-01-01

    The side chain carboxyl groups of acidic proteins found in the extra-cellular matrix (ECM) of mineralized tissues play a key role in promoting or inhibiting the growth of minerals such as hydroxyapatite (HAP), the principal mineral component of bone and teeth. Among the acidic proteins found in the saliva is statherin, a 43-residue tyrosine-rich peptide that is a potent lubricant in the salivary pellicle and an inhibitor of both HAP crystal nucleation and growth. Three acidic amino acids – D1, E4, and E5 – are located in the N-terminal 15 amino acid segment, with a fourth amino acid, E26, located outside the N-terminus. We have utilized 13C{31P} REDOR NMR to analyze the role played by acidic amino acids in the binding mechanism of statherin to the HAP surface by measuring the distance between the δ-carboxyl 13C spins of the three glutamic acid side chains of statherin (residues E4, E5, E26) and 31P spins of the phosphate groups at the HAP surface. 13C{31P} REDOR studies of glutamic-5-13C acid incorporated at positions E4 and E26 indicate a 13C–31P distance of more than 6.5 Å between the side chain carboxyl 13C spin of E4 and the closest 31P in the HAP surface. In contrast, the carboxyl 13C spin at E5 has a much shorter 13C–31P internuclear distance of 4.25±0.09 Å, indicating that the carboxyl group of this side chain interacts directly with the surface. 13C T1ρ and slow-spinning MAS studies indicate that the motions of the side chains of E4 and E5 are more restricted than that of E26. Together, these results provide further insight into the molecular interactions of statherin with HAP surfaces. PMID:19678690

  13. Transport of phosphocholine in higher plant cells: sup 31 P nuclear magnetic resonance studies

    SciTech Connect

    Gout, E.; Bligny, R.; Roby, C.; Douce, R. )

    1990-06-01

    Phosphocholine (PC) is an abundant primary form of organic phosphate that is transported in plant xylem sap. Addition of PC to the perfusate of compressed P{sub i}-starved sycamore cells monitored by {sup 31}P NMR spectroscopy resulted in an accumulation of PC and all the other phosphate esters in the cytoplasmic compartment. Addition of hemicholinium-3, an inhibitor of choline uptake, to the perfusate inhibited PC accumulation but not inorganic phosphate (P{sub i}). When the P{sub i}-starved cells were perfused with a medium containing either P{sub i} or PC, the resulting P{sub i} distribution in the cell was the same. Addition of choline instead of PC to the perfusate of compressed cells resulted in an accumulation of PC in the cytoplasmic compartment from choline kinase activity. In addition, PC phosphatase activity has been discovered associated with the cell wall. These results indicate that PC was rapidly hydrolyzed outside the cell and that choline and P{sub i} entered the cytosolic compartment where choline kinase re-forms PC.

  14. (31)P NMR phospholipid profiling of soybean emulsion recovered from aqueous extraction.

    PubMed

    Yao, Linxing; Jung, Stephanie

    2010-04-28

    The quantity and composition of phospholipids in full-fat soybean flour, flakes, and extruded flakes and in the cream fraction recovered after aqueous extraction (AEP) and enzyme-assisted aqueous extraction (EAEP) of these substrates were studied with (31)P NMR. Extruded flakes had significantly more phosphatidic acid (PA) than flakes and flour prior to aqueous extraction. The PA content of the cream recovered after AEP and EAEP of extruded flakes was similar to that of the starting material, whereas the PA content of the creams from flour and flakes significantly increased. Changes in the PA content could be explained by the action of phospholipase D during the processing step and aqueous extraction. Total phospholipids in the oil recovered from the creams varied from 0.09 to 0.75%, and free oil yield, which is an indicator of cream stability, varied from 6 to 78%. Total phospholipid did not correlate with emulsion stability when it was lower than 0.20%. Inactivation of phospholipase D prior to aqueous extraction of flour resulted in a cream emulsion less stable toward enzymatic demulsification and containing less PA and total phospholipids than untreated flour. The phospholipid distributions in the cream, skim, and insolubles obtained from AEP flour were 7, 51, and 42%, respectively. PMID:20329795

  15. 31P NMR spectroscopy of rat organs, in situ, using chronically implanted radiofrequency coils.

    PubMed Central

    Koretsky, A P; Wang, S; Murphy-Boesch, J; Klein, M P; James, T L; Weiner, M W

    1983-01-01

    A technique for making 31P NMR spectroscopic measurements in rat kidney, heart, and liver in vivo is presented. Two-turn solenoid coils were surgically implanted around the organ sufficiently in advance of NMR experiments to allow recovery of the animal. These chronically implanted coils allowed acquisition of high-resolution spectra at 40.5 and 97.3 MHz. No resolution improvement occurred at the higher field. Spectra were stable for up to 24 hr, during which time a variety of experiments could be performed. By accumulating spectra at 10-min intervals, the effects of intraperitoneal fructose injections were monitored; in kidney and liver, a rapid increase in sugar phosphates at the expense of Pi and ATP resulted. Fructose had no effect on heart metabolite levels. Spectra from the heart in vivo were obtained at systole and diastole by gating the spectrometer to the aortic pressure wave; no differences in phosphate metabolites were detected. Finally, saturation transfer techniques were used to monitor the rate of ATP synthesis in the kidney. The unidirectional rate constant for the conversion of Pi to ATP was 0.12 +/- 0.03 sec-1. Images PMID:6584867

  16. In vivo 31P and multilabel 13C NMR measurements for evaluation of plant metabolic pathways.

    PubMed

    Rijhwani, S K; Ho, C H; Shanks, J V

    1999-01-01

    Reliable measurements of intracellular metabolites are useful for effective plant metabolic engineering. This study explored the application of in situ 31P and 13C NMR spectroscopy for long-term measurements of intracellular pH and concentrations of several metabolites in glycolysis, glucan synthesis, and central carbon metabolic pathways in plant tissues. An NMR perfusion reactor system was designed to allow Catharanthus roseus hairy root cultures to grow for 3-6 weeks, during which time NMR spectroscopy was performed. Constant cytoplasmic pH (7.40+/-0.06), observed during the entire experiment, indicated adequate oxygenation. 13C NMR spectroscopy was performed on hairy root cultures grown in solutions containing 1-13C-, 2-13C-, and 3-13C-labeled glucose in separate experiments and the flow of label was monitored. Activities of pentose phosphate pathways, nonphotosynthetic CO2 fixation, and glucan synthesis pathways were evident from the experimental results. Scrambling of label in glucans also indicated recycling of triose phosphate and their subsequent conversion to hexose phosphates. PMID:10935751

  17. 31P-nuclear magnetic resonance studies of chronic myocardial ischemia in the Yucatan micropig.

    PubMed

    Rath, D P; Bailey, M; Zhang, H; Jiang, Z; Abduljalil, A M; Weisbrode, S; Hamlin, R L; Robitaille, P M

    1995-01-01

    In this work, an x-irradiation/high fat/high cholesterol diet-induced atherogenic model was invoked to examine the effects of severe diffuse atherosclerosis on myocardial metabolism in the in vivo porcine heart. This model was studied using spatially localized 31P-nuclear magnetic resonance (NMR) to monitor pH and the levels of inorganic phosphate, phosphomonoesters, creatine phosphate, and adenosine triphosphate as a function of workload transmurally in control swine and in animals suffering from chronic ischemic heart disease. These preliminary studies revealed that the development of severe atherosclerosis and the accompanying chronically diseased state produce changes in high energy phosphates and that increases in rate pressure products result in demonstrable signs of ischemia in the myocardium which span the entire left ventricular wall. Ischemic changes include a global increase in inorganic phosphate and corresponding decreases in creatine phosphate, ATP, and pH. Importantly, changes in intracellular pH are noted with even the slightest increase in workload suggesting that these diseased hearts display elevated glycolytic activity. By challenging these animals with increased cardiac workload, we directly visualize how the chronically compromised heart responds to severe oxygen challenges in a clinically relevant model of this situation. PMID:7814609

  18. 31P-nuclear magnetic resonance studies of chronic myocardial ischemia in the Yucatan micropig.

    PubMed Central

    Rath, D P; Bailey, M; Zhang, H; Jiang, Z; Abduljalil, A M; Weisbrode, S; Hamlin, R L; Robitaille, P M

    1995-01-01

    In this work, an x-irradiation/high fat/high cholesterol diet-induced atherogenic model was invoked to examine the effects of severe diffuse atherosclerosis on myocardial metabolism in the in vivo porcine heart. This model was studied using spatially localized 31P-nuclear magnetic resonance (NMR) to monitor pH and the levels of inorganic phosphate, phosphomonoesters, creatine phosphate, and adenosine triphosphate as a function of workload transmurally in control swine and in animals suffering from chronic ischemic heart disease. These preliminary studies revealed that the development of severe atherosclerosis and the accompanying chronically diseased state produce changes in high energy phosphates and that increases in rate pressure products result in demonstrable signs of ischemia in the myocardium which span the entire left ventricular wall. Ischemic changes include a global increase in inorganic phosphate and corresponding decreases in creatine phosphate, ATP, and pH. Importantly, changes in intracellular pH are noted with even the slightest increase in workload suggesting that these diseased hearts display elevated glycolytic activity. By challenging these animals with increased cardiac workload, we directly visualize how the chronically compromised heart responds to severe oxygen challenges in a clinically relevant model of this situation. Images PMID:7814609

  19. Modified Prony Method to Resolve and Quantify in Vivo31P NMR Spectra of Tumors

    NASA Astrophysics Data System (ADS)

    Barone, P.; Guidoni, L.; Ragona, R.; Viti, V.; Furman, E.; Degani, H.

    Prony's method, successfully used in processing NMR signals, performs poorly at low signal-to-noise ratios. To overcome this problem, a statistical approach has been adopted by using Prony's method as a sampling device from the distribution associated with the true spectrum. Specifically, Prony's method is applied for each regression order p and number of data points n, both considered in a suitable range, and the estimates of frequencies, amplitudes, and decay factors are pooled separately. A histogram of the pooled frequencies is computed and, looking at the histogram, a lower and an upper frequency bound for each line of interest is determined. All frequency estimates in each of the determined intervals as well as associated decay factors and amplitudes are considered to be independent normal variates. A mean value and a corresponding 95% confidence interval are computed for each parameter. 31P NMR signals from MCF7 human breast cancer cells, inoculated into athymic mice and which developed into tumors, have been processed with traditional methods and with this modified Prony's method. The main components of the phosphomonoester peak, namely those deriving from phosphorylcholine and phosphorylethanolamine, are always well resolved with this new approach and their relative amplitudes can be consequently evaluated. Peak intensities of these two signals show different behavior during treatment of tumors with the antiestrogenic drug tamoxifen. The results of this new approach are compared with those obtainable with traditional techniques.

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

    NASA Astrophysics Data System (ADS)

    Szumera, Magdalena

    2015-02-01

    Glasses have been synthesized in the system P2O5sbnd SiO2sbnd K2Osbnd MgOsbnd CaO modified by addition of MoO3. Glasses were prepared by conventional fusion method from 40 g batches. The influence of Mo-cations on the analysed glass structure was investigated by means of Raman and 31P MAS-NMR techniques. It has been found that molybdate units can form Mo[MoO4/MoO6]sbnd Osbnd P and/or Mo[MoO4/MoO6]sbnd Osbnd Si bonds with non-bridging oxygens atoms of Q2 methaphosphate units, resulting in the transformation of chain methaphosphate structure into pyrophosphate and finally into orthophosphate structure. It has been also found that increasing amount of MoO3 in the structure of investigated glasses causes their gradual depolymerization and molybdenum ions in the analysed glass matrix act as modifying cations.

  1. 31P-NMR studies of isolated adult heart cells: effect of myoglobin inactivation.

    PubMed

    Gupta, R K; Wittenberg, B A

    1991-10-01

    31P nuclear magnetic resonance (NMR) studies of isolated adult rat heart cells revealed that the cells maintained high-energy phosphates for up to 6 h in polyamide hollow fibers perfused with well-oxygenated nutrient medium. Glucose plus pyruvate superfused heart cells maintained [phosphocreatine]/[ATP] at 1.4 +/- 0.1, internal pH at 7.09 +/- 0.04 (external pH = 7.25), and intracellular free Mg2+ at 0.51 +/- 0.04 mM. In glucose-containing media, hypoxia was accompanied by a reversible decrease in intracellular ATP and phosphocreatine of approximately 50% and 80%, respectively, while the intracellular free Mg2+ was reversibly increased by 40%. However, inhibition of glycolysis by iodoacetate in aerobic pyruvate-containing medium did not significantly alter high-energy phosphate content. Inactivation of intracellular myoglobin with 1-2 mM sodium nitrite, which reduces the steady-state respiratory oxygen consumption rate by 30%, caused a significant (30%) decrease in intracellular phosphocreatine peak, which was reversed upon removal of sodium nitrite. The nitrite-induced decrease in phosphocreatine was also observed in iodoacetate-treated myocytes but not in oligomycin-treated cells. These results indicate that functional myoglobin enhances high-energy phosphate synthesis in well-oxygenated myocytes. PMID:1928397

  2. 31P magnetic resonance phospholipid profiles of neoplastic human breast tissues.

    PubMed Central

    Merchant, T. E.; Meneses, P.; Gierke, L. W.; Den Otter, W.; Glonek, T.

    1991-01-01

    Phospholipids from malignant, benign and noninvolved human breast tissues were extracted by chloroform-methanol (2:1) and analysed by 31P MR spectroscopy at 202.4 MHz. Thirteen phospholipids were identified as constituents of the profiles obtained among the 55 tissue specimens analysed. Observed patterns in phospholipid tissues profiles were distinct, allowing qualitative characterisation of the three tissue groups. Multivariate analysis of lysophosphatidylcholine (LPC) and an uncharacterised phospholipid were shown to be independently significant in predicting benign tissue histology as either fibrocystic disease or fibroadenoma in 92% of cases. Univariate analysis of relative mole-percentage of phosphorus concentrations of individual phospholipids using the Scheffé comparison procedure revealed that in malignant tissues, phosphatidylethanolamine was significantly elevated compared to benign (+ 32%) and noninvolved tissues (+ 22%). Phosphatidylinositol (+ 33%) and phosphatidylcholine plasmalogen (PC plas) (+ 25%) were increased in malignant compared to benign and LPC was decreased (-44%) in malignant compared to noninvolved. LPC was significantly depressed (-39%) in benign tissue compared to normal. Phospholipid indices computed to further characterise the three tissue groups showed PC plas/PC elevated in malignant tissue compared to benign and PE plas/PE depressed in malignant tissue compared to noninvolved. These findings support previous investigations reporting that the alkyl-phospholipid analogues of phosphatidylcholine are released by malignant tissues and that levels of ethanolamine are elevated in malignant tissues. Indices describing the choline-containing phospholipids showed that these lipids are depressed significantly in malignant tissue relative to healthy tissue. PMID:2039694

  3. Intermolecular (119)Sn,(31)P Through-Space Spin-Spin Coupling in a Solid Bivalent Tin Phosphido Complex.

    PubMed

    Arras, Janet; Eichele, Klaus; Maryasin, Boris; Schubert, Hartmut; Ochsenfeld, Christian; Wesemann, Lars

    2016-05-01

    A bivalent tin complex [Sn(NP)2] (NP = [(2-Me2NC6H4)P(C6H5)](-)) was prepared and characterized by X-ray diffraction and solution and solid-state nuclear magnetic resonance (NMR) spectroscopy. In agreement with the X-ray structures of two polymorphs of the molecule, (31)P and (119)Sn CP/MAS NMR spectra revealed one crystallographic phosphorus and tin site with through-bond (1)J((117/119)Sn,(31)P) and through-space (TS)J((117/119)Sn,(31)P) spin-spin couplings. Density functional theory (DFT) calculations of the NMR parameters confirm the experimental data. The observation of through-space (TS)J((117/119)Sn,(31)P) couplings was unexpected, as the distances of the phosphorus atoms of one molecule and the tin atom of the neighboring molecule (>4.6 Å) are outside the sum of the van der Waals radii of the atoms P and Sn (4.32 Å). The intermolecular Sn···P separations are clearly too large for bonding interactions, as supported by a natural bond orbital (NBO) analysis. PMID:27071033

  4. Nuclear Spin Polarization of Phosphorus Donors in Silicon. Direct Evidence from 31P-Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Gumann, Patryk; Ramanathan, Chandrasekhar; Patange, Om; Moussa, Osama; Thewalt, Mike; Riemann, Helge; Abrosimov, Nikolay; Becker, Peter; Pohl, Hans-Joachim; Itoh, Kohei; Cory, David G.

    2014-03-01

    We experimentally demonstrate the optical hyperpolarization and coherent control of 31P, nuclear spins in single crystal silicon via the inductive readout of the nuclear magnetic resonance (NMR) signal of 31P at a concentration of 1.5 x 1015 cc-1. The obtained polarization is sufficient the 31P spin polarization of 1.17 x 1015 in a 10 mm x 10 mm sample, observed in one FID with signal-to-noise ration of 113. The linewidth is 800 Hz. The Hahn echo pulse sequence reveals a 31P T2 time of 0.42 s at 1.6 K, which was extended by the Carr Purcell cycle to 1.2 s at the same temperature. The maximum build-up of the nuclear polarization was achieved within ~577 seconds, at 4.2 K, in 6.7 T, using optical excitations provided by an infra-red laser. This work has been supported by CERC Canada.

  5. Chemical Characterization and Water Content Determination of Bio-Oils Obtained from Various Biomass Species using 31P NMR Spectroscopy

    SciTech Connect

    David, K.; Ben, H.; Muzzy, J.; Feik, C.; Iisa, K.; Ragauskas, A.

    2012-03-01

    Pyrolysis is a promising approach to utilize biomass for biofuels. One of the key challenges for this conversion is how to analyze complicated components in the pyrolysis oils. Water contents of pyrolysis oils are normally analyzed by Karl Fischer titration. The use of 2-chloro-4,4,5,5,-tetramethyl-1,3,2-dioxaphospholane followed by {sup 31}P NMR analysis has been used to quantitatively analyze the structure of hydroxyl groups in lignin and whole biomass. Results: {sup 31}P NMR analysis of pyrolysis oils is a novel technique to simultaneously characterize components and analyze water contents in pyrolysis oils produced from various biomasses. The water contents of various pyrolysis oils range from 16 to 40 wt%. The pyrolysis oils obtained from Loblolly pine had higher guaiacyl content, while that from oak had a higher syringyl content. Conclusion: The comparison with Karl Fischer titration shows that {sup 31}P NMR could also reliably be used to measure the water content of pyrolysis oils. Simultaneously with analysis of water content, quantitative characterization of hydroxyl groups, including aliphatic, C-5 substituted/syringyl, guaiacyl, p-hydroxyl phenyl and carboxylic hydroxyl groups, could also be provided by {sup 31}P NMR analysis.

  6. [ 31P]NMR measurements of hexokinase activity in intact red blood cells with 2-deoxyglucose as substrate

    NASA Astrophysics Data System (ADS)

    Halabi, F.; Seguin, J. P.; Fonroget, J.; Goethals, G.

    [ 31P] NMR spectroscopy is demonstrated to be a suitable tool to follow the time course of 2-deoxyglucose-6-phosphate in intact human erythrocytes incubated with 2-deoxyglucose. It allowed to determine hexokinase Vmax and K m in near physiological conditions.

  7. 31P NMR study of erythrocytes from a patient with hereditary pyrimidine-5'-nucleotidase deficiency.

    PubMed Central

    Swanson, M S; Angle, C R; Stohs, S J; Wu, S T; Salhany, J M; Eliot, R S; Markin, R S

    1983-01-01

    The composition of phosphate metabolites and the intracellular pH in erythrocytes from a patient with hereditary pyrimidine-5'-nucleotidase deficiency were examined using 31P NMR spectroscopy. Several resonances were identified in spectra from intact cells and from extracts. The 2,3-bisphosphoglycerate line intensities were normal but the NTP resonances were about twice normal due to the presence of millimolar quantities of pyrimidine phosphates. Several intense resonances were also observed in the diphosphodiester region of the spectrum. One compound contributing to these lines has been identified as cytidine diphosphocholine. The resonances of NTPs were in a position indicating that the additional triphosphates were also bound by Mg2+. Direct measurement shows that there is a nearly proportional increase in total cell Mg2+ in the patient's cells, in agreement with the interpretation of the spectra. The intracellular pH was about 0.2 unit lower in the patient's erythrocytes. This lower pH is due to the elevation in intracellular fixed negative charges and the shift in permeable anions consequent to the Donnan equilibrium. We suggest that the lower intracellular pH may explain the lower oxygen affinity of these cells in the presence of otherwise normal 2,3-bisphosphoglycerate levels and the increased Mg2+ triphosphates level, because the Mg2+ form of NTPs is known not to alter the oxygen affinity of hemoglobin under physiologic conditions. Furthermore, the lower intracellular pH can also explain the abnormalities in glycolytic intermediates observed for these cells. PMID:6296865

  8. Application of (31P) NMR in analyzing the degradation efficiency of organic phosphorus degrading-bacteria.

    PubMed

    Lu, Yang; Sun, Xin; Ji, Si-Yao; Wang, Jian-Feng; Huang, Yao-Jian; Zhao, Yu-Fen; Xu, Peng-Xiang

    2007-07-01

    HPLC and HPLC-MS are the fastest and most accurate techniques for analysis of organic phosphorus pesticide (OPP) at the present time. Using these techniques, 14 strains of methamidopho (MAP) degrading-bacteria from the area contaminated with MAP have been identified. The results from HPLC and HPLC-MS analyses showed that the highest degradation rate was 73% after 7 days. In order to determine what metabolites will be formed after degradation, a key issue that has been neglected for a long time, we used ((31)P) NMR to track the degradation process. The results showed that different strains produced different metabolites. Ten strains were divided into three groups (groups A, B and C) by their metabolic profiling. Strains in group A degraded MAP into phosphor acid by breaking down all P-N, P-O and P-S bonds in 7 days. Strains in groups B and C had only broken down partially P-N and P-S bonds at the same time. Therefore, the bacterial strains in group A had a greater application potential than the other two groups. In addition, most metal phosphates are unsolvable in water. The analysis of X-ray showed, that the phosphate radicals generated by bacterial degradation induce crystallogenesis of heavy metal salts in water phase and also cause the chemical sedimentation of their crystals. Furthermore, these crystals are hydrogen phosphates. The results suggested that the MAP-degrading bacteria could be used for cleaning up not only the organic phosphorous pesticide contamination but also the phosphorous and heavy metal contamination in water environment simultaneously. PMID:17072553

  9. Regional Differences of Metabolic Response During Dynamic Incremental Exercise by (31)P-CSI.

    PubMed

    Kaneko, Yasuhisa; Kime, Ryotaro; Hongo, Yoshinori; Ohno, Yusuke; Sakamoto, Ayumi; Katsumura, Toshihito

    2016-01-01

    The aim of this study was to detect the differences in muscle metabolic response of the quadriceps during incremental dynamic knee exercise using regional (31)Phosphorus Chemical Shift Imaging ((31)P-CSI). Sixteen healthy men participated in this study (age 28 ± 5 years, height 171.4 ± 3.9 cm, weight 67.1 ± 9.8 kg). The experiments were carried out with a 1.5-T superconducting magnet with a 5-in. diameter circular surface coil. The subjects performed isometric unilateral knee extension exercise to detect their maximum voluntary contraction (MVC) in prone position. Then they performed dynamic unilateral knee extension exercise in the magnet at 10, 20, 30 and 40 % of their MVC with the transmit-receive coil placed under the right quadriceps. The subjects pulled down a rope with the adjusted weight attached to the ankle at a frequency of 0.5 Hz for 380 s. Intracellular pH (pHi) was calculated from the median chemical shift of the inorganic phosphate (Pi) peak relative to phosphocreatine (PCr). The quadriceps were divided into three regions, (1) medial, (2) anterior, (3) lateral, and in comparison, there was no significant difference in Pi/PCr nor in pHi between regions, except Pi/PCr of the medial region was significantly higher than the anterior region at maximum intensity (p < 0.05). These results suggest that regional muscle metabolic response is similar in the quadriceps except at maximum intensity. PMID:27526153

  10. Multimodal neuroimaging provides a highly consistent picture of energy metabolism, validating 31P MRS for measuring brain ATP synthesis

    PubMed Central

    Chaumeil, Myriam M.; Valette, Julien; Guillermier, Martine; Brouillet, Emmanuel; Boumezbeur, Fawzi; Herard, Anne-Sophie; Bloch, Gilles; Hantraye, Philippe; Lebon, Vincent

    2009-01-01

    Neuroimaging methods have considerably developed over the last decades and offer various noninvasive approaches for measuring cerebral metabolic fluxes connected to energy metabolism, including PET and magnetic resonance spectroscopy (MRS). Among these methods, 31P MRS has the particularity and advantage to directly measure cerebral ATP synthesis without injection of labeled precursor. However, this approach is methodologically challenging, and further validation studies are required to establish 31P MRS as a robust method to measure brain energy synthesis. In the present study, we performed a multimodal imaging study based on the combination of 3 neuroimaging techniques, which allowed us to obtain an integrated picture of brain energy metabolism and, at the same time, to validate the saturation transfer 31P MRS method as a quantitative measurement of brain ATP synthesis. A total of 29 imaging sessions were conducted to measure glucose consumption (CMRglc), TCA cycle flux (VTCA), and the rate of ATP synthesis (VATP) in primate monkeys by using 18F-FDG PET scan, indirect 13C MRS, and saturation transfer 31P MRS, respectively. These 3 complementary measurements were performed within the exact same area of the brain under identical physiological conditions, leading to: CMRglc = 0.27 ± 0.07 μmol·g−1·min−1, VTCA = 0.63 ± 0.12 μmol·g−1·min−1, and VATP = 7.8 ± 2.3 μmol·g−1·min−1. The consistency of these 3 fluxes with literature and, more interestingly, one with each other, demonstrates the robustness of saturation transfer 31P MRS for directly evaluating ATP synthesis in the living brain. PMID:19234118

  11. Superiority of blood over saline resuscitation from hemorrhagic shock: a 31P magnetic resonance spectroscopy study.

    PubMed Central

    Mann, D V; Robinson, M K; Rounds, J D; DeRosa, E; Niles, D A; Ingwall, J S; Wilmore, D W; Jacobs, D O

    1997-01-01

    OBJECTIVE: To study the relation between blood and saline administration, postresuscitation hematocrit (Hct) level, and metabolic recovery after hemorrhagic shock. SUMMARY BACKGROUND DATA: It is generally believed that crystalloid can be substituted, in whole or in part, for blood during resuscitation of hemorrhagic shock. This is based on the belief that Hct can be safely reduced but should not fall below a critical level. METHODS: Male rats weighing 200 g were subjected to an isobaric hemorrhagic shock at a mean arterial pressure of 30 mmHg for 14 minutes, after which they were randomized to one of three resuscitation regimens. Control group (n = 36) were resuscitated by return of all shed blood. Mid-Hct (n = 39) and low-Hct (n = 60) groups were depleted of one third and one half of their circulating blood volumes, respectively, and were resuscitated with three times that volume of normal saline. Skeletal muscle intracellular energetics and pH were measured serially using 31P magnetic resonance spectroscopy at baseline, during shock, and after resuscitation. Arterial blood was sampled at the same time points. The number of surviving animals in each group at 24 hours was recorded. RESULTS: After resuscitation, surviving rats in the low-Hct group demonstrated a greater consumption of high-energy phosphocreatine stores than did the other groups (control = 0.479 +/- 0.003, mid-Hct = 0.465 +/- 0.004, low-Hct = 0.457 +/- 0.007, mean +/- standard error of the mean; p < 0.01 low-Hct vs. other groups by analysis of variance). The rats that received saline resuscitation developed a relative intracellular acidosis (control = 7.29 +/- 0.02, mid-Hct = 7.25 +/- 0.02, low-Hct = 7.23 +/- 0.02; p < 0.05 controls vs. other groups by analysis of variance). At 24 hours, the death rates were significantly different among the groups: control = 1 of 36 rats (2.8%), mid-Hct = 6 of 39 (15.4%), and low-Hct = 14 of 60 (23.3%) (p < 0.05 by chi square analysis). CONCLUSION: The oxygen

  12. 2D 31P solid state NMR spectroscopy, electronic structure and thermochemistry of PbP7

    NASA Astrophysics Data System (ADS)

    Benndorf, Christopher; Hohmann, Andrea; Schmidt, Peer; Eckert, Hellmut; Johrendt, Dirk; Schäfer, Konrad; Pöttgen, Rainer

    2016-03-01

    Phase pure polycrystalline PbP7 was prepared from the elements via a lead flux. Crystalline pieces with edge-lengths up to 1 mm were obtained. The assignment of the previously published 31P solid state NMR spectrum to the seven distinct crystallographic sites was accomplished by radio-frequency driven dipolar recoupling (RFDR) experiments. As commonly found in other solid polyphosphides there is no obvious correlation between the 31P chemical shift and structural parameters. PbP7 decomposes incongruently under release of phosphorus forming liquid lead as remainder. The thermal decomposition starts at T>550 K with a vapor pressure almost similar to that of red phosphorus. Electronic structure calculations reveal PbP7 as a semiconductor according to the Zintl description and clearly shows the stereo-active Pb-6s2 lone pairs in the electron localization function ELF.

  13. Distinguishing Bicontinuous Lipid Cubic Phases from Isotropic Membrane Morphologies Using 31P Solid-State NMR Spectroscopy

    PubMed Central

    Yang, Yu; Yao, Hongwei

    2015-01-01

    Nonlamellar lipid membranes are frequently induced by proteins that fuse, bend, and cut membranes. Understanding the mechanism of action of these proteins requires the elucidation of the membrane morphologies that they induce. While hexagonal phases and lamellar phases are readily identified by their characteristic solid-state NMR lineshapes, bicontinuous lipid cubic phases are more difficult to discern, since the static NMR spectra of cubic-phase lipids consist of an isotropic 31P or 2H peak, indistinguishable from the spectra of isotropic membrane morphologies such as micelles and small vesicles. To date, small-angle X-ray scattering is the only method to identify bicontinuous lipid cubic phases. To explore unique NMR signatures of lipid cubic phases, we first describe the orientation distribution of lipid molecules in cubic phases and simulate the static 31P chemical shift lineshapes of oriented cubic-phase membranes in the limit of slow lateral diffusion. We then show that 31P T2 relaxation times differ significantly between isotropic micelles and cubic-phase membranes: the latter exhibit two-orders-of magnitude shorter T2 relaxation times. These differences are explained by the different timescales of lipid lateral diffusion on the cubic-phase surface versus the timescales of micelle tumbling. Using this relaxation NMR approach, we investigated a DOPE membrane containing the transmembrane domain (TMD) of a viral fusion protein. The static 31P spectrum of DOPE shows an isotropic peak, whose T2 relaxation times correspond to that of a cubic phase. Thus, the viral fusion protein TMD induces negative Gaussian curvature, which is an intrinsic characteristic of cubic phases, to the DOPE membrane. This curvature induction has important implications to the mechanism of virus-cell fusion. This study establishes a simple NMR diagnostic probe of lipid cubic phases, which is expected to be useful for studying many protein-induced membrane remodeling phenomena in biology

  14. Characterization of phosphorus in sludges and sludge amended soils using /sup 31/P nuclear magnetic resonance spectroscopy

    SciTech Connect

    Hinedi, Z.R.

    1987-01-01

    /sup 31/P NMR spectroscopy was an effective tool in the characterization of phosphorus (P) in municipal sewage sludges and sludge amended soils. Waste activated and aerobically digested sludges contained higher percentages of organic P than anaerobically digested sludges. The /sup 31/P Cross Polarization Magic Angle Spinning (/sup 31/P CP MAS) spectrum of an aerobically digested sludge indicated the presence of a significant organic P fraction over the inorganic P fraction. The /sup 31/P NMR spectra of sludge-borne phospholipids dissolved in cholate, to which a complexing agent was added, were found to be better resolved than those dissolved in chloroform. Phytic acid and ribonucleic acid were shown to be constituents of organic P in sludges based upon their susceptibility to different phosphoric ester hydrolases. Sludge amended soils were incubated to examine the transformations of sludge-borne P in soils. It was found that soil pH affected the biodegradation of organic P as well as that of pyrophosphate. Phosphorus-monoesters and pyrophosphates hydrolyzed after 70 days of incubation under alkaline soil condition while they persisted beyond 140 days of incubation under acid soil condition. The P-diesters completely hydrolyzed after 28 days of incubation under acid and alkaline soil conditions. The solubility study showed that the P in a sludge amended soil was undersaturated with respect to Ca-P, Fe-P and Al-P minerals considered. The finding suggested that the activity of the P solid phase under study might be less than unity which would be indicative of a coprecipitated solid solution.

  15. Crystallinity and compositional changes in carbonated apatites: Evidence from {sup 31}P solid-state NMR, Raman, and AFM analysis

    SciTech Connect

    McElderry, John-David P.; Zhu, Peizhi; Mroue, Kamal H.; Xu, Jiadi; Pavan, Barbara; Fang, Ming; Zhao, Guisheng; McNerny, Erin; Kohn, David H.; Franceschi, Renny T.; Holl, Mark M.Banaszak; Tecklenburg, Mary M.J.; Ramamoorthy, Ayyalusamy; Morris, Michael D.

    2013-10-15

    Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and {sup 31}P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse {sup 31}P NMR linewidth and inverse Raman PO{sub 4}{sup 3−}ν{sub 1} bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3–10.3 wt% CO{sub 3}{sup 2−} range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the {sup 31}P NMR chemical shift frequency and the Raman phosphate ν{sub 1} band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals. - Graphical abstract: Carbonated apatite shows an abrupt change in spectral (NMR, Raman) and morphological (AFM) properties at a composition of about one carbonate substitution per unit cell. Display Omitted - Highlights: • Crystallinity (XRD), particle size (AFM) of carbonated apatites and bone mineral. • Linear relationships among crystallinity, {sup 31}P NMR and Raman inverse bandwidths. • Low and high carbonated apatites use different charge-balancing ion-loss mechanism.

  16. Ab initio and DFT study of 31P-NMR chemical shifts of sphingomyelin and dihydrosphingomyelin lipid molecule

    NASA Astrophysics Data System (ADS)

    Sugimori, K.; Kawabe, H.; Nagao, H.; Nishikawa, K.

    One of the phospholipids, sphingomyelin (SM, N-acyl-sphingosine-1-phosphorylcholine) is the most abundant component of mammalian membranes in brain, nervous tissues, and human ocular lens. It plays an important role for apoptosis, aging, and signal transduction. Recently, Yappert and coworkers have shown that human lens sphingomyelin and its hydrogenated derivative, dihydrosphingomyelin (DHSM) are interacted with Ca2+ ions to develop human cataracts. Previously, we have investigated conformational differences between an isolated SM/DHSM molecule and Ca2+-coordinated form by using density functional theory (DFT) for geometry optimization and normal mode analysis. As a result, one of stable conformers of SMs has a hydrogen bonding between hydroxyl group and phosphate group, whereas another conformer has a hydrogen bonding between hydroxyl and phosphate amide group. In this study, 31P-Nuclear Magnetic Resonance (NMR) shielding constants of the obtained conformers are investigated by using ab initio and DFT with NMR-gauge invariant atomic orbitals (NMR-GIAO) calculations. The experimental 31P-NMR chemical shifts of SMs and DHSMs have significant small value around 0.1 ppm. We consider the relative conformational changes between SMs and DHSMs affect the slight deviations of 31P-NMR chemical shifts, and discuss intramolecular hydrogen bondings and the solvent effect in relation to NMR experimental reference.

  17. Protein analysis by 31p NMR spectroscopy in ionic liquid: quantitative determination of enzymatically created cross-links.

    PubMed

    Monogioudi, Evanthia; Permi, Perttu; Filpponen, Ilari; Lienemann, Michael; Li, Bin; Argyropoulos, Dimitris; Buchert, Johanna; Mattinen, Maija-Liisa

    2011-02-23

    Cross-linking of β-casein by Trichoderma reesei tyrosinase (TrTyr) and Streptoverticillium mobaraense transglutaminase (Tgase) was analyzed by (31)P nuclear magnetic resonance (NMR) spectroscopy in ionic liquid (IL). According to (31)P NMR, 91% of the tyrosine side chains were cross-linked by TrTyr at high dosages. When Tgase was used, no changes were observed because a different cross-linking mechanism was operational. However, this verified the success of the phosphitylation of phenolics within the protein matrix in the IL. Atomic force microscopy (AFM) in solid state showed that disk-shaped nanoparticles were formed in the reactions with average diameters of 80 and 20 nm for TrTyr and Tgase, respectively. These data further advance the current understanding of the action of tyrosinases on proteins on molecular and chemical bond levels. Quantitative (31)P NMR in IL was shown to be a simple and efficient method for the study of protein modification. PMID:21218836

  18. Observation of 1H-13C and 1H-1H proximities in a paramagnetic solid by NMR at high magnetic field under ultra-fast MAS.

    PubMed

    Li, Shenhui; Trébosc, Julien; Lafon, Olivier; Zhou, Lei; Shen, Ming; Pourpoint, Frédérique; Amoureux, Jean-Paul; Deng, Feng

    2015-02-01

    The assignment of NMR signals in paramagnetic solids is often challenging since: (i) the large paramagnetic shifts often mask the diamagnetic shifts specific to the local chemical environment, and (ii) the hyperfine interactions with unpaired electrons broaden the NMR spectra and decrease the coherence lifetime, thus reducing the efficiency of usual homo- and hetero-nuclear NMR correlation experiments. Here we show that the assignment of (1)H and (13)C signals in isotopically unmodified paramagnetic compounds with moderate hyperfine interactions can be facilitated by the use of two two-dimensional (2D) experiments: (i) (1)H-(13)C correlations with (1)H detection and (ii) (1)H-(1)H double-quantum↔single-quantum correlations. These methods are experimentally demonstrated on isotopically unmodified copper (II) complex of l-alanine at high magnetic field (18.8 T) and ultra-fast Magic Angle Spinning (MAS) frequency of 62.5 kHz. Compared to (13)C detection, we show that (1)H detection leads to a 3-fold enhancement in sensitivity for (1)H-(13)C 2D correlation experiments. By combining (1)H-(13)C and (1)H-(1)H 2D correlation experiments with the analysis of (13)C longitudinal relaxation times, we have been able to assign the (1)H and (13)C signals of each l-alanine ligand. PMID:25557861

  19. (31)P-MRS of healthy human brain: ATP synthesis, metabolite concentrations, pH, and T1 relaxation times.

    PubMed

    Ren, Jimin; Sherry, A Dean; Malloy, Craig R

    2015-11-01

    The conventional method for measuring brain ATP synthesis is (31)P saturation transfer (ST), a technique typically dependent on prolonged pre-saturation with γ-ATP. In this study, ATP synthesis rate in resting human brain is evaluated using EBIT (exchange kinetics by band inversion transfer), a technique based on slow recovery of γ-ATP magnetization in the absence of B1 field following co-inversion of PCr and ATP resonances with a short adiabatic pulse. The unidirectional rate constant for the Pi → γ-ATP reaction is 0.21 ± 0.04 s(-1) and the ATP synthesis rate is 9.9 ± 2.1 mmol min(-1)  kg(-1) in human brain (n = 12 subjects), consistent with the results by ST. Therefore, EBIT could be a useful alternative to ST in studying brain energy metabolism in normal physiology and under pathological conditions. In addition to ATP synthesis, all detectable (31)P signals are analyzed to determine the brain concentration of phosphorus metabolites, including UDPG at around 10 ppm, a previously reported resonance in liver tissues and now confirmed in human brain. Inversion recovery measurements indicate that UDPG, like its diphosphate analogue NAD, has apparent T1 shorter than that of monophosphates (Pi, PMEs, and PDEs) but longer than that of triphosphate ATP, highlighting the significance of the (31)P-(31)P dipolar mechanism in T1 relaxation of polyphosphates. Another interesting finding is the observation of approximately 40% shorter T1 for intracellular Pi relative to extracellular Pi, attributed to the modulation by the intracellular phosphoryl exchange reaction Pi ↔ γ-ATP. The sufficiently separated intra- and extracellular Pi signals also permit the distinction of pH between intra- and extracellular environments (pH 7.0 versus pH 7.4). In summary, quantitative (31)P MRS in combination with ATP synthesis, pH, and T1 relaxation measurements may offer a promising tool to detect biochemical alterations at early stages of brain dysfunctions and diseases

  20. Crystalline 1H-1,2,3-triazol-5-ylidenes

    DOEpatents

    Bertrand, Guy; Gulsado-Barrios, Gregorio; Bouffard, Jean; Donnadieu, Bruno

    2016-08-02

    The present invention provides novel and stable crystalline 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of making 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of using 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes in catalytic reactions.

  1. Analysis of 31P MR spectroscopy data using artificial neural networks for longitudinal evaluation of muscle diseases: dermatomyositis.

    PubMed

    Park, J H; Kari, S; King, L E; Olsen, N J

    1998-01-01

    Classical myopathic dermatomyositis (DM) is a chronic autoimmune disease characterized by an erythematous rash and severe, proximal muscle weakness. A disease variant, amyopathic DM, presents with the typical rash but without clinical evidence of muscle weakness. Prednisone and immunosuppressive drugs alleviate symptoms in many patients. Accurate longitudinal evaluations of patients are important to limit serious side effects of these drugs, including osteoporosis, cataracts, and growth inhibition. Metabolic abnormalities detected with 31P magnetic resonance spectroscopy (MRS) provide the best quantitative data for evaluating these patients. With 31P MRS, the levels of inorganic phosphate (Pi), phosphocreatine (PCr), ATP, and phosphodiesters (PDE) were determined in the quadricep muscles of patients during rest and exercise. Artificial neural network (ANN) analyses of these data were previously used for accurate classification of patients with myopathic or amyopathic DM and normal controls. In the present investigation, an artificial neural network was employed for further analysis of the 31P metabolite levels in quantitative, longitudinal evaluations of the extent (percent) of clinical improvement or deterioration during treatment with prednisone and immunosuppressive drugs. The ANN results showed that adult patients in a severe myopathic state could improve with treatment to a clinical status of amyopathic DM. In contrast, severely weak juvenile patients in the myopathic state recovered to normal status. One juvenile patient did not improve and remained in the myopathic state. Additionally, a serious clinical relapse in an amyopathic patient was predicted with serial ANN analyses well in advance of the actual clinical event. These network analyses show potential utility for clinical applications in muscle diseases. PMID:9719579

  2. Using 31P-NMR to investigate dynamics of soil phosphorus compounds in the Rothamsted Long Term Experiments

    NASA Astrophysics Data System (ADS)

    Blackwell, Martin; Turner, Ben; Granger, Steve; Hooper, Tony; Darch, Tegan; Hawkins, Jane; Yuan, Huimin; McGrath, Steve

    2015-04-01

    The technique of 31P-NMR spectroscopy has done more to advance the knowledge of phosphorus forms (especially organic phosphorus) in environmental samples than any other method. The technique has advanced such that specific compounds can be identified where previously only broad categories such as orthophosphate monoesters and diesters were distinguishable. The Soil Archive and Long Term Experiments at Rothamsted Research, UK, potentially provides an unequalled opportunity to use this technique to observe changes in soil phosphorus compounds with time and under different treatments, thereby enhancing our understanding of phosphorus cycling and use by plants. Some of the earliest work using this technique on soils was carried out by Hawkes et al. in 1984 and this used soils from two of the oldest Rothamsted Long Term Experiments, namely Highfield and Park Grass. Here we revisit the samples studied in this early work and reanalyse them using current methodology to demonstrate how the 31P-NMR technique has advanced. We also present results from a study on the phosphorus chemistry in soils along the Hoosfield acid strip (Rothamsted, UK), where a pH gradient from 3.7 to 7.8 occurs in a single soil with little variation in total phosphorus (mean ± standard deviation 399 ± 27 mg P kg-1). Soil pH was found to be an important factor in determining the proportion of phosphomonoesters and phosphodiesters in the soil organic phosphorus, although total organic phosphorus concentrations were a relatively consistent proportion of the total soil phosphorus (36 ± 2%) irrespective of soil pH. Key words. 31P-NMR, soil organic phosphorus, long term experiments, Hoosfield acid strip

  3. Local structure of spin Peierls compound TiPO4: 47/49Ti and 31P NMR study

    NASA Astrophysics Data System (ADS)

    Stern, Raivo; Heinmaa, Ivo; Leitmäe, Alexander; Joon, Enno; Tsirlin, Alexander; Kremer, Reinhard; Glaum, Robert

    TiPO4 structure is made of slightly corrugated TiO2 ribbon chains of edge-sharing TiO6 octahedra. The almost perfect 1D spin 1/2 Ti3 + chains are well separated by PO4 tetrahedra. By magnetic susceptibility and MAS-NMR measurements [1] it was shown that TiPO4 has nonmagnetic singlet ground state with remarkably high Spin-Peierls (SP) transition temperature. The high-T magnetic susceptibility of TiPO4 follows well that of a S =1/2 Heisenberg chain with very strong nearest-neighbor AF spin-exchange coupling constant of J =965K. On cooling TiPO4 shows two successive phase transitions at 111K and 74K, with incommensurate (IC) SP phase between them. We studied local structure and dynamics in TiPO4 single crystal using 47/49Ti and 31P NMR in the temperature range 40K to 300K, and determined the principal values and orientation of the magnetic shift tensors for 31P and 47,49Ti nuclei. Since 47,49Ti (S =5/2 and S =7/2, respectively) have quadrupolar moments, we also found the principal axis values and orientations of the electric field gradient (efg) tensor in SP phase and at 295K. In SP phase the structure contains 2 magnetically inequivalent P sites and only one Ti site. From the T-dependence of the relaxation rate of 31P and 47Ti nuclei we determined activation energy Ea = 550 K for spin excitations in SP phase. J. Law et al ., PRB 83, 180414(R) (2011).

  4. Intracellular pH of perfused single frog skin: combined 19F- and 31P-NMR analysis.

    PubMed

    Civan, M M; Lin, L E; Peterson-Yantorno, K; Taylor, J; Deutsch, C

    1984-11-01

    Intracellular pH (pHc) has been determined in frog skin by applying two different methods of pH measurement, 19F and 31P nuclear magnetic resonance (NMR) analysis, to the same tissues. Results from both NMR approaches confirm an observation by Lin, Shporer, and Civan [Am. J. Physiol. 248 (Cell Physiol. 17): 1985] that acidification of the extracellular medium reverses the sign of the pH gradient present under baseline conditions. The fluorinated probe, alpha-(difluoromethyl)-alanine methyl ester, was introduced into the epithelial cells by preincubating skins for 4.7-10.4 h at room temperature in Ringer solutions containing 1 mM ester. The free amino acid was subsequently released by intracellular esterase activity, thus providing a high enough probe concentration for NMR analysis to be practicable. From measurements of short-circuit current and transepithelial resistance under base-line and experimental conditions and the appearance of phosphocreatine (PCr) in the 31P spectrum of preloaded tissues, the fluorinated probe appears to be nontoxic to frog skin. Measurement of the chemical shift of methylphosphonate relative to PCr permitted calculation of extracellular pH. Estimation of the intracellular pH was performed both by measurement of the chemical shift of inorganic phosphate (Pi) relative to PCr and by measurement of the central peak spacing of the 19F spectrum. From four direct comparisons of the two techniques in two experiments, the difference in the estimated pH was only 0.03 +/- 0.07 pH units, supporting the concept that 31P-NMR analysis is a valid method of measuring pH in this tissue. PMID:6496729

  5. Measurement of changes in high-energy phosphates in the cardiac cycle using gated 31P nuclear magnetic renonance.

    PubMed Central

    Fossel, E T; Morgan, H E; Ingwall, J S

    1980-01-01

    Levels of the high-energy phosphate-containing compounds, ATP and creatine phosphate, and of inorganic phosphate (Pi) were measured as a function of position in the cardiac cycle. Measurements were made on isolated, perfused, working rat hearts through the use of gated 31P nuclear magnetic resonance spectroscopy. Levels of ATP and creatine phosphate were found to vary during the cardiac cycle and were maximal at minimal aortic pressure and minimal at maximal aortic pressure. Pi varied inversely with the high-energy phosphates. PMID:6932041

  6. Assessment of membrane protection by /sup 31/P-NMR effects of lidocaine on calcium-paradox in myocardium

    SciTech Connect

    Sakai, Hirosumi; Yoshiyama, Minoru; Teragaki, Masakazu; Takeuchi, Kazuhide; Takeda, Takeda; Ikata, Mari; Ishikawa, Makoto; Miura, Iwao

    1989-01-01

    In studying calcium paradox, perfused rat hearts were used to investigate the myocardial protective effects of lidocaine. Intracellular contents of phosphates were measured using the /sup 31/P-NMR method. In hearts reexposed to calcium, following 3 minute calcium-free perfusion, a rapid contracture occurred, followed by rapid and complete disappearance of intracellular phosphates with no resumption of cardiac function. In hearts where lidocaine was administered from the onset of the calcium-free perfusion until 2 minutes following the onset of reexposure to calcium, both intracellular phosphates and cardiac contractility were maintained. Therefore, it can be said that cell membranes were protected by lidocaine.

  7. [sup 31]P and [sup 27]Al NMR investigations of highly acidic, aqueous solutions containing aluminum and phosphorus

    SciTech Connect

    Mortlock, R.F.; Bell, A.T.; Radke, C.J. Univ. of California, Berkeley )

    1993-01-21

    [sup 31]P and [sup 27]Al NMR spectroscopies have been used to characterize acidic, aqueous solutions of orthophosphoric acid, aluminum chloride, and tetramethylammonium (TMA) hydroxide. The final compositions of the solutions range from 0.1 to 1 mol % P, 0.0 to 20 mol % HCl, P/Al = 0.1 to 20, and P/(TMA)[sub 2]O = 2 to 20. Soluble aluminophosphate cations form reactions of hexaaqua Al monomeric cations, [Al(H[sub 2]O)[sub 6

  8. Nuclear magnetic resonance characterization of a paramagnetic DNA-drug complex with high spin cobalt; assignment of the 1H and 31P NMR spectra, and determination of electronic, spectroscopic and molecular properties.

    PubMed

    Gochin, M

    1998-08-01

    The proton NMR spectrum of the ternary complex between the octamer duplex d(TTGGCCAA)2, two molecules of the drug chromomycin-A3, and a divalent cobalt ion has been assigned. Assignment procedures used standard two-dimensional techniques and relied upon the expected NOE contacts observed in the equivalent diamagnetic complex containing zinc. The magnetic susceptibility tensor for the cobalt was determined and used to calculate shifts for all nuclei, aiding in the assignment process and verification. Relaxation, susceptibility, temperature and field dependence studies of the paramagnetic spectrum enabled determination of electronic properties of the octahedral cobalt complex. The electronic relaxation tau(s) was determined to be 2.5 +/- 1.5 ps; the effective isotropic g value was found to be 2.6 +/- 0.2, indicating strong spin-orbit coupling. The magnetic susceptibility tensor was determined to be chi(xx) = 8.9 x 10(-3) cm3/mol, chi(yy) = 9.5 x 10(-3) cm3/mol, chi(zz) = 12.8 * 10(-3) cm3/mol. A tentative rotational correlation time of 8 ns was obtained for the complex. Both macroscopic and microscopic susceptibility measurements revealed deviations from Curie behavior over the temperature range accessible in the study. Non-selective relaxation rates were found to be inaccurate for defining distances from the metal center. However, pseudocontact shifts could be calculated with high accuracy using the dipolar shift equation. Isotropic hyperfine shifts were factored into contact and dipolar terms, revealing that the dipolar shift predominates and that contact shifts are relatively small. PMID:9751997

  9. Muscle phosphoglycerate mutase (PGAM) deficiency in the first Caucasian patient: biochemistry, muscle culture and 31P-MR spectroscopy.

    PubMed

    Vita, G; Toscano, A; Bresolin, N; Meola, G; Fortunato, F; Baradello, A; Barbiroli, B; Frassineti, C; Zaniol, P; Messina, C

    1994-03-01

    Muscle phosphoglycerate mutase (PGAM) deficiency has been so far identified in only six patients, five of these being African Americans. We report the results of clinical, morphological, biochemical, muscle culture and 31P-MR spectroscopy studies in the first Caucasian patient with muscle PGAM deficiency. A 23-year-old man had a 10-year history of cramps after physical exertion with one episode of pigmenturia. Neurological examination and EMG study were normal. ECG and echocardiography revealed hypertrophy of the interventricular septum and slight dilation of the left chambers of the heart. Muscle biopsy revealed increased glycogen content and some accumulation of mitochondria. Muscle PGAM activity was markedly decreased (6.5% and 9.7% of control value in two different biopsies). Citrate synthase and other mitochondrial respiratory chain enzyme activities were much higher than normal. In contrast to the marked decrease of PGAM activity observed in muscle biopsy, total enzyme activity in the patient's aneural muscle culture was normal, being represented exclusively by BB isoenzyme. The deficiency of PGAM-MM isoenzyme was reproduced in the patient's innervated muscle culture. Muscle 31P-MR spectroscopy showed accumulation of phosphomonoesters only on fast "glycolytic" exercise. On "aerobic" exercise, Vmax, calculated from the work-energy cost transfer function, showed an increase consistent with the morphological and biochemical evidence of mitochondrial proliferation. This might represent a sort of compensatory aerobic effort in an attempt to restore muscle power. PMID:8006681

  10. Characterization of the testicular cell types present in the rat by in vivo 31P magnetic resonance spectroscopy

    SciTech Connect

    van der Grond, J.; Van Pelt, A.M.; van Echteld, C.J.; Dijkstra, G.; Grootegoed, J.A.; de Rooij, D.G.; Mali, W.P. )

    1991-07-01

    Testes of vitamin A-deficient Wistar rats before and after vitamin A replacement, of rats irradiated in utero, and of control rats were investigated by in vivo 31P magnetic resonance (MR) spectroscopy. The testicular phosphomonoester/ATP (PM/ATP) ratio ranged from 0.79 {plus minus} 0.05 for testes that contained only interstitial tissue and Sertoli cells to 1.64 {plus minus} 0.04 for testes in which spermatocytes were the most advanced cell types present. When new generations of spermatids entered the seminiferous epithelium, this ratio decreased. The testicular phosphodiester/ATP (PD/ATP) ratio amounted to 0.16 {plus minus} 0.06 for testes in which Sertoli cells, spermatogonia, or spermatocytes were the most advanced cell type present. When new generations of spermatids entered the seminiferous epithelium, the PD/ATP ratio rapidly increased and finally reached a value of 0.71 {plus minus} 0.06 for fully developed testes. Taken together, specific patterns of the PM/ATP ratio, the PD/ATP ratio, and pH were obtained that were correlated to the presence of spermatogonia, spermatocytes, round spermatids, and elongated spermatids or to the absence of spermatogenic cells. Hence, a good impression of the status of the seminiferous epithelium in the rat can be obtained by in vivo 31P MR spectroscopy.

  11. A solid-state 31P-NMR investigation of the allosteric transition in glycogen phosphorylase b.

    PubMed Central

    Challoner, R; McDowell, C A; Stirtan, W; Withers, S G

    1993-01-01

    The catalytic role of the cofactor phosphate moiety at the active site of glycogen phosphorylase has been the subject of many investigations including solution-state high-resolution 31P-NMR studies. In this study the pyridoxal phosphate moiety in both the inactive and active forms of microcrystalline phosphorylase b has been investigated by high-resolution 31P magic-angle spinning NMR. The symmetry of the shielding tensor in model compounds at varying degrees of ionization is investigated and the results indicate a marked difference between the dianionic and monoanionic model compounds. Consequently the observed similarity in the principal tensor components describing the shielding tensor of the phosphorus nuclei present at the active site of both the R- and T-state conformations suggests that there is no change in ionization site upon activation in contrast to suggestions based upon isotropic shifts. Since previous relaxation measurements have pointed to the need to consider motional influences in such systems, several plausible models are considered. Subject to the assumption of congruency between the principal axis system describing the shielding interaction and molecular frame determined by the molecular symmetry axes, we conclude that the phosphate cofactor is dianionic in both forms. PMID:8457672

  12. The intact muscle lipid composition of bulls: an investigation by MALDI-TOF MS and 31P NMR.

    PubMed

    Dannenberger, Dirk; Süss, Rosmarie; Teuber, Kristin; Fuchs, Beate; Nuernberg, Karin; Schiller, Jürgen

    2010-02-01

    The analysis of beef lipids is normally based on chromatographic techniques and/or gas chromatography in combination with mass spectrometry (GC/MS). Modern techniques of soft-ionization MS were so far scarcely used to investigate the intact lipids in muscle tissues of beef. The objective of the study was to investigate whether matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry and (31)P nuclear magnetic resonance (NMR) spectroscopy are useful tools to study the intact lipid composition of beef. For the MALDI-TOF MS and (31)P NMR investigations muscle samples were selected from a feeding experiment with German Simmental bulls fed different diets. Beside the triacylglycerols (TAGs), phosphatidylethanolamine (PE), phosphatidylcholine (PC) and phosphatidylinositol (PI) species the MALDI-TOF mass spectra of total muscle lipids gave also intense signals of cardiolipin (CL) species. The application of different matrix compounds, 2,5-dihydroxybenzoic acid (DHB) and 9-aminoacridine (9-AA), leads to completely different mass spectra: 9-AA is particularly useful for the detection of (polar) phospholipids, whereas apolar lipids, such as cholesterol and triacylglycerols, are exclusively detected if DHB is used. Finally, the quality of the negative ion mass spectra is much higher if 9-AA is used. PMID:19900429

  13. /sup 31/P NMR analysis of membrane phospholipid organization in viable, reversibly electropermeabilized Chinese hamster ovary cells

    SciTech Connect

    Lopez, A.; Rols, M.P.; Teissie, J.

    1988-02-23

    Chinese hamster ovary (CHO) cells were reversibly permeabilized by submitting them to short, high-intensity, square wave pulses (1.8 kV/cm, 100 ..mu..s). The cells remained in a permeable state without loss of viability for several hours at 4/sup 0/C. A new anisotropic peak with respect to control cells was observed on /sup 31/P NMR spectroscopic analysis of the phospholipid components. This peak is only present when the cells are permeable, and normal anisotropy is recovered after resealing. Taking into account the fusogenicity of electropermeabilized cells, comparative studies were performed on 5% poly(ethylene glycol) treated cells. The /sup 31/P NMR spectra of the phospholipids displayed the same anisotropic peak as in the case of the electropermeabilized cells. In the two cases, this anisotropic peak was located downfield from the main peak associated to the phospholipids when organized in bilayers. The localization of this anisotropic peak is very different from the one of a hexagonal phase. The authors proposed a reorganization of the polar head group region leading to a weakening of the hydration layer to account for these observations. This was also thought to explain the electric field induced fusogenicity of these cells.

  14. Analysis of the bond-valence method for calculating (29) Si and (31) P magnetic shielding in covalent network solids.

    PubMed

    Holmes, Sean T; Alkan, Fahri; Iuliucci, Robbie J; Mueller, Karl T; Dybowski, Cecil

    2016-07-01

    (29) Si and (31) P magnetic-shielding tensors in covalent network solids have been evaluated using periodic and cluster-based calculations. The cluster-based computational methodology employs pseudoatoms to reduce the net charge (resulting from missing co-ordination on the terminal atoms) through valence modification of terminal atoms using bond-valence theory (VMTA/BV). The magnetic-shielding tensors computed with the VMTA/BV method are compared to magnetic-shielding tensors determined with the periodic GIPAW approach. The cluster-based all-electron calculations agree with experiment better than the GIPAW calculations, particularly for predicting absolute magnetic shielding and for predicting chemical shifts. The performance of the DFT functionals CA-PZ, PW91, PBE, rPBE, PBEsol, WC, and PBE0 are assessed for the prediction of (29) Si and (31) P magnetic-shielding constants. Calculations using the hybrid functional PBE0, in combination with the VMTA/BV approach, result in excellent agreement with experiment. © 2016 Wiley Periodicals, Inc. PMID:27117609

  15. Lateralization effects of image-guided 31P magnetoresonance spectroscopic parameters in the frontal lobe of schizophrenics and healthy controls

    NASA Astrophysics Data System (ADS)

    Huebner, Gabriele; Volz, Hans-Peter; Riehemann, Stefan; Wenda, Berit; Roessger, Grit; Rzanny, Reinhard; Sauer, Heinrich

    1999-05-01

    Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) has gained much interest in schizophrenia research in the last years since it allows the non-invasive measurement of high- energy phosphates and phospholipids in vivo. We investigated hemispherical differences of the concentrations of different phosphorus compounds in the frontal lobes. For this purpose, well defined volumes in the dorsolateral prefrontal cortex of 32 healthy controls and 51 schizophrenic patients were examined. Schizophrenic patients showed significant lateralization effects of phosphodiesters (PDE) and the intracellular pH-value. Differences in the lateralization of 31P-MRS parameters between patients and healthy volunteers were only detected for the pH-value. While healthy controls exhibit lower pH-values in the left frontal lobe (6.96), in schizophrenic patients we found lower pH-values in the right (6.89). Detailed examinations showed that this effect is mainly based on the subgroup of schizophrenics who received atypical neuroleptic medication.

  16. Evaluation of [sup 31]P magnetic resonance spectroscopy localization techniques in human myocardium and soft-tissue sarcomas

    SciTech Connect

    Li, Chun-Wei.

    1993-01-01

    The overall goals of this thesis are to establish and evaluate [sup 31]P MR spectroscopy localization techniques for their application to the study of human myocardium and sarcomas. Several localization techniques which include 1D-CSI, ISIS, ISIS/CSI, and 2D-CSI were evaluated in the myocardial muscle of normal subjects and patients receiving 5-fluorouracil (5-FU) chemotherapy. Among these localization techniques, 2D-CSI is recommended since it shows good selectivity, good flexibility and a good compromise between sensitivity patient toleration limits. These localization techniques were also evaluated in patients with osteosarcoma and soft-tissue sarcomas. Among these localization techniques, 1D-CSI is recommended for big and superficial tumors. Further definition of the voxel is provided by using 2D-CSI or 3D-CSI in the case of small or deep seated tumors. Several techniques that should improve the [sup 31]P MR spectroscopic study of patients in the future are evaluated on the phantom. These include the presaturation of the chest wall muscle for improved myocardial spectral using the CSI sequence, implementation of the BIR-4 pulse for variable angle adjustable pulse, and the proton decoupling technique for improved resolution and sensitivity. The good performance of the phantoms studies show that these techniques can be further extended to the normal subject and patient studies.

  17. Fructose-induced aberration of metabolism in familial gout identified by sup 31 P magnetic resonance spectroscopy

    SciTech Connect

    Seegmiller, J.E. Univ. of California, San Diego ); Dixon, R.M.; Kemp, G.J.; Rajagopalan, B.; Radda, G.K. ); Angus, P.W. Austin Hospital, Heidelburg, Victoria ); McAlindon, T.E.; Dieppe, P. )

    1990-11-01

    The hyperuricemia responsible for the development of gouty arthritis results from a wide range of environmental factors and underlying genetically determined aberrations of metabolism. {sup 31}P magnetic resonance spectroscopy studies of children with hereditary fructose intolerance revealed a readily detectable rise in phosphomonoesters with a marked fall in inorganic phosphate in their liver in vivo and a rise in serum urate in response to very low doses of oral fructose. Parents and some family members heterozygous for this enzyme deficiency showed a similar pattern when given a substantially larger dose of fructose. Three of the nine heterozygotes thus identified also had clinical gout, suggesting the possibility of this defect being a fairly common cause of gout. In the present study this same noninvasive technology was used to identify the same spectral pattern in 2 of the 11 families studied with hereditary gout. In one family, the index patient's three brothers and his mother all showed the fructose-induced abnormality of metabolism, in agreement with the maternal inheritance of metabolism, in agreement with the maternal inheritance of the gout in this family group. The test dose of fructose used produced a significantly larger increment in the concentration of serum urate in the patients showing the changes in {sup 31}P magnetic resonance spectra than in the other patients with familial gout or in nonaffected members, thus suggesting a simpler method for initial screening for the defect.

  18. 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

  19. FTIR and {sup 31}P-NMR spectroscopic analyses of surface species in phosphate-catalyzed lactic acid conversion

    SciTech Connect

    Gunter, G.C.; Tam, M.S.; Miller, D.J.

    1996-11-01

    The surface species present on silica/alumina-supported sodium phosphates, active catalysts for the conversion of lactic acid to acrylic acid and 2,3-pentanedione, are examined by pre- and postreaction MAS {sup 31}P-NMR and FTIR spectroscopies. Species present following lactic acid conversion are identified by transmission FTIR of phosphates supported on silicon disks (as a model catalyst system) and verified by {sup 31}P-NMR and diffuse reflectance IR spectroscopy of actual catalysts used in reaction. Monosodium phosphate (NaH{sub 2}PO{sub 4}) condenses to a mixture of sodium polyphosphate (NaPO{sub 3}){sub n} and sodium trimetaphosphate (Na{sub 3}P{sub 3}O{sub 9}), which exhibit little catalytic activity for converting lactic acid to desired products. Disodium phosphate (Na{sub 2}HPO{sub 4}) condenses to tetrasodium pyrophosphate (Na{sub 4}P{sub 2}O{sub 7}), and proton transfer from lactic acid to pyrophosphate results in the formation of sodium lactate. Trisodium phosphate (Na{sub 3}PO{sub 4}) accepts a proton from lactic acid to form sodium lactate and disodium phosphate, which condenses to pyrophosphate. The presence of pyrophosphate and sodium lactate on supported disodium and trisodium phosphates explains their similar catalytic properties; the larger quantity of sodium lactate present on trisodium phosphate leads to higher conversions at lower temperatures. 40 refs., 14 figs., 2 tabs.

  20. 1H NMR spectra part 31: 1H chemical shifts of amides in DMSO solvent.

    PubMed

    Abraham, Raymond J; Griffiths, Lee; Perez, Manuel

    2014-07-01

    The (1)H chemical shifts of 48 amides in DMSO solvent are assigned and presented. The solvent shifts Δδ (DMSO-CDCl3 ) are large (1-2 ppm) for the NH protons but smaller and negative (-0.1 to -0.2 ppm) for close range protons. A selection of the observed solvent shifts is compared with calculated shifts from the present model and from GIAO calculations. Those for the NH protons agree with both calculations, but other solvent shifts such as Δδ(CHO) are not well reproduced by the GIAO calculations. The (1)H chemical shifts of the amides in DMSO were analysed using a functional approach for near ( ≤ 3 bonds removed) protons and the electric field, magnetic anisotropy and steric effect of the amide group for more distant protons. The chemical shifts of the NH protons of acetanilide and benzamide vary linearly with the π density on the αN and βC atoms, respectively. The C=O anisotropy and steric effect are in general little changed from the values in CDCl3. The effects of substituents F, Cl, Me on the NH proton shifts are reproduced. The electric field coefficient for the protons in DMSO is 90% of that in CDCl3. There is no steric effect of the C=O oxygen on the NH proton in an NH…O=C hydrogen bond. The observed deshielding is due to the electric field effect. The calculated chemical shifts agree well with the observed shifts (RMS error of 0.106 ppm for the data set of 257 entries). PMID:24824670

  1. 31P NMR study of magnetic phase transitions of MnP single crystal under 2 GPa pressure

    NASA Astrophysics Data System (ADS)

    Fan, GuoZhi; Zhao, Bo; Wu, Wei; Zheng, Ping; Luo, JianLin

    2016-05-01

    Superconductivity on the border of the long-range magnetic order has been discovered in MnP under high pressures. In order to investigate the nature of the magnetic properties adjacent to the superconducting state, we performed zero-field 31P NMR for MnP single crystal under ambient and hydrostatic pressure of 2 GPa, respectively. Radio frequency power level was used to determine whether NMR signal originates from a helical state or not. When 2 GPa pressure was applied, the signal from helical state exists even above 160 K, while that from the ferromagnetic phase was not observed. Our NMR results indicate that the magnetic phase which is adjacent to the superconducting state is in a helical magnetic structure.

  2. 31P NMR study of daunorubicin-d(CGTACG) complex in solution. Evidence of the intercalation sites.

    PubMed

    Ragg, E; Mondelli, R; Battistini, C; Garbesi, A; Colonna, F P

    1988-08-15

    The interaction of daunorubicin with the self-complementary DNA fragment d(CGTACG) was studied by 31P NMR spectroscopy. The individual phosphates have been assigned for the nucleotide and the complex and signals from bound and free species in slow exchange at 19 degrees C were detected. In solution, the hexanucleotide binds two molecules of daunorubicin, which intercalate in the d(CG) sequence at both ends of the helix. Evidence for local deformations of the backbone at the sites of C5pG6, C1pG2 and G2pT3 phosphates is given. The binding constants for the stepwise equilibrium and the rate of dissociation of the intercalated duplex were also determined. PMID:3402614

  3. Formation of Po isotopes in the reactions {sup 27}Al + {sup 175}Lu and {sup 31}P + {sup 169}Tm

    SciTech Connect

    Andreev, A.N.; Bogdanov, D.D.; Eremin, A.V.

    1995-05-01

    The excitation functions and the cross sections for the formation of {sup 192-198}Po isotopes in the reactions {sup 27}Al + {sup 175}Lu and {sup 31}P + {sup 169}Tm are measured. A comparison of the results obtained for these reactions with the data on the cross sections for the formation of Po isotopes in the reaction {sup 100}Mo + {sup 92-100}Mo leads to the conclusion that the characteristics of the evaporation channel do not depend on the mass of the bombarding ion up to the complete symmetry in the input channel. It is shown that the experimental data can be adequately described using the statistical approach to the deexcitation of a compound nucleus only under the assumption that the liquid-drop fission barrier is reduced significantly for neutron-deficient Po isotopes. 21 refs., 5 figs., 2 tabs.

  4. Analysis of 31P MAS NMR spectra and transversal relaxation of bacteriophage M13 and tobacco mosaic virus.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1994-01-01

    Phosphorus magic angle spinning nuclear magnetic resonance (NMR) spectra and transversal relaxation of M13 and TMV are analyzed by use of a model, which includes both local backbone motions of the encapsulated nucleic acid molecules and overall rotational diffusion of the rod-shaped virions about their length axis. Backbone motions influence the sideband intensities by causing a fast restricted reorientation of the phosphodiesters. To evaluate their influence on the observed sideband patterns, we extend the model that we used previously to analyze nonspinning 31P NMR lineshapes (Magusin, P.C.M.M., and M. A. Hemminga. 1993a. Biophys. J. 64:1861-1868) to magic angle spinning NMR experiments. Backbone motions also influence the conformation of the phosphodiesters, causing conformational averaging of the isotropic chemical shift, which offers a possible explanation for the various linewidths of the centerband and the sidebands observed for M13 gels under various conditions. The change of the experimental lineshape of M13 as a function of temperature and hydration is interpreted in terms of fast restricted fluctuation of the dihedral angles between the POC and the OCH planes on both sides of the 31P nucleus in the nucleic acid backbone. Backbone motions also seem to be the main cause of transversal relaxation measured at spinning rates of 4 kHz or higher. At spinning rates less than 2 kHz, transversal relaxation is significantly faster. This effect is assigned to slow, overall rotation of the rod-shaped M13 phage about its length axis. Equations are derived to simulate the observed dependence of T2e on the spinning rate. PMID:8038391

  5. Direct Speciation of Phosphorus in Alum-Amended Poultry Litter: Solid-State 31P NMR Investigation

    SciTech Connect

    Hunger, Stefan; Cho, Herman M.; Sims, James T.; Sparks, Donald L.

    2004-02-01

    Amending poultry litter (PL) with aluminum sulfate (alum) has proven to be effective in reducing water-soluble phosphorus (P) in the litter and in runoff from fields that have received PL applications; it has therefore been suggested as a best management practice. Although its effectiveness has been demonstrated on a macroscopic scale in the field, little is known about P speciation in either alumamended or unamended litter. This knowledge is important for the evaluation of the long-term stability and bioavailability of P, which is a necessary prerequisite for the assessment of the sustainability of intensive poultry operations. Both solid state MAS and CP-MAS {sup 31}P NMR as well as {sup 31}P({sup 27}Al) TRAPDOR were used to investigate P speciation in alumamended and unamended PL. The results indicate the presence of a complex mixture of organic and inorganic orthophosphate phases. A calcium phosphate phase, probably a surface precipitate on calcium carbonate, could be identified in both unamended and alum-amended PL, as well as physically bound HPO{sub 4}{sup 2-}. Phosphate associated with Al was found in the alum-amended PL, most probably a mixture of a poorly ordered wavellite and phosphate surface complexes on aluminum hydroxide that had been formed by the hydrolysis of alum. However, a complex mixture of organic and inorganic phosphate species could not be resolved. Phosphate associated with Al comprised on average 40{+-}14% of the total P in alum-amended PL, whereas calcium phosphate phases comprised on average 7{+-}4% in the alum-amended PL and 14{+-}5% in the unamended PL.

  6. sup 31 P nuclear magnetic resonance study of the effect of azide on xylose fermentation by Candida tropicalis

    SciTech Connect

    Lohmeier-Vogel, E.; Vogel, H. ); Skoog, K.; Hahn-Haegerdal, B. )

    1989-08-01

    Maximal ethanol production by Candida tropicalis grown on xylose was obtained at an oxygen transfer rate of 5 to 7 mmol/liter per h. Addition of 0.2 mM azide increased the ethanol yield by a factor of 3 to 4, based on the cell mass produced, and decreased the formation of the by-product xylitol by 80%. In the presence of azide, ethanol was reassimilated before the carbon source was depleted. At all oxygenation levels studied, azide caused 25 to 60% of the carbon to be lost, most probable as carbon dioxide. Identical spectra were obtained with {sup 31}P nuclear magnetic resonance spectroscopy performed on extracts of C. tropicalis grown on xylose in the absence and presence of azide. Azide lowered the levels of sugar phosphates. Enzymatic analysis showed extremely low levels of fructose 1,6-diphosphate compared with the levels obtained in the absence of azide, while the level of malate, a citric acid cycle intermediate, was not influenced by azide. {sup 31}P nuclear magnetic resonance spectroscopy performed on xylose-grown whole cells of C. tropicalis showed that azide lowered the intracellular pH, inhibited the uptake of external P{sub i}, and decreased the buildup of polyphosphate in relation to results with untreated cells. Similar results were obtained with the uncoupler of oxidative phosphorylation carbonyl cyanide m-chlorophenylhydrazone (CCCP), except that CCCP treatment led to extremely high levels of internal P{sub i}. The dual effect of azide as a respiratory inhibitor and as an uncoupler is discussed with respect to the metabolism and product formation in xylose-assimilating C. tropicalis.

  7. /sup 31/P NMR probes of sipunculan erythrocytes containing the O/sub 2/-carying protein hemerythrin

    SciTech Connect

    Robitaille, P.M.L.; Kurtz, D.M. Jr

    1988-06-14

    Reported are the first examinations by /sup 31/P NMR of erythrocytes containing the non-heme iron O/sub 2/ carrying protein hemerythrin (Hr). Intact coelomic erythrocytes from the sipunculids Phascolopsis gouldii and Themiste zostericola were shown by /sup 31/P NMR to contain O-phosphorylethanolamine and 2-amino-ethylphosphonate as the major soluble phosphorus metabolites. This combination of major metabolites appears to be unique to sipunculan erythrocytes. Nucleoside triphosphates and mannose 1-phosphate were present in lower concentrations. The concentration of O-phosphorylethanolamine within P. gouldii erythrocytes was established to be > 20 mM. T. zostericola erythrocytes contained relatively high levels of 2-amino-ethylphosphonate and lower levels of O-phosphorylethanolamine compared with those of P. gouldii. For P. gouldii and T. zostericola the intracellular pHs were determined to be 7.2 +/- 0.1 and 7.1 +/- 0.1, respectively, in air-equilibrated erythrocytes, and 6.5 +/- 0.1 in anaerobic P. gouldii erythrocytes. O-Phosphorylethanolamine was found to bind weakly to P. gouldii metHr. This interaction is best characterized by either negative cooperativity or nonspecific binding. O-phosphorylethanolamine strongly inhibits azide binding to the iron site of P. gouldii metHr at pH 7.2. The rate of azide binding decreases by approx. 85-fold in the presence of 0.33 M O-phosphorylethanolamine. However, neither O-phosphorylethanolamine nor 2-aminoethylphosphonate at 0.33 M was found to have any significant effect on O/sub 2/ affinity of P. gouldii deoxyHr. Alternative functions for the two metabolites are suggested.

  8. Determination of neo- and D-chiro-inositol hexakisphosphate in soils by solution 31P NMR spectroscopy.

    PubMed

    Turner, Benjamin L; Cheesman, Alexander W; Godage, H Yasmin; Riley, Andrew M; Potter, Barry V L

    2012-05-01

    The inositol phosphates are an abundant but poorly understood group of organic phosphorus compounds found widely in the environment. Four stereoisomers of inositol hexakisphosphate (IP(6)) occur, although for three of these (scyllo, neo, and D-chiro) the origins, dynamics, and biological function remain unknown, due in large part to analytical limitations in their measurement in environmental samples. We synthesized authentic neo- and D-chiro-IP(6) and used them to identify signals from these compounds in three soils from the Falkland Islands. Both compounds resisted hypobromite oxidation and gave quantifiable (31)P NMR signals at δ = 6.67 ppm (equatorial phosphate groups of the 4-equatorial/2-axial conformer of neo-IP(6)) and δ = 6.48 ppm (equatorial phosphate groups of the 2-equatorial/4-axial conformer of D-chiro-IP(6)) in soil extracts. Inositol hexakisphosphate accounted for 46-54% of the soil organic phosphorus, of which the four stereoisomers constituted, on average, 55.9% (myo), 32.8% (scyllo), 6.1% (neo), and 5.2% (D-chiro). Reappraisal of the literature based on the new signal assignments revealed that neo- and D-chiro-IP(6) occur widely in both terrestrial and aquatic ecosystems. These results confirm that the inositol phosphates can constitute a considerable fraction of the organic phosphorus in soils and reveal the prevalence of neo- and D-chiro-IP(6) in the environment. The hypobromite oxidation and solution (31)P NMR spectroscopy procedure allows the simultaneous quantification of all four IP(6) stereoisomers in environmental samples and provides a platform for research into the origins and ecological significance of these enigmatic compounds. PMID:22489788

  9. Analysis of 31P nuclear magnetic resonance lineshapes and transversal relaxation of bacteriophage M13 and tobacco mosaic virus.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1993-01-01

    The experimentally observed 31P lineshapes and transversal relaxation of 15% (wt/wt) M13, 30% M13, and 30% tobacco mosaic virus (TMV) are compared with lineshapes and relaxation curves that are simulated for various types of rotational diffusion using the models discussed previously (Magusin, P. C. M. M., and M. A. Hemminga. 1993. Biophys. J. 64:1851-1860). It is found that isotropic diffusion cannot explain the observed lineshape effects. A rigid rod diffusion model is only successful in describing the experimental data obtained for 15% M13. For 30% M13 the experimental lineshape and relaxation curve cannot be interpreted consistently and the TMV lineshape cannot even be simulated alone, indicating that the rigid rod diffusion model does not generally apply. A combined diffusion model with fast isolated motions of the encapsulated nucleic acid dominating the lineshape and a slow overall rotation of the virion as a whole, which mainly is reflected in the transversal relaxation, is able to provide a consistent picture for the 15 and 30% M13 samples, but not for TMV. Strongly improved lineshape fits for TMV are obtained assuming that there are three binding sites with different mobilities. The presence of three binding sites is consistent with previous models of TMV. The best lineshapes are simulated for a combination of one mobile and two static sites. Although less markedly, the assumption that two fractions of DNA with different mobilities exist within M13 also improves the simulated lineshapes. The possible existence of two 31P fractions in M13 sheds new light on the nonintegral ratio 2.4:1 between the number of nucleotides and protein coat subunits in the phage: 83% of the viral DNA is less mobile, suggesting that the binding of the DNA molecule to the protein coat actually occurs at the integral ratio of two nucleotides per protein subunit. PMID:8369412

  10. Characterization of phosphorus forms in lake macrophytes and algae by solution (31)P nuclear magnetic resonance spectroscopy.

    PubMed

    Feng, Weiying; Zhu, Yuanrong; Wu, Fengchang; Meng, Wei; Giesy, John P; He, Zhongqi; Song, Lirong; Fan, Mingle

    2016-04-01

    Debris from aquatic macrophytes and algae are important recycling sources of phosphorus (P), which can result in continuing blooms of algae by recycling bioavailable P in the eutrophic lakes. However, knowledge of forms of P in aquatic macrophytes and algae and their contribution to internal loads of P in lakes is limited. Without such knowledge, it is difficult to develop appropriate strategies to remediate and or restore aquatic ecosystems that have become eutrophic. Therefore, in this work, P was extracted from six types of aquatic macrophytes and algae collected from Tai Lake of China and characterized by use of solution (31)P-nuclear magnetic resonance (NMR) spectroscopy. When extracted by 0.5 M NaOH-25 mM EDTA, extraction recovery of total P(TP) and organic P(Po) exceeded 90 %. Concentrations of Po in algae and aquatic macrophytes were 5552 mg kg(-1) and 1005 mg kg(-1) and accounted for 56.0 and 47.2 % of TP, respectively. When Po, including condensed P, was characterized by solution (31)P-NMR Po in algae included orthophosphate monoesters (79.8 %), pyrophosphate (18.2 %), and orthophosphate diester (2.0 %), and Po in aquatic macrophytes included orthophosphate monoesters (90.3 %), pyrophosphate (4.2 %), and orthophosphate diester (5.5 %). Additionally, orthophosphate monoesters in algal debris mainly included β-glycerophosphate (44.1 %), α-glycerophosphate (13.5 %), and glucose 6-phosphate (13.5 %). Orthophosphate monoesters in aquatic macrophytes mainly included β-glycerophosphate (27.9 %), α-glycerophosphate (24.6 %), and adenosine 5' monophosphate (8.2 %). Results derived from this study will be useful in better understanding nutrient cycling, relevant eutrophication processes, and pollution control for freshwater lakes. PMID:26681323

  11. Evaluation of recombinant CXCL8(3-73)K11R/G31P in muscle fibrosis and Trichinella larvae encapsulation in a murine model of trichinellosis.

    PubMed

    Yan, Wenhui; Li, Fang; Qin, Yuanhua; Ren, Yixin; Zheng, Lili; Dai, Xiaodong; Mao, Weifeng; Cui, Yu

    2016-06-01

    Trichinella spiralis (T. spiralis) larvae in raw or inadequately cooked meat can cause chronic infections in a wide range of hosts including humans. During the development inside the skeletal muscles, T. spiralis larvae infect muscle cells accompanying with the infiltration of host inflammatory cells, eventually create a new type of cell known as nurse cell developing a surrounding vascular network to support the larvae development. Controlling of host inflammatory responses and angiogenesis influences both the nurse cell differentiation and the parasite larvae development. CXCL8 is a chemokine that acts on G-protein coupled receptors, of which activation contributes to fibrosis and angiogenesis. CXCL8(3-73)K11R/G31P (G31P) has been reported as a CXCL8 analogue. The aim of this study is to investigate the effect of G31P in inflammatory responses and the development of T. spiralis larvae in muscle tissues of mice infected with T. spiralis. The level of inflammatory factors and the morphology of T. spiralis larvae in infected tissues were investigated through ELISA and electron-microscopy analysis. G31P up-regulated IFN-γ and down-regulated CXCL8 level, and impaired the encapsulation of T. spiralis larvae in vivo. The results showed that G31P influenced the development of T. spiralis larvae in muscle tissues. PMID:27089392

  12. Rotation of Lipids in Membranes: Molecular Dynamics Simulation, 31P Spin-Lattice Relaxation, and Rigid-Body Dynamics

    PubMed Central

    Klauda, Jeffery B.; Roberts, Mary F.; Redfield, Alfred G.; Brooks, Bernard R.; Pastor, Richard W.

    2008-01-01

    Molecular dynamics simulations and 31P-NMR spin-lattice (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}R_{1}\\end{equation*}\\end{document}) relaxation rates from 0.022 to 21.1 T of fluid phase dipalmitoylphosphatidylcholine bilayers are compared. Agreement between experiment and direct prediction from simulation indicates that the dominant slow relaxation (correlation) times of the dipolar and chemical shift anisotropy spin-lattice relaxation are ∼10 ns and 3 ns, respectively. Overall reorientation of the lipid body, consisting of the phosphorus, glycerol, and acyl chains, is well described within a rigid-body model. Wobble, with \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}D_{{\\bot}}=\\end{equation*}\\end{document} 1–2 × 108 s−1, is the primary component of the 10 ns relaxation; this timescale is consistent with the tumbling of a lipid-sized cylinder in a medium with the viscosity of liquid hexadecane. The value for \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}D_{{\\Vert}},\\end{equation*}\\end{document} the diffusion constant for rotation about the long axis of the lipid body, is difficult to determine precisely because of averaging by fast motions and wobble; it is tentatively estimated to be 1 × 107 s−1. The resulting D‖/D⊥

  13. The effects of pregnancy and parturition on phosphorus metabolites in rat uterus studied by 31P nuclear magnetic resonance.

    PubMed Central

    Dawson, M J; Wray, S

    1985-01-01

    Concentrations of phosphorus metabolites and intracellular pH have been measured in non-pregnant, late-pregnant and post-partum rat uterus using 31P nuclear magnetic resonance (31P n.m.r.). Intact uterine tissue was superfused with oxygenated de-Jalon solution at 4, 20 or 37 degrees C while inside the n.m.r. spectrometer. The phosphocreatine concentration [PCr], was higher and the inorganic phosphate concentration [Pi], lower than values determined by chemical analysis of extracts from both pregnant and non-pregnant rat uterus. [PCr] was 1.4-fold greater in late-pregnant than in non-pregnant rat uterus. Following parturition, large changes were observed in [PCr], [Pi] and in an unidentified metabolite in the phosphomonoester (PME) region of the n.m.r. spectrum. The time course of the recovery of these metabolites to prepregnant values was determined. The [PCr] remained below the non-pregnant value for at least 1 week post-partum and the [Pi] was elevated, compared to the non-pregnant value, during this period. More rapid changes were seen in the [PME], which doubled on day 0 post-partum but almost returned to its non-pregnant value on day 1 post-partum. No significant difference was observed between intracellular pH values in late-pregnant and non-pregnant rat uterus; however, there was a large acid shift following parturition. Intracellular pH depended upon the temperature at which the tissue was maintained. The effect of muscular work during parturition was investigated by comparing Caesarian-sectioned uteri with uteri which had undergone normal parturition. Uteri examined 1 day after Caesarian operation showed no differences in metabolite levels from normal, 1 day post-partum uteri. We conclude that concentrations of phosphorus metabolites depend upon the physiological state of the uterus. We suggest that the changes following parturition are not a consequence of the mechanical work performed by the uterus, but must be caused by some other event associated with

  14. Interactions of ciprofloxacin with DPPC and DPPG: fluorescence anisotropy, ATR-FTIR and 31P NMR spectroscopies and conformational analysis.

    PubMed

    Bensikaddour, Hayet; Snoussi, Karim; Lins, Laurence; Van Bambeke, Françoise; Tulkens, Paul M; Brasseur, Robert; Goormaghtigh, Erik; Mingeot-Leclercq, Marie-Paule

    2008-11-01

    The interactions between a drug and lipids may be critical for the pharmacological activity. We previously showed that the ability of a fluoroquinolone antibiotic, ciprofloxacin, to induce disorder and modify the orientation of the acyl chains is related to its propensity to be expelled from a monolayer upon compression [1]. Here, we compared the binding of ciprofloxacin on DPPC and DPPG liposomes (or mixtures of phospholipids [DOPC:DPPC], and [DOPC:DPPG]) using quasi-elastic light scattering and steady-state fluorescence anisotropy. We also investigated ciprofloxacin effects on the transition temperature (T(m)) of lipids and on the mobility of phosphate head groups using Attenuated Total Reflection Fourier Transform Infrared-Red Spectroscopy (ATR-FTIR) and (31)P Nuclear Magnetic Resonance (NMR) respectively. In the presence of ciprofloxacin we observed a dose-dependent increase of the size of the DPPG liposomes whereas no effect was evidenced for DPPC liposomes. The binding constants K(app) were in the order of 10(5) M(-1) and the affinity appeared dependent on the negative charge of liposomes: DPPG>DOPC:DPPG (1:1; M:M)>DPPC>DOPC:DPPC (1:1; M:M). As compared to the control samples, the chemical shift anisotropy (Deltasigma) values determined by (31)P NMR showed an increase of 5 and 9 ppm for DPPC:CIP (1:1; M:M) and DPPG:CIP (1:1; M:M) respectively. ATR-FTIR experiments showed that ciprofloxacin had no effect on the T(m) of DPPC but increased the order of the acyl chains both below and above this temperature. In contrast, with DPPG, ciprofloxacin induced a marked broadening effect on the transition with a decrease of the acyl chain order below its T(m) and an increase above this temperature. Altogether with the results from the conformational analysis, these data demonstrated that the interactions of ciprofloxacin with lipids depend markedly on the nature of their phosphate head groups and that ciprofloxacin interacts preferentially with anionic lipid compounds

  15. Metabolic responses to forced dives in Pekin duck measured by indirect calorimetry and 31P-MRS.

    PubMed

    Stephenson, R; Jones, D R

    1992-12-01

    We tested the hypothesis that forced-dived ducks experience a reduction in metabolic rate during prolonged submergence. Unidirectionally ventilated conscious ducks were subjected to forced dives by temporarily stopping the airflow in the ventilation system and simultaneously filling a face mask with cold water. A typical cardiovascular response to submergence was observed: bradycardia and maintained arterial blood pressure. Phosphorylated metabolite concentrations in the pectoral muscle were measured noninvasively by phosphorus magnetic resonance spectroscopy (31P-MRS). ATP content was constant, and phosphocreatine was depleted via the creatine kinase reaction at a rate similar to the resting rate of ATP turnover, which was estimated to be 0.9 mumol.min-1 x g-1 in resting perfused pectoral muscle of pentobarbital-anesthetized ducks. Oxygen from myoglobin supplied at most 12% of the ATP required by the resting muscle during dives. Whole animal postdive excess oxygen consumption and blood lactic acid accumulation suggested that the shortfall in aerobic metabolism during forced dives was compensated by an increase in anaerobic metabolism. PMID:1481944

  16. Skeletal muscle ATP synthesis and cellular H+ handling measured by localized 31P-MRS during exercise and recovery

    PubMed Central

    Fiedler, Georg B.; Schmid, Albrecht I.; Goluch, Sigrun; Schewzow, Kiril; Laistler, Elmar; Niess, Fabian; Unger, Ewald; Wolzt, Michael; Mirzahosseini, Arash; Kemp, Graham J.; Moser, Ewald; Meyerspeer, Martin

    2016-01-01

    31P magnetic resonance spectroscopy (MRS) is widely used for non-invasive investigation of muscle metabolism dynamics. This study aims to extend knowledge on parameters derived from these measurements in detail and comprehensiveness: proton (H+) efflux, buffer capacity and the contributions of glycolytic (L) and oxidative (Q) rates to ATP synthesis were calculated from the evolutions of phosphocreatine (PCr) and pH. Data are reported for two muscles in the human calf, for each subject and over a wide range of exercise intensities. 22 subjects performed plantar flexions in a 7T MR-scanner, leading to PCr changes ranging from barely noticeable to almost complete depletion, depending on exercise protocol and muscle studied by localized MRS. Cytosolic buffer capacity was quantified for the first time non-invasively and individually, as was proton efflux evolution in early recovery. Acidification started once PCr depletion reached 60–75%. Initial and end-exercise L correlated with end-exercise levels of PCr and approximately linear with pH. Q calculated directly from PCr and pH derivatives was plausible, requiring fewer assumptions than the commonly used ADP-model. In conclusion, the evolution of parameters describing cellular energy metabolism was measured over a wide range of exercise intensities, revealing a relatively complete picture of muscle metabolism. PMID:27562396

  17. In vivo /sup 31/P NMR studies of corn root tissue and its uptake of toxic metals. [Zea mays L

    SciTech Connect

    Pfeffer, P.E.; Tu, S.I.; Gerasimowicz, W.V.; Cavanaugh, J.R.

    1986-01-01

    Excised corn root tissue has been evaluated for its viability, integrity of compartmentation, intracellular pH gradients, total mobile phosphorus content and nucleotide concentrations under different levels of acidity, and mineral stresses using in vivo /sup 31/P nuclear magnetic resonance spectroscopy at 21 to 23/sup 0/C. Perfusion with Al/sup 3 +/ ion at low pH (4.0) for 20 hours caused the overall concentration of nucleotides in the cytoplasm to decrease significantly relative to the control. Respiratory activity as measured by O/sub 2/ uptake decreased by a comparable amount over this time period. The addition of glucose to the Al-containing perfusate negated the inhibitory effects on the respiratory system. Treatment of the tissue with paramagnetic manganese ion while perfusing in the presence of O/sub 2/ allowed for the observation of the sequence of events leading to the irreversible trapping of Mn/sup 2 +/ in the vacuole. Pretreatment of the roots with Mg/sup 2 +/ prevented Mn/sup 2 +/ migration to the vacuole over the time period of this experiment. Hypoxia prevented all but a limited uptake of Mn/sup 2 +/ into the cytoplasm of the root tips. No evidence of Mn/sup 2 +/ complexation of either cytoplasmic or vacuole Pi suggests that the energy derived from O/sub 2/ consuming processes is necessary for the facilitated movement of this divalent cation.

  18. Centerband-only analysis of rotor-unsynchronized spin echo for measurement of lipid (31) P chemical shift anisotropy.

    PubMed

    Umegawa, Yuichi; Yamaguchi, Toshiyuki; Murata, Michio; Matsuoka, Shigeru

    2015-07-01

    Structural diversity and molecular flexibility of phospholipids are essential for biological membranes to play key roles in numerous cellular processes. Uncovering the behavior of individual lipids in membrane dynamics is crucial for understanding the molecular mechanisms underlying biological functions of cell membranes. In this paper, we introduce a simple method to investigate dynamics of lipid molecules in multi-component systems by measuring the (31) P chemical shift anisotropy (CSA) under magic angle spinning (MAS) conditions. For achieving both signal separation and CSA determination, we utilized a centerband-only analysis of rotor-unsynchronized spin echo (COARSE). This analysis is based on the curve fitting of periodic modulation of centerband intensity along the interpulse delay time in rotor-unsynchronized spin-echo experiments. The utility of COARSE was examined by using phospholipid vesicles, a three-component lipid raft model system, and archaeal purple membranes. We found that the apparent advantages of this method are high resolution and high sensitivity given by the moderate MAS speed and the one-dimensional acquisition with short spin-echo delays. COARSE provides an alternative method for CSA measurement that is effective in the investigation of lipid polymorphologies. PMID:26017552

  19. Characterization of the phosphoserine of pepsinogen using /sup 31/P nuclear magnetic resonance: corroboration of X-ray crystallographic results

    SciTech Connect

    Williams, S.P.; Bridger, W.A.; James, M.N.G.

    1986-10-21

    The endogenous phosphoserine residue in porcine pepsinogen has been titrated with use of phosphorus-31 nuclear magnetic resonance (/sup 31/P NMR). It has an observed pK/sub a/sub 2// of 6.7 and a narrow line width (approx. =10 Hz). The phosphate can be readily removed by an acid phosphatase from potato; however, it is resistant to hydrolysis by several alkaline phosphatases. The X-ray crystal structure of porcine pepsinogen at 1.8-A resolution shows a rather weak and diffuse region of electron density in the vicinity of the phosphorylated serine residue. This suggests considerable dynamic mobility or conformational disorder of the phosphate. In order to define more fully this behavior the NMR data have been used to corroborate these crystallographic results. All these physical data are consistent with a highly mobile phosphoserine residue on the surface of the zymogen and freely exposed to solvent. In addition, certain properties of this phosphoserine moiety on pepsinogen are similar to those of one of the phosphorylated residues of ovalbumin. The possible significance of this is discussed.

  20. Skeletal muscle ATP synthesis and cellular H(+) handling measured by localized (31)P-MRS during exercise and recovery.

    PubMed

    Fiedler, Georg B; Schmid, Albrecht I; Goluch, Sigrun; Schewzow, Kiril; Laistler, Elmar; Niess, Fabian; Unger, Ewald; Wolzt, Michael; Mirzahosseini, Arash; Kemp, Graham J; Moser, Ewald; Meyerspeer, Martin

    2016-01-01

    (31)P magnetic resonance spectroscopy (MRS) is widely used for non-invasive investigation of muscle metabolism dynamics. This study aims to extend knowledge on parameters derived from these measurements in detail and comprehensiveness: proton (H(+)) efflux, buffer capacity and the contributions of glycolytic (L) and oxidative (Q) rates to ATP synthesis were calculated from the evolutions of phosphocreatine (PCr) and pH. Data are reported for two muscles in the human calf, for each subject and over a wide range of exercise intensities. 22 subjects performed plantar flexions in a 7T MR-scanner, leading to PCr changes ranging from barely noticeable to almost complete depletion, depending on exercise protocol and muscle studied by localized MRS. Cytosolic buffer capacity was quantified for the first time non-invasively and individually, as was proton efflux evolution in early recovery. Acidification started once PCr depletion reached 60-75%. Initial and end-exercise L correlated with end-exercise levels of PCr and approximately linear with pH. Q calculated directly from PCr and pH derivatives was plausible, requiring fewer assumptions than the commonly used ADP-model. In conclusion, the evolution of parameters describing cellular energy metabolism was measured over a wide range of exercise intensities, revealing a relatively complete picture of muscle metabolism. PMID:27562396

  1. (31)P Solid-State NMR study of the chemical setting process of a dual-paste injectable brushite cements.

    PubMed

    Legrand, A P; Sfihi, H; Lequeux, N; Lemaître, J

    2009-10-01

    The composition and evolution of a brushite-type calcium phosphate cement was investigated by Solid-State NMR and X-ray during the setting process. The cement is obtained by mixing beta-tricalcium phosphate [Ca(3)(PO(4))(2), beta-TCP] and monocalcium phosphate monohydrate [Ca(H(2)PO(4))(2).H(2)O, MCPM] in presence of water, with formation of dicalcium phosphate dihydrate or brushite [CaHPO(2).2H(2)O, DCPD]. Analysis of the initial beta-TCP paste has shown the presence of beta-calcium pyrophosphate [Ca(2)P(2)O(7), beta-CPy] and that of the initial MCPM a mixture of MCPM and dicalcium phosphate [CaHPO(4), DCP]. Follow-up of the chemical composition by (31)P Solid-State NMR enables to show that the chemical setting process appeared to reach an end after 20 min. The constant composition observed at the end of the process was similarly determined. PMID:19365821

  2. Modulation of 2,3-diphosphoglycerate 31P-NMR resonance positions by red cell membrane shape.

    PubMed

    Fossel, E T; Solomon, A K

    1976-06-17

    Na+ transport in the red cells of the dog is dependent on cell volume, a 20% change in cell volume leading to a 25-fold increase in apparent Na+ flux; the effect is dependent upon metabolic energy. We have found that swelling and shrinking dog red cells causes a shift in the 31P-NMR peak of 2,3-diphosphoglycerate, which is present in dog red cells at 5.5 mM. Control experiments indicate that the 2,3-diphosphoglycerate resonance peak shifts may not be attributed to: interaction with hemoglobin, changes in cell pH, ionic strength, diamagnetic susceptibility or small changes in the Mg2+/2,3-diphosphoglycerate ratio. Experiments with chlorpromazine and pentanol which alter red cell membrane area by a mechanism different from osmotic swelling suggest that 2,3-diphosphoglycerate interacts with a binding site in the cell that is dependent upon the physical condition of the dog red cell membrane. PMID:1276226

  3. Phospholipid fingerprints of milk from different mammalians determined by 31P NMR: towards specific interest in human health.

    PubMed

    Garcia, Cyrielle; Lutz, Norbert W; Confort-Gouny, Sylviane; Cozzone, Patrick J; Armand, Martine; Bernard, Monique

    2012-12-01

    Our objective was to identify and quantify phospholipids in milk from different species (human HM, cow CoM, camel CaM, and mare MM) using an optimised (31)P NMR spectroscopy procedure. The phospholipid fingerprints were species-specific with a broader variety of classes found in HM and MM; HM and CaM were richer in sphingomyelin (78.3 and 117.5μg/ml) and plasmalogens (27.3 and 24μg/ml), possibly important for infant development. Total phospholipid content was higher in CaM (0.503mM) and lower in MM (0.101mM) compared to HM (0.324mM) or CoM (0.265mM). Our optimised method showed good sensitivity, high resolution, and easy sample preparation with minimal loss of target molecules. It is suitable for determining the accurate composition of a large number of bioactive phospholipids with putative health benefits, including plasmalogens, and should aid in selecting appropriate ingredient sources for infant milk substitutes or fortifiers, and for functional foods dedicated to adults. PMID:22953921

  4. Effects of chloramphenicol on brain energy metabolism using 31P spectroscopy: influences on sleep-wake states in rat.

    PubMed

    Chahboune, Halima; Mahdjoub, Rachid; Desgoutte, Pierre; Rousset, Colette; Briguet, André; Cespuglio, Raymond

    2008-08-01

    Effects of chloramphenicol (antibiotic inhibiting complex-1 of respiratory chain) and thioamphenicol (TAP, a structural analog of CAP inactive on complex-1) were examined on cerebral energy metabolites and sleep-wake cycle architecture in rat. In the first group, animals were chronically equipped with a cranial surface resonator and (31)P spectroscopic measurements were performed using a 2 T magnetic resonance spectrometer (operating frequency 34.46 MHz). CAP administration (400 mg/kg, tail vein, light period) induced deficits in phosphocreatine (-30%, p < 0.01) and ATP (-40%, p < 0.01), whereas TAP (400 mg/kg) had no effect. In the second group, animals were chronically implanted with polygraphic electrodes for EEG and electromyogram recordings. CAP administered intraperitoneally at light-onset reduced rapid-eye movement (REM) sleep (-60% in the first 6 h of light period, p < 0.01), increased waking state (+65% in the first 6 h of light period, p < 0.01), and slightly affected slow-wave sleep (SWS). During waking state, theta and sigma power bands of the EEG were, respectively, increased and decreased (p < 0.05). During SWS, delta power band was reinforced (p < 0.05), while theta, alpha, and sigma bands were decreased (p < 0.05). No changes occurred during REM sleep. TAP had no effect on sleep-wake states and spectral components of the EEG. Overall, these data indicate that REM sleep occurrence is linked to an aerobic production of ATP. PMID:18507739

  5. Simple and effective exercise design for assessing in vivo mitochondrial function in clinical applications using 31P magnetic resonance spectroscopy

    PubMed Central

    Sleigh, Alison; Lupson, Victoria; Thankamony, Ajay; Dunger, David B.; Savage, David B.; Carpenter, T. Adrian; Kemp, Graham J.

    2016-01-01

    The growing recognition of diseases associated with dysfunction of mitochondria poses an urgent need for simple measures of mitochondrial function. Assessment of the kinetics of replenishment of the phosphocreatine pool after exercise using 31P magnetic resonance spectroscopy can provide an in vivo measure of mitochondrial function; however, the wider application of this technique appears limited by complex or expensive MR-compatible exercise equipment and protocols not easily tolerated by frail participants or those with reduced mental capacity. Here we describe a novel in-scanner exercise method which is patient-focused, inexpensive, remarkably simple and highly portable. The device exploits an MR-compatible high-density material (BaSO4) to form a weight which is attached directly to the ankle, and a one-minute dynamic knee extension protocol produced highly reproducible measurements of post-exercise PCr recovery kinetics in both healthy subjects and patients. As sophisticated exercise equipment is unnecessary for this measurement, our extremely simple design provides an effective and easy-to-implement apparatus that is readily translatable across sites. Its design, being tailored to the needs of the patient, makes it particularly well suited to clinical applications, and we argue the potential of this method for investigating in vivo mitochondrial function in new cohorts of growing clinical interest. PMID:26751849

  6. 13C/31P NMR studies on the role of glucose transport/phosphorylation in human glycogen supercompensation.

    PubMed

    Price, T B; Laurent, D; Petersen, K F

    2003-05-01

    This study measured muscle glycogen during a 7-day carbohydrate loading protocol. Twenty healthy subjects (12 male, 8 female) performed 1 hr treadmill/toe-raise exercise immediately before a 3-day low carbohydrate (LoCHO) diet (20 % carbohydrate, 60 % fat, 20 % protein). On day 3 they repeated the exercise and began a 4-day high carbohydrate (HiCHO) diet (90 % carbohydrate, 2 % fat, 8 % protein). The order of administration of the diet was reversed in a subpopulation (n = 3). Interleaved natural abundance 13C/ 31P NMR spectra were obtained before and immediately after exercise, and each day during the controlled diets in order to determine concentrations of glycogen (GLY), glucose-6-phosphate (G6P), and muscle pH. Following exercise, muscle GLY and pH were reduced (p < 0.001) while muscle G6P was elevated (p

  7. 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.

  8. Coal liquefaction process streams characterization and evaluation: Estimation of total phenol concentrations in coal liquefaction resids by [sup 31]P NMR spectroscopy

    SciTech Connect

    Mohan, J.T.; Verkade, J.G. )

    1992-11-01

    In this study, Iowa State University researchers used [sub 31]P-tagged reagents to derivatize the labile hydrogen functional groups in the THF-soluble portion of 850[degrees]F[sup +] distillation resid materials and the THF-soluble portion of process oils derived from direct coal liquefaction.[sup 31]P-NMR was used to analyze the derivatized samples. NMR peak assignments can be made by comparison to model compounds similarly derivatized. Species can be quantified by integration of the NMR signals. Different [sup 31]P-NMR tagged reagents can be used to produce different degrees of peak resolution in the NMR spectrum. This, in turn, partially dictates the degree of speciation and/or quantification of species, or classes of compounds, that can be accomplished. Iowa State chose a [sup 31]P-tagged reagent (ClPOCMe[sub 2]CMe[sub 2]O) which was shown previously to be particularly useful in the derivatization of phenols. The derivatized samples all exhibited a small group of peaks attributed to amines and a broad group of peaks in the phenol region. The presence of paramagnetic species in the samples caused the NMR signals to broaden. Electron paramagnetic resonance (EPR) spectra confirmed the presence of paramagnetic organic free radicals in selected samples. Various methods were employed to process the NMR data. The complexity and broadness of the phenol peak, however, made speciation of the phenols impractical.

  9. Coal liquefaction process streams characterization and evaluation: Estimation of total phenol concentrations in coal liquefaction resids by {sup 31}P NMR spectroscopy

    SciTech Connect

    Mohan, J.T.; Verkade, J.G.

    1992-11-01

    In this study, Iowa State University researchers used {sub 31}P-tagged reagents to derivatize the labile hydrogen functional groups in the THF-soluble portion of 850{degrees}F{sup +} distillation resid materials and the THF-soluble portion of process oils derived from direct coal liquefaction.{sup 31}P-NMR was used to analyze the derivatized samples. NMR peak assignments can be made by comparison to model compounds similarly derivatized. Species can be quantified by integration of the NMR signals. Different {sup 31}P-NMR tagged reagents can be used to produce different degrees of peak resolution in the NMR spectrum. This, in turn, partially dictates the degree of speciation and/or quantification of species, or classes of compounds, that can be accomplished. Iowa State chose a {sup 31}P-tagged reagent (ClPOCMe{sub 2}CMe{sub 2}O) which was shown previously to be particularly useful in the derivatization of phenols. The derivatized samples all exhibited a small group of peaks attributed to amines and a broad group of peaks in the phenol region. The presence of paramagnetic species in the samples caused the NMR signals to broaden. Electron paramagnetic resonance (EPR) spectra confirmed the presence of paramagnetic organic free radicals in selected samples. Various methods were employed to process the NMR data. The complexity and broadness of the phenol peak, however, made speciation of the phenols impractical.

  10. Brief Report: Approaches to [Superscript 31]P-MRS in Awake, Non-Sedated Children with and without Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Erickson, Laura C.; Scott-Van Zeeland, Ashley A.; Hamilton, Gavin; Lincoln, Alan; Golomb, Beatrice A.

    2012-01-01

    We piloted a suite of approaches aimed to facilitate a successful series of up to four brain and muscle [superscript 31]Phosphorus-Magnetic Resonance Spectroscopy ([superscript 31]P-MRS) scans performed in one session in 12 "awake", non-sedated subjects (ages 6-18), 6 with autism spectrum disorders (ASD) and 6 controls. We targeted advanced…

  11. Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

    PubMed Central

    Singh, Manish K; Kumar, Mukesh; Chamala, Raghu Ram; Yedulla, Vijayender R; Wagner, Domenick; Leung, Evan; Yang, Lijia; Matin, Asha; Ahmad, Sadia

    2014-01-01

    Summary (1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From 31P{1H}, [18O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO− and AtO− produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO− is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd π–allyl complexes by departure of BtO− has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis. PMID:25246951

  12. In vivo mouse myocardial (31)P MRS using three-dimensional image-selected in vivo spectroscopy (3D ISIS): technical considerations and biochemical validations.

    PubMed

    Bakermans, Adrianus J; Abdurrachim, Desiree; van Nierop, Bastiaan J; Koeman, Anneke; van der Kroon, Inge; Baartscheer, Antonius; Schumacher, Cees A; Strijkers, Gustav J; Houten, Sander M; Zuurbier, Coert J; Nicolay, Klaas; Prompers, Jeanine J

    2015-10-01

    (31)P MRS provides a unique non-invasive window into myocardial energy homeostasis. Mouse models of cardiac disease are widely used in preclinical studies, but the application of (31)P MRS in the in vivo mouse heart has been limited. The small-sized, fast-beating mouse heart imposes challenges regarding localized signal acquisition devoid of contamination with signal originating from surrounding tissues. Here, we report the implementation and validation of three-dimensional image-selected in vivo spectroscopy (3D ISIS) for localized (31)P MRS of the in vivo mouse heart at 9.4 T. Cardiac (31)P MR spectra were acquired in vivo in healthy mice (n = 9) and in transverse aortic constricted (TAC) mice (n = 8) using respiratory-gated, cardiac-triggered 3D ISIS. Localization and potential signal contamination were assessed with (31)P MRS experiments in the anterior myocardial wall, liver, skeletal muscle and blood. For healthy hearts, results were validated against ex vivo biochemical assays. Effects of isoflurane anesthesia were assessed by measuring in vivo hemodynamics and blood gases. The myocardial energy status, assessed via the phosphocreatine (PCr) to adenosine 5'-triphosphate (ATP) ratio, was approximately 25% lower in TAC mice compared with controls (0.76 ± 0.13 versus 1.00 ± 0.15; P < 0.01). Localization with one-dimensional (1D) ISIS resulted in two-fold higher PCr/ATP ratios than measured with 3D ISIS, because of the high PCr levels of chest skeletal muscle that contaminate the 1D ISIS measurements. Ex vivo determinations of the myocardial PCr/ATP ratio (0.94 ± 0.24; n = 8) confirmed the in vivo observations in control mice. Heart rate (497 ± 76 beats/min), mean arterial pressure (90 ± 3.3 mmHg) and blood oxygen saturation (96.2 ± 0.6%) during the experimental conditions of in vivo (31)P MRS were within the normal physiological range. Our results show that respiratory-gated, cardiac-triggered 3D ISIS allows for non-invasive assessments of in vivo

  13. sup 31 P NMR saturation-transfer study of the in situ kinetics of the mitochondrial adenine nucleotide translocase

    SciTech Connect

    Masiakos, P.T.; Williams, G.D.; Berkich, D.A.; Smith, M.B.; LaNoue, K.F. )

    1991-08-27

    The exchange of intramitochondrial ATP (ATP{sub in}) for extramitochondrial ATP (ATP{sub out}) was measured by using {sup 31}P NMR spectroscopy over a range of temperatures in isolated rat liver mitochondria oxidizing glutamate and succinate in the presence of external ATP but no added ADP (state 4). The rate of this exchange is more than an order of magnitude faster than rates reported previously that were determined by using isotopic techniques in the presence of oligomycin, the potent ATPase inhibitor. Differences are ascribed in part to the low levels of matrix ATP present in oligomycin-treated mitochondrial. Intramitochondrial ATP content regulates the rate of the ATP{sub in}/ATP{sub out} exchange. At 18C, the concentration of internal ATP that produces half-maximal transport rate is 6.6{plus minus}0.12 nmol/mg of mitochondrial protein. The relationship between substrate concentration and flux is sigmoidal and is 90% saturated at 11.3{plus minus}0.18 nmol/mg of mitochondrial protein. Since the measured rates of exchange of ATP{sub in} for ATP{sub out} are almost 10 times faster than the ATP synthase (ATP/P{sub i}) exchange rates, the translocase cannot limit net ATP/P{sub i} exchange in state 4. It may, nonetheless, limit net synthesis of ATP under other conditions when matrix ATP concentration is lower than in state 4 and when external ADP is present at higher concentrations than in these experiments.

  14. Decreased energy requirement of toad retina during light adaptation as demonstrated by 31P nuclear magnetic resonance.

    PubMed Central

    Apte, D V; Ebrey, T G; Dawson, M J

    1993-01-01

    1. The effect of light and dark adaptation on the levels of phosphorus metabolites (nucleotide di- and triphosphates, phosphocreatine, pyridine nucleotide, inorganic phosphate, phosphodiesters, phosphomonoesters, and uridine diphosphate-glucose) in the toad (Bufo marinus) retina and retinal extracts was studied by 31P nuclear magnetic resonance (NMR) spectroscopy. 2. Spectra were acquired using an NMR probe specifically designed for superfusion and illumination of a single retina. Retinae were maintained at a steady state for up to 10 h in an electrolyte solution containing 10 mM Hepes buffer and bubbled with 98% O2-2% CO2, pH 7.8 at 20 degrees C. 3. The intracellular concentrations of the phosphorus metabolites were measured in total darkness or during prolonged exposure to light. The concentration of nucleoside triphosphates (NTP) in the dark-adapted retina was about 1.5 mM and that of phosphocreatine (PCr) was about 0.7 mM. 4. In saturating levels of light, 6.0 x 10(11) or 1.5 x 10(13) quanta s-1 cm-2 at 520 nm, the levels of PCr and phosphomonoesters rose, the levels of NTP and protons (pH) were maintained, and the levels of pyridine nucleotides and nucleotide diphosphates (NDP) fell. 5. A rise in the level of PCr in the presence of an unchanged level of NTP in the light-adapted retina indicates that the energy consumption of the retina is greater in the dark. 6. These results are in agreement with the results of oxygen consumption, glucose dependence, and electrophysiological studies which also indicate that the metabolic energy requirement of the retina decreases in light. PMID:8229802

  15. Partial trisomy 2q due to a maternal balanced translocation t(2;22) (q31;p12)

    SciTech Connect

    Steinberg, L.S.; Bleiman, M.; Punnett, H.H.

    1994-09-01

    Features consistent among reported patients with 2q duplications due to familial translocations or de novo duplications include pre- and postnatal growth failure, ocular defects such as congenital glaucoma, cardiac defects, micrognathia, urogenital defects, renal defects, connective tissue laxity, neurologic defects, and dermatologic abnormalities. Genotype/phenotype correlations of patients with trisomy 2q due to familial translocations are complicated by the presence of the deletions of the other chromosome involved. We have had the opportunity to observe `pure` trisomy 2q31-qter resulting from adjacent-1 segregation from 46,XX,t(2;22)(q31;p12) in a carrier mother with apparent loss of the 22 NOR region. He was the 2453 gm product of a gestation complicated by gestational diabetes to a 29-year-old G1 P0 mother and a 30-year-old father. At birth, he was noted to have hypotonia, micrognathia, microphthalmia, left cryptorchidism, hypospadias, bilateral clinodactyly of the fifth digits, mild hyperextensibility of the joints, dry skin disorder, and bilateral hydronephrosis by ultrasound. He was treated for hypoglycemia in the nursery and had a vesicostomy at two months for vesicoureteral reflux. A hearing test at two months found moderate hearing loss in the right ear and mild to moderate hearing loss in the left ear. At 3 months he had surgery for a PDA and bilateral glaucoma and was treated for periods of hypothermia and type IV renal tubular acidosis. This patient and others with unbalanced translocations involving the NOR region of an acrocentric chromosome allow for genotype/phenotype correlation of the `pure` trisomic region.

  16. Dietary fat modulation of mammary tumor growth and metabolism demonstrated by /sup 31/P-nuclear magnetic resonance

    SciTech Connect

    Erickson, K.L.; Buckman, D.K.; Hubbard, N.E.; Ross, B.

    1986-03-05

    The relationship of dietary fat concentration and saturation on the growth and metabolic activity of line 168 was studied using syngeneic mice fed 6 experimental diets before and during tumor growth. Tumor latency was significantly greater for mice fed a diet containing the minimum of essential fatty acids (EFA, 0.5% corn oil) or 8% coconut oil (SF) than for mice fed 8 or 20% safflower oil (PUF) or 20% SF. Changes in dietary fat resulted in alterations of tumor cell and serum fatty acid composition but not the number of inflammatory cells infiltrating the tumor. /sup 31/P-surface coil NMR was used to measure possible changes in tumor metabolism in vivo. Although pH decreased from 7.2 to 6.6 as the tumor volume increased, there was no difference in pH among dietary groups. There was an inverse relationship between both sugar phosphate (SP)/Pi and ATP/Pi ratios and tumor volume; those ratios for mice fed an EFA deficient or minimal EFA diet decreased at a different rate than ratios for mice fed diets with additional fat. Tumors of mice fed diets containing no or a low level (0.3%) of 18:2 had higher SP/ATP ratios than mice fed diets containing a moderate level (approx. 4%) of 18:2. Thus, high levels of dietary fat had a significant effect on promotion of mammary tumors during early stages of tumor growth. Differences in tumor volume associated with dietary fat may be related to changes in the levels of high energy phosphate metabolites.

  17. 31P-NMR analysis of congestive heart failure in the SHHF/Mcc-facp rat heart.

    PubMed

    Michael O'Donnell, J; Narayan, P; Bailey, M Q; Abduljalil, A M; Altschuld, R A; McCune, S A; Robitaille, P M

    1998-02-01

    31P-NMR was used to monitor myocardial bioenergetics in compensated and failing SHHF/MCC-fa(cp) (SHF) rat hearts. The SHHF/Mcc-fa(cp) (spontaneous hypertension and heart failure) rat is a relatively new genetic model in which all individuals spontaneously develop congestive heart failure, most during the second year of life. Failing SHF rat hearts displayed a pronounced decrease in resting PCr:ATP ratios (P<0.001), which was explained by a significant (P<0. 0001) drop in total creatine (47.2+/-3.1 nmol/mg protein) v age matched controls (106+/-3 nmol/mg protein). In end stage failure, NMR determined PCr was 2.9+/-0.1 micro mol/g wet weight under basal conditions. In contrast, 6- and 20-month-old controls and compensated SHFs had PCr values of 5.3+/-0.1, and 5.1+/-0.5 and 5. 1+/-0.2 micro mol/g wet weight. Both compensated and failing SHF hearts were metabolically compromised when the rate pressure product (RPP) was increased, as evidenced by an increase in Pi and a drop in PCr. Compensated SHF hearts, however, were able to increase rate pressure products (RRP, mmHg X beats/min) from 44.5+/-1.4 to 66.6+/-3. 4 K with dobutamine infusion, whereas hearts in end-stage failure were able to increase their RPP from baseline values of 27+/-4 K to only 37+/-7 K. The data indicate that a pronounced decline in PCr and total creatine signals the transition from compensatory hypertrophy to decompensation and failure in the SHF rat model of hypertensive cardiomyopathy. PMID:9515000

  18. Mitochondrial NAD(P)H In vivo: Identifying Natural Indicators of Oxidative Phosphorylation in the 31P Magnetic Resonance Spectrum

    PubMed Central

    Conley, Kevin E.; Ali, Amir S.; Flores, Brandon; Jubrias, Sharon A.; Shankland, Eric G.

    2016-01-01

    Natural indicators provide intrinsic probes of metabolism, biogenesis and oxidative protection. Nicotinamide adenine dinucleotide metabolites (NAD(P)) are one class of indicators that have roles as co-factors in oxidative phosphorylation, glycolysis, and anti-oxidant protection, as well as signaling in the mitochondrial biogenesis pathway. These many roles are made possible by the distinct redox states (NAD(P)+ and NAD(P)H), which are compartmentalized between cytosol and mitochondria. Here we provide evidence for detection of NAD(P)+ and NAD(P)H in separate mitochondrial and cytosol pools in vivo in human tissue by phosphorus magnetic resonance spectroscopy (31P MRS). These NAD(P) pools are identified by chemical standards (NAD+, NADP+, and NADH) and by physiological tests. A unique resonance reflecting mitochondrial NAD(P)H is revealed by the changes elicited by elevation of mitochondrial oxidation. The decline of NAD(P)H with oxidation is matched by a stoichiometric rise in the NAD(P)+ peak. This unique resonance also provides a measure of the improvement in mitochondrial oxidation that parallels the greater phosphorylation found after exercise training in these elderly subjects. The implication is that the dynamics of the mitochondrial NAD(P)H peak provides an intrinsic probe of the reversal of mitochondrial dysfunction in elderly muscle. Thus, non-invasive detection of NAD(P)+ and NAD(P)H in cytosol vs. mitochondria yields natural indicators of redox compartmentalization and sensitive intrinsic probes of the improvement of mitochondrial function with an intervention in human tissues in vivo. These natural indicators hold the promise of providing mechanistic insight into metabolism and mitochondrial function in vivo in a range of tissues in health, disease and with treatment. PMID:27065875

  19. 31P nuclear magnetic resonance studies of the association of basic proteins with multilayers of diacyl phosphatidylserine.

    PubMed

    Smith, R; Cornell, B A; Keniry, M A; Separovic, F

    1983-08-10

    Lysozyme, cytochrome c, poly(L-lysine), myelin basic protein and ribonuclease were used to form multilayer dispersions containing about 50% protein (by weight) with bovine brain diacyl phosphatidylserine (PS). 31P nuclear magnetic resonance shift anisotropies, spin-spin (T2) and spin-lattice (T1) relaxation times for the lipid headgroup phosphorus were measured at 36.44 MHz. At pH 7.5, lysozyme, cytochrome c, poly(L-lysine) and ribonuclease were shown to increase the chemical shift anisotropy of PS by between 12-20%. Myelin basic protein altered the shape of the phosphate resonance, suggesting the presence of two lipid components, one of which had a modified headgroup conformation. The presence of cytochrome c led to the formation of a narrow spike at the isotropic shift position of the spectrum. Of the various proteins or peptides we have studied, only poly(L-lysine) and cytochrome c had any effect on the T1 of PS (1050 ms). Both caused a 20-30% decrease in T1 of the lamellar-phase phosphate peak. The narrow peak in the presence of cytochrome c had a very short T1 of 156 ms. The possibility is considered that the cytochrome Fe3+ contributes to the phosphate relaxation in this case. The effect of all proteins on the T2 of the phosphorus resonance was to cause an increase from the value for pure PS (1.6 ms) to between 2 and 5 ms. The results obtained with proteins are compared with the effects of small ions and intrinsic membrane proteins on the order and motion of the headgroups of lipids in bilayers. PMID:6191774

  20. Effect of Ca:Mg ratio on precipitated P species identified using 31P solid state NMR

    NASA Astrophysics Data System (ADS)

    Manimel Wadu, M.

    2009-04-01

    M.C.W. Manimel Wadu1, O.O Akinremi1, S. Kroeker2 1Department of Soil Science, University of Manitoba, Winnipeg, R3T 2N2, Canada 2Department of Chemistry, University of Manitoba, Winnipeg, R3T 2N2, Canada Agronomic efficiency of added P fertilizer is reduced by the precipitation reactions with the exchangeable Ca and Mg in calcareous soils. We hypothesized that the ratio of Ca to Mg on the soil exchange complex will affect the species of P that is precipitated and its solubility in the soil. A laboratory experiment was conducted using a model calcareous soil system which was composed of resin (Amberlite IRP69) and sand coated with CaCO3 packed into a column. The resin was pre saturated with Ca and Mg in order to achieve five different saturation ratios of Ca:Mg approximately as 100:0, 70:30, 50:50, 30:70 and 0:100. Monoammonium Phosphate was applied to the soil surface to simulate one-dimensional diffusive transport. The column was then incubated for 2 weeks. Chemical analysis for water and acid soluble P, pH, NH4, Ca and Mg was performed on 2mm sections of the soil to a depth of 10 cm. This paper will present and discuss the distribution of P along the soil column. Unlike similar studies that have speculated on the precipitation of P, this study will identify and quantify the P species that is formed using 31P solid state NMR technique. Such knowledge will be helpful in understanding the effect of Ca and Mg on P availability in calcareous system and the role of each cation on P precipitation. Key words: P fertilizers, Ca, Mg, model system, solid state NMR

  1. High resolution 1H solid state NMR studies of polyethyleneterephthalate

    NASA Astrophysics Data System (ADS)

    Cheung, T. T. P.; Gerstein, B. C.; Ryan, L. M.; Taylor, R. E.; Dybowski, D. R.

    1980-12-01

    Molecular motions and spatial properties of the solid polymer polyethyleneterephthalate have been investigated using high resolution 1H solid state NMR techniques. The longitudinal spin relaxation time T1ρ of protons (1H) in the rotating frame was measured for a spin locking field ranging from 5 to 20 G. The decay of the 1H magnetization indicated the existence of two distinct T1ρ's and their field dependence shows that they are associated with two mobile phases of the polymer. The 1H magnetization also relaxes under the dipolar narrowed Carr-Purcell (DNCP) multipulse sequence with two dintinct T1y relaxation times. The ratios T1y's and T1ρ's deviate significantly from the expected theoretical values. The combined experiment with magic angle spinning and the DNCP sequence followed by homonuclear dipolar decoupling reveals the individual T1y relaxation of the resolved methylene and aromatic protons. These two species of protons were found to relax with the same T1y's, thus implying that spin diffusion must have taken place under the homonuclear dipolar decoupling multipulse. The qualitative description of spin diffusion under homonuclear decoupling is given. The combined experiment with spin locking and the DNCP sequence yields the correspondence between the two T1ρ's and the two T1y's. The long T1ρ corresponds to the short T1y whereas the short T1ρ corresponds to the long T1y. Communication between the two spatial phases via spin diffusion was also observed in this experiment by monitoring the recovery of the 1H magnitization associated with the short T1ρ after it has been eliminated during the spin locking. The total 1H magnetization is allowed to equilibrate in the laboratory frame for a variable time much shorter than T1 after the spin locking field has been turned off. The spatial relationship between the two phases is discussed.

  2. Localized double-quantum-filtered 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomas, M. A.; Hetherington, H. P.; Meyerhoff, D. J.; Twieg, D. B.

    The image-guided in vivo spectroscopic (ISIS) pulse sequence has been combined with a double-quantum-filter scheme in order to obtain localized and water-suppressed 1H NMR spectra of J-coupled metabolites. The coherence-transfer efficiency associated with the DQ filter for AX and A 3X spin systems is described. Phantom results of carnosine, alanine, and ethanol in aqueous solution are presented. For comparison, the 1H NMR spectrum of alanine in aqueous solution with the binomial (1331, 2662) spin-echo sequence is also shown.

  3. Interaction of Lipopolysaccharide and Phospholipid in Mixed Membranes: Solid-State 31P-NMR Spectroscopic and Microscopic Investigations

    PubMed Central

    Nomura, Kaoru; Inaba, Takehiko; Morigaki, Kenichi; Brandenburg, Klaus; Seydel, Ulrich; Kusumoto, Shoichi

    2008-01-01

    Lipopolysaccharide (LPS), which constitutes the outermost layer of Gram-negative bacterial cells as a typical component essential for their life, induces the first line defense system of innate immunity of higher animals. To understand the basic mode of interaction between bacterial LPS and phospholipid cell membranes, distribution patterns were studied by various physical methods of deep rough mutant LPS (ReLPS) of Escherichia coli incorporated in phospholipid bilayers as simple models of cell membranes. Solid-state 31P-NMR spectroscopic analysis suggested that a substantial part of ReLPS is incorporated into 1,2-dimyristoyl-sn-glycero-3-phosphocholine lipid bilayers when multilamellar vesicles were prepared from mixtures of these. In egg L-α-phosphatidylcholine (egg-PC)-rich membranes, ReLPS undergoes micellization. In phosphatidylethanolamine-rich membranes, however, micellization was not observed. We studied by microscopic techniques the location of ReLPS in membranes of ReLPS/egg-PC (1:10 M/M) and ReLPS/egg-PC/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) (1:9:1 M/M/M). The influence of ReLPS on the physicochemical properties of the membranes was studied as well. Microscopic images of both giant unilamellar vesicles and supported planar lipid bilayers showed that LPS was uniformly incorporated in the egg-PC lipid bilayers. In the egg-PC/POPG (9:1 M/M) lipid bilayers, however, ReLPS is only partially incorporated and becomes a part of the membrane in a form of aggregates (or as mixed aggregates with the lipids) on the bilayer surface. The lipid lateral diffusion coefficient measurements at various molar ratios of ReLPS/egg-PC/POPG indicated that the incorporated ReLPS reduces the diffusion coefficients of the phospholipids in the membrane. The retardation of diffusion became more significant with increasing POPG concentrations in the membrane at high ReLPS/phospholipid ratios. This work demonstrated that the phospholipid composition has critical

  4. Comparison of (31)P saturation and inversion magnetization transfer in human liver and skeletal muscle using a clinical MR system and surface coils.

    PubMed

    Buehler, Tania; Kreis, Roland; Boesch, Chris

    2015-02-01

    (31)P MRS magnetization transfer ((31)P-MT) experiments allow the estimation of exchange rates of biochemical reactions, such as the creatine kinase equilibrium and adenosine triphosphate (ATP) synthesis. Although various (31)P-MT methods have been successfully used on isolated organs or animals, their application on humans in clinical scanners poses specific challenges. This study compared two major (31)P-MT methods on a clinical MR system using heteronuclear surface coils. Although saturation transfer (ST) is the most commonly used (31)P-MT method, sequences such as inversion transfer (IT) with short pulses might be better suited for the specific hardware and software limitations of a clinical scanner. In addition, small NMR-undetectable metabolite pools can transfer MT to NMR-visible pools during long saturation pulses, which is prevented with short pulses. (31)P-MT sequences were adapted for limited pulse length, for heteronuclear transmit-receive surface coils with inhomogeneous B1 , for the need for volume selection and for the inherently low signal-to-noise ratio (SNR) on a clinical 3-T MR system. The ST and IT sequences were applied to skeletal muscle and liver in 10 healthy volunteers. Monte-Carlo simulations were used to evaluate the behavior of the IT measurements with increasing imperfections. In skeletal muscle of the thigh, ATP synthesis resulted in forward reaction constants (k) of 0.074 ± 0.022 s(-1) (ST) and 0.137 ± 0.042 s(-1) (IT), whereas the creatine kinase reaction yielded 0.459 ± 0.089 s(-1) (IT). In the liver, ATP synthesis resulted in k = 0.267 ± 0.106 s(-1) (ST), whereas the IT experiment yielded no consistent results. ST results were close to literature values; however, the IT results were either much larger than the corresponding ST values and/or were widely scattered. To summarize, ST and IT experiments can both be implemented on a clinical body scanner with heteronuclear transmit-receive surface coils; however, ST results are

  5. Use of (77)Se and (125)Te NMR Spectroscopy to Probe Covalency of the Actinide-Chalcogen Bonding in [Th(En){N(SiMe3)2}3](-) (E = Se, Te; n = 1, 2) and Their Oxo-Uranium(VI) Congeners.

    PubMed

    Smiles, Danil E; Wu, Guang; Hrobárik, Peter; Hayton, Trevor W

    2016-01-27

    Reaction of [Th(I)(NR2)3] (R = SiMe3) (1) with 1 equiv of either [K(18-crown-6)]2[Se4] or [K(18-crown-6)]2[Te2] affords the thorium dichalcogenides, [K(18-crown-6)][Th(η(2)-E2)(NR2)3] (E = Se, 2; E = Te, 3), respectively. Removal of one chalcogen atom via reaction with Et3P, or Et3P and Hg, affords the monoselenide and monotelluride complexes of thorium, [K(18-crown-6)][Th(E)(NR2)3] (E = Se, 4; E = Te, 5), respectively. Both 4 and 5 were characterized by X-ray crystallography and were found to feature the shortest known Th-Se and Th-Te bond distances. The electronic structure and nature of the actinide-chalcogen bonds were investigated with (77)Se and (125)Te NMR spectroscopy accompanied by detailed quantum-chemical analysis. We also recorded the (77)Se NMR shift for a U(VI) oxo-selenido complex, [U(O)(Se)(NR2)3](-) (δ((77)Se) = 4905 ppm), which features the highest frequency (77)Se NMR shift yet reported, and expands the known (77)Se chemical shift range for diamagnetic substances from ∼3300 ppm to almost 6000 ppm. Both (77)Se and (125)Te NMR chemical shifts of given chalcogenide ligands were identified as quantitative measures of the An-E bond covalency within an isoelectronic series and supported significant 5f-orbital participation in actinide-ligand bonding for uranium(VI) complexes in contrast to those involving thorium(IV). Moreover, X-ray diffraction studies together with NMR spectroscopic data and density functional theory (DFT) calculations provide convincing evidence for the actinide-chalcogen multiple bonding in the title complexes. Larger An-E covalency is observed in the [U(O)(E)(NR2)3](-) series, which decreases as the chalcogen atom becomes heavier. PMID:26667146

  6. Applications of 1H-NMR to Biodiesel Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, or used cooking oils. It is produced by reacting these materials with an alcohol in the presence of a catalyst to give the corresponding mono-alkyl esters. 1H-NMR is a routine analytical method that has been used for...

  7. A compilation of information on the {sup 31}P(p,{alpha}){sup 28}Si reaction and properties of excited levels in the compound nucleus {sup 32}S

    SciTech Connect

    Miller, R.E.; Smith, D.L.

    1997-11-01

    This report documents a survey of the literature, and provides a compilation of data contained therein, for the {sup 31}P(p,{alpha}){sup 28}Si reaction. Attention is paid here to resonance states in the compound-nuclear system {sup 32}S formed by {sup 31}P + p, with emphasis on the alpha-particle decay channels, {sup 28}Si + {alpha} which populate specific levels in {sup 28}Si. The energy region near the proton separation energy for {sup 32}S is especially important in this context for applications in nuclear astrophysics. Properties of the excited states in {sup 28}Si are also considered. Summaries of all the located references are provided and numerical data contained in them are compiled in EXFOR format where applicable.

  8. Assessment of Preparation Methods for Organic Phosphorus Analysis in Phosphorus-Polluted Fe/Al-Rich Haihe River Sediments Using Solution 31P-NMR

    PubMed Central

    Zhang, Wenqiang; Shan, Baoqing; Zhang, Hong; Tang, Wenzhong

    2013-01-01

    Fe/Al-rich river sediments that were highly polluted with phosphorus (P) were used in tests to determine the optimum preparation techniques for measuring organic P (Po) using solution 31P nuclear magnetic resonance spectroscopy (31P-NMR). The optimum pre-treatment, extraction time, sediment to solution ratio and sodium hydroxide-ethylenediaminetetraacetic acid (NaOH-EDTA) extractant solution composition were determined. The total P and Po recovery rates were higher from freeze- and air-dried samples than from fresh samples. An extraction time of 16 h was adequate for extracting Po, and a shorter or longer extraction time led to lower recoveries of total P and Po, or led to the degradation of Po. An ideal P recovery rate and good-quality NMR spectra were obtained at a sediment:solution ratio of 1∶10, showing that this ratio is ideal for extracting Po. An extractant solution of 0.25 M NaOH and 50 mM EDTA was found to be more appropriate than either NaOH on its own, or a more concentrated NaOH-EDTA mixture for 31P-NMR analysis, as this combination minimized interference from paramagnetic ions and was appropriate for the detected range of Po concentrations. The most appropriate preparation method for Po analysis, therefore, was to extract the freeze-dried and ground sediment sample with a 0.25 M NaOH and 50 mM EDTA solution at a sediment:solution ratio of 1∶10, for 16 h, by shaking. As lyophilization of the NaOH-EDTA extracts proved to be an optimal pre-concentration method for Po analysis in the river sediment, the extract was lyophilized as soon as possible, and analyzed by 31P-NMR. PMID:24143192

  9. [31P-NMR analysis of high energy phosphorous compounds (ATP and phosphocreatine) in the living rat brain--effects of halothane anesthesia and a hypoxic condition].

    PubMed

    Yuasa, T; Miyatake, T; Kuwabara, T; Umeda, M; Eguchi, K

    1983-11-01

    31phosphorus nuclear magnetic resonance (31P-NMR) measurements have provided new and valuable insights for studying the metabolism of living systems. The aim of this paper is to introduce a technique of application of 31P-NMR measurements using a surface coil method, and to discuss the effects of halothane anesthesia and hypoxic hypoxia on the energetic metabolism of intact rat brains. All measurements were made using a JEOL FX 270 spectrometer with a super conducting magnet of 54-mm bore diameter. The magnetic field intensity of this machine is 6.3 tesla, and the resonance frequency used for 31P was 109.14 MHz. We remodelled an ordinary probe to take a live rat, and the animals were made to inhale anesthetic halothane or mixture of oxygen and nitrogen at various concentrations controlled by a flow regulator. The best conditions for measurements with our surface coil method were determined in this study as follows: (1) 90 degrees pulse width and selectivity, Fig. 1 shows signal selectivity in depthwise direction changed with 90 degrees pulse width, which was set to 20 microseconds. (2) Sensitivity and resolution; To obtain a spectrum of 31P-NMR from a rat brain 500 accumulations of free induction decays were considered suitable for both time and space resolution. Fig. 2 shows variations of signal intensity with pulse repetition time, which was set to 2 sec. It took about 17 min for averaging to get a spectrogram. (3) Quantitative accuracy and qualification; As shown in Fig. 3, a linear relationship was found between the signal intensity of beta-phosphate of ATP and the concentration of ATP solutions, thus proving the quantitative accuracy of our systems.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6661335

  10. Muscle metabolism and activation heterogeneity by combined 31P chemical shift and T2 imaging, and pulmonary O2 uptake during incremental knee-extensor exercise

    PubMed Central

    Cannon, Daniel T.; Howe, Franklyn A.; Whipp, Brian J.; Ward, Susan A.; McIntyre, Dominick J.; Ladroue, Christophe; Griffiths, John R.; Kemp, Graham J.

    2013-01-01

    The integration of skeletal muscle substrate depletion, metabolite accumulation, and fatigue during large muscle-mass exercise is not well understood. Measurement of intramuscular energy store degradation and metabolite accumulation is confounded by muscle heterogeneity. Therefore, to characterize regional metabolic distribution in the locomotor muscles, we combined 31P magnetic resonance spectroscopy, chemical shift imaging, and T2-weighted imaging with pulmonary oxygen uptake during bilateral knee-extension exercise to intolerance. Six men completed incremental tests for the following: 1) unlocalized 31P magnetic resonance spectroscopy; and 2) spatial determination of 31P metabolism and activation. The relationship of pulmonary oxygen uptake to whole quadriceps phosphocreatine concentration ([PCr]) was inversely linear, and three of four knee-extensor muscles showed activation as assessed by change in T2. The largest changes in [PCr], [inorganic phosphate] ([Pi]) and pH occurred in rectus femoris, but no voxel (72 cm3) showed complete PCr depletion at exercise cessation. The most metabolically active voxel reached 11 ± 9 mM [PCr] (resting, 29 ± 1 mM), 23 ± 11 mM [Pi] (resting, 7 ± 1 mM), and a pH of 6.64 ± 0.29 (resting, 7.08 ± 0.03). However, the distribution of 31P metabolites and pH varied widely between voxels, and the intervoxel coefficient of variation increased between rest (∼10%) and exercise intolerance (∼30–60%). Therefore, the limit of tolerance was attained with wide heterogeneity in substrate depletion and fatigue-related metabolite accumulation, with extreme metabolic perturbation isolated to only a small volume of active muscle (<5%). Regional intramuscular disturbances are thus likely an important requisite for exercise intolerance. How these signals integrate to limit muscle power production, while regional “recruitable muscle” energy stores are presumably still available, remains uncertain. PMID:23813534

  11. Phosphorus speciation in agro-industrial byproducts: sequential fractionation, solution (31)P NMR, and P K- and L(2,3)-edge XANES spectroscopy.

    PubMed

    Negassa, Wakene; Kruse, Jens; Michalik, Dirk; Appathurai, Narayana; Zuin, Lucia; Leinweber, Peter

    2010-03-15

    Little is known about P species in agro-industrial byproducts from developing countries, which may be either pollutants or valuable soil amendments. The present study speciated P in dry (COD) and wet (COW) coffee, sisal (SIS), barley malt (BEB) and sugar cane processing (FIC) byproducts, and filter cakes of linseed (LIC) and niger seed (NIC)with sequential fractionation, solution (31)P nuclear magnetic resonance (NMR) spectroscopy, and P K- and L(2,3)-edge X-ray absorption near-edge structure (XANES) spectroscopy. The sequential P fractionation recovered 59% to almost 100% of total P (P(t)), and more than 50% of P(t) was extracted by H(2)O and NaHCO(3) in five out of seven samples. Similarly, the NaOH + EDTA extraction for solution (31)P NMR recovered 48-94% of P(t). The (31)P NMR spectra revealed orthophosphate (6-81%), pyrophosphate (0-10%), and orthophosphate monoesters (6-94%). Orthophosphate predominated in COD, COW, SIS, and FIC, whereas BEB, UC, and NIC were rich in orthophosphate monoesters. The concentrations of P(i), and P(o) determined in the sequential and NaOH + EDTA extractions and (31)P NMR spectra were strongly and positively correlated (r = 0.88-1.00). Furthermore, the P K- and L(2,3)-edge XANES confirmed the H(2)SO(4)--P(i) detected in the sequential fractionation by unequivocal identification of Ca--P phases in a few samples. The results indicate that the combined use of all four analytical methods is crucial for comprehensive P speciation in environmental samples and the application of these byproducts to soil. PMID:20146464

  12. {sup 31}P NMR study of the complexation of TBP with lanthanides and actinides in solution and in a clay matrix

    SciTech Connect

    Hartzell, C.J.

    1994-07-24

    Goal was to use NMR to study TBP/lanthanide complexes in the interlayer or on edge sites of clays. Work in this laboratory yielded details of the complexation of Eu(NO{sub 3}){sub 3} and Pr(NO{sub 3}){sub 3} with TBP in hexane solution; this information is crucial to interpretation of results of NMR studies of the complexes exchanged into clays. The solution {sup 31}P-chemical shift values were improved by repeating the studies on the lanthanide salts dissolved directly into neat TBP. NMR studies of these neat solutions of the Eu(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex and the Pr(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex show that the {sup 31}P chemical shift remains relatively constant for TBP: lanthanide ratios below 3: 1. At higher ratios, the chemical shift approaches that of free TBP, indicating rapid exchange of TBP between the free and complexed state. Exchange of these complexes into the clay hectorite yielded discrete {sup 31}P-NMR signals for the Eu{lg_bullet}TBP complex at -190 ppm and free TBP at -6 ppm. Adsorption of the Pr{lg_bullet}TBP complex yielded broad signals at 76 ppm for the complex and -6 ppm for free TBP. There was no evidence of exchange between the incorporated complex and the free TBP.

  13. Vacuolar glyphosate-sequestration correlates with glyphosate resistance in ryegrass (Lolium spp.) from Australia, South America, and Europe: a 31P NMR investigation.

    PubMed

    Ge, Xia; d'Avignon, D André; Ackerman, Joseph J H; Collavo, Alberto; Sattin, Maurizio; Ostrander, Elizabeth L; Hall, Erin L; Sammons, R Douglas; Preston, Christopher

    2012-02-01

    Lolium spp., ryegrass, variants from Australia, Brazil, Chile, and Italy showing differing levels of glyphosate resistance were examined by (31)P NMR. Extents of glyphosate (i) resistance (LD(50)), (ii) inhibition of 5-enopyruvyl-shikimate-3-phosphate synthase (EPSPS) activity (IC(50)), and (iii) translocation were quantified for glyphosate-resistant (GR) and glyphosate-sensitive (GS) Lolium multiflorum Lam. variants from Chile and Brazil. For comparison, LD(50) and IC(50) data for Lolium rigidum Gaudin variants from Italy were also analyzed. All variants showed similar cellular uptake of glyphosate by (31)P NMR. All GR variants showed glyphosate sequestration within the cell vacuole, whereas there was minimal or no vacuole sequestration in the GS variants. The extent of vacuole sequestration correlated qualitatively with the level of resistance. Previous (31)P NMR studies of horseweed ( Conyza canadensis (L.) Cronquist) revealed that glyphosate sequestration imparted glyphosate resistance. Data presented herein suggest that glyphosate vacuolar sequestration is strongly contributing, if not the major contributing, resistance mechanism in ryegrass as well. PMID:22224711

  14. /sup 31/P NMR saturation-transfer and /sup 13/C NMR kinetic studies of glycolytic regulation during anaerobic and aerobic glycolysis

    SciTech Connect

    Campbell-Burk, S.L.; den Hollander, J.A.; Alger, J.R.; Shulman, R.G.

    1987-11-17

    /sup 31/P NMR saturation-transfer techniques have been employed in glucose-gown derepressed yeast to determine unidirectional fluxes in the upper part of the Embden-Meyerhof-Parnas pathway. The experiments were performed during anaerobic and aerobic glycolysis by saturating the ATP/sub ..gamma../ resonances and monitoring changes in the phosphomonoester signals from glucose 6-phosphate and fructose 1,6-bisphosphate. These experiments were supplemented with /sup 13/C NMR measurements of glucose utilization rates and /sup 13/C NMR label distribution studies. Combined with data obtained previously from radioisotope measurement, these /sup 31/P and /sup 13/C NMR kinetic studies allowed estimation of the net glycolytic flow in addition to relative flows through phosphofructokinase (PFK) and Fru-1,6-P/sub 2/ase during anaerobic and aerobic glycolysis. The /sup 31/P NMR saturation-transfer results are consistent with previous results obtained from measurements of metabolite levels, radioisotope data, and /sup 13/C NMR studies, providing additional support for in vivo measurement of the flows during glycolysis.

  15. Development of a CP 31P NMR broadline simulation methodology for studying the interactions of antihypertensive AT1 antagonist losartan with phospholipid bilayers.

    PubMed

    Fotakis, Charalambos; Christodouleas, Dionisios; Chatzigeorgiou, Petros; Zervou, Maria; Benetis, Nikolas-Ploutarch; Viras, Kyriakos; Mavromoustakos, Thomas

    2009-03-18

    A cross-polarization (CP) (31)P NMR broadline simulation methodology was developed for studying the effects of drugs in phospholipids bilayers. Based on seven-parameter fittings, this methodology provided information concerning the conformational changes and dynamics effects of losartan in the polar region of the dipalmitoylphosphatidylcholine bilayers. The test molecule for this study was losartan, an antihypertensive drug known to exert its effect on AT(1) transmembrane receptors. The results were complemented and compared with those of differential scanning calorimetry, solid-state (13)C NMR spectroscopy, Raman spectroscopy, and electron spin resonance. More specifically, these physical chemical methodologies indicated that the amphipathic losartan molecule interacts with the hydrophilic-head zone of the lipid bilayers. The CP (31)P NMR broadline simulations showed that the lipid molecules in the bilayers containing losartan displayed greater collective tilt compared to the tilt displayed by the load-free bilayers, indicating improved packing. The Raman results displayed a decrease in the trans/gauche ratio and increased intermolecular interactions of the acyl chains in the liquid crystalline phase. Additional evidence, suggesting that losartan possibly anchors in the realm of the headgroup, was derived from upfield shift of the average chemical shift sigma(iso) of the (31)P signal in the presence of losartan and from shift of the observed peak at 715 cm(-1) attributed to C-N stretching in the Raman spectra. PMID:19289049

  16. 4D prediction of protein (1)H chemical shifts.

    PubMed

    Lehtivarjo, Juuso; Hassinen, Tommi; Korhonen, Samuli-Petrus; Peräkylä, Mikael; Laatikainen, Reino

    2009-12-01

    A 4D approach for protein (1)H chemical shift prediction was explored. The 4th dimension is the molecular flexibility, mapped using molecular dynamics simulations. The chemical shifts were predicted with a principal component model based on atom coordinates from a database of 40 protein structures. When compared to the corresponding non-dynamic (3D) model, the 4th dimension improved prediction by 6-7%. The prediction method achieved RMS errors of 0.29 and 0.50 ppm for Halpha and HN shifts, respectively. However, for individual proteins the RMS errors were 0.17-0.34 and 0.34-0.65 ppm for the Halpha and HN shifts, respectively. X-ray structures gave better predictions than the corresponding NMR structures, indicating that chemical shifts contain invaluable information about local structures. The (1)H chemical shift prediction tool 4DSPOT is available from http://www.uku.fi/kemia/4dspot . PMID:19876601

  17. Serial 1H-MRS in GM2 gangliosidoses.

    PubMed

    Assadi, Mitra; Baseman, Susan; Janson, Christopher; Wang, Dah-Jyuu; Bilaniuk, Larissa; Leone, Paola

    2008-03-01

    GM2 gangliosidoses are a group of neuronal storage disorders caused by deficiency in the lysosomal enzyme hexosaminidase A. Clinically, the disease is marked by a relentless encephalopathy. Proton magnetic resonance spectroscopy (1H-MRS) provides in-vivo measurement of various brain metabolites including N-acetyl aspartate+N-acetyl aspartate glutamate (NAA), myo-inositol (mI), choline (Cho) and creatine (Cr). The NAA represents neuronal integrity while elevation in the mI reflects abnormal inflammation and gliosis in the brain tissue. An elevation in the Cho levels suggest cell membrane breakdown and demyelination. We report the clinical and laboratory data in two patients with GM2 gangliosidoses. Serial 1H-MRS evaluations were performed to drive metabolite ratios of NAA/Cr, mI/Cr and Cho/Cr. We acquired the data from four regions of interest (ROI) according to a standard protocol. The results documented a progressive elevation in mI/Cr in all four ROI in patient one and only one ROI (occipital gray matter) in patient 2. We also documented a decline in the NAA/Cr ratios in both cases in most ROI. These results were compared to six age-matched controls and confirmed statistically significant elevation in the mI in our cases. In conclusion, 1H-MRS alterations were suggestive of neuronal loss and inflammation in these patients. 1H-MRS may be a valuable tool in monitoring the disease progress and response to therapy in GM2 gangliosidoses. Elevation in the mI may prove to be more sensitive than the other metabolite alterations. PMID:17387512

  18. 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.

  19. Proton-detected 3D 1H/13C/1H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

    2015-10-01

    A proton-detected 3D 1H/13C/1H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of 13C-1H connectivities, and proximities of 13C-1H and 1H-1H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including 1H-1H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) 1H/1H and 2D 13C/1H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of 1H-1H proximity and 13C-1H connectivity. In addition, the 2D (F1/F2) 1H/13C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of 1H-1H dipolar couplings, enables the measurement of proximities between 13C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of 1H-1H-13C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ṡ H2O ṡ HCl demonstrate the efficiency of the 3D experiment.

  20. Proton-detected 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H-1H RFDR mixing on a natural abundant sample under ultrafast MAS

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Nishiyama, Yusuke

    2015-09-01

    In this contribution, we have demonstrated a proton detection-based approach on a natural abundant powdered L-Histidine HCl-H2O sample at ultrafast magic angle spinning (MAS) to accomplish 14N/14N correlation from a 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H finite-pulse radio frequency-driven recoupling (fp-RFDR). Herein the heteronuclear magnetization transfer between 14N and 1H has been achieved by HMQC experiment, whereas 14N/14N correlation is attained through enhanced 1H-1H spin diffusion process due to 1H-1H dipolar recoupling during the RFDR mixing. While the use of ultrafast MAS (90 kHz) provides sensitivity enhancement through increased 1H transverse relaxation time (T2), the use of micro-coil probe which can withstand strong 14N radio frequency (RF) fields further improves the sensitivity per unit sample volume.

  1. Does visual cortex lactate increase following photic stimulation in migraine without aura patients? A functional (1)H-MRS study.

    PubMed

    Reyngoudt, Harmen; Paemeleire, Koen; Dierickx, Anneloor; Descamps, Benedicte; Vandemaele, Pieter; De Deene, Yves; Achten, Eric

    2011-06-01

    Proton magnetic resonance spectroscopy ((1)H-MRS) has been used in a number of studies to assess noninvasively the temporal changes of lactate (Lac) in the activated human brain. Migraine neurobiology involves lack of cortical habituation to repetitive stimuli and a mitochondrial component has been put forward. Our group has recently demonstrated a reduction in the high-energy phosphates adenosine triphosphate (ATP) and phosphocreatine (PCr) in the occipital lobe of migraine without aura (MwoA) patients, at least in a subgroup, in a phosphorus MRS ((31)P-MRS) study. In previous studies, basal Lac levels or photic stimulation (PS)-induced Lac levels were found to be increased in patients with migraine with aura (MwA) and migraine patients with visual symptoms and paraesthesia, paresia and/or dysphasia, respectively. The aim of this study was to perform functional (1)H-MRS at 3 T in 20 MwoA patients and 20 control subjects. Repetitive visual stimulation was applied using MR-compatible goggles with 8 Hz checkerboard stimulation during 12 min. We did not observe any significant differences in signal integrals, ratios and absolute metabolite concentrations, including Lac, between MwoA patients and controls before PS. Lac also did not increase significantly during and following PS, both for MwoA patients and controls. Subtle Lac changes, smaller than the sensitivity threshold (i.e. estimated at 0.1-0.2 μmol/g at 3 T), cannot be detected by MRS. Our study does, however, argue against a significant switch to non-aerobic glucose metabolism during long-lasting PS of the visual cortex in MwoA patients. PMID:21301922

  2. Hydrogen concentration dependence of 1H Knight shift in NbH x studied by 1H MAS NMR

    NASA Astrophysics Data System (ADS)

    Ueda, Takahiro; Hayashi, Shigenobu; Hayamizu, Kikuko

    1993-08-01

    Hydrogen concentration dependence of the Knight shift of protons in NbH x(0.05≤×≤1.05) has been studied by means of 1H MAS (magic angle sample spinning) NMR. In the mixed-phase samples of the α and β phases (0.05<×≤0.7), it is found that the 1H Knight shift of β-NbH x depends on the phase fraction. The shift variation in the β phase can be correlated with the unit cell volume, being explained by the variation of the density of electronic states at the Fermi level N(0) due to the compression of the crystal lattice. On the other hand, in the single β-phase samples (0.7<×≤1.05), the 1H Knight shift becomes smaller as the hydrogen concentration increases. This variation can be explained by increase in the number of electrons in the unit cell with the hydrogen concentration, resulting in the N(0) increase.

  3. Dynamic 1H NMR Studies of Schiff Base Derivatives

    NASA Astrophysics Data System (ADS)

    Köylü, M. Z.; Ekinci, A.; Böyükata, M.; Temel, H.

    2016-01-01

    The spin-lattice relaxation time T 1 and the spin-spin relaxation time T 2 of two Schiff base derivatives, N,N'-ethylenebis(salicylidene)-1,2-diaminoethane (H2L1) and N,N'-ethylenebis (salicylidene)-1,3-diaminopropane (H2L2), in DMSO-d6 solvent were studied as a function of temperature in the range of 20-50°C using a Bruker Avance 400.132 MHz 1H NMR spectrometer. Based on the activation energy ( E a) and correlation time (τc), we believe that the Schiff base derivatives perform a molecular tumbling motion.

  4. 31P-nuclear magnetic resonance spectroscopy in vivo of six human melanoma xenograft lines: tumour bioenergetic status and blood supply.

    PubMed Central

    Lyng, H.; Olsen, D. R.; Southon, T. E.; Rofstad, E. K.

    1993-01-01

    Six human melanoma xenograft lines grown s.c. in BALB/c-nu/nu mice were subjected to 31P-nuclear magnetic resonance (31P-NMR) spectroscopy in vivo. The following resonances were detected: phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE), phosphocreatine (PCr) and nucleoside triphosphate gamma, alpha and beta (NTP gamma, alpha and beta). The main purpose of the work was to search for possible relationships between 31P-NMR resonance ratios and tumour pH on the one hand and blood supply per viable tumour cell on the other. The latter parameter was measured by using the 86Rb uptake method. Tumour bioenergetic status [the (PCr + NTP beta)/Pi resonance ratio], tumour pH and blood supply per viable tumour cell decreased with increasing tumour volume for five of the six xenograft lines. The decrease in tumour bioenergetic status was due to a decrease in the (PCr + NTP beta)/total resonance ratio as well as an increase in the Pi/total resonance ratio. The decrease in the (PCr + NTP beta)/total resonance ratio was mainly a consequence of a decrease in the PCr/total resonance ratio for two lines and mainly a consequence of a decrease in the NTP beta/total resonance ratio for three lines. The magnitude of the decrease in the (PCr + NTP beta)/total resonance ratio and the magnitude of the decrease in tumour pH were correlated to the magnitude of the decrease in blood supply per viable tumour cell. Tumour pH decreased with decreasing tumour bioenergetic status, and the magnitude of this decrease was larger for the tumour lines showing a high than for those showing a low blood supply per viable tumour cell. No correlations across the tumour lines were found between tumour pH and tumour bioenergetic status or any other resonance ratio on the one hand and blood supply per viable tumour cell on the other. The differences in the 31P-NMR spectrum between the tumour lines were probably caused by differences in the intrinsic biochemical properties of the tumour

  5. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

    PubMed Central

    Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

    2013-01-01

    The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

  6. Phosphatidylinositol-specific phospholipase C from Bacillus cereus combines intrinsic phosphotransferase and cyclic phosphodiesterase activities: A sup 31 P NMR study

    SciTech Connect

    Shashidhar, M.S.; Kuppe, A. ); Volwerk, J.J.; Griffith, O.H.

    1990-09-04

    The inositol phosphate products formed during the cleavage of phosphatidylinositol by phosphatidylinositol-specific phospholipase C from Bacillus cereus were analyzed by {sup 31}P NMR. {sup 31}P NMR spectroscopy can distinguish between the inositol phosphate species and phosphatidylinositol. Chemical shift values (with reference to phosphoric acid) observed are {minus}0.41, 3.62, 4.45, and 16.30 ppm for phosphatidylinositol, myo-inositol 1-monophosphate, myo-inositol 2-monophosphate, and myo-inositol 1,2-cyclic monophosphate, respectively. It is shown that under a variety of experimental conditions this phospholipase C cleaves phosphatidylinositol via an intramolecular phosphotransfer reaction producing diacylglycerol and D-myo-inositol 1,2-cyclic monophosphate. The authors also report the new and unexpected observation that the phosphatidylinositol-specific phospholipase C from B. cereus is able to hydrolyze the inositol cyclic phosphate to form D-myo-inositol 1-monophosphate. The enzyme, therefore, possesses phosphotransferase and cyclic phosphodiesterase activities. The second reaction requires thousandfold higher enzyme concentrations to be observed by {sup 31}P NMR. This reaction was shown to be regiospecific in that only the 1-phosphate was produced and stereospecific in that only D-myo-inositol 1,2-cyclic monophosphate was hydrolyzed. Inhibition with a monoclonal antibody specific for the B.cereus phospholipase C showed that the cyclic phosphodiesterase activity is intrinsic to the bacterial enzyme. They propose a two-step mechanism for the phosphatidyl-inositol-specific phospholipase C from B. cereus involving sequential phosphotransferase and cyclic phosphodiesterase activities. This mechanism bears a resemblance to the well-known two-step mechanism of pancreatic ribonuclease, RNase A.

  7. Gray Matter-Specific Changes in Brain Bioenergetics after Acute Sleep Deprivation: A 31P Magnetic Resonance Spectroscopy Study at 4 Tesla

    PubMed Central

    Plante, David T.; Trksak, George H.; Jensen, J. Eric; Penetar, David M.; Ravichandran, Caitlin; Riedner, Brady A.; Tartarini, Wendy L.; Dorsey, Cynthia M.; Renshaw, Perry F.; Lukas, Scott E.; Harper, David G.

    2014-01-01

    Study Objectives: A principal function of sleep may be restoration of brain energy metabolism caused by the energetic demands of wakefulness. Because energetic demands in the brain are greater in gray than white matter, this study used linear mixed-effects models to examine tissue-type specific changes in high-energy phosphates derived using 31P magnetic resonance spectroscopy (MRS) after sleep deprivation and recovery sleep. Design: Experimental laboratory study. Setting: Outpatient neuroimaging center at a private psychiatric hospital. Participants: A total of 32 MRS scans performed in eight healthy individuals (mean age 35 y; range 23-51 y). Interventions: Phosphocreatine (PCr) and β-nucleoside triphosphate (NTP) were measured using 31P MRS three dimensional-chemical shift imaging at high field (4 Tesla) after a baseline night of sleep, acute sleep deprivation, and 2 nights of recovery sleep. Novel linear mixed-effects models were constructed using spectral and tissue segmentation data to examine changes in bioenergetics in gray and white matter. Measurements and Results: PCr increased in gray matter after 2 nights of recovery sleep relative to sleep deprivation with no significant changes in white matter. Exploratory analyses also demonstrated that increases in PCr were associated with increases in electroencephalographic slow wave activity during recovery sleep. No significant changes in β-NTP were observed. Conclusions: These results demonstrate that sleep deprivation and subsequent recovery-induced changes in high-energy phosphates primarily occur in gray matter, and increases in phosphocreatine after recovery sleep may be related to sleep homeostasis. Citation: Plante DT, Trksak GH, Jensen JE, Penetar DM, Ravichandran C, Riedner BA, Tartarini WL, Dorsey CM, Renshaw PF, Lukas SE, Harper DG. Gray matter-specific changes in brain bioenergetics after acute sleep deprivation: a 31P magnetic resonance spectroscopy study at 4 Tesla. SLEEP 2014

  8. Phosphate ions in bone: identification of a calcium-organic phosphate complex by 31P solid-state NMR spectroscopy at early stages of mineralization.

    PubMed

    Wu, Y; Ackerman, J L; Strawich, E S; Rey, C; Kim, H-M; Glimcher, M J

    2003-05-01

    Previous 31P cross-polarization and differential cross-polarization magic angle spinning (CP/MAS and DCP/MAS) solid-state NMR spectroscopy studies of native bone and of the isolated crystals of the calcified matrix synthesized by osteoblasts in cell culture identified and characterized the major PO(-3)(4) phosphate components of the mineral phase. The isotropic and anisotropic chemical shift parameters of the minor HPO(-2)(4) component in bone mineral and in mineral deposited in osteoblast cell cultures were found to differ significantly from those of brushite, octacalcium phosphate, and other synthetic calcium phosphates. However, because of in vivo and in vitro evidence that phosphoproteins may play a significant role in the nucleation of the solid mineral phase of calcium phosphate in bone and other vertebrate calcified tissues, the focus of the current solid-state 31P NMR experiments was to detect the possible presence of and characterize the phosphoryl groups of phosphoproteins in bone at the very earliest stages of bone mineralization, as well as the possible presence of calcium-phosphoprotein complexes. The present study demonstrates that by far the major phosphate components identified by solid-state 31P NMR in the very earliest stages of mineralization are protein phosphoryl groups which are not complexed with calcium. However, very small amounts of calcium-complexed protein phosphoryl groups as well as even smaller, trace amounts of apatite crystals were also present at the earliest phases of mineralization. These data support the hypothesis that phosphoproteins complexed with calcium play a significant role in the initiation of bone calcification. PMID:12724829

  9. Carbon-13, sup 15 N, and sup 31 P NMR studies on 6-hydroxy-L-nicotine oxidase from Arthrobacter oxidans

    SciTech Connect

    Pust, S.; Vervoort, J.; Decker, K.; Bacher, A.; Mueller, F. )

    1989-01-24

    The interaction between the apoprotein of 6-hydroxy-L-nicotine oxidase from Arthrobacter oxidans and the prosthetic group FAD has been investigated by {sup 13}C, {sup 15}N and {sup 31}P NMR techniques. The FAD prosthetic group was selectively enriched in {sup 13}C and {sup 15}N isotopes by adding isotopically labeled riboflavin derivatives to the growth medium of riboflavin-requiring mutant cells. In the oxidized state the chemical shift of the C(7) and C(8) atoms indicates that the xylene moiety of the isoalloxazine ring is embedded in a hydrophobic environment. The binding of the competitive inhibitor, 6-hydroxy-D-nicotine, influences the resonances of the C(4a) and the N(5) atom strongly. It is suggested that these shifts are due to a strong hydrogen-bonding interaction between the N(5) atom and the inhibitor. On reduction all resonances, except those of the C(10a) and the N(1) atoms, shift upfield, indicating the increased electron density in the ring system. It can unambiguously be concluded from the chemical shift of the N(1) atom that the reduced flavin is anionic. The doublet character of the N(3) and N(5) resonances suggests that bulk water has no access to the active center. The strong downfield shift of the N(1) position indicates that this atom is embedded in a polar environment, but it does not indicate the presence of a positively charged residue. The {sup 31}P NMR spectra show that the resonances of the pyrophosphate group of the bound FAD differ slightly from those of free FAD. Besides the {sup 31}P resonances from FAD, four peaks around 0 ppm are observed that belongs to bound phosphorus residues. The residues are not located close to the isoalloxazine ring.

  10. ¹¹³Cd NMR experiments reveal an unusual metal cluster in the solution structure of the yeast splicing protein Bud31p.

    PubMed

    van Roon, Anne-Marie M; Yang, Ji-Chun; Mathieu, Daniel; Bermel, Wolfgang; Nagai, Kiyoshi; Neuhaus, David

    2015-04-13

    Establishing the binding topology of structural zinc ions in proteins is an essential part of their structure determination by NMR spectroscopy. Using (113)Cd NMR experiments with (113)Cd-substituted samples is a useful approach but has previously been limited mainly to very small protein domains. Here we used (113)Cd NMR spectroscopy during structure determination of Bud31p, a 157-residue yeast protein containing an unusual Zn3Cys9 cluster, demonstrating that recent hardware developments make this approach feasible for significantly larger systems. PMID:25703931

  11. 113Cd NMR Experiments Reveal an Unusual Metal Cluster in the Solution Structure of the Yeast Splicing Protein Bud31p**

    PubMed Central

    van Roon, Anne-Marie M; Yang, Ji-Chun; Mathieu, Daniel; Bermel, Wolfgang; Nagai, Kiyoshi; Neuhaus, David

    2015-01-01

    Establishing the binding topology of structural zinc ions in proteins is an essential part of their structure determination by NMR spectroscopy. Using 113Cd NMR experiments with 113Cd-substituted samples is a useful approach but has previously been limited mainly to very small protein domains. Here we used 113Cd NMR spectroscopy during structure determination of Bud31p, a 157-residue yeast protein containing an unusual Zn3Cys9 cluster, demonstrating that recent hardware developments make this approach feasible for significantly larger systems. PMID:25703931

  12. {sup 31}P NMR analysis of coal moieties bearing -OH, -NH, and -SH functions. Quarterly report, June 1, 1991--August 31, 1991

    SciTech Connect

    Verkade, J.G.

    1991-12-31

    The purpose of this research is to develop a convenient, reliable and rapid NMR method for the determination of labile-hydrogen functional groups and organic sulfur compounds which are components of coal and coal-derived materials. For this purpose, the former functional groups, including water molecules, are derivatized with reagents containing NMR-active nuclei such as {sup 31}P or {sup 119}Sn, while sulfur groups are derivatized with {sup 195}Pt NMR tagging reagents. Knowledge of the heteroatom composition of coals is necessary for the development of increasingly sophisticated coal processing technologies.

  13. Quantitative study of atomic ordering in Ga0.5In0.5P thin films by 31P nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Tycko, Robert; Dabbagh, Gary; Kurtz, Sarah R.; Goral, John P.

    1992-06-01

    We use 31P nuclear-magnetic-resonance (NMR) spectra to measure the degree of cation ordering in thin films of the semiconductor alloy Ga0.5In0.5P grown by organometallic vapor-phase epitaxy. We show that the five possible GanIn4-nP clusters in GaxIn1-xP give rise to resolved NMR lines under magic-angle spinning, allowing a determination of the degree of cation ordering from the relative areas of the five lines. The ordering is shown to be weak (order parameter <=0.6) even in films that appear highly ordered in transmission electron microscopy.

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

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-28

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of (1)H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of (1)H/(1)H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials. PMID:26026440

  15. Genetic Variation in Myosin 1H Contributes to Mandibular Prognathism

    PubMed Central

    Tassopoulou-Fishell, Maria; Deeley, Kathleen; Harvey, Erika M.; Sciote, James; Vieira, Alexandre R.

    2013-01-01

    Introduction Several candidate loci have been suggested as influencing mandibular prognathism (1p22.1, 1p22.2, 1p36, 3q26.2, 5p13-p12, 6q25, 11q22.2-q22.3, 12q23, 12q13.13, and 19p13.2). The goal of this study was to replicate these results in a well-characterized homogeneous sample set. Methods Thirty-three single nucleotide polymorphisms spanning all candidate regions were studied in 44 prognathic and 35 Class I subjects from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository. The 44 mandibular prognathism subjects had an average age of 18.4 years, 31 were females and 13 males, and 24 were White, 15 African American, two Hispanic, and three Asian. The 35 Class I subjects had an average age of 17.6 years, 27 were females and 9 males, and 27 were White, six African Americans, one Hispanic, and two Asian. Skeletal mandibular prognathism diagnosis included cephalometric values indicative of Class III such as ANB smaller than two degrees, negative Witts appraisal, and positive A–B plane. Additional mandibular prognathism criteria included negative OJ and visually prognathic (concave) profile as determined by the subject's clinical evaluation. Orthognathic subjects without jaw deformations were used as a comparison group. Mandibular prognathism and orthognathic subjects were matched based on race, sex and age. Genetic markers were tested by polymerase chain reaction using TaqMan chemistry. Chi-square and Fisher exact tests were used to determine overrepresentation of marker allele with alpha of 0.05. Results An association was unveiled between a marker in MYO1H (rs10850110) and the mandibular prognathism phenotype (p=0.03). MYO1H is a Class-I myosin that is in a different protein group than the myosin isoforms of muscle sarcomeres, which are the basis of skeletal muscle fiber typing. Class I myosins are necessary for cell motility, phagocytosis and vesicle transport. Conclusions More strict clinical definitions may increase

  16. Hydrophobization of epoxy nanocomposite surface with 1H,1H,2H,2H-perfluorooctyltrichlorosilane for superhydrophobic properties

    NASA Astrophysics Data System (ADS)

    Psarski, Maciej; Marczak, Jacek; Celichowski, Grzegorz; Sobieraj, Grzegorz B.; Gumowski, Konrad; Zhou, Feng; Liu, Weimin

    2012-10-01

    Nature inspires the design of synthetic materials with superhydrophobic properties, which can be used for applications ranging from self-cleaning surfaces to microfluidic devices. Their water repellent properties are due to hierarchical (micrometer- and nanometre-scale) surface morphological structures, either made of hydrophobic substances or hydrophobized by appropriate surface treatment. In this work, the efficiency of two surface treatment procedures, with a hydrophobic fluoropolymer, synthesized and deposited from 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) is investigated. The procedures involved reactions from the gas and liquid phases of the PFOTS/hexane solutions. The hierarchical structure is created in an epoxy nanocomposite surface, by filling the resin with alumina nanoparticles and micron-sized glass beads and subsequent sandblasting with corundum microparticles. The chemical structure of the deposited fluoropolymer was examined using XPS spectroscopy. The topography of the modified surfaces was characterized using scanning electron microscopy (SEM), and atomic force microscopy (AFM). The hydrophobic properties of the modified surfaces were investigated by water contact and sliding angles measurements. The surfaces exhibited water contact angles of above 150° for both modification procedures, however only the gas phase modification provided the non-sticking behaviour of water droplets (sliding angle of 3°). The discrepancy is attributed to extra surface roughness provided by the latter procedure.

  17. Determination of relative orientation between (1)H CSA tensors from a 3D solid-state NMR experiment mediated through (1)H/(1)H RFDR mixing under ultrafast MAS.

    PubMed

    Pandey, Manoj Kumar; Nishiyama, Yusuke

    2015-09-01

    To obtain piercing insights into inter and intramolecular H-bonding, and π-electron interactions measurement of (1)H chemical shift anisotropy (CSA) tensors is gradually becoming an obvious choice. While the magnitude of CSA tensors provides unique information about the local electronic environment surrounding the nucleus, the relative orientation between these tensors can offer further insights into the spatial arrangement of interacting nuclei in their respective three-dimensional (3D) space. In this regard, we present a 3D anisotropic/anisotropic/isotropic proton chemical shift (CSA/CSA/CS) correlation experiment mediated through (1)H/(1)H radio frequency-driven recoupling (RFDR) which enhances spin diffusion through recoupled (1)H-(1)H dipolar couplings under ultrafast magic angle spinning (MAS) frequency (70kHz). Relative orientation between two interacting 1H CSA tensors is obtained by fitting two-interacting (1)H CSA tensors by fitting two-dimensional (2D) (1)H/(1)H CSA/CSA spectral slices through extensive numerical simulations. To recouple (1)H CSAs in the indirect frequency dimensions of a 3D experiment we have employed γ-encoded radio frequency (RF) pulse sequence based on R-symmetry (R188(7)) with a series of phase-alternated 2700(°)-90180(°) composite-180° pulses on citric acid sample. Due to robustness of applied (1)H CSA recoupling sequence towards the presence of RF field inhomogeneity, we have successfully achieved an excellent (1)H/(1)H CSA/CSA cross-correlation efficiency between H-bonded sites of citric acid. PMID:26065628

  18. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks–Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  19. Studies of uptake and suppresion of Mn/sup 2 +/ migration in highly vacuolated sycamore (Acer pseudoplatanus L) cells by /sup 31/P NMR

    SciTech Connect

    Roby, C.; Bligny, R.; Douce, R.; Pfeffer, P.E.

    1987-04-01

    Recent /sup 31/P NMR studies have demonstrated that Mn/sup 2 +/ appears to invade the cells of heterogeneous excised tissue of corn root tips sequentially, first entering the cytoplasmic compartment, where it complexes with nucleotides and P/sub i/. Under aerobic conditions, further migration across the tonoplast, followed by vacoule trapping was visualized through paramagnetic broadening of the vacoular P/sub i/ resonance. Cultured cells such as Acer pseudoplatanus L offer better opportunities for studying cellular activity by /sup 31/P NMR because of their homogeneity and uniformly rapid response to various metabolic disturbances. In contrast to excised root tissue, Mn/sup 2 +/ showed no measurable accumulation in the cytoplasmic compartments of these cells under aerobic conditions. However, a rapid crossing of the large tonoplast resulted in immediate vacuolar metal ion sequestration. Anoxia did not foster leakage of Mn/sup 2 +/ from the vacuole to the cytoplasm, while hypoxia completely halted all movement of Mn/sup 2 +/ across the plasmalema. This disparity in terms of cell and tissue morphology, membrane permeability and possible tissue trapping of metal ions will be discussed.

  20. Temperature-dependent interconversion of phosphoramidite-Cu complexes detected by combined diffusion studies, 31P NMR, and low-temperature NMR spectroscopy.

    PubMed

    Schober, Katrin; Zhang, Hongxia; Gschwind, Ruth M

    2008-09-17

    For copper-catalyzed enantioselective conjugate additions, knowledge about the precatalytic and catalytic complexes has not yet been sufficiently developed to understand the strong influence of different temperatures on these famous reactions. Therefore, NMR experiments with four Cu(I) salts and two phosphoramidite ligands have been performed to elucidate the temperature dependence and the low-temperature structures of these copper complexes. The existence of the precatalytic binuclear complex with a mixed trigonal/tetrahedral coordination on copper is for the first time proven with direct NMR spectroscopic methods. Below 200 K, intermolecular interactions between free ligands and [Cu2X2L3] complexes induce binuclear [Cu2X2L4] complexes similar to the crystal structures. By combining diffusion experiments and (31)P integrals at different temperatures, it is for the first time possible to follow the formation of stoichiometrically different complexes, even under experimental conditions in which the (31)P signals of the complexes are spectroscopically not resolved due to exchange processes. This allows a first correlation between the complex species observed and the synthetic conditions reported. Furthermore, different preferences to build homo- or heterochiral complexes are detected for binaphthol and biphenol phosphoramidite complexes. PMID:18717560

  1. Trimethylphosphine-Assisted Surface Fingerprinting of Metal Oxide Nanoparticle by (31)P Solid-State NMR: A Zinc Oxide Case Study.

    PubMed

    Peng, Yung-Kang; Ye, Lin; Qu, Jin; Zhang, Li; Fu, Yingyi; Teixeira, Ivo F; McPherson, Ian James; He, Heyong; Tsang, Shik Chi Edman

    2016-02-24

    Nano metal oxides are becoming widely used in industrial, commercial and personal products (semiconductors, optics, solar cells, catalysts, paints, cosmetics, sun-cream lotions, etc.). However, the relationship of surface features (exposed planes, defects and chemical functionalities) with physiochemical properties is not well studied primarily due to lack of a simple technique for their characterization. In this study, solid state (31)P MAS NMR is used to map surfaces on various ZnO samples with the assistance of trimethylphosphine (TMP) as a chemical probe. As similar to XRD giving structural information on a crystal, it is demonstrated that this new surface-fingerprint technique not only provides qualitative (chemical shift) but also quantitative (peak intensity) information on the concentration and distribution of cations and anions, oxygen vacancies and hydroxyl groups on various facets from a single deconvoluted (31)P NMR spectrum. On the basis of this technique, a new mechanism for photocatalytic •OH radical generation from direct surface-OH oxidation is revealed, which has important implications regarding the safety of using nano oxides in personal care products. PMID:26812527

  2. 31P NMR characterization and efficiency of new types of water-insoluble phosphate fertilizers to supply plant-available phosphorus in diverse soil types.

    PubMed

    Erro, Javier; Baigorri, Roberto; Yvin, Jean-Claude; Garcia-Mina, Jose M

    2011-03-01

    Hydroponic plant experiments demonstrated the efficiency of a type of humic acid-based water-insoluble phosphate fertilizers, named rhizosphere controlled fertilizers (RCF), to supply available phosphorus (P) to different plant species. This effect was well correlated to the root release of specific organic acids. In this context, the aims of this study are (i) to study the chemical nature of RCF using solid-state (31)P NMR and (ii) to evaluate the real efficiency of RCF matrix as a source of P for wheat plants cultivated in an alkaline and acid soil in comparison with traditional water-soluble (simple superphosphate, SSP) and water-insoluble (dicalcium phosphate, DCP) P fertilizers. The (31)P NMR study revealed the formation of multimetal (double and triple, MgZn and/or MgZnCa) phosphates associated with chelating groups of the humic acid through the formation of metal bridges. With regard to P fertilizer efficiency, the results obtained show that the RCF matrix produced higher plant yields than SSP in both types of soil, with DCP and the water-insoluble fraction from the RCF matrix (WI) exhibiting the best results in the alkaline soil. By contrast, in the acid soil, DCP showed very low efficiency, WI performed on a par with SSP, and RCF exhibited the highest efficiency, thus suggesting a protector effect of humic acid from soil fixation. PMID:21254775

  3. Coupling of Li motion and structural distortions in olivine LiMnPO4 from 7Li and 31P NMR

    NASA Astrophysics Data System (ADS)

    Rudisch, Christian; Grafe, Hans-Joachim; Geck, Jochen; Partzsch, Sven; Zimmermann, M. v.; Wizent, Nadja; Klingeler, Rüdiger; Büchner, Bernd

    2013-08-01

    We present a detailed 7Li- and 31P-NMR study on single crystalline LiMnPO4 in the paramagnetic and antiferromagnetic phase (AFM, TN˜34 K). This allows us to determine the spin directions in the field-induced spin-flop phase. In addition, the anisotropic dipolar hyperfine coupling tensor of the 7Li and 31P nuclei is also fully determined by orientation and temperature-dependent NMR experiments and compared to the calculated values from crystal structure data. Deviations of the experimental values from the theoretical ones are discussed in terms of Mn disorder which is induced by Li disorder. In fact, the disorder in the Mn sublattice is directly revealed by diffuse x-ray scattering data. The present results provide experimental evidence for the Li diffusion strongly coupling to structural distortions within the MnPO4 host, which is expected to significantly affect the Li mobility as well as the performance of batteries based on this material.

  4. The contribution of magnetic susceptibility effects to transmembrane chemical shift differences in the 31P NMR spectra of oxygenated erythrocyte suspensions.

    PubMed

    Kirk, K; Kuchel, P W

    1988-01-01

    Triethyl phosphate, dimethyl methylphosphonate, and the hypophosphite ion all contain the phosphoryl functional group. When added to an oxygenated erythrocyte suspension, the former compound gives rise to a single 31P NMR resonance, whereas the latter compounds give rise to separate intra- and extracellular 31P NMR resonances. On the basis of experiments with intact oxygenated cell suspensions (in which the hematocrit was varied) and with oxygenated cell lysates (in which the lysate concentration was varied), it was concluded that the chemical shifts of the intra- and extracellular populations of triethyl phosphate differ as a consequence of the diamagnetic susceptibility of intracellular oxyhemoglobin but that this difference is averaged by the rapid exchange of the compound across the cell membrane. The difference in the magnetic susceptibility of the intra- and extracellular compartments contributes to the observed separation of the intra- and extracellular resonances of dimethyl methylphosphonate and hypophosphite. The magnitude of this contribution is, however, substantially less than that calculated using a simple two-compartment model and varies with the hematocrit of the suspension. Furthermore, it is insufficient to fully account for the transmembrane chemical shift differences observed for dimethyl methylphosphonate and hypophosphite. An additional effect is operating to move the intracellular resonances of these compounds to a lower chemical shift. The effect is mediated by an intracellular component, and the magnitude of the resultant chemical shift variations depends upon the chemical structure of the phosphoryl compound involved. PMID:3275636

  5. In vivo 31P nuclear magnetic resonance spectroscopy of experimental murine tumours and human tumour xenografts: effects of blood flow modification.

    PubMed Central

    Bremner, J. C.; Counsell, C. J.; Adams, G. E.; Stratford, I. J.; Wood, P. J.; Dunn, J. F.; Radda, G. K.

    1991-01-01

    The effect of hydralazine on tumours appears to vary depending on tumour type. Blood flow and radiation sensitivity decrease more in murine tumours than human tumour xenografts. In this study a comparison between various tumour types has been made using in vivo 31P nuclear magnetic resonance spectroscopy (NMRS) to follow the metabolic responses occurring after clamping or intravenous administration of hydralazine (5 mg kg-1). Large increases in the Pi/total phosphate ratio were found with the murine sarcomas, KHT and RIF-1 implanted into C3H/He mice. However little or no effect was seen for the two human xenografted tumours, HX118 and HT29 implanted in MFI nu/nu/01a mice. An intermediate response was observed for KHT tumours grown in nu/nu mice. All tumours showed a large response to clamping. The anaesthetic Hypnorm/Hypnovel has a great influence on the response of the tumour metabolism to hydralazine appearing to both prolong and increase the changes induced. There is evidence to support the theory that the changes in 31P spectra are related to the oxygen status of the tumours. PMID:1931606

  6. On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae

    NASA Astrophysics Data System (ADS)

    Godinot, Claire; Gaysinski, Marc; Thomas, Olivier P.; Ferrier-Pagès, Christine; Grover, Renaud

    2016-02-01

    31P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 μM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on 31P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ.

  7. On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae.

    PubMed

    Godinot, Claire; Gaysinski, Marc; Thomas, Olivier P; Ferrier-Pagès, Christine; Grover, Renaud

    2016-01-01

    (31)P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 μM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on (31)P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ. PMID:26902733

  8. Formations of hydroxyapatite and inositol hexakisphosphate in poultry litter during the composting period: sequential fractionation, P K-edge XANES and solution (31)P NMR investigations.

    PubMed

    Hashimoto, Yohey; Takamoto, Akira; Kikkawa, Ren; Murakami, Keiichi; Yamaguchi, Noriko

    2014-05-20

    Little is known about how the solubility and chemical speciation of phosphorus (P) in poultry litters are altered during the composting period. This study investigated the quantitative and qualitative changes in organic P (Po) and inorganic P (Pi) compositions in poultry litters during the seven-day composting period using sequential extraction in combination with P K-edge X-ray absorption near-edge structure (XANES) and solution (31)P nuclear magnetic resonance (NMR) spectroscopy. The result of sequential extraction illustrated that the significant decrease of H2O-P by 55% in poultry litters occurred concomitantly with the increase of HCl-Pi and HCl-Po during the composting period (p < 0.05). X-ray diffraction results for poultry litter samples showed three distinct peaks indicative of hydroxyapatite. Phosphorus K-edge XANES confirmed the increase of hydroxyapatite during the composting period, corresponding to the increase of HCl-Pi determined by the sequential extraction. The NaOH-EDTA extraction for solution (31)P NMR revealed that myo-inositol hexakisphosphate (IHP) constituted about 80% of phosphate monoesters and was increased from 16 to 28% in the poultry litter during the composting period. The combined applications of chemical extraction and molecular-spectroscopic techniques determined that water-soluble P in poultry litter was transformed into less soluble phases, primarily hydroxyapatite and IHP, during the composting period. PMID:24735189

  9. In Vivo 31P-Nuclear Magnetic Resonance Studies of Glyphosate Uptake, Vacuolar Sequestration, and Tonoplast Pump Activity in Glyphosate-Resistant Horseweed1[W

    PubMed Central

    Ge, Xia; d’Avignon, D. André; Ackerman, Joseph J.H.; Sammons, R. Douglas

    2014-01-01

    Horseweed (Conyza canadensis) is considered a significant glyphosate-resistant (GR) weed in agriculture, spreading to 21 states in the United States and now found globally on five continents. This laboratory previously reported rapid vacuolar sequestration of glyphosate as the mechanism of resistance in GR horseweed. The observation of vacuole sequestration is consistent with the existence of a tonoplast-bound transporter. 31P-Nuclear magnetic resonance experiments performed in vivo with GR horseweed leaf tissue show that glyphosate entry into the plant cell (cytosolic compartment) is (1) first order in extracellular glyphosate concentration, independent of pH and dependent upon ATP; (2) competitively inhibited by alternative substrates (aminomethyl phosphonate [AMPA] and N-methyl glyphosate [NMG]), which themselves enter the plant cell; and (3) blocked by vanadate, a known inhibitor/blocker of ATP-dependent transporters. Vacuole sequestration of glyphosate is (1) first order in cytosolic glyphosate concentration and dependent upon ATP; (2) competitively inhibited by alternative substrates (AMPA and NMG), which themselves enter the plant vacuole; and (3) saturable. 31P-Nuclear magnetic resonance findings with GR horseweed are consistent with the active transport of glyphosate and alternative substrates (AMPA and NMG) across the plasma membrane and tonoplast in a manner characteristic of ATP-binding cassette transporters, similar to those that have been identified in mammalian cells. PMID:25185124

  10. On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae

    PubMed Central

    Godinot, Claire; Gaysinski, Marc; Thomas, Olivier P.; Ferrier-Pagès, Christine; Grover, Renaud

    2016-01-01

    31P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 μM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on 31P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ. PMID:26902733

  11. Contribution of magnetic susceptibility effects to transmembrane chemical shift differences in the /sup 31/P NMR spectra of oxygenated erythrocyte suspensions

    SciTech Connect

    Kirk, K.; Kuchel, P.W.

    1988-01-05

    Triethyl phosphate, dimethyl methylphosphonate, and the hypophosphite ion all contain the phosphoryl functional group. When added to an oxygenated erythrocyte suspension, the former compound gives rise to a single /sup 31/P NMR resonance, whereas the latter compounds give rise to separate intra- and extracellular /sup 31/P NMR resonances. On the basis of experiments with intact oxygenated cell suspensions (in which the hematocrit was varied) and with oxygenated cell lysates (in which the lysate concentration was varied) it was concluded that the chemical shifts of the intra- and extracellular populations of triethyl phosphate differ as a consequence of the diamagnetic susceptibility of intracellular oxyhemoglobin but that this difference is averaged by the rapid exchange of the compound across the cell membrane. The difference is the magnetic susceptibility of the intra- and extracellular compartments contributes to the observed separation of the intra- and extracellular resonances of dimethyl methylphosphonate and hypophosphite. The magnitude of this contribution is, however, substantially less than that calculated using a simple two-compartment model and varies with the hematocrit of the suspension. Furthermore, it is insufficient to fully account for the transmembrane chemical shift differences observed for dimethyl methylphosphonate and hypophosphite. An additional effect is operating to move the intracellular resonances of these compounds to a lower chemical shift. The effect is mediated by an intracellular component, and the magnitude of the resultant chemical shift variations depends upon the chemical structure of the phosphoryl compound involved.

  12. A new NMR method for determining the particle thickness in nanocomposites, using T2,H-selective X{1H} recoupling.

    PubMed

    Schmidt-Rohr, K; Rawal, A; Fang, X-W

    2007-02-01

    A new nuclear magnetic resonance approach for characterizing the thickness of phosphate, silicate, carbonate, and other nanoparticles in organic-inorganic nanocomposites is presented. The particle thickness is probed using the strongly distant-dependent dipolar couplings between the abundant protons in the organic phase and X nuclei (31P, 29Si, 13C, 27Al, 23Na, etc.) in the inorganic phase. This approach requires pulse sequences with heteronuclear dephasing only by the polymer or surface protons that experience strong homonuclear interactions, but not by dispersed OH or water protons in the inorganic phase, which have long transverse relaxation times T2,H. This goal is achieved by heteronuclear recoupling with dephasing by strong homonuclear interactions of protons (HARDSHIP). The pulse sequence alternates heteronuclear recoupling for approximately 0.15 ms with periods of homonuclear dipolar dephasing that are flanked by canceling 90 degrees pulses. The heteronuclear evolution of the long-T2,H protons is refocused within two recoupling periods, so that 1H spin diffusion cannot significantly dephase these coherences. For the short-T2,H protons of a relatively immobile organic matrix, the heteronuclear dephasing rate depends simply on the heteronuclear second moment. Homonuclear interactions do not affect the dephasing, even though no homonuclear decoupling is applied, because long-range 1H-X dipolar couplings approximately commute with short-range 1H-1H couplings, and heteronuclear recoupling periods are relatively short. This is shown in a detailed analysis based on interaction representations. The algorithm for simulating the dephasing data is described. The new method is demonstrated on a clay-polymer nanocomposite, diamond nanocrystals with protonated surfaces, and the bioapatite-collagen nanocomposite in bone, as well as pure clay and hydroxyapatite. The diameters of the nanoparticles in these materials range between 1 and 5 nm. Simulations show that spherical

  13. Non-invasive assessment of phosphate metabolism and oxidative capacity in working skeletal muscle in healthy young Chinese volunteers using (31)P Magnetic Resonance Spectroscopy.

    PubMed

    Li, Ming; Chen, Fei; Wang, Huiting; Wu, Wenbo; Zhang, Xin; Tian, Chuanshuai; Yu, Haiping; Liu, Renyuan; Zhu, Bin; Zhang, Bing; Dai, Zhenyu

    2016-01-01

    Background. Generally, males display greater strength and muscle capacity than females while performing a task. Muscle biopsy is regarded as the reference method of evaluating muscle functions; however, it is invasive and has sampling errors, and is not practical for longitudinal studies and dynamic measurement during excise. In this study, we built an in-house force control and gauge system for quantitatively applying force to quadriceps while the subjects underwent (31)P Magnetic Resonance Spectroscopy ((31)P-MRS); our aim was to investigate if there is a sex difference of phosphate metabolite change in working muscles in young heathy Chinese volunteers. Methods. Volunteers performed knee-extending excises using a force control and gauge system while lying prone in a Philips 3T Magnetic Resonance (MR) scanner. The (31)P-MRS coil was firmly placed under the middle of the quadriceps . (31)P-MRS measurements of inorganic phosphate (Pi), phosphocreatine (PCr) and adenosine triphosphate (ATP) were acquired from quadriceps while subjects were in a state of pre-, during- and post-exercise. The PCr, Pi, PCr/Pi, PCr/ATP, pH, work/energy cost ratio (WE), kPCr and oxidative capacity were compared between males and females. Results. A total of 17 volunteers underwent the study. Males: N = 10, age = 23.30 ± 1.25years; females: N = 7, age = 23.57 ± 0.79 years. In this study, males had significantly greater WE (16.33 ± 6.46 vs. 7.82 ± 2.16, p = 0.002) than females. Among PCr, Pi, PCr/Pi, PCr/ATP, pH, kPCr and oxidative capacity at different exercise status, only PCr/Pi (during-exercise, males = 5.630 ± 1.647, females = 4.014 ± 1.298, p = 0.047), PCr/ATP (during-exercise, males =1.273 ± 0.219, females = 1.523 ± 0.167, p = 0.025), and ATP (post-exercise, males = 24.469 ± 3.911 mmol/kg, females = 18.353 ± 4.818 mmol/kg, p = 0.035) had significant sex differences. Males had significantly greater PCr/Pi, but less PCr/ATP than females during exercise, suggesting males had

  14. Non-invasive assessment of phosphate metabolism and oxidative capacity in working skeletal muscle in healthy young Chinese volunteers using 31P Magnetic Resonance Spectroscopy

    PubMed Central

    Wang, Huiting; Wu, Wenbo; Zhang, Xin; Tian, Chuanshuai; Yu, Haiping; Liu, Renyuan; Zhu, Bin

    2016-01-01

    Background. Generally, males display greater strength and muscle capacity than females while performing a task. Muscle biopsy is regarded as the reference method of evaluating muscle functions; however, it is invasive and has sampling errors, and is not practical for longitudinal studies and dynamic measurement during excise. In this study, we built an in-house force control and gauge system for quantitatively applying force to quadriceps while the subjects underwent 31P Magnetic Resonance Spectroscopy (31P-MRS); our aim was to investigate if there is a sex difference of phosphate metabolite change in working muscles in young heathy Chinese volunteers. Methods. Volunteers performed knee-extending excises using a force control and gauge system while lying prone in a Philips 3T Magnetic Resonance (MR) scanner. The 31P-MRS coil was firmly placed under the middle of the quadriceps . 31P-MRS measurements of inorganic phosphate (Pi), phosphocreatine (PCr) and adenosine triphosphate (ATP) were acquired from quadriceps while subjects were in a state of pre-, during- and post-exercise. The PCr, Pi, PCr/Pi, PCr/ATP, pH, work/energy cost ratio (WE), kPCr and oxidative capacity were compared between males and females. Results. A total of 17 volunteers underwent the study. Males: N = 10, age = 23.30 ± 1.25years; females: N = 7, age = 23.57 ± 0.79 years. In this study, males had significantly greater WE (16.33 ± 6.46 vs. 7.82 ± 2.16, p = 0.002) than females. Among PCr, Pi, PCr/Pi, PCr/ATP, pH, kPCr and oxidative capacity at different exercise status, only PCr/Pi (during-exercise, males = 5.630 ± 1.647, females = 4.014 ± 1.298, p = 0.047), PCr/ATP (during-exercise, males =1.273 ± 0.219, females = 1.523 ± 0.167, p = 0.025), and ATP (post-exercise, males = 24.469 ± 3.911 mmol/kg, females = 18.353 ± 4.818 mmol/kg, p = 0.035) had significant sex differences. Males had significantly greater PCr/Pi, but less PCr/ATP than females during exercise, suggesting males had higher

  15. Measurement of delta(1)J((199)Hg, (31)P) in [HgPCy3(OAc)2]2 and relativistic ZORA DFT investigations of mercury-phosphorus coupling tensors.

    PubMed

    Bryce, David L; Courchesne, Noémie Manuelle Dorval; Perras, Frédéric A

    2009-12-01

    Using 31P solid-state NMR spectroscopy, anisotropy in the indirect 199Hg-31P spin-spin coupling tensor (DeltaJ) for powdered [HgPCy3(OAc)2]2 (1) has been measured as 4700 +/- 300 Hz. Zeroth-order regular approximation (ZORA) density functional theory (DFT) calculations, including scalar and spin-orbit relativistic effects, performed on 1 and a series of other related compounds show that DeltaJ(199Hg, (31)P) arises entirely from the ZORA Fermi-contact-spin-dipolar cross term. The calculations validate assumptions made in the spectral analysis of 1 and in previous determinations of DeltaJ in powder samples, namely that J is axially symmetric and shares its principal axis system with the direct dipolar coupling tensor (D). Agreement between experiment and theory for various 199Hg, 31P spin-spin coupling anisotropies is reasonable; however, experimental values of 1J(199Hg, 31P)(iso) are significantly underestimated by the calculations. The most important improvements in the agreement were obtained as a result of including more of the crystal lattice in the model used for the calculations, e.g., a change of 43% was noted for 1J(199Hg, 31P)(iso) in [HgPPh3(NO3)2]2 depending on whether the two or three nearest nitrate ions are included in the model. Finally, we have written a computer program to simulate the effects of non-axial symmetry in J and of non-coincidence of the J and D on powder NMR spectra. Simulations clearly show that both of these effects have a pronounced impact on the 31P NMR spectrum of 199Hg-31P spin pairs, suggesting that the effects should be observable experimentally if a suitable compound can be identified. PMID:20056396

  16. 1H NMR metabolomics study of age profiling in children

    PubMed Central

    Gu, Haiwei; Pan, Zhengzheng; Xi, Bowei; Hainline, Bryan E.; Shanaiah, Narasimhamurthy; Asiago, Vincent; Nagana Gowda, G. A.; Raftery, Daniel

    2014-01-01

    Metabolic profiling of urine provides a fingerprint of personalized endogenous metabolite markers that correlate to a number of factors such as gender, disease, diet, toxicity, medication, and age. It is important to study these factors individually, if possible to unravel their unique contributions. In this study, age-related metabolic changes in children of age 12 years and below were analyzed by 1H NMR spectroscopy of urine. The effect of age on the urinary metabolite profile was observed as a distinct age-dependent clustering even from the unsupervised principal component analysis. Further analysis, using partial least squares with orthogonal signal correction regression with respect to age, resulted in the identification of an age-related metabolic profile. Metabolites that correlated with age included creatinine, creatine, glycine, betaine/TMAO, citrate, succinate, and acetone. Although creatinine increased with age, all the other metabolites decreased. These results may be potentially useful in assessing the biological age (as opposed to chronological) of young humans as well as in providing a deeper understanding of the confounding factors in the application of metabolomics. PMID:19441074

  17. Preliminary 1H NMR study on archaeological waterlogged wood.

    PubMed

    Maccotta, Antonella; Fantazzini, Paola; Garavaglia, Carla; Donato, Ines D; Perzia, Patrizia; Brai, Maria; Morreale, Filippa

    2005-01-01

    Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological decay from the long contact with the water. When wood artefacts are brought to the surface and directly dried in air, there is the collapse of the cellular structures, and wood loses its original form and dimensions and cannot be used for study and museum exhibits. In this work we have undertaken the study of some wood finds coming from Ercolano's harbour by MRR and MRI under different conditions, and we have obtained a characterization of pore space in wood and images of the spatial distribution of the confined water in the wood. PMID:16485652

  18. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, K.N.; Xu, J.

    1997-04-29

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

  19. The Conformations and Structures of 1H-NONAFLUOROBUTANE

    NASA Astrophysics Data System (ADS)

    Fournier, Joseph A.; Bohn, Robert K.; Montgomery, John A.; , Jr.

    2012-06-01

    The all trans conformers of perfluorocarbons, unlike hydrocarbons, are helical with C-C-C-C dihedral angles about 1640. Fluorocarbons with H substitution can replace chlorofluorocarbons as propellants and compressor fluids without the disadvantage of causing ozone depletion in the upper atmosphere. 1H-perfluorobutane, CHF_2CF_2CF_2CF_3, has been studied by pulsed-jet Fourier transform microwave spectroscopy. The spectrum is very rich. Quantum chemical calculations identify five stable conformers with relative energies up to 1.1 kcal/mol. Thus far three conformers have been characterized and many lines remain unassigned. The assigned species have CCCCanti/CCCH gauche as well as the anti/anti and gauche/anti forms. Rotational constant values are 1428.9501(2) MHz, 593.323877(6) MHz, and 546.43578(6) MHz for the anti/gauche species, 1323.664(3) MHz, 617.6051(5) MHz for the ant/anti species, and 1066.9384(4) MHz, 768.4736(4) MHz, and 671.3145(4) MHz for the gauche/anti form.

  20. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, Kenneth N.; Xu, Jide

    1997-01-01

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

  1. 1H NMR Metabolomics Analysis of Glioblastoma Subtypes

    PubMed Central

    Cuperlovic-Culf, Miroslava; Ferguson, Dean; Culf, Adrian; Morin, Pier; Touaibia, Mohamed

    2012-01-01

    Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by unpredictable clinical behaviors that suggest distinct molecular subtypes. With the tumor metabolic phenotype being one of the hallmarks of cancer, we have set upon to investigate whether GBMs show differences in their metabolic profiles. 1H NMR analysis was performed on metabolite extracts from a selection of nine glioblastoma cell lines. Analysis was performed directly on spectral data and on relative concentrations of metabolites obtained from spectra using a multivariate regression method developed in this work. Both qualitative and quantitative sample clustering have shown that cell lines can be divided into four groups for which the most significantly different metabolites have been determined. Analysis shows that some of the major cancer metabolic markers (such as choline, lactate, and glutamine) have significantly dissimilar concentrations in different GBM groups. The obtained lists of metabolic markers for subgroups were correlated with gene expression data for the same cell lines. Metabolic analysis generally agrees with gene expression measurements, and in several cases, we have shown in detail how the metabolic results can be correlated with the analysis of gene expression. Combined gene expression and metabolomics analysis have shown differential expression of transporters of metabolic markers in these cells as well as some of the major metabolic pathways leading to accumulation of metabolites. Obtained lists of marker metabolites can be leveraged for subtype determination in glioblastomas. PMID:22528487

  2. A theoretical study of rotational diffusion models for rod-shaped viruses. The influence of motion on 31P nuclear magnetic resonance lineshapes and transversal relaxation.

    PubMed Central

    Magusin, P C; Hemminga, M A

    1993-01-01

    Information about the interaction between nucleic acids and coat proteins in intact virus particles may be obtained by studying the restricted backbone dynamics of the incapsulated nucleic acids using 31P nuclear magnetic resonance (NMR) spectroscopy. In this article, simulations are carried out to investigate how reorientation of a rod-shaped virus particle as a whole and isolated nucleic acid motions within the virion influence the 31P NMR lineshape and transversal relaxation dominated by the phosphorus chemical shift anisotropy. Two opposite cases are considered on a theoretical level. First, isotropic rotational diffusion is used as a model for mobile nucleic acids that are loosely or partially bound to the protein coat. The effect of this type of diffusion on lineshape and transversal relaxation is calculated by solving the stochastic Liouville equation by an expansion in spherical functions. Next, uniaxial rotational diffusion is assumed to represent the mobility of phosphorus in a virion that rotates as a rigid rod about its length axis. This type of diffusion is approximated by an exchange process among discrete sites. As turns out from these simulations, the amplitude and the frequency of the motion can only be unequivocally determined from experimental data by a combined analysis of the lineshape and the transversal relaxation. In the fast motional region both the isotropic and the uniaxial diffusion model predict the same transversal relaxation as the Redfield theory. For very slow motion, transversal relaxation resembles the nonexponential relaxation as observed for water molecules undergoing translational diffusion in a magnetic field gradient. In this frequency region T2e is inversely proportional to the cube root of the diffusion coefficient. In addition to the isotropic and uniaxial diffusion models, a third model is presented, in which fast restricted nucleic acid backbone motions dominating the lineshape are superimposed on a slow rotation of the

  3. Characterizing phosphorus speciation of Chesapeake Bay sediments using chemical extraction, 31P NMR, and X-ray absorption fine structure spectroscopy.

    PubMed

    Li, Wei; Joshi, Sunendra R; Hou, Guangjin; Burdige, David J; Sparks, Donald L; Jaisi, Deb P

    2015-01-01

    Nutrient contamination has been one of the lingering issues in the Chesapeake Bay because the bay restoration is complicated by temporally and seasonally variable nutrient sources and complex interaction between imported and regenerated nutrients. Differential reactivity of sedimentary phosphorus (P) pools in response to imposed biogeochemical conditions can record past sediment history and therefore a detailed sediment P speciation may provide information on P cycling particularly the stability of a P pool and the formation of one pool at the expense of another. This study examined sediment P speciation from three sites in the Chesapeake Bay: (i) a North site in the upstream bay, (ii) a middle site in the central bay dominated by seasonally hypoxic bottom water, and (iii) a South site at the bay-ocean boundary using a combination of sequential P extraction (SEDEX) and spectroscopic techniques, including (31)P NMR, P X-ray absorption near edge structure spectroscopy (XANES), and Fe extended X-ray absorption fine structure (EXAFS). Results from sequential P extraction reveal that sediment P is composed predominantly of ferric Fe-bound P and authigenic P, which was further confirmed by solid-state (31)P NMR, XANES, and EXAFS analyses. Additionally, solution (31)P NMR results show that the sediments from the middle site contain high amounts of organic P such as monoesters and diesters, compared to the other two sites, but that these compounds rapidly decrease with sediment depth indicating remineralized P could have precipitated as authigenic P. Fe EXAFS enabled to identify the changes in Fe mineral composition and P sinks in response to imposed redox condition in the middle site sediments. The presence of lepidocrocite, vermiculite, and Fe smectite in the middle site sediments indicates that some ferric Fe minerals can still be present along with pyrite and vivianite, and that ferric Fe-bound P pool can be a major P sink in anoxic sediments. These results provide

  4. Effects of decreased pH on membrane structural organization of Escherichia coli grown in different fatty acid-supplemented media: a 31P NMR study.

    PubMed

    Ianzini, F; Guidoni, L; Simone, G; Viti, V; Yatvin, M B

    1990-04-01

    Total membranes from Escherichia coli cells grown in different fatty acid-supplemented media have been examined by 31P NMR at different pH values. The isolated inner and outer membranes were also studied and compared to the liposomes formed with the corresponding extracted lipids. While the liposomes show structures that are correlated with lipid composition, degree of fatty acid unsaturation, and pH, the membrane structure is mainly bilayer. The presence of two bilayer phases characterized by different chemical shift anisotropy values (delta nu csa) is detectable at neutral pH; a perturbation of the bilayer phase characterized by the smallest delta nu csa is produced by low pH. Moreover, an isotropic peak is always present in the membrane NMR spectra: its attribution to cardiolipin molecules is discussed on the basis of digestion experiments with phospholipase C. PMID:2181934

  5. Hydration behaviour of POPC/C(12)-Bet mixtures investigated by sorption gravimetry, (31)P NMR spectroscopy and X-ray diffraction.

    PubMed

    Pfeiffer, H; Weichert, H; Klose, G; Heremans, K

    2012-02-01

    The hydration behaviour of mixtures of the zwitterionic phospholipid 1-palmitoyl-2-oleolyl-sn-glycero-3-phosphocholine (POPC) and the zwitterionic surfactant N,N-dimethyl-N-dodecyl-betain (C(12)-Bet) was investigated by sorption gravimetry, solid-state (31)P NMR-spectroscopy and small angle X-ray diffraction (SAXD). Negative excess hydration (dehydration) was found for almost all hydration degrees investigated. This behaviour is explained by the formation of an inner salt between the dipoles of phospholipid and surfactant headgroups that show a reverse sequence of partial charges with respect to the hydrocarbon backbone. The formation of an inner-salt most probably reduces potential water binding sites. Moreover, NMR data suggest that the incorporation of the zwitterionic surfactant into the phospholipid membrane is correlated with reorientation of the phosphate axis towards the membrane director as well as with reduced lateral and wobbling diffusion. PMID:22285958

  6. Treatment of glycogenosys type V (McArdle disease) with creatine and ketogenic diet with clinical scores and with 31P-MRS on working leg muscle

    PubMed Central

    Vorgerd, M; Zange, J

    2007-01-01

    Summary McArdle’s disease is caused by genetic defects of the musclespecific isozyme of glycogen phosphorylase, which block ATP formation from glycogen in skeletal muscle. Creatine supplementation and ketogenic diet have been tested as potential supplements for muscle energy metabolism which may improve muscle symptomatic. Outcome measures were clinical scores describing muscle symptomatic and parameters derived from 31P-MRS examinations on working muscle. In two placebo controlled cross-over studies low dose creatine showed beneficial effects on muscle symptoms and performance whereas high dose creatine distinctly worsened muscle symptomatic in patients. In both studies, however, the absence of an elevation in phosphocreatine indicated the absence of a creatine uptake by the muscle fibre. The effects of creatine on muscle symptomatic may be independent from energy metabolism in muscle. In a case study, ketogenic diet improved muscle symptomatic and performance. However, these effects again did not result in 31PMRS visible changes in muscle energy metabolism. PMID:17915573

  7. Topographical analysis of regulatory and metal ion binding sites on glutamine synthetase from Escherichia coli: 13C and 31P nuclear magnetic resonance and fluorescence energy transfer study

    PubMed Central

    Villafranca, J. J.; Rhee, S. G.; Chock, P. B.

    1978-01-01

    The paramagnetic effect of Mn(II) on 13C and 31P nuclear magnetic resonance signals from the [2-13C]ATP adenylylated glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming); EC 6.3.1.2] from Escherichia coli was measured. This effect permitted the determination of distances from the 2-C position and the phosphorus of covalently bound AMP to the two Mn(II) binding sites, n1 and n2. Binding of Mn(II) to the n1 site converts an inactive apo-enzyme to its active form, while the metal ion bound at n2 occupies the metal-nucleotide substrate site. The distances from Mn(II) at the n1 and n2 sites to phosphorus are ∼10 and ∼7 Å and to the 2-C position of the adenine ring are ∼12 and ∼11 Å, respectively. The fluorescence energy transfer method was used to determine distances between Co(II) at n1 and n2 and the adenylyl site. For this experiment the enzyme was adenylylated with ε-ATP. The distances between ε-adenine and Co(II) at n1 and n2 are ∼13 and ∼11 Å, respectively. Quantitation of the paramagnetic effect due to Co(II) on the 31P nuclear magnetic resonance signal yielded values of 8 and 6 Å for the distances between the phosphorus of the covalently bound AMP and the n1 and n2 sites, respectively. The results reveal that the covalent modification site is very close to the catalytic center of the enzyme. In this study both nuclear magnetic resonance and fluorescence energy transfer techniques have been used to determine distances between the same set of sites on an enzyme surface. PMID:26053

  8. 31P NMR analysis of intracellular pH of Swiss Mouse 3T3 cells: effects of extracellular Na+ and K+ and mitogenic stimulation.

    PubMed

    Civan, M M; Williams, S R; Gadian, D G; Rozengurt, E

    1986-01-01

    Swiss mouse 3T3 cells grown on microcarrier beads were superfused with electrolyte solution during continuous NMR analysis. Conventional 31P and 19F probes of intracellular pH (pHc) were found to be impracticable. Cells were therefore superfused with 1 to 4 mM 2-deoxyglucose, producing a large intracellular, pH-sensitive signal of 2-deoxyglucose phosphate (2DGP). The intracellular incorporation of 2DGP inhibited the Embden-Meyerhof pathway. However, intracellular ATP was at least in part retained and the cellular responsivity to changes in extracellular ionic composition and to the application of growth factors proved intact. Transient replacement of external Na+ with choline or K+ reversibly acidified the intracellular fluids. Quiescent cells and mitogenically stimulated cells displayed the same dependence of shifts in pHc on external Na+ concentration (CoNa). PHc also depended on intracellular Na+ concentration (CcNa). Increasing ccNa by withdrawing external K+ (thereby inhibiting the Na,K-pump) caused reversible intracellular acidification; subsequently reducing CoNa produced a larger acid shift in pHc than with external K+ present. Comparison of separate preparations indicated that pHc was higher in stimulated than in quiescent cells. Transient administration of mitogens also reversibly alkalinized quiescent cells studied continuously. This study documents the feasibility of monitoring pHc of Swiss mouse 3T3 cells using 31P NMR analysis of 2DGP. The results support the concept of a Na/H antiport operative in these cells, both in quiescence and after mitogenic stimulation. The data document by an independent technique that cytoplasmic alkalinization is an early event in mitogenesis, and that full activity of the Embden-Meyerhof pathway is not required for the expression of this event. PMID:3543375

  9. Adenosine triphosphate infusion increases liver energy status in advanced lung cancer patients: an in vivo 31P magnetic resonance spectroscopy study.

    PubMed

    Leij-Halfwerk, Susanne; Agteresch, Hendrik J; Sijens, Paul E; Dagnelie, Pieter C

    2002-02-01

    We recently observed inhibition of weight loss in patients with advanced nonsmall-cell lung cancer after intravenous infusion of ATP. Because liver ATP levels were found to be decreased in lung cancer patients with weight loss, the present 31P magnetic resonance spectroscopy (MRS) study was aimed at investigating whether ATP infusion restores liver energy status in these patients. Nine patients with advanced nonsmall-cell lung cancer (stage IIIB/IV) were studied 1 week before (baseline) and at 22 to 24 hours of continuous ATP infusion (37-75 microg/kg/min). Localized hepatic 31P MR spectra (repetition time 15 seconds), obtained in the overnight-fasted state, were analyzed for ATP and P(i) content. Ten healthy subjects (without ATP infusion) served as control. Liver ATP levels in lung cancer patients increased from 8.8 +/- 0.7% (relative to total MR-detectable phosphate; mean +/- SE) at baseline to 12.2 +/- 0.9% during ATP infusion (P <.05), i.e., a level similar to that in healthy subjects (11.9 +/- 0.9%). The increase in ATP level during ATP infusion was most prominent in patients with > or = 5% weight loss (baseline: 7.9 +/- 0.7%, during ATP infusion: 12.8 +/- 1.0%, P < 0.01). In conclusion, ATP infusion restores hepatic energy levels in patients with advanced lung cancer, especially in weight-losing patients. These changes may contribute to the previously reported beneficial effects of ATP infusion on the nutritional status of lung cancer patients. PMID:11826418

  10. 31P NMR 2D Mapping of Creatine Kinase Forward Flux Rate in Hearts with Postinfarction Left Ventricular Remodeling in Response to Cell Therapy.

    PubMed

    Gao, Ling; Cui, Weina; Zhang, Pengyuan; Jang, Albert; Zhu, Wuqiang; Zhang, Jianyi

    2016-01-01

    Utilizing a fast 31P magnetic resonance spectroscopy (MRS) 2-dimensional chemical shift imaging (2D-CSI) method, this study examined the heterogeneity of creatine kinase (CK) forward flux rate of hearts with postinfarction left ventricular (LV) remodeling. Immunosuppressed Yorkshire pigs were assigned to 4 groups: 1) A sham-operated normal group (SHAM, n = 6); 2) A 60 minutes distal left anterior descending coronary artery ligation and reperfusion (MI, n = 6); 3) Open patch group; ligation injury plus open fibrin patch over the site of injury (Patch, n = 6); and 4) Cell group, hiPSCs-cardiomyocytes, -endothelial cells, and -smooth muscle cells (2 million, each) were injected into the injured myocardium pass through a fibrin patch (Cell+Patch, n = 5). At 4 weeks, the creatine phosphate (PCr)/ATP ratio, CK forward flux rate (Flux PCr→ATP), and k constant of CK forward flux rate (kPCr→ATP) were severely decreased at border zone myocardium (BZ) adjacent to MI. Cell treatment results in significantly increase of PCr/ATP ratio and improve the value of kPCr→ATP and Flux PCr→ATP in BZ myocardium. Moreover, the BZ myocardial CK total activity and protein expression of CK mitochondria isozyme and CK myocardial isozyme were significantly reduced, but recovered in response to cell treatment. Thus, cell therapy results in improvement of BZ bioenergetic abnormality in hearts with postinfarction LV remodeling, which is accompanied by significantly improvements in BZ CK activity and CK isozyme expression. The fast 2D 31P MR CSI mapping can reliably measure the heterogeneity of bioenergetics in hearts with post infarction LV remodeling. PMID:27606901

  11. High-energy phosphate metabolism during incremental calf exercise in humans measured by 31 phosphorus magnetic resonance spectroscopy (31P MRS).

    PubMed

    Schocke, Michael F H; Esterhammer, Regina; Kammerlander, Christian; Rass, Anton; Kremser, Christian; Fraedrich, Gustav; Jaschke, Werner R; Greiner, Andreas

    2004-01-01

    Several previous 31 phosphorus magnetic resonance spectroscopy ((31)P MRS) studies performing incremental or progressive muscle exercises have observed that a decrease in pH is accompanied with an acceleration in phosphocreatine (PCr) hydrolysis. The purpose of this study was to investigate the relationship between PCr breakdown and pH during isotonic, exhaustive, incremental plantar flexion exercises. We included eight healthy, male volunteers into this study. Using a 1.5 Tesla MR scanner and a self-built exercise bench, we performed serial free induction decay (FID) (31)P MRS measurements with a time resolution of 1 min at rest, isotonic calf muscle exercise, and recovery. The exercise protocol consisted of 5-min intervals with 4.5, 6, 7.5, and 9 W workload followed by 9-min recovery. Changes in PCr and inorganic phosphate (Pi) were determined as percent changes in comparison to the baseline. In addition, pH values were calculated. This study obtained significant decreases in PCr corresponding to the gradual increases in workload. In each workload level that was succeeded by all volunteers, PCr hydrolysis passed into a steady state. After an early biphasic response, we detected a significant decrease in pH from the first to the second minute of the 6-W workload level followed by a further continuous decrease in pH up to the second minute of the recovery phase. The decrease in pH was not accompanied by acceleration in PCr hydrolysis. In conclusion, this study shows that PCr hydrolysis during incremental plantar flexion exercises passes into a steady state at different workload levels. The observed decrease in pH does not result in acceleration of PCr hydrolysis. PMID:14972400

  12. Roles of Arginine and Lysine Residues in the Translocation of a Cell-Penetrating Peptide from 13C, 31P and 19F Solid-State NMR

    PubMed Central

    Su, Yongchao; Doherty, Tim; Waring, Alan J.; Ruchala, Piotr; Hong, Mei

    2009-01-01

    Cell-penetrating peptides (CPPs) are small cationic peptides that cross the cell membrane while carrying macromolecular cargoes. We use solid-state NMR to investigate the structure and lipid interaction of two cationic residues, Arg10 and Lys13, in the CPP penetratin. 13C chemical shifts indicate that Arg10 adopts a rigid β-strand conformation in the liquid-crystalline state of anionic lipid membranes. This behavior contrasts with all other residues observed so far in this peptide, which adopt a dynamic β-turn conformation with coil-like chemical shifts at physiological temperature. Low-temperature 13C-31P distances between the peptide and the lipid phosphates indicate that both the Arg10 guanidinium Cζ and the Lys13 Cε lie in close proximity to the lipid 31P (4.0 - 4.2 Å), proving the existence of charge-charge interaction for both Arg10 and Lys13 in the gel-phase membrane. However, since lysine substitution in CPPs are known to reduce their translocation ability, we propose that low temperature stabilizes both lysine and arginine interactions with the phosphates, whereas at high temperature the lysine-phosphate interaction is much weaker than the arginine-phosphate interaction. This is supported by the unusually high rigidity of the Arg10 sidechain and its β-strand conformation at high temperature. The latter is proposed to be important for ion pair formation by allowing close approach of the lipid headgroups to guanidinium sidechains. 19F and 13C spin diffusion experiments indicate that penetratin is oligomerized into β-sheets in gel-phase membranes. These solid-state NMR data indicate that guanidinium-phosphate interactions exist in penetratin, and guanidinium groups play a stronger structural role than ammonium groups in the lipid-assisted translocation of CPPs across liquid-crystalline cell membranes. PMID:19364134

  13. Effects of Coenzyme Q10 on Skeletal Muscle Oxidative Metabolism in Statin Users Assessed Using 31P Magnetic Resonance Spectroscopy: a Randomized Controlled Study

    PubMed Central

    Buettner, Catherine; Greenman, Robert L.; Ngo, Long H.; Wu, Jim S.

    2016-01-01

    Objectives Statins partially block the production of coenzyme Q10 (CoQ10), an essential component for mitochondrial function. Reduced skeletal muscle mitochondrial oxidative capacity has been proposed to be a cause of statin myalgia and can be measured using 31phosphorus magnetic resonance spectroscopy (31P-MRS). The purpose of this study is to assess the effect of CoQ10 oral supplementation on mitochondrial function in statin users using 31P-MRS. Design/Setting In this randomized, double-blind, placebo-controlled pilot study, 21 adults aged 47–73 were randomized to statin+placebo (n=9) or statin+CoQ10 (n=12). Phosphocreatine (PCr) recovery kinetics of calf muscles were assessed at baseline (off statin and CoQ10) and 4 weeks after randomization to either statin+CoQ10 or statin+placebo. Results Baseline and post-treatment PCr recovery kinetics were assessed for 19 participants. After 4 weeks of statin+ CoQ10 or statin+placebo, the overall relative percentage change (100*(baseline−follow up)/baseline) in PCr recovery time was −15.1% compared with baseline among all participants, (p-value=0.258). Participants randomized to statin+placebo (n=9) had a relative percentage change in PCr recovery time of −18.9%, compared to −7.7% among participants (n=10) receiving statin+CoQ10 (p-value=0.448). Conclusions In this pilot study, there was no significant change in mitochondrial function in patients receiving 4 weeks of statin+CoQ10 oral therapy when compared to patients on statin+placebo. PMID:27610419

  14. 40 CFR 721.10373 - 1H-Imidazole, 1-(1-methylethyl)-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1H-Imidazole, 1-(1-methylethyl)-. 721... Substances § 721.10373 1H-Imidazole, 1-(1-methylethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1H-imidazole, 1-(1-methylethyl)- (PMN...

  15. 40 CFR 721.10373 - 1H-Imidazole, 1-(1-methylethyl)-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1H-Imidazole, 1-(1-methylethyl)-. 721... Substances § 721.10373 1H-Imidazole, 1-(1-methylethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1H-imidazole, 1-(1-methylethyl)- (PMN...

  16. 40 CFR 721.10373 - 1H-Imidazole, 1-(1-methylethyl)-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 1H-Imidazole, 1-(1-methylethyl)-. 721... Substances § 721.10373 1H-Imidazole, 1-(1-methylethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1H-imidazole, 1-(1-methylethyl)- (PMN...

  17. 1H and 13C Solid-state NMR of Gossypium barbadense (Pima) Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interaction of water with cellulose and its influence on the nuclear spin dynamics in G. barbadense (Pima) cotton were investigated by 1H and 13C solid-state NMR techniques. 1H spin diffusion results from a Goldman-Shen experiment indicate that the water is multilayered. 1H MAS experiments pro...

  18. 1H and 13C Solid-state NMR of G. barbadense (Pima) Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interaction of water with cellulose and its influence on the nuclear spin dynamics in G. barbadense (Pima) cotton were investigated with 1H and 13C solid-state NMR techniques. 1H spin diffusion results from a Goldman-Shen experiment indicate that the water is multilayered. 1H MAS experiment...

  19. Effect of Oxygen Concentration on Viability and Metabolism in a Fluidized-Bed Bioartificial Liver Using 31P and 13C NMR Spectroscopy

    PubMed Central

    Jeffries, Rex E.; Gamcsik, Michael P.; Keshari, Kayvan R.; Pediaditakis, Peter; Tikunov, Andrey P.; Young, Gregory B.; Lee, Haakil; Watkins, Paul B.

    2013-01-01

    Many oxygen mass-transfer modeling studies have been performed for various bioartificial liver (BAL) encapsulation types; yet, to our knowledge, there is no experimental study that directly and noninvasively measures viability and metabolism as a function of time and oxygen concentration. We report the effect of oxygen concentration on viability and metabolism in a fluidized-bed NMR-compatible BAL using in vivo 31P and 13C NMR spectroscopy, respectively, by monitoring nucleotide triphosphate (NTP) and 13C-labeled nutrient metabolites, respectively. Fluidized-bed bioreactors eliminate the potential channeling that occurs with packed-bed bioreactors and serve as an ideal experimental model for homogeneous oxygen distribution. Hepatocytes were electrostatically encapsulated in alginate (avg. diameter, 500 μm; 3.5×107 cells/mL) and perfused at 3 mL/min in a 9-cm (inner diameter) cylindrical glass NMR tube. Four oxygen treatments were tested and validated by an in-line oxygen electrode: (1) 95:5 oxygen:carbon dioxide (carbogen), (2) 75:20:5 nitrogen:oxygen:carbon dioxide, (3) 60:35:5 nitrogen:oxygen:carbon dioxide, and (4) 45:50:5 nitrogen:oxygen:carbon dioxide. With 20% oxygen, β-NTP steadily decreased until it was no longer detected at 11 h. The 35%, 50%, and 95% oxygen treatments resulted in steady β-NTP levels throughout the 28-h experimental period. For the 50% and 95% oxygen treatment, a 13C NMR time course (∼5 h) revealed 2-13C-glycine and 2-13C-glucose to be incorporated into [2-13C-glycyl]glutathione (GSH) and 2-13C-lactate, respectively, with 95% having a lower rate of lactate formation. 31P and 13C NMR spectroscopy is a noninvasive method for determining viability and metabolic rates. Modifying tissue-engineered devices to be NMR compatible is a relatively easy and inexpensive process depending on the bioreactor shape. PMID:22835003

  20. Phosphide oxides RE2AuP2O (RE = La, Ce, Pr, Nd): synthesis, structure, chemical bonding, magnetism, and 31P and 139La solid state NMR.

    PubMed

    Bartsch, Timo; Wiegand, Thomas; Ren, Jinjun; Eckert, Hellmut; Johrendt, Dirk; Niehaus, Oliver; Eul, Matthias; Pöttgen, Rainer

    2013-02-18

    Polycrystalline samples of the phosphide oxides RE(2)AuP(2)O (RE = La, Ce, Pr, Nd) were obtained from mixtures of the rare earth elements, binary rare earth oxides, gold powder, and red phosphorus in sealed silica tubes. Small single crystals were grown in NaCl/KCl fluxes. The samples were studied by powder X-ray diffraction, and the structures were refined from single crystal diffractometer data: La(2)AuP(2)O type, space group C2/m, a = 1515.2(4), b = 424.63(8), c = 999.2(2) pm, β = 130.90(2)°, wR2 = 0.0410, 1050 F(2) values for Ce(2)AuP(2)O, and a = 1503.6(4), b = 422.77(8), c = 993.0(2) pm, β = 130.88(2)°, wR2 = 0.0401, 1037 F(2) values for Pr(2)AuP(2)O, and a = 1501.87(5), b = 420.85(5), c = 990.3(3) pm, β = 131.12(1)°, wR2 = 0.0944, 1143 F(2) values for Nd(2)AuP(2)O with 38 variables per refinement. The structures are composed of [RE(2)O](4+) polycationic chains of cis-edge-sharing ORE(4/2) tetrahedra and polyanionic strands [AuP(2)](4-), which contain gold in almost trigonal-planar phosphorus coordination by P(3-) and P(2)(4-) entities. The isolated phosphorus atoms and the P(2) pairs in La(2)AuP(2)O could clearly be distinguished by (31)P solid state NMR spectroscopy and assigned on the basis of a double quantum NMR technique. Also, the two crystallographically inequivalent La sites could be distinguished by static (139)La NMR in conjunction with theoretical electric field gradient calculations. Temperature-dependent magnetic susceptibility measurements show diamagnetic behavior for La(2)AuP(2)O. Ce(2)AuP(2)O and Pr(2)AuP(2)O are Curie-Weiss paramagnets with experimental magnetic moments of 2.35 and 3.48 μ(B) per rare earth atom, respectively. Their solid state (31)P MAS NMR spectra are strongly influenced by paramagnetic interactions. Ce(2)AuP(2)O orders antiferromagnetically at 13.1(5) K and shows a metamagnetic transition at 11.5 kOe. Pr(2)AuP(2)O orders ferromagnetically at 7.0 K. PMID:23374070

  1. Evidence for a "metabolically inactive" inorganic phosphate pool in adenosine triphosphate synthase reaction using localized 31P saturation transfer magnetic resonance spectroscopy in the rat brain at 11.7 T.

    PubMed

    Tiret, Brice; Brouillet, Emmanuel; Valette, Julien

    2016-09-01

    With the increased spectral resolution made possible at high fields, a second, smaller inorganic phosphate resonance can be resolved on (31)P magnetic resonance spectra in the rat brain. Saturation transfer was used to estimate de novo adenosine triphosphate synthesis reaction rate. While the main inorganic phosphate pool is used by adenosine triphosphate synthase, the second pool is inactive for this reaction. Accounting for this new pool may not only help us understand (31)P magnetic resonance spectroscopy metabolic profiles better but also better quantify adenosine triphosphate synthesis. PMID:27354096

  2. Skeletal muscle intracellular pH and levels of high energy phosphates during hypercapnia in intact lizards by /sup 31/P NMR

    SciTech Connect

    Johnson, D.C.; Hitzig, B.M.; Elmden, K.; McFarland, E.; Koutcher, J.; Kazemi, H.

    1986-03-05

    Lizards have been shown to reduce ventilation during CO/sub 2/ breathing. This is thought to be detrimental to the maintenance of intracellular pH (pHi) and levels of high energy phosphates. The authors subjected chameleons (n=4) to 5% CO/sub 2/ breathing and made serial measurements of tail (skeletal) muscle pHi, levels of phosphocreatine (PCr), and ATP utilizing high resolution /sup 31/P NMR. pHi was unchanged from controls (7.27 +/- 0.06 units) (mean +/- SE) during 30 minutes of hypercapnia (7.19 +/- 0.09 units) (p>.2) demonstrating effective regulation of skeletal muscle pHi; however, there were significant decreases in the PCr/ATP ratios to 65% +/- 5% (p<.05) of control. The reduced PCr/ATP ratio does not appear due to decreased O/sub 2/ availability because there were no increases in the levels of glycolytic intermediates and inorganic phosphate which would indicate tissue hypoxia. It is possible that an active process requiring ATP is required for the maintenance of pHi in the presence of hypercapnia and that the reduction of PCr/ATP ratio is a reflection of an increased utilization of ATP.

  3. Time Averaging and Fitting of Nonlinear Metabolic Changes: The Issue of the Time Index Choice Applied to 31P MRS Investigation of Muscle Energetics

    NASA Astrophysics Data System (ADS)

    Simond, G.; Bendahan, D.; Cozzone, P. J.

    2001-03-01

    We present an exact analytical method dedicated to fitting time-dependent exponential-like changes in MR spectra. As an illustration, this method has been applied to fitting metabolic changes recorded by 31P MRS in human skeletal muscle occurring during a rest-exercise-recovery protocol. When recording metabolic changes with the accumulative method, the time averaging of the MR signals implies the choice of a time index for fitting any changes in the features of the associated MR spectra. A critical examination of the different ways (constant, linear, and exponential) of choosing the time index is reported. By numerical analysis, we have calculated the errors generated by the three methods and we have compared their sensitivity to noise. In the case of skeletal muscle, both constant and linear methods introduce large and uncontrolled errors for the whole set of metabolic parameters derived from [PCr] changes. In contrast, the exponential method affords a reliable estimation of critical parameters in muscle bioenergetics in both normal and pathological situations. This method is very easy to implement and provides an exact analytical solution to fitting changes in MR spectra recorded by the accumulative method.

  4. 31P nuclear magnetic resonance studies of high energy phosphates and pH in human muscle fatigue. Comparison of aerobic and anaerobic exercise.

    PubMed Central

    Miller, R G; Boska, M D; Moussavi, R S; Carson, P J; Weiner, M W

    1988-01-01

    The goal of these experiments was to investigate the relationship of ATP, phosphocreatine (PCr), inorganic phosphate (Pi), monobasic phosphate (H2PO4-), and pH to human muscle fatigue. Phosphates and pH were measured in adductor pollicis using 31P nuclear magnetic resonance at 2.0 Tesla. The force of muscle contraction was simultaneously measured with a force transducer. The effects of aerobic and anaerobic exercise were compared using two exercise protocols: 4 min sustained maximal voluntary contraction (MVC) and 40 min of repeated intermittent contractions (75% MVC). The sustained maximal contraction produced a rapid decline of MVC and PCr, and was accompanied by a rapid rise of Pi, H+, and H2PO4-. Intermittent exercise produced steady state changes of MVC, pH, and phosphates. No significant changes of ATP were found in either protocol. During fatiguing exercise, PCr and Pi had a nonlinear relationship with MVC. H+ showed a more linear correlation, while H2PO4- showed the best correlation with MVC. Furthermore, the correlations between MVC and H2PO4- were similar in sustained (r = 0.70) and intermittent (r = 0.73) exercise. The highly significant linear relationship between increases of H+ and H2PO4- and the decline of MVC strongly suggests that both H+ and H2PO4- are important determinants of human muscle fatigue. PMID:3350969

  5. In vivo (31)P magnetic resonance spectroscopy and morphometric analysis of the perfused vascular architecture of human glioma xenografts in nude mice.

    PubMed Central

    van der Sanden, B. P.; Rijken, P. F.; Heerschap, A.; Bernsen, H. J.; van der Kogel, A. J.

    1997-01-01

    The relationship between the bioenergetic status of human glioma xenografts in nude mice and morphometric parameters of the perfused vascular architecture was studied using (31)P magnetic resonance spectroscopy (MRS), fluorescence microscopy and two-dimensional digital image analysis. Two tumour lines with a different vascular architecture were used for this study. Intervascular distances and non-perfused area fractions varied greatly between tumours of the same line and tumours of different lines. The inorganic phosphate-nucleoside triphosphate (P(i)/NTP) ratio increased rapidly as mean intervascular distances increased from 100 microm to 300 microm. Two morphometric parameters - the percentage of intervascular distances larger than 200 microm (ivd200) and the non-perfused area fraction at a distance larger than 100 microm from a nearest perfused vessel (area100), - were deduced from these experiments and related to the P(i)/NTP ratio of the whole tumour. It is assumed that an aerobic to anaerobic transition influences the bioenergetic status, i.e. the P(i)/NTP ratio increased linearly with the percentage of ivd200 and the area100. PMID:9166934

  6. Use of superfused rat skeletal muscle for metabolic studies: assessment of pH by 31P n.m.r.

    PubMed Central

    Meynial-Denis, D; Mignon, M; Foucat, L; Bonnet, Y; Bielicki, G; Renou, J P; Lacourt, P; Lacourt, A; Arnal, M

    1993-01-01

    We developed a muscle superfusion system suitable for metabolic studies of small isolated rat muscle ex vivo in real time and in a non-destructive manner by n.m.r. spectroscopy. In order to determine biochemical stability of superfused extensor digitorum longus (EDL) muscle (from fasted 45 and 100 g rats), the energy state and the pH of muscle were continuously monitored by 31P n.m.r. spectroscopy. ATP and phosphocreatine remained stable during 2 h whatever the muscle size (20 or 45 mg). Neither metabolite was a sensitive probe of possible metabolic compartmentation within muscle under our experimental conditions. By contrast, the chemical shift of Pi by its sensitivity to pH was a discriminant factor in the assessment of muscle stability. Indeed, heterogeneity of pH was observed only in the 45 mg EDL muscle resulting from a core region with loss of glycogen. Together, these observations suggest deviations of energy metabolism to supply ATP. Consequently, pH may be considered as a new real-time criterion for monitoring a metabolic heterogeneity due to changes in energy metabolism of muscle preparations ex vivo. Images Figure 1 PMID:8343121

  7. Uptake of metal ions by a new chelating ion exchange resin. Part 3: Protonation constants via potentiometric titration and solid state [sup 31]P NMR spectroscopy

    SciTech Connect

    Nash, K.L.; Rickert, P.G.; Muntean, J.V.; Alexandratos, S.D.

    1994-01-01

    A new chelating ion exchange resin which incorporates methylenediphosphonate, carboxylate, and sulfonate functional groups in a polystyrene-divinylbenzene matrix has been prepared. This resin exhibits exceptionally high affinity for polyvalent cations even from moderately acidic aqueous media. Metal ion coordination occurs primarily at the diphosphonate group with the secondary binding sites contributing to charge neutralization when necessary and possible, and to increasing hydrophilicity of the resin pores. In the present investigation, the protonation equilibria of the phosphonate groups in the resin are investigated via potentiometric titration and solid-state [sup 31]P NMR spectroscopy of the resin. Intrinsic equilibrium constants for the first two diphosphonate protonation reactions are pK[sub 4] = 10.47 and pK[sub 3] = 7.24. The last two protons added to the diphosphonate group are acidic having pK[sub a] values less than 2.5. These protonation constants are consistent with those reported previously for monomer analog 1,1-diphosphonic acids. This result implies that thermodynamic data available in the literature can be used to predict the relative affinity of the resin for polyvalent cations. 17 refs., 2 figs., 3 tabs.

  8. Thin-layer chromatography combined with MALDI-TOF-MS and 31P-NMR to study possible selective bindings of phospholipids to silica gel.

    PubMed

    Teuber, Kristin; Riemer, Thomas; Schiller, Jürgen

    2010-12-01

    High-performance thin-layer chromatography (HPTLC) is a highly established separation method in the field of lipid and (particularly) phospholipid (PL) research. HPTLC is not only used to identify certain lipids in a mixture but also to isolate lipids (preparative TLC). To do this, the lipids are separated and subsequently re-eluted from the silica gel. Unfortunately, it is not yet known whether all PLs are eluted to the same extent or whether some lipids bind selectively to the silica gel. It is also not known whether differences in the fatty acyl compositions affect the affinities to the stationary phase. We have tried to clarify these questions by using a readily available extract from hen egg yolk as a selected example of a lipid mixture. After separation, the complete lanes or selected spots were eluted from the silica gel and investigated by a combination of MALDI-TOF MS and (31)P NMR spectroscopy. The data obtained were compared with the composition of the total extract (without HPTLC). Although there were significant, solvent-dependent losses in the amount of each lipid, the relative composition of the mixture remained constant; there were also only very slight changes in the fatty acyl compositions of the individual PL classes. Therefore, lipid isolation by TLC may be used without any risk of major sample alterations. PMID:20694807

  9. Studies of vanadium-phosphorus-oxygen selective oxidation catalysts by sup 31 P and sup 51 V NMR spin-echo and volume susceptibility measurements

    SciTech Connect

    Li, Juan.

    1991-10-01

    The purpose of this work is to characterize the vanadium-phosphorous oxide (V-P-O) catalysts for the selective oxidation of n-butane and 1-butene to maleic anhydride. The utility of solid state nuclear magnetic resonance as an analytical tool in this investigation lies in its sensitivity to the electronic environment surrounding the phosphorous and vanadium nuclei, and proximity of paramagnetic species. Spin-echo mapping NMR of {sup 31}p and {sup 51}v and volume magnetic susceptibility measurements were used as local microscopic probes of the presence of V{sup 5+}, V{sup 4+}, V{sup 3+} species in the model compounds: {beta}-VOPO{sub 4}, {beta}-VOPO{sub 4} treated with n-butane/1-butene, (VO){sub 2}P{sub 2}O{sub 7} treated with n-butane/1-butene; and industrial catalysts with P/V (phosphorus to vanadium) ratio of 0.9, 1.0 and 1.1, before and after treatment with n-butane and 1-butene. The NMR spectra provide a picture of how the oxidation states of vanadium are distributed in these catalysts. 73 refs., 32 figs., 8 tabs.

  10. Triacontanol and jasmonic acid differentially modulate the lipid organization as evidenced by the fluorescent probe behavior and 31P nuclear magnetic resonance shifts in model membranes.

    PubMed

    Sivakumar Swamy, G; Swamy, Sivakumar G; Ramanarayan, K; Inamdar, Laxmi S; Inamdar, Sanjeev R

    2009-04-01

    Fluorescence resonance energy transfer (FRET), time-resolved fluorescence and anisotropy decays were determined in large unilamellar vesicles (LUVs) of egg phosphatidylcholine with the FRET pair N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dipalmitoyl-sn-glycero-3-phospho-ethanolamine as donor and lissamine rhodamine B 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine as acceptor, using 2-ps pulses from a Ti:sapphire laser on LUVs with incorporated plant growth regulators: triacontanol (TRIA) and jasmonic acid (JA). FRET efficiency, energy transfer rate, rotation correlation time, microviscosity, and diffusion coefficient of lateral diffusion of lipids were calculated from these results. It was observed that TRIA and JA differentially modulated all parameters studied. The effect of JA in such modulations was always partially reversed by TRIA. Also, the generalized polarization of laurdan fluorescence indicated that JA enhances the degree of hydration in lipid bilayers to a larger extent than does TRIA. Solid-state (31)P magic-angle spinning nuclear magnetic resonance spectra of LUVs showed two chemical shifts, at 0.009 and -11.988 ppm, at low temperatures (20 degrees C), while at increasing temperatures (20-60 degrees C) only one (at -11.988 ppm) was prominent and the other (0.009 ppm) gradually became obscure. However, LUVs with TRIA exhibited only one of the shifts at 0.353 ppm even at lower temperatures and JA did not affect the chemical shifts. PMID:19418089

  11. [sup 31]P and [sup 27]Al NMR investigations of the effects of pH on aqueous solutions containing aluminum and phosphorus

    SciTech Connect

    Mortlock, R.F.; Bell, A.T.; Radke, C.J. Univ. of California, Berkeley )

    1993-01-21

    [sup 31]P and [sup 27]Al NMR spectroscopies are used to characterize the distribution of soluble aluminophosphate species in aqueous solutions of tetramethylammonium (TMA) hydroxide, phosphoric acid, and aluminum chloride. Solution compositions range from 0.1 to 1 mol % P, P/Al = 0.1-5, P/(TMA)[sub 2]O = 0.37-10. For solutions of 1 mol % P, a phase diagram is constructed for various concentrations of TMAOH and Al. The phase diagram is divided into three regions: a high-pH region (pH [ge] 6), a medium-pH range (2 [le] pH [le] 10) in which stable solid phases exist, and a low-pH region (pH [le] 2). In the low-pH region, soluble aluminophosphate complexes form between P species (H[sub 3]PO[sub 4] acid dimers, H[sub 3]PO[sub 4] molecules, and H[sub 2]PO[sub 4][sup [minus

  12. The effect of ethanol on hydroxyl and carbonyl groups in biopolyol produced by hydrothermal liquefaction of loblolly pine: (31)P-NMR and (19)F-NMR analysis.

    PubMed

    Celikbag, Yusuf; Via, Brian K; Adhikari, Sushil; Buschle-Diller, Gisela; Auad, Maria L

    2016-08-01

    The goal of this study was to investigate the role of ethanol and temperature on the hydroxyl and carbonyl groups in biopolyol produced from hydrothermal liquefaction of loblolly pine (Pinus spp.) carried out at 250, 300, 350 and 390°C for 30min. Water and water/ethanol mixture (1/1, wt/wt) were used as liquefying solvent in the HTL experiments. HTL in water and water/ethanol is donated as W-HTL and W/E-HTL, respectively. It was found that 300°C and water/ethanol solvent was the optimum liquefaction temperature and solvent, yielding up to 68.1wt.% bio-oil and 2.4wt.% solid residue. (31)P-NMR analysis showed that biopolyol produced by W-HTL was rich in phenolic OH while W/E-HTL produced more aliphatic OH rich biopolyols. Moreover, biopolyols with higher hydroxyl concentration were produced by W/E-HTL. Carbonyl groups were analyzed by (19)F-NMR, which showed that ethanol reduced the concentration of carbonyl groups. PMID:27126078

  13. Early estrogen-induced metabolic changes and their inhibition by actinomycin D and cycloheximide in human breast cancer cells: sup 31 P and sup 13 C NMR studies

    SciTech Connect

    Neeman, M.; Degani, H. )

    1989-07-01

    Metabolic changes following estrogen stimulation and the inhibition of these changes in the presence of actinomycin D and cycloheximide were monitored continuously in perfused human breast cancer T47D clone 11 cells with {sup 31}P and {sup 13}C NMR techniques. The experiments were performed by estrogen rescue of tamoxifen-treated cells. Immediately after perfusion with estrogen-containing medium, a continuous enhancement in the rates of glucose consumption, lactate production by glycolysis, and glutamate synthesis by the Krebs cycle occurred with a persistent 2-fold increase at 4 hr. Pretreatment with either actinomycin D or cycloheximide, at concentrations known to inhibit mRNA and protein synthesis, respectively, and simultaneous treatment with estrogen and each inhibitor prevented the estrogen-induced changes in glucose metabolism. This suggested that the observed estrogen stimulation required synthesis of mRNA and protein. These inhibitors also modulated several metabolic activities that were not related to estrogen stimulation. The observed changes in the in vivo kinetics of glucose metabolism may provide a means for the early detection of the response of human breast cancer cells to estrogen versus tamoxifen treatment.

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

    NASA Astrophysics Data System (ADS)

    Risskov Sørensen, Daniel; Nielsen, Ulla Gro; Skou, Eivind M.

    2014-11-01

    A systematic study of composite powders of niobium oxide phosphate (NbOPO4) and phosphoric acid (H3PO4) has been performed in order to characterize the material's ability to perform as an electrolyte material in medium temperature fuel cells and electrolyzers. Powders of H3PO4 contents between 13.1 and 74.2 M% were produced and characterized with powder X-ray diffraction, 31P MAS NMR and impedance spectroscopy. NMR revealed that a significant degree of dehydration and vaporization of H3PO4 takes place above 200 °C, and increases with temperature. At 500 °C the NbOPO4 and H3PO4 has reacted to form niobium pyrophosphate (Nb2P4O15). Impedance spectroscopy showed an increase in conductivity with increasing acid concentration, whereas the conductivity decreased slightly with increasing temperature. The highest conductivity measured was 2.5·10-3 S/cm for a sample containing 74.2 M% of H3PO4. Lastly, it was shown that NbOPO4 has no significant conductivity of its own.

  15. Neutral zinc(II) O,O-di-alkyldithiopho- sphates-variable temperature 31P NMR and quantum chemical study of the ZDDP monomer-dimer equilibrium.

    PubMed

    Harrison, J J; Chan, C Y; Onopchenko, A; Pradhan, A R; Petersen, M

    2008-02-01

    A full line-shape analysis of the VT 31P NMR spectra was carried out for the monomer-dimer equilibrium of neutral ZDDP. The energy surface and the energetics of the monomer-dimer equilibrium (DeltaH degrees , DeltaG degrees , Ea, DeltaH(not equal), and DeltaG(not equal)) are reported for three variants wherein the alkyl groups in the ZDDP are 2-ethylhexyl, isopropyl, and isobutyl. We explored a reaction pathway between the monomer and dimer form by means of density functional theory (DFT). The linear combination of atomic orbitals (LCAO) code DMol3 was used together with a synchronous transient method to effectively locate transition states. Vibrational eigenmodes of all intermediates were computed to capture finite temperature effects. Methyl and ethyl were considered as alkyl groups. Two novel intermediates were located-a four-membered ring and a six-membered ring intermediate along the reaction coordinate. Comparison of the experimentally derived and computed energy surfaces was carried out. PMID:18098153

  16. Effect of sugars on headgroup mobility in freeze-dried dipalmitoylphosphatidylcholine bilayers: solid-state 31P NMR and FTIR studies.

    PubMed

    Tsvetkova, N M; Phillips, B L; Crowe, L M; Crowe, J H; Risbud, S H

    1998-12-01

    The effect of the carbohydrates trehalose, glucose, and hydroxyethyl starch (HES) on the motional properties of the phosphate headgroup of freeze-dried dipalmitoylphosphatidylcholine (DPPC) liposomes was studied by means of 31P NMR, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The results show that trehalose, which is a strong glass former (Tg = 115 degreesC), elevates the onset of the lipid headgroup rotations and preserves some rotational mobility of the phosphate headgroups after cooling from the liquid-crystalline state. Glucose (Tg = 30 degreesC), a very effective depressant of the phase transition temperature of freeze-dried DPPC, markedly elevates the initiation of the temperature of headgroup rotations. On the other hand, the monosaccharide does not preserve the headgroup disordering when cooled from the liquid-crystalline state. These effects are consistent with formation of hydrogen bonds between the OH groups of the sugar and the polar headgroups of DPPC. They show, however, that hydrogen bonding is not sufficient for preservation of the dynamic properties of freeze-dried DPPC. HES, although a very good glass former (Tg > 110 degreesC), does not depress the phase transition temperature and affects only slightly the rotational properties of freeze-dried DPPC. This lack of effect of HES is associated with the absence of direct interactions with the lipid phosphates, as evidenced by the FTIR results. These data show that vitrification of the additive is not sufficient to affect the dynamic properties of dried DPPC. PMID:9826615

  17. Ab Initio Calculation of Nuclear Magnetic Resonance Chemical Shift Anisotropy Tensors 1. Influence of Basis Set on the Calculation of 31P Chemical Shifts

    SciTech Connect

    Alam, T.M.

    1998-09-01

    The influence of changes in the contracted Gaussian basis set used for ab initio calculations of nuclear magnetic resonance (NMR) phosphorous chemical shift anisotropy (CSA) tensors was investigated. The isotropic chemical shitl and chemical shift anisotropy were found to converge with increasing complexity of the basis set at the Hartree-Fock @IF) level. The addition of d polarization function on the phosphorous nucIei was found to have a major impact of the calculated chemical shi~ but diminished with increasing number of polarization fimctions. At least 2 d polarization fimctions are required for accurate calculations of the isotropic phosphorous chemical shift. The introduction of density fictional theory (DFT) techniques through tie use of hybrid B3LYP methods for the calculation of the phosphorous chemical shift tensor resulted in a poorer estimation of the NMR values, even though DFT techniques result in improved energy and force constant calculations. The convergence of the W parametem with increasing basis set complexity was also observed for the DFT calculations, but produced results with consistent large deviations from experiment. The use of a HF 6-31 l++G(242p) basis set represents a good compromise between accuracy of the simulation and the complexity of the calculation for future ab initio calculations of 31P NMR parameters in larger complexes.

  18. Metallothionein 1 h tumour suppressor activity in prostate cancer is mediated by euchromatin methyltransferase 1

    PubMed Central

    Han, Yu-Chen; Zheng, Zhong-Liang; Zuo, Ze-Hua; Yu, Yan P; Chen, Rui; Tseng, George C; Nelson, Joel B; Luo, Jian-Hua

    2014-01-01

    Metallothioneins (MTs) are a group of metal binding proteins thought to play a role in the detoxification of heavy metals. Here we showed by microarray and validation analyses that MT1h, a member of MT, is down-regulated in many human malignancies. Low expression of MT1h was associated with poor clinical outcomes in both prostate and liver cancer. We found that the promoter region of MT1h was hypermethylated in cancer and that demethylation of the MT1h promoter reversed the suppression of MT1h expression. Forced expression of MT1h induced cell growth arrest, suppressed colony formation, retarded migration, and reduced invasion. SCID mice with tumour xenografts with inducible MT1h expression had lower tumour volumes as well as fewer metastases and deaths than uninduced controls. MT1h was found to interact with euchromatin histone methyltransferase 1 (EHMT1) and enhanced its methyltransferase activity on histone 3. Knocking down of EHMT1 or a mutation in MT1h that abrogates its interaction with EHMT1 abrogated MT1h tumour suppressor activity. This demonstrates tumour suppressor activity in a heavy metal binding protein that is dependent on activation of histone methylation. PMID:23355073

  19. Intersample fluctuations in phosphocreatine concentration determined by 31P-magnetic resonance spectroscopy and parameter estimation of metabolic responses to exercise in humans

    PubMed Central

    Rossiter, H B; Howe, F A; Ward, S A; Kowalchuk, J M; Griffiths, J R; Whipp, B J

    2000-01-01

    The ATP turnover rate during constant-load exercise is often estimated from the initial rate of change of phosphocreatine concentration ([PCr]) using 31P-magnetic resonance spectroscopy (MRS). However, the phase and amplitude characteristics of the sample-to-sample fluctuations can markedly influence this estimation (as well as that for the time constant (τ) of the [PCr] change) and confound its physiological interpretation especially for small amplitude responses. This influence was investigated in six healthy males who performed repeated constant-load quadriceps exercise of a moderate intensity in a whole-body MRS system. A transmit- receive surface coil was placed under the right quadriceps, allowing determination of intramuscular [PCr]; pulmonary oxygen uptake (V̇O2) was simultaneously determined, breath-by-breath, using a mass spectrometer and a turbine volume measuring module. The probability density functions (PDF) of [PCr] and V̇O2 fluctuations were determined for each test during the steady states of rest and exercise and the PDF was then fitted to a Gaussian function. The standard deviation of the [PCr] and V̇O2 fluctuations at rest and during exercise (sr and sw, respectively) and the peak centres of the distributions (xcr and xcw) were determined, as were the skewness (γ1) and kurtosis (γ2) coefficients. There was no difference between sr and sw for [PCr] relative to the resting control baseline (sr= 1.554%Δ (s.d.= 0.44), sw= 1.514%Δ (s.d.= 0.35)) or the PDF peak centres (xcr=−0.013 %Δ (s.d.= 0.09), xcw−0.197 %Δ (s.d.= 0.18)). The standard deviation and peak centre of the ‘noise’ in V̇O2 also did not vary between rest and exercise (sr= 0.0427 l min−1 (s.d.= 0.0104), sw= 0.0640 l min−1 (s.d.= 0.0292); xcr=−0.0051 l min−1 (s.d.= 0.0069), xcw 0.0022 l min−1 (s.d.= 0.0034)). Our results demonstrate that the intersample ‘noise’ associated with [PCr] determination by 31P-MRS may be characterised as a stochastic Gaussian

  20. Characterization of soil phosphorus in a fire-affected forest Cambisol by chemical extractions and (31)P-NMR spectroscopy analysis.

    PubMed

    Turrion, María-Belén; Lafuente, Francisco; Aroca, María-José; López, Olga; Mulas, Rafael; Ruipérez, Cesar

    2010-07-15

    This study was conducted to investigate the long-term effects of fire on soil phosphorus (P) and to determine the efficiency of different procedures in extracting soil P forms. Different P forms were determined: labile forms (Olsen-P, Bray-P, and P extracted by anion exchange membranes: AEM-P); moderately labile inorganic and organic P, obtained by NaOH-EDTA extraction after removing the AEM-P fraction; and total organic and inorganic soil P. (31)P-NMR spectroscopy was used to characterize the structure of alkali-soluble P forms (orthophosphate, monoester, pyrophosphate, and DNA). The studied area was a Pinus pinaster forest located at Arenas de San Pedro (southern Avila, Spain). The soils were Dystric Cambisols over granites. Soil samples were collected at 0-2 cm, 2-5 cm, and 10-15 cm depths, two years after a fire in the burned area and in an adjacent unburned forest area. Fire increased the total N, organic C, total P, and organic and inorganic P content in the surface soil layer. In burned soil, the P extracted by the sequential procedure (AEM and NaOH+EDTA) was about 95% of the total P. Bray extraction revealed a fire-induced increase in the sorption surfaces. Analysis by chemical methods overestimated the organic P fraction in the EDTA-NaOH extract in comparison with the determination by ignition procedure. This overestimation was more important in the burned than unburned soil samples, probably due to humification promoted by burning, which increased P sorption by soil particles. The fire-induced changes on the structure of alkali-soluble P were an increase in orthophosphate-P and a decrease in monoester-P and DNA-P. PMID:20452650

  1. Analysis of Metabolism in Dormant Spores of Bacillus Species by 31P Nuclear Magnetic Resonance Analysis of Low-Molecular-Weight Compounds

    PubMed Central

    Ghosh, Sonali; Korza, George; Maciejewski, Mark

    2014-01-01

    This work was undertaken to obtain information on levels of metabolism in dormant spores of Bacillus species incubated for weeks at physiological temperatures. Spores of Bacillus megaterium and Bacillus subtilis strains were harvested shortly after release from sporangia and incubated under various conditions, and dormant spore metabolism was monitored by 31P nuclear magnetic resonance (NMR) analysis of molecules including 3-phosphoglyceric acid (3PGA) and ribonucleotides. Incubation for up to 30 days at 4, 37, or 50°C in water, at 37 or 50°C in buffer to raise the spore core pH from ∼ 6.3 to 7.8, or at 4°C in spent sporulation medium caused no significant changes in ribonucleotide or 3PGA levels. Stage I germinated spores of Bacillus megaterium that had slightly increased core water content and a core pH of 7.8 also did not degrade 3PGA and accumulated no ribonucleotides, including ATP, during incubation for 8 days at 37°C in buffered saline. In contrast, spores incubated for up to 30 days at 37 or 50°C in spent sporulation medium degraded significant amounts of 3PGA and accumulated ribonucleotides, indicative of RNA degradation, and these processes were increased in B. megaterium spores with a core pH of ∼7.8. However, no ATP was accumulated in these spores. These data indicate that spores of Bacillus species stored in water or buffer at low or high temperatures exhibited minimal, if any, metabolism of endogenous compounds, even when the spore core pH was 7.8 and core water content was increased somewhat. However, there was some metabolism in spores stored in spent sporulation medium. PMID:25548246

  2. Structural investigations of silicate-phosphate glasses containing MoO3 by FTIR, Raman and 31P MAS NMR spectroscopies.

    PubMed

    Szumera, M

    2014-09-15

    Molybdenum is a transition metal (refers to the "d" block of the periodic table) whose atom has an incomplete d sub-shell. It is known that in silicate glasses molybdenum may exist under four oxidation states: Mo6+, Mo5+, Mo4+ and Mo3+, simultaneously molybdenum cations, depending on their content in the glass network, may either be a glass forming component, or act as a modifier. The contemporary literature data show studies conducted mostly on the structure of silicate, phosphate, borate and borosilicate glasses containing molybdenum ions, but not silicate-phosphate glasses. Therefore, the author has undertaken detailed studies using FTIR, Raman and 31P MAS NMR techniques in order to examine the effect of MoO3 addition into the structure of silicate-phosphate glasses from SiO2P2O5K2OCaOMgO system. On the basis of obtained results it was concluded that molybdenum ions in the analysed glasses act as a modifier, which follows from the gradual breakage of oxygen bridges, i.e. POP, SiOSi, and SiOP, and the following formation of connections such as Mo[MoO4]OSi and/or Mo[MoO4]OP. In summary, it is concluded that the increase of MoO3 content (up to 4.4 mol.%) in the structure of glasses of SiO2P2O5K2OMgOCaO system results in weakening of the structure and gradual increase of the degree of silico-oxygen and phosphor-oxygen frameworks depolymerisation. PMID:24759778

  3. /sup 31/P NMR saturation-transfer measurements in Saccharomyces cerevisiae: characterization of phosphate exchange reactions by iodoacetate and antimycin A inhibition

    SciTech Connect

    Campbell-Burk, S.L.; Jones, K.A.; Shulman, R.G.

    1987-11-17

    /sup 31/P nuclear magnetic resonance (NMR) saturation-transfer (ST) techniques have been used to measure steady-state flows through phosphate-adenosine 5'-triphosphate (ATP) exchange reactions in glucose-grown derepressed yeast. The results have revealed that the reactions catalyzed by glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase (GAPDH/PGK) and by the mitochondrial ATPase contribute to the observed ST. Contributions from these reactions were evaluated by performing ST studies under various metabolic conditions in the presence and absence of either iodoacetate, a specific inhibitor of GAPDH, or the respiratory chain inhibitor antimycin A. Intracellular phosphate (P/sub i/) longitudinal relaxation times were determined by performing inversion recovery experiments during steady-state ATP/sub lambda/ saturation and were used in combination with ST data to determine P/sub i/ consumption rates. /sup 13/C NMR and O/sub 2/ electrode measurements were also conducted to monitor changes in rates of glucose consumption and O/sub 2/ consumption, respectively, under the various metabolic conditions examined. The results suggest that GAPDH/PGK-catalyzed P/sub i/-ATP exchange is responsible for antimycin-resistant saturation transfer observed in anaerobic and aerobic glucose-fed yeast. Kinetics through GAPDH/PGK were found to depend on metabolic conditions. The coupled system appears to operate in a unidirectional manner during anaerobic glucose metabolism and bidirectionally when the cells are respiring on exogenously supplied ethanol. Additionally, mitochondrial ATPase activity appears to be responsible for the transfer observed in iodoacetate-treated aerobic cells supplied with either glucose or ethanol, with synthesis of ATP occurring unidirectionally.

  4. Bryostatin 1, a novel antineoplastic agent and protein kinase C activator, induces human myalgia and muscle metabolic defects: a 31P magnetic resonance spectroscopic study.

    PubMed Central

    Hickman, P. F.; Kemp, G. J.; Thompson, C. H.; Salisbury, A. J.; Wade, K.; Harris, A. L.; Radda, G. K.

    1995-01-01

    Bryostatin 1, a novel antineoplastic agent and protein kinase C (PKC) activator, has been found to induce myalgia (muscle pain) 48 h after administration in clinical trials. This is the dose-limiting toxicity and has restricted the duration of therapy in phase I trials. To investigate the mechanisms and try to increase toleration of the drug, we studied calf muscle metabolism of 14 patients at rest and during exercise and subsequent recovery using 31P magnetic resonance spectroscopy (MRS) before and 4 h, 48-72 h and 1-2 weeks following bryostatin therapy. In resting muscle there was a significant (P < 0.001) increase in the phosphodiester/adenosine 5'-triphosphate (PDE/ATP) ratio 48 h post bryostatin and in patients with myalgia compared with pre-bryostatin control studies. Following exercise, patients with myalgia showed significantly slower phosphocreatine (PCr) and ADP recovery half-time (P < or = 0.05) suggesting impaired mitochondrial (oxidative) energy production, possibly due to a direct effect on the mitochondria or secondary to reduced blood flow. The apparent proton efflux rate following exercise was significantly reduced 4 h after bryostatin (P < or = 0.05), suggesting reduced blood flow. The rate of post-exercise reoxygenation was studied in four patients by near-infrared spectroscopy 4 h post bryostatin. In three of these the rate was reduced, consistent with reduced muscle blood flow. Bryostatin 1 appeared to cause a long-lasting impairment of oxidative metabolism and proton washout from muscle, consistent with a vasoconstrictive action. Thus these studies provide evidence for two mechanisms of the dose-limiting toxicity for bryostatin. Prospective studies on the use of vasodilators to improve the tolerance of the drug should be carried out. PMID:7547256

  5. 31P NMR lineshapes of beta-P (ATP) in the presence of Mg2+ and Ca2+: estimate of exchange rates.

    PubMed

    Vasavada, K V; Ray, B D; Nageswara Rao, B D

    1984-08-01

    The 31P NMR chemical shift of beta-P of adenosine triphosphate (ATP) undergoes a substantial change (approximately 2-3 ppm) upon chelation of divalent ions such as Mg2+ or Ca2+. In the presence of nonsaturating amounts of Mg2+ or Ca2+, the lineshape of this resonance depends on the characteristic association and dissociation rates of these metal-ATP complexes. A procedure for computer simulation of this lineshape is outlined. A comparison of computer-simulated lineshapes with the experimental lineshapes obtained at 121 MHz was used to determine the following dissociation rate of Mg2+ and Ca2+ from their ATP complexes at 20 degrees C and pH 8.0: Ca2+, greater than 3 X 10(5) s-1 (Hepes buffer); Mg2+, 1200 s-1 (no buffer), 1000 s-1 (Tris buffer) and 2100 s-1 (Hepes buffer). The limits of error are +/- 10% in these values. For the Mg2+ complexes, the rates were determined as a function of temperature to obtain activation energies (with a maximum deviation of 10% in the least-squares fit): 8.1 Kcal/mole (no buffer and Hepes buffer) and 6.8 kcal/mole (Tris buffer). Lineshapes of the beta-P resonance simulated as a function of Mg2+ concentration, using 2100 s-1 for the dissociation rate, are also presented. The computer simulation of lineshapes offers a reliable and straightforward method for the determination of exchange rates of diamagnetic cations from their ATP complexes, under a variety of sample conditions. PMID:6332879

  6. Ascorbic acid prolongs the viability and stability of isolated perfused lungs: A mechanistic study using 31P and hyperpolarized 13C nuclear magnetic resonance.

    PubMed

    Shaghaghi, Hoora; Kadlecek, Stephen; Siddiqui, Sarmad; Pourfathi, Mehrdad; Hamedani, Hooman; Clapp, Justin; Profka, Harrilla; Rizi, Rahim

    2015-12-01

    Ex vivo lung perfusion (EVLP) has recently shown promise as a means of more accurately gauging the health of lung grafts and improving graft performance post-transplant. However, reperfusion of ischemic lung promotes the depletion of high-energy compounds and a progressive loss of normal mitochondrial function, and it remains unclear how and to what extent the EVLP approach contributes to this metabolic decline. Although ascorbate has been used to mitigate the effects of ischemia-reperfusion injury, the nature of its effects during EVLP are also not clear. To address these uncertainties, this study monitored the energy status of lungs during EVLP and after the administration of ascorbate using (31)P and hyperpolarized (13)C NMR (nuclear magnetic resonance). Our experiments demonstrated that the oxidative phosphorylation capacity and pyruvate dehydrogenase flux of lungs decline during ex vivo perfusion. The addition of ascorbate to the perfusate prolonged lung viability by 80% and increased the hyperpolarized (13)C bicarbonate signal by a factor of 2.7. The effect of ascorbate is apparently due not to its antioxidant quality but rather to its ability to energize cellular respiration given that it increased the lung's energy charge significantly, whereas other antioxidants (glutathione and α-lipoic acid) did not alter energy metabolism. During ascorbate administration, inhibition of mitochondrial complex I with rotenone depressed energy charge and shifted the metabolic state of the lung toward glycolysis; reenergizing the electron transport chain with TMPD (N,N,N',N'-tetramethyl-p-phenylenediamine) recovered metabolic activity. This indicates that ascorbate slows the decline of the ex vivo perfused lung's mitochondrial activity through an independent interaction with the electron transport chain complexes. PMID:26165188

  7. Characteristics and degradation of carbon and phosphorus from aquatic macrophytes in lakes: Insights from solid-state (13)C NMR and solution (31)P NMR spectroscopy.

    PubMed

    Liu, Shasha; Zhu, Yuanrong; Meng, Wei; He, Zhongqi; Feng, Weiying; Zhang, Chen; Giesy, John P

    2016-02-01

    Water extractable organic matter (WEOM) derived from macrophytes plays an important role in biogeochemical cycling of nutrients, including carbon (C), nitrogen (N) and phosphorus (P) in lakes. However, reports of their composition and degradation in natural waters are scarce. Therefore, compositions and degradation of WEOM derived from six aquatic macrophytes species of Tai Lake, China, were investigated by use of solid-state (13)C NMR and solution (31)P NMR spectroscopy. Carbohydrates were the predominant constituents of WEOM fractions, followed by carboxylic acid. Orthophosphate (ortho-P) was the dominant form of P (78.7% of total dissolved P) in the water extracts, followed by monoester P (mono-P) (20.6%) and little diester P (0.65%). The proportion of mono-P in total P species increased with the percentage of O-alkyl and O-C-O increasing in the WEOM, which is likely due to degradation and dissolution of biological membranes and RNA from aquatic plants. Whereas the proportion of mono-P decreased with alkyl-C, NCH/OCH3 and COO/N-C=O increasing, which may be owing to the insoluble compounds including C functional groups of alkyl-C, NCH/OCH3 and COO/N-C=O, such as aliphatic biopolymers, lignin and peptides. Based on the results of this study and information in the literature about water column and sediment, we propose that WEOM, dominated by polysaccharides, are the most labile and bioavailable component in debris of macrophytes. Additionally, these WEOMs would also be a potential source for bioavailable organic P (e.g., RNA, DNA and phytate) for lakes. PMID:26624522

  8. Influence of muscle temperature during fatiguing work with the first dorsal interosseous muscle in man: a 31P-NMR spectroscopy study.

    PubMed

    Wade, A J; Broadhead, M W; Cady, E B; Llewelyn, M E; Tong, H N; Newham, D J

    2000-02-01

    Six healthy subjects rapidly lifted and lowered a small (250 g) weight with the first dorsal interosseous muscle (FDI) of one hand while the work performed was recorded continuously until fatigue (defined as losing the ability to continue lifting). Work was recorded in units of chart recorder trace displacement from baseline (centimeters) as an isotonic transducer followed the movement of the weight. In all experiments, the temperature of the hand was first adjusted by immersion in a controlled-temperature water bath. In the warmest condition, the skin surface temperature over the FDI was 30.5(0.30) degrees C [mean (SE)]. After moderate cooling, this surface temperature was 21.5(0.16) degrees C. Cooling significantly reduced the time taken to reach fatigue and more than halved the work capacity. An intermediate degree of cooling was also used in four subjects, showing that most of the effects seen were changing incrementally. Before work, and at fatigue, intracellular metabolic conditions in the FDI were studied by phosphorus nuclear magnetic resonance (31P-NMR) spectroscopy, with occlusion of the blood flow maintained during measurements. The mean intracellular pH of the FDI was also calculated. The changes observed were all consistent with the fact that intense work requires energy which must be derived largely from intracellular stores of phosphocreatine and glycogen. Less work made less demand upon reserves, and created lower concentrations of waste products and by-products. The observations did not, however, allow us to explain why fatigue occurred at a particular point or why work capacity was reduced by cooling. PMID:10638378

  9. 4(1H)-Pyridone and 4(1H)-Quinolone Derivatives as Antimalarials with Erythrocytic, Exoerythrocytic, and Transmission Blocking Activities

    PubMed Central

    Monastyrskyi, Andrii; Kyle, Dennis E.; Manetsch, Roman

    2015-01-01

    Infectious diseases are the second leading cause of deaths in the world with malaria being responsible for approximately the same amount of deaths as cancer in 2012. Despite the success in malaria prevention and control measures decreasing the disease mortality rate by 45% since 2000, the development of single-dose therapeutics with radical cure potential is required to completely eradicate this deadly condition. Targeting multiple stages of the malaria parasite is becoming a primary requirement for new candidates in antimalarial drug discovery and development. Recently, 4(1H)-pyridone, 4(1H)-quinolone, 1,2,3,4-tetrahydroacridone, and phenoxyethoxy-4(1H)-quinolone chemotypes have been shown to be antimalarials with blood stage activity, liver stage activity, and transmission blocking activity. Advancements in structure-activity relationship and structure-property relationship studies, biological evaluation in vitro and in vivo, as well as pharmacokinetics of the 4(1H)-pyridone and 4(1H)-quinolone chemotypes will be discussed. PMID:25116582

  10. Automated structure verification based on a combination of 1D (1)H NMR and 2D (1)H - (13)C HSQC spectra.

    PubMed

    Golotvin, Sergey S; Vodopianov, Eugene; Pol, Rostislav; Lefebvre, Brent A; Williams, Antony J; Rutkowske, Randy D; Spitzer, Timothy D

    2007-10-01

    A method for structure validation based on the simultaneous analysis of a 1D (1)H NMR and 2D (1)H - (13)C single-bond correlation spectrum such as HSQC or HMQC is presented here. When compared with the validation of a structure by a 1D (1)H NMR spectrum alone, the advantage of including a 2D HSQC spectrum in structure validation is that it adds not only the information of (13)C shifts, but also which proton shifts they are directly coupled to, and an indication of which methylene protons are diastereotopic. The lack of corresponding peaks in the 2D spectrum that appear in the 1D (1)H spectrum, also gives a clear picture of which protons are attached to heteroatoms. For all these benefits, combined NMR verification was expected and found by all metrics to be superior to validation by 1D (1)H NMR alone. Using multiple real-life data sets of chemical structures and the corresponding 1D and 2D data, it was possible to unambiguously identify at least 90% of the correct structures. As part of this test, challenging incorrect structures, mostly regioisomers, were also matched with each spectrum set. For these incorrect structures, the false positive rate was observed as low as 6%. PMID:17694570

  11. Stereospecificity of (1) H, (13) C and (15) N shielding constants in the isomers of methylglyoxal bisdimethylhydrazone: problem with configurational assignment based on (1) H chemical shifts.

    PubMed

    Afonin, Andrei V; Pavlov, Dmitry V; Ushakov, Igor A; Keiko, Natalia A

    2012-07-01

    In the (13) C NMR spectra of methylglyoxal bisdimethylhydrazone, the (13) C-5 signal is shifted to higher frequencies, while the (13) C-6 signal is shifted to lower frequencies on going from the EE to ZE isomer following the trend found previously. Surprisingly, the (1) H-6 chemical shift and (1) J(C-6,H-6) coupling constant are noticeably larger in the ZE isomer than in the EE isomer, although the configuration around the -CH═N- bond does not change. This paradox can be rationalized by the C-H⋯N intramolecular hydrogen bond in the ZE isomer, which is found from the quantum-chemical calculations including Bader's quantum theory of atoms in molecules analysis. This hydrogen bond results in the increase of δ((1) H-6) and (1) J(C-6,H-6) parameters. The effect of the C-H⋯N hydrogen bond on the (1) H shielding and one-bond (13) C-(1) H coupling complicates the configurational assignment of the considered compound because of these spectral parameters. The (1) H, (13) C and (15) N chemical shifts of the 2- and 8-(CH(3) )(2) N groups attached to the -C(CH(3) )═N- and -CH═N- moieties, respectively, reveal pronounced difference. The ab initio calculations show that the 8-(CH(3) )(2) N group conjugate effectively with the π-framework, and the 2-(CH(3) )(2) N group twisted out from the plane of the backbone and loses conjugation. As a result, the degree of charge transfer from the N-2- and N-8- nitrogen lone pairs to the π-framework varies, which affects the (1) H, (13) C and (15) N shieldings. PMID:22615146

  12. CHHC and 1H-1H Magnetization Exchange: Analysis by Experimental Solid-State NMR and 11-Spin Density-Matrix Simulations

    PubMed Central

    Aluas, Mihaela; Tripon, Carmen; Griffin, John M.; Filip, Xenia; Ladizhansky, Vladimir; Griffin, Robert G.; Brown, Steven P.; Filip, Claudiu

    2009-01-01

    A protocol is presented for correcting the effect of non-specific cross polarization in CHHC solid-state MAS NMR experiments, thus allowing the recovery of the 1H-1H magnetization exchange functions from the mixing-time dependent buildup of experimental CHHC peak intensity. The presented protocol also incorporates a scaling procedure to take into account the effect of multiplicity of a CH2 or CH3 moiety. Experimental CHHC buildup curves are presented for L-Tyrosine.HCl samples where either all or only one in ten molecules are U-13C labeled. Good agreement between experiment and 11-spin SPINEVOLUTION simulation (including only isotropic 1H chemical shifts) is demonstrated for the initial buildup (tmix < 100 μs) of CHHC peak intensity corresponding to an intramolecular close (2.5 Å) H-H proximity. Differences in the initial CHHC buildup are observed between the 1 in 10 dilute and 100 % samples for cases where there is a close intermolecular H-H proximity in addition to a close intramolecular H-H proximity. For the dilute sample, CHHC cross peak intensities tended to significantly lower values for long mixing times (500 μs) as compared to the 100 % sample. This difference is explained as being due to the dependence of the limiting total magnetization on the ratio Nobs/Ntot between the number of protons that are directly attached to a 13C nucleus and hence contribute significantly to the observed 13C CHHC NMR signal, and the total number of 1H spins into the system. 1H-1H magnetization exchange curves extracted from CHHC spectra for the 100 % L-Tyrosine.HCl sample exhibit a clear sensitivity to the root sum squared dipolar coupling, with fast build-up being observed for the shortest intramolecular distances (2.5 Å) and slower, yet observable build-up for the longer intermolecular distances (up to 5 Å). PMID:19467890

  13. The complete genome sequence of the Arcobacter butzleri cattle isolate 7h1h

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arcobacter butzleri strain 7h1h was isolated in the UK from a clinically healthy dairy cow. The genome of this isolate was sequenced to completion. Here we present the annotation and analysis of the completed 7h1h genome, as well as comparison of this genome to the existing A. butzleri RM4018 and ED...

  14. A classical approach in simple nuclear fusion reaction {sub 1}H{sup 2}+{sub 1}H{sup 3} using two-dimension granular molecular dynamics model

    SciTech Connect

    Viridi, S.; Kurniadi, R.; Waris, A.; Perkasa, Y. S.

    2012-06-06

    Molecular dynamics in 2-D accompanied by granular model provides an opportunity to investigate binding between nuclei particles and its properties that arises during collision in a fusion reaction. A fully classical approach is used to observe the influence of initial angle of nucleus orientation to the product yielded by the reaction. As an example, a simplest fusion reaction between {sub 1}H{sup 2} and {sub 1}H{sup 3} is observed. Several products of the fusion reaction have been obtained, even the unreported ones, including temporary {sub 2}He{sup 4} nucleus.

  15. Responders to Wide-Pulse, High-Frequency Neuromuscular Electrical Stimulation Show Reduced Metabolic Demand: A 31P-MRS Study in Humans

    PubMed Central

    Wegrzyk, Jennifer; Fouré, Alexandre; Le Fur, Yann; Maffiuletti, Nicola A.; Vilmen, Christophe; Guye, Maxime; Mattei, Jean-Pierre; Place, Nicolas; Bendahan, David; Gondin, Julien

    2015-01-01

    Conventional (CONV) neuromuscular electrical stimulation (NMES) (i.e., short pulse duration, low frequencies) induces a higher energetic response as compared to voluntary contractions (VOL). In contrast, wide-pulse, high-frequency (WPHF) NMES might elicit–at least in some subjects (i.e., responders)–a different motor unit recruitment compared to CONV that resembles the physiological muscle activation pattern of VOL. We therefore hypothesized that for these responder subjects, the metabolic demand of WPHF would be lower than CONV and comparable to VOL. 18 healthy subjects performed isometric plantar flexions at 10% of their maximal voluntary contraction force for CONV (25 Hz, 0.05 ms), WPHF (100 Hz, 1 ms) and VOL protocols. For each protocol, force time integral (FTI) was quantified and subjects were classified as responders and non-responders to WPHF based on k-means clustering analysis. Furthermore, a fatigue index based on FTI loss at the end of each protocol compared with the beginning of the protocol was calculated. Phosphocreatine depletion (ΔPCr) was assessed using 31P magnetic resonance spectroscopy. Responders developed four times higher FTI’s during WPHF (99 ± 37 ×103 N.s) than non-responders (26 ± 12 ×103 N.s). For both responders and non-responders, CONV was metabolically more demanding than VOL when ΔPCr was expressed relative to the FTI. Only for the responder group, the ∆PCr/FTI ratio of WPHF (0.74 ± 0.19 M/N.s) was significantly lower compared to CONV (1.48 ± 0.46 M/N.s) but similar to VOL (0.65 ± 0.21 M/N.s). Moreover, the fatigue index was not different between WPHF (-16%) and CONV (-25%) for the responders. WPHF could therefore be considered as the less demanding NMES modality–at least in this subgroup of subjects–by possibly exhibiting a muscle activation pattern similar to VOL contractions. PMID:26619330

  16. Solid state {sup 31}P MAS NMR spectroscopy and conductivity measurements on NbOPO{sub 4} and H{sub 3}PO{sub 4} composite materials

    SciTech Connect

    Risskov Sørensen, Daniel; Nielsen, Ulla Gro; Skou, Eivind M.

    2014-11-15

    A systematic study of composite powders of niobium oxide phosphate (NbOPO{sub 4}) and phosphoric acid (H{sub 3}PO{sub 4}) has been performed in order to characterize the material's ability to perform as an electrolyte material in medium temperature fuel cells and electrolyzers. Powders of H{sub 3}PO{sub 4} contents between 13.1 and 74.2 M% were produced and characterized with powder X-ray diffraction, {sup 31}P MAS NMR and impedance spectroscopy. NMR revealed that a significant degree of dehydration and vaporization of H{sub 3}PO{sub 4} takes place above 200 °C, and increases with temperature. At 500 °C the NbOPO{sub 4} and H{sub 3}PO{sub 4} has reacted to form niobium pyrophosphate (Nb{sub 2}P{sub 4}O{sub 15}). Impedance spectroscopy showed an increase in conductivity with increasing acid concentration, whereas the conductivity decreased slightly with increasing temperature. The highest conductivity measured was 2.5·10{sup −3} S/cm for a sample containing 74.2 M% of H{sub 3}PO{sub 4}. Lastly, it was shown that NbOPO{sub 4} has no significant conductivity of its own. - Graphical abstract: Conductivity of NbOPO{sub 4}/H{sub 3}PO{sub 4} composites as a function of equivalent P{sub 2}O{sub 5} content. The conductivity is insignificant for pure NbOPO{sub 4}. - Highlights: • Composites have been made from NbOPO{sub 4} and H{sub 3}PO{sub 4}. • The composites composition has been investigated with solid state NMR. • The composites have shown clear signs of acid dehydration upon heating. • The conductivity of the composites increases for increasing acid content. • NbOPO{sub 4} has no significant conductivity of its own.

  17. Transcriptional regulation of α1H T-type calcium channel under hypoxia.

    PubMed

    Sellak, Hassan; Zhou, Chun; Liu, Bainan; Chen, Hairu; Lincoln, Thomas M; Wu, Songwei

    2014-10-01

    The low-voltage-activated T-type Ca(2+) channels play an important role in mediating the cellular responses to altered oxygen tension. Among three T-type channel isoforms, α1G, α1H, and α1I, only α1H was found to be upregulated under hypoxia. However, mechanisms underlying such hypoxia-dependent isoform-specific gene regulation remain incompletely understood. We, therefore, studied the hypoxia-dependent transcriptional regulation of α1G and α1H gene promoters with the aim to identify the functional hypoxia-response elements (HREs). In rat pulmonary artery smooth muscle cells (PASMCs) and pheochromocytoma (PC12) cells after hypoxia (3% O2) exposure, we observed a prominent increase in α1H mRNA at 12 h along with a significant rise in α1H-mediated T-type current at 24 and 48 h. We then cloned two promoter fragments from the 5'-flanking regions of rat α1G and α1H gene, 2,000 and 3,076 bp, respectively, and inserted these fragments into a luciferase reporter vector. Transient transfection of PASMCs and PC12 cells with these recombinant constructs and subsequent luciferase assay revealed a significant increase in luciferase activity from the reporter containing the α1H, but not α1G, promoter fragment under hypoxia. Using serial deletion and point mutation analysis strategies, we identified a functional HRE at site -1,173cacgc-1,169 within the α1H promoter region. Furthermore, an electrophoretic mobility shift assay using this site as a DNA probe demonstrated an increased binding activity to nuclear protein extracts from the cells after hypoxia exposure. Taken together, these findings indicate that hypoxia-induced α1H upregulation involves binding of hypoxia-inducible factor to an HRE within the α1H promoter region. PMID:25099734

  18. Transcriptional regulation of α1H T-type calcium channel under hypoxia

    PubMed Central

    Sellak, Hassan; Zhou, Chun; Liu, Bainan; Chen, Hairu; Lincoln, Thomas M.

    2014-01-01

    The low-voltage-activated T-type Ca2+ channels play an important role in mediating the cellular responses to altered oxygen tension. Among three T-type channel isoforms, α1G, α1H, and α1I, only α1H was found to be upregulated under hypoxia. However, mechanisms underlying such hypoxia-dependent isoform-specific gene regulation remain incompletely understood. We, therefore, studied the hypoxia-dependent transcriptional regulation of α1G and α1H gene promoters with the aim to identify the functional hypoxia-response elements (HREs). In rat pulmonary artery smooth muscle cells (PASMCs) and pheochromocytoma (PC12) cells after hypoxia (3% O2) exposure, we observed a prominent increase in α1H mRNA at 12 h along with a significant rise in α1H-mediated T-type current at 24 and 48 h. We then cloned two promoter fragments from the 5′-flanking regions of rat α1G and α1H gene, 2,000 and 3,076 bp, respectively, and inserted these fragments into a luciferase reporter vector. Transient transfection of PASMCs and PC12 cells with these recombinant constructs and subsequent luciferase assay revealed a significant increase in luciferase activity from the reporter containing the α1H, but not α1G, promoter fragment under hypoxia. Using serial deletion and point mutation analysis strategies, we identified a functional HRE at site −1,173cacgc−1,169 within the α1H promoter region. Furthermore, an electrophoretic mobility shift assay using this site as a DNA probe demonstrated an increased binding activity to nuclear protein extracts from the cells after hypoxia exposure. Taken together, these findings indicate that hypoxia-induced α1H upregulation involves binding of hypoxia-inducible factor to an HRE within the α1H promoter region. PMID:25099734

  19. 2D 1H and 3D 1H-15N NMR of zinc-rubredoxins: contributions of the beta-sheet to thermostability.

    PubMed Central

    Richie, K. A.; Teng, Q.; Elkin, C. J.; Kurtz, D. M.

    1996-01-01

    Based on 2D 1H-1H and 2D and 3D 1H-15N NMR spectroscopies, complete 1H NMR assignments are reported for zinc-containing Clostridium pasteurianum rubredoxin (Cp ZnRd). Complete 1H NMR assignments are also reported for a mutated Cp ZnRd, in which residues near the N-terminus, namely, Met 1, Lys 2, and Pro 15, have been changed to their counterparts, (-), Ala and Glu, respectively, in rubredoxin from the hyperthermophilic archaeon, Pyrococcus furiosus (Pf Rd). The secondary structure of both wild-type and mutated Cp ZnRds, as determined by NMR methods, is essentially the same. However, the NMR data indicate an extension of the three-stranded beta-sheet in the mutated Cp ZnRd to include the N-terminal Ala residue and Glu 15, as occurs in Pf Rd. The mutated Cp Rd also shows more intense NOE cross peaks, indicating stronger interactions between the strands of the beta-sheet and, in fact, throughout the mutated Rd. However, these stronger interactions do not lead to any significant increase in thermostability, and both the mutated and wild-type Cp Rds are much less thermostable than Pf Rd. These correlations strongly suggest that, contrary to a previous proposal [Blake PR et al., 1992, Protein Sci 1:1508-1521], the thermostabilization mechanism of Pf Rd is not dominated by a unique set of hydrogen bonds or electrostatic interactions involving the N-terminal strand of the beta-sheet. The NMR results also suggest that an overall tighter protein structure does not necessarily lead to increased thermostability. PMID:8732760

  20. Intermolecular Interactions between Eosin Y and Caffeine Using (1)H-NMR Spectroscopy.

    PubMed

    Okuom, Macduff O; Wilson, Mark V; Jackson, Abby; Holmes, Andrea E

    2013-12-31

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using (1)H-NMR, (1)H-COSY, and (1)H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  1. Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

    PubMed Central

    Okuom, Macduff O.; Wilson, Mark V.; Jackson, Abby; Holmes, Andrea E.

    2014-01-01

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  2. 31P MR spectroscopy and computational modeling identify a direct relation between Pi content of an alkaline compartment in resting muscle and phosphocreatine resynthesis kinetics in active muscle in humans.

    PubMed

    van Oorschot, Joep W M; Schmitz, Joep P J; Webb, Andrew; Nicolay, Klaas; Jeneson, Jeroen A L; Kan, Hermien E

    2013-01-01

    The assessment of mitochondrial properties in skeletal muscle is important in clinical research, for instance in the study of diabetes. The gold standard to measure mitochondrial capacity non-invasively is the phosphocreatine (PCr) recovery rate after exercise, measured by (31)P Magnetic Resonance spectroscopy ((31)P MRS). Here, we sought to expand the evidence base for an alternative method to assess mitochondrial properties which uses (31)P MRS measurement of the Pi content of an alkaline compartment attributed to mitochondria (Pi2; as opposed to cytosolic Pi (Pi1)) in resting muscle at high magnetic field. Specifically, the PCr recovery rate in human quadriceps muscle was compared with the signal intensity of the Pi2 peak in subjects with varying mitochondrial content of the quadriceps muscle as a result of athletic training, and the results were entered into a mechanistic computational model of mitochondrial metabolism in muscle to test if the empirical relation between Pi2/Pi1 ratio and the PCr recovery was consistent with theory. Localized (31)P spectra were obtained at 7T from resting vastus lateralis muscle to measure the intensity of the Pi2 peak. In the endurance trained athletes a Pi2/Pi1 ratio of 0.07 ± 0.01 was found, compared to a significantly lower (p<0.05) Pi2/Pi1 ratio of 0.03 ± 0.01 in the normally active group. Next, PCr recovery kinetics after in magnet bicycle exercise were measured at 1.5T. For the endurance trained athletes, a time constant τPCr 12 ± 3 s was found, compared to 24 ± 5s in normally active subjects. Without any parameter optimization the computational model prediction matched the experimental data well (r(2) of 0.75). Taken together, these results suggest that the Pi2 resonance in resting human skeletal muscle observed at 7T provides a quantitative MR-based functional measure of mitochondrial density. PMID:24098796

  3. Characterisation of the 1H and 13C NMR spectra of methylcitric acid

    NASA Astrophysics Data System (ADS)

    Krawczyk, Hanna; Martyniuk, Tomasz

    2007-06-01

    Methylcitric acid (MCA) was synthesised in Reformatsky reaction (2 RS, 3 RS stereoisomers) and in the nucleophilic addition (2 RS, 3 SR stereoisomers). The stereoselectivity of these reactions was analysed. 1H and 13C NMR spectra of diastereoisomers of methylcitric acid were recorded and interpreted. The values of 1H chemical shifts and 1H- 1H coupling constants were analysed. Proton-decoupled high-resolution 13C NMR spectra of MCA diastereoisomers were measured in a series of dilute water solutions of various acidities. These data may provide a basis for unequivocal determination of the presence of MCA in the urine samples of patients' suffering from propionic acidemia, methylmalonic aciduria, or holocarboxylase synthetase deficiency. NMR spectroscopy enables determination of MCA diastereoisomers in body fluids and can be a complementary and useful diagnostic tool.

  4. Regioselectively Controlled Synthesis of N-Substituted (Trifluoromethyl)pyrimidin-2(1H)-ones.

    PubMed

    da Silva, Andreia M P W; da Silva, Fabio M; Bonacorso, Helio G; Frizzo, Clarissa P; Martins, Marcos A P; Zanatta, Nilo

    2016-05-01

    A simple and regioselectively controlled method for the preparation of both 1,4- and 1,6-regioisomers of 1-substituted 4(6)-trifluoromethyl-pyrimidin-2(1H)-ones is described. Both regioisomers were synthesized from the cyclocondensation reaction of 4-substituted 1,1,1-trifluoro-4-methoxybut-3-en-2-ones: with nonsymmetric ureas for the 1-substituted 4-(trifluoromethyl)pyrimidin-2(1H)-ones (1,4-isomer) and with nonsymmetric 1-substituted 2-methylisothiourea sulfates for the synthesis of 1-substituted 6-(trifluoromethyl)pyrimidin-2(1H)-ones (1,6-isomer). Each method furnished only the respective isomer in very good yields. The structure of the products was assigned based on the (1)H and (13)C NMR as well as 2D HMBC spectral analysis. PMID:27070191

  5. Lemna minor L. as a model organism for ecotoxicological studies performing 1H NMR fingerprinting.

    PubMed

    Aliferis, Konstantinos A; Materzok, Sylwia; Paziotou, Georgia N; Chrysayi-Tokousbalides, Maria

    2009-08-01

    A validated method applying (1)H NMR fingerprinting for the study of metabolic changes caused in Lemna minor L. by various phytotoxic substances is presented. (1)H NMR spectra of crude extracts from untreated and treated colonies with the herbicides glyphosate, mesotrione, norflurazon, paraquat and the phytotoxin pyrenophorol were subjected to multivariate analyses for detecting differences between groups of treatments. Partial least squares-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) were carried out in order to discriminate and classify treatments according to the observed changes in the metabolome of the plant. Although the compounds at the concentrations used did not cause macroscopically observable symptoms of phytotoxicity, characteristic metabolic changes were detectable by analyzing (1)H NMR spectra. Analyses results revealed that metabonomics applying (1)H NMR fingerprinting is a potential method for the investigation of toxicological effects of xenobiotics on L. minor, and possibly on other duckweed species, helping in the understanding of such interactions. PMID:19443011

  6. Proton-detected 3D {sup 1}H/{sup 13}C/{sup 1}H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy; Nishiyama, Yusuke

    2015-10-28

    A proton-detected 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of {sup 13}C-{sup 1}H connectivities, and proximities of {sup 13}C-{sup 1}H and {sup 1}H-{sup 1}H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including {sup 1}H-{sup 1}H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) {sup 1}H/{sup 1}H and 2D {sup 13}C/{sup 1}H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of {sup 1}H-{sup 1}H proximity and {sup 13}C-{sup 1}H connectivity. In addition, the 2D (F1/F2) {sup 1}H/{sup 13}C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of {sup 1}H-{sup 1}H dipolar couplings, enables the measurement of proximities between {sup 13}C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of {sup 1}H-{sup 1}H-{sup 13}C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ⋅ H{sub 2}O ⋅ HCl demonstrate the efficiency of the 3D experiment.

  7. One-Pot Synthesis of Substituted Trifluoromethylated 2,3-Dihydro-1H-imidazoles.

    PubMed

    Deutsch, Amrei; Jessen, Christoph; Deutsch, Carl; Karaghiosoff, Konstantin; Hoffmann-Röder, Anja

    2016-07-15

    An operationally simple one-pot reaction for the preparation of a novel class of racemic trifluoromethylated 2,3-dihydro-1H-imidazoles derived from electron-poor N,O-acetals and aryl Grignard reagents is described. In addition, access to highly functionalized 2-trifluoromethyl-2,3-dihydro-1H-imidazoles was accomplished by reaction of N-aryl hemiaminal ethers and N-aryl trifluoroethylamines in the presence of an excess of n-butyllithium. PMID:27359260

  8. Complete 1H, 15N and 13C assignment of trappin-2 and 1H assignment of its two domains, elafin and cementoin.

    PubMed

    Loth, Karine; Alami, Soha Abou Ibrahim; Habès, Chahrazed; Garrido, Solène; Aucagne, Vincent; Delmas, Agnès F; Moreau, Thierry; Zani, Marie-Louise; Landon, Céline

    2016-04-01

    Trappin-2 is a serine protease inhibitor with a very narrow inhibitory spectrum and has significant anti-microbial activities. It is a 10 kDa cationic protein composed of two distinct domains. The N-terminal domain (38 residues) named cementoin is known to be intrinsically disordered when it is not linked to the elafin. The C-terminal domain (57 residues), corresponding to elafin, is a cysteine-rich domain stabilized by four disulfide bridges and is characterized by a flat core and a flexible N-terminal part. To our knowledge, there is no structural data available on trappin-2. We report here the complete (1)H, (15)N and (13)C resonance assignment of the recombinant trappin-2 and the (1)H assignments of cementoin and elafin, under the same experimental conditions. This is the first step towards the 3D structure determination of the trappin-2. PMID:26878852

  9. [(1)H] magnetic resonance spectroscopy of urine: diagnosis of a guanidinoacetate methyl transferase deficiency case.

    PubMed

    Tassini, Maria; Zannolli, Raffaella; Buoni, Sabrina; Engelke, Udo; Vivi, Antonio; Valensin, Gianni; Salomons, Gajja S; De Nicola, Anna; Strambi, Mirella; Monti, Lucia; Morava, Eva; Wevers, Ron A; Hayek, Joseph

    2010-01-01

    For the first time, the use of urine [(1)H] magnetic resonance spectroscopy has allowed the detection of 1 case of guanidinoacetate methyl transferase in a database sample of 1500 pediatric patients with a diagnosis of central nervous system impairment of unknown origin. The urine [(1)H] magnetic resonance spectroscopy of a 9-year-old child, having severe epilepsy and nonprogressive mental and motor retardation with no apparent cause, revealed a possible guanidinoacetic acid increase. The definitive assignment of guanidinoacetic acid was checked by addition of pure substance to the urine sample and by measuring [(1)H]-[(1)H] correlation spectroscopy. Diagnosis of guanidinoacetate methyl transferase deficiency was further confirmed by liquid chromatography-mass spectrometry, brain [(1)H] magnetic resonance spectroscopy, and mutational analysis of the guanidinoacetate methyl transferase gene. The replacement therapy was promptly started and, after 1 year, the child was seizure free. We conclude that for this case, urine [(1)H] magnetic resonance spectroscopy screening was able to diagnose guanidinoacetate methyl transferase deficiency. PMID:19461121

  10. Modeling Ti/Ge Distribution in LiTi2-xGex(PO4)3 NASICON Series by (31)P MAS NMR and First-Principles DFT Calculations.

    PubMed

    Diez-Gómez, Virginia; Arbi, Kamel; Sanz, Jesús

    2016-08-01

    Ti/Ge distribution in rhombohedral LiTi2-xGex(PO4)3 NASICON series has been analyzed by (31)P magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy and first-principles density functional theory (DFT) calculations. Nuclear magnetic resonance is an excellent probe to follow Ti/Ge disorder, as it is sensitive to the atomic scale environment without long-range periodicity requirements. In the samples considered here, PO4 units are surrounded by four Ti/Ge octahedra, and then, five different components ascribed to P(OTi)4, P(OTi)3(OGe), P(OTi)2(OGe)2, P(OTi)(OGe)3, and P(OGe)4 environments are expected in (31)P MAS NMR spectra of R3̅c NASICON samples. However, (31)P MAS NMR spectra of analyzed series display a higher number of signals, suggesting that, although the overall symmetry remains R3̅c, partial substitution causes a local decrement in symmetry. With the aid of first-principles DFT calculations, 10 detected (31)P NMR signals have been assigned to different Ti4-nGen arrangements in the R3 subgroup symmetry. In this assignment, the influence of octahedra of the same or different R2(PO4)3 structural units has been considered. The influence of bond distances, angles and atom charges on (31)P NMR chemical shieldings has been discussed. Simulation of the LiTi2-xGex(PO4)3 series suggests that detection of 10 P environments is mainly due to the existence of two oxygen types, O1 and O2, whose charges are differently affected by Ge and Ti occupation of octahedra. From the quantitative analysis of detected components, a random Ti/Ge distribution has been deduced in next nearest neighbor (NNN) sites that surround tetrahedral PO4 units. This random distribution was supported by XRD data displaying Vegard's law. PMID:27373306

  11. Higher energy electronic transitions of HC(2n+1)H+ (n=2-7) and HC(2n+1)H (n=4-7) in neon matrices.

    PubMed

    Fulara, Jan; Nagy, Adam; Garkusha, Iryna; Maier, John P

    2010-07-14

    Electronic absorption spectra of linear HC(2n+1)H(+) (n=2-7) were recorded in 6 K neon matrices following their mass-selective deposition. Four new electronic band systems are identified; the strongest E (2)Pi(g/u)<--X (2)Pi(u/g) lies in the UV and the second most intense C (2)Pi(g/u)<--X (2)Pi(u/g) is located in the visible range. The known A (2)Pi(g/u)<--X (2)Pi(u/g) absorption is an order of magnitude weaker than C (2)Pi(g/u)<--X (2)Pi(u/g). Transitions to the B and D states are also discussed. The wavelengths of the HC(2n+1)H(+) (n=2-7) electronic systems obey a linear relation as a function of the size of the cations, similar to other carbon chains. The B (3)Sigma(u)(-)<--X (3)Sigma(g)(-) transition in the UV of neutral HC(2n+1)H (n=4-7) has also been identified upon photobleaching of the cations trapped in the matrices. PMID:20632752

  12. Predictability of 1-h postload plasma glucose concentration: A 10-year retrospective cohort study

    PubMed Central

    Kuang, Lifen; Huang, Zhimin; Hong, Zhenzhen; Chen, Ailing; Li, Yanbing

    2015-01-01

    Aims/Introduction Elevated 1-h postload plasma glucose concentration (1hPG) during oral glucose tolerance test has been linked to an increased risk of type 2 diabetes and a poorer cardiometabolic risk profile. The present study analyzed the predictability and cut-off point of 1hPG in predicting type 2 diabetes in normal glucose regulation (NGR) subjects, and evaluated the long-term prognosis of NGR subjects with elevated 1hPG in glucose metabolism, kidney function, metabolic states and atherosclerosis. Materials and Methods A total of 116 Han Chinese classified as NGR in 2002 at the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China, were investigated. Follow-up was carried out in 2012 to evaluate the progression of glucose metabolism, kidney function, metabolic syndrome and carotid atherosclerosis. Results The areas under receiver operating characteristic curves were higher for 1hPG than FPG or 2hPG (0.858 vs 0.806 vs 0.746). The cut-off value of 1hPG with the maximal sum of sensitivity and specificity in predicting type 2 diabetes in NGR subjects was 8.85 mmol/L. The accumulative incidence of type 2 diabetes in subjects with 1hPG ≥8.85 mmol/L was higher than those <8.85 mmol/L (46.2% vs 3.3%, P = 0.000; relative risk 13.846, 95% confidence interval 4.223–45.400). On follow up, the prevalence of metabolic syndrome and abnormal carotid intima-media thickness in the subjects with 1hPG ≥8.85 mmol/L tended to be higher compared with those <8.85 mmol/L. Conclusions 1hPG is a good predictor of type 2 diabetes in NGR subjects, and the best cut-off point is 8.85 mmol/L. Some tendency indicates that NGR subjects with 1hPG ≥8.85 mmol/L are more prone to metabolic syndrome and carotid atherosclerosis. PMID:26543538

  13. 14N quadrupole resonance and 1H T1 dispersion in the explosive RDX.

    PubMed

    Smith, John A S; Blanz, Martin; Rayner, Timothy J; Rowe, Michael D; Bedford, Simon; Althoefer, Kaspar

    2011-12-01

    The explosive hexahydro-1,3,5-trinitro-s-triazine (CH2-N-NO2)3, commonly known as RDX, has been studied by 14N NQR and 1H NMR. NQR frequencies and relaxation times for the three ν+ and ν- lines of the ring 14N nuclei have been measured over the temperature range 230-330 K. The 1H NMR T1 dispersion has been measured for magnetic fields corresponding to the 1H NMR frequency range of 0-5.4 M Hz. The results have been interpreted as due to hindered rotation of the NO2 group about the N-NO2 bond with an activation energy close to 92 kJ mol(-1). Three dips in the 1H NMR dispersion near 120, 390 and 510 kHz are assigned to the ν0, ν- and ν+ transitions of the 14NO2 group. The temperature dependence of the inverse line-width parameters T2∗ of the three ν+ and ν- ring nitrogen transitions between 230 and 320 K can be explained by a distribution in the torsional oscillational amplitudes of the NO2 group about the N-NO2 bond at crystal defects whose values are consistent with the latter being mainly edge dislocations or impurities in the samples studied. Above 310 K, the 14N line widths are dominated by the rapid decrease in the spin-spin relaxation time T2 due to hindered rotation of the NO2 group. A consequence of this is that above this temperature, the 1H T1 values at the quadrupole dips are dominated by the spin mixing time between the 1H Zeeman levels and the combined 1H and 14N spin-spin levels. PMID:21978662

  14. The structure and properties of 5,6-dinitro-1H-benzotriazole

    NASA Astrophysics Data System (ADS)

    Santa María, Dolores; Claramunt, Rosa M.; Torralba, M. Carmen; Torres, M. Rosario; Alkorta, Ibon; Elguero, José

    2016-06-01

    5,6-Dinitro-1H-benzotriazole crystallizes in the monoclinic system, space group P21/c. The asymmetric unit contains the planar 1H-tautomer together with a water molecule of crystallization. Each water molecule is hydrogen bonded to three adjacent 5,6-dinitrobenzotriazoles forming a tape along the b-axis of the crystal. These tapes stack along the c-axis through hydrogen bonds involving the water molecules and one of the nitro groups leading to a bidimensional structure. Solid-state 13C and 15N CPMAS NMR allow to confirm that the tautomer present is the 1H one. In DMSO-d6 solution the results are quite different and, based on GIAO/B3LYP/6-311++G(d,p) calculations, lead us to conclude that the major tautomer is the 5,6-dinitro-2H-benzotriazole, a surprising result that contradicts the rule that the major tautomer in solution coincides with the one present in the crystal. An anhydrous pseudopolymorph of 5,6-dinitro-1H-benzotriazole has been obtained as a non-crystalline form and from solid-state NMR and theoretical calculations, we conclude that it is an 1H-tautomer.

  15. Hematocrit and oxygenation dependence of blood (1)H(2)O T(1) at 7 Tesla.

    PubMed

    Grgac, Ksenija; van Zijl, Peter C M; Qin, Qin

    2013-10-01

    Knowledge of blood (1)H2O T1 is critical for perfusion-based quantification experiments such as arterial spin labeling and cerebral blood volume-weighted MRI using vascular space occupancy. The dependence of blood (1)H2O T1 on hematocrit fraction (Hct) and oxygen saturation fraction (Y) was determined at 7 T using in vitro bovine blood in a circulating system under physiological conditions. Blood (1)H2O R1 values for different conditions could be readily fitted using a two-compartment (erythrocyte and plasma) model, which are described by a monoexponential longitudinal relaxation rate constant dependence. It was found that T1 = 2171 ± 39 ms for Y = 1 (arterial blood) and 2010 ± 41 ms for Y = 0.6 (venous blood), for a typical Hct of 0.42. The blood (1)H2O T1 values in the normal physiological range (Hct from 0.35 to 0.45, and Y from 0.6 to 1.0) were determined to range from 1900 to 2300 ms. The influence of oxygen partial pressure (pO2) and the effect of plasma osmolality for different anticoagulants were also investigated. It is discussed why blood (1)H2O T1 values measured in vivo for human blood may be about 10-20% larger than found in vitro for bovine blood at the same field strength. PMID:23169066

  16. A statistical approach for analyzing the development of 1H multiple-quantum coherence in solids.

    PubMed

    Mogami, Yuuki; Noda, Yasuto; Ishikawa, Hiroto; Takegoshi, K

    2013-05-21

    A novel statistical approach for analyzing (1)H multiple-quantum (MQ) spin dynamics in so-called spin-counting solid-state NMR experiments is presented. The statistical approach is based on the percolation theory with Monte Carlo methods and is examined by applying it to the experimental results of three solid samples having unique hydrogen arrangement for 1-3 dimensions: the n-alkane/d-urea inclusion complex as a one-dimensional (1D) system, whose (1)H nuclei align approximately in 1D, and magnesium hydroxide and adamantane as a two-dimensional (2D) and a three-dimensional (3D) system, respectively. Four lattice models, linear, honeycomb, square and cubic, are used to represent the (1)H arrangement of the three samples. It is shown that the MQ dynamics in adamantane is consistent with that calculated using the cubic lattice and that in Mg(OH)2 with that calculated using the honeycomb and the square lattices. For n-C20H42/d-urea, these 4 lattice models fail to express its result. It is shown that a more realistic model representing the (1)H arrangement of n-C20H42/d-urea can describe the result. The present approach can thus be used to determine (1)H arrangement in solids. PMID:23580152

  17. Specific control of BMP signaling and mesenchymal differentiation by cytoplasmic phosphatase PPM1H

    PubMed Central

    Shen, Tao; Sun, Chuang; Zhang, Zhengmao; Xu, Ningyi; Duan, Xueyan; Feng, Xin-Hua; Lin, Xia

    2014-01-01

    Bone morphogenetic proteins (BMPs) belong to the TGF-β superfamily of structurally related signaling proteins that regulate a wide array of cellular functions. The key step in BMP signal transduction is the BMP receptor-mediated phosphorylation of transcription factors Smad1, 5, and 8 (collectively Smad1/5/8), which leads to the subsequent activation of BMP-induced gene transcription in the nucleus. In this study, we describe the identification and characterization of PPM1H as a novel cytoplasm-localized Smad1/5/8-specific phosphatase. PPM1H directly interacts with Smad1/5/8 through its Smad-binding domain, and dephosphorylates phospho-Smad1/5/8 (P-Smad1/5/8) in the cytoplasm. Ectopic expression of PPM1H attenuates BMP signaling, whereas loss of PPM1H activity or expression greatly enhances BMP-dependent gene regulation and mesenchymal differentiation. In conclusion, this study suggests that PPM1H acts as a gatekeeper to prevent excessive BMP signaling through dephosphorylation and subsequent nuclear exclusion of P-Smad1/5/8 proteins. PMID:24732009

  18. Synthesis and preliminary evaluation of 3-thiocyanato-1H-indoles as potential anticancer agents.

    PubMed

    Fortes, Margiani P; da Silva, Paulo B N; da Silva, Teresinha G; Kaufman, Teodoro S; Militão, Gardenia C G; Silveira, Claudio C

    2016-08-01

    A novel series of twenty 3-thiocyanato-1H-indoles, carrying diversification at positions N-1, C-2 and C-5 of the heterocyclic core, were synthesized; their antiproliferative activity against four human cancer cell lines (HL60, HEP-2, NCI-H292 and MCF-7) was evaluated, employing doxorubicin as positive control. Indole, N-methylindole and 2-(4-chlorophenyl)-N-methylindole demonstrated to be essentially inactive, whereas several of their congener 3-thiocyanato-1H-indoles displayed good to excellent levels of potency (IC50 ≤ 6 μM), while being non-hemolytic. N-Phenyl-3-thiocyanato-1H-indole and 1-methyl-2-(4-chlorophenyl)-3-thiocyanato-1H-indole showed good to high potency against all the cell lines. On the other side, the N-(4-chlorophenyl)-, 2-(4-chlorophenyl)- and 2-phenyl- 3-thiocyanato-1H-indole derivatives were slightly less active against the test cell lines. Overall, these results suggest that the indole-3-thiocyanate motif can be suitably decorated to afford highly cytotoxic compounds and that the substituted indole can be employed as a useful scaffold toward more potent compounds. PMID:27116711

  19. Selective excitation enables assignment of proton resonances and (1)H-(1)H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy.

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-21

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of (1)H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as (13)C or (15)N. In this method, after the initial preparation of proton magnetization and cross-polarization to (13)C nuclei, transverse magnetization of desired (13)C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific (13)C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of (1)H-(1)H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids. PMID:26203019

  20. Selective excitation enables assignment of proton resonances and 1H-1H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-01

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of 1H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as 13C or 15N. In this method, after the initial preparation of proton magnetization and cross-polarization to 13C nuclei, transverse magnetization of desired 13C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific 13C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of 1H-1H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

  1. Selective excitation enables assignment of proton resonances and {sup 1}H-{sup 1}H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-21

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of {sup 1}H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as {sup 13}C or {sup 15}N. In this method, after the initial preparation of proton magnetization and cross-polarization to {sup 13}C nuclei, transverse magnetization of desired {sup 13}C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific {sup 13}C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of {sup 1}H-{sup 1}H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

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

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-28

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

  3. 40 CFR 721.1750 - 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium salts. 721.1750 Section 721.1750... 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium...-tyl-oxy)-, sodium salt (PMN P-92-35), and 1H-benzotriazole, 5-(pentyloxy)- , potassium salt (PMN...

  4. 40 CFR 721.1750 - 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium salts. 721.1750 Section 721.1750... 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium...-tyl-oxy)-, sodium salt (PMN P-92-35), and 1H-benzotriazole, 5-(pentyloxy)- , potassium salt (PMN...

  5. 40 CFR 721.1750 - 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium salts. 721.1750 Section 721.1750... 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium...-tyl-oxy)-, sodium salt (PMN P-92-35), and 1H-benzotriazole, 5-(pentyloxy)- , potassium salt (PMN...

  6. 40 CFR 721.1750 - 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium salts. 721.1750 Section 721.1750... 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium...-tyl-oxy)-, sodium salt (PMN P-92-35), and 1H-benzotriazole, 5-(pentyloxy)- , potassium salt (PMN...

  7. 40 CFR 721.1750 - 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium salts. 721.1750 Section 721.1750... 1H-Benzotriazole, 5-(pen-tyl-oxy)- and 1H-ben-zo-tri-a-zole, 5-(pen-tyl-oxy)-, sodium and potassium...-tyl-oxy)-, sodium salt (PMN P-92-35), and 1H-benzotriazole, 5-(pentyloxy)- , potassium salt (PMN...

  8. 1H-1,2,4-diazaphospholes: Synthesis, structural characterization, and DFT calculation

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Wen; Ding, Ling-Yan; Wang, Bing-Qiang; He, Yao-Yun; Guo, Yue; Jia, Xue-Feng; Zheng, Wenjun

    2014-01-01

    A few 1H-1,2,4-diazaphospholes H[3,5-R2dp] (R = methyl (5a), p-tolyl (5b), 1-naphthyl (5c), 2-furanyl (5d), 2-thienyl (5e), and isopropyl (5f)) were prepared and structurally characterized by a substantial experimental modification of the synthetic protocol. The molecules of all compounds are linked into oligomers via the bridges of NH⋯N hydrogen bonds in solid state. The tetrameric feature of 5a, and 5d-f represents a new motif of hydrogen-bonded 1H-1,2,4-diazaphospholes in solid state. The DFT calculation at the B3LYP/6-311++G** level suggested the possible proton disorder with intermolecular solid state proton transfer (ISSPT) between 1H-1,2,4-diazaphosphole rings.

  9. Synthesis, characterization and theoretical studies of 5-(benzylthio)-1-cylopentyl-1H-tetrazole.

    PubMed

    Saglam, S; Disli, A; Erdogdu, Y; Marchewka, M K; Kanagathara, N; Bay, B; Güllüoğlu, M T

    2015-01-25

    In this study, 5-(benzylthio)-1-cylopentyl-1H-tetrazole (5B1C1HT) have been synthesized. Boiling points of the obtained compound have been determined and it has been characterized by FT-IR, (1)H NMR, (13)C-APT and LC-MS spectroscopy techniques. The FT-IR, (1)H NMR and (13)C-APT spectral measurements of the 5B1C1HT compound and complete assignment of the vibrational bands observed in spectra has been discussed. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on Density Functional Theory (DFT) at 6-311++G(**), cc-pVDZ and cc-pVTZ basis sets. The optimized geometry with 6-311++G(**) basis sets were used to determine the total energy distribution, harmonic vibrational frequencies, IR intensities. PMID:25171051

  10. Synthesis, characterization and theoretical studies of 5-(benzylthio)-1-cylopentyl-1H-tetrazole

    NASA Astrophysics Data System (ADS)

    Saglam, S.; Disli, A.; Erdogdu, Y.; Marchewka, M. K.; Kanagathara, N.; Bay, B.; Güllüoğlu, M. T.

    2015-01-01

    In this study, 5-(benzylthio)-1-cylopentyl-1H-tetrazole (5B1C1HT) have been synthesized. Boiling points of the obtained compound have been determined and it has been characterized by FT-IR, 1H NMR, 13C-APT and LC-MS spectroscopy techniques. The FT-IR, 1H NMR and 13C-APT spectral measurements of the 5B1C1HT compound and complete assignment of the vibrational bands observed in spectra has been discussed. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on Density Functional Theory (DFT) at 6-311++G**, cc-pVDZ and cc-pVTZ basis sets. The optimized geometry with 6-311++G** basis sets were used to determine the total energy distribution, harmonic vibrational frequencies, IR intensities.

  11. Multislice 1H magnetic resonance spectroscopic imaging: assessment of epilepsy, Alzheimer's disease, and amyotrophic lateral sclerosis

    NASA Astrophysics Data System (ADS)

    Weiner, Michael W.; Maudsley, Andrew A.; Schuff, Norbert; Soher, Brian J.; Vermathen, Peter P.; Fein, George; Laxer, Kenneth D.

    1998-07-01

    Proton magnetic resonance spectroscopic imaging (1H MRSI) with volume pre-selection (i.e. by PRESS) or multislice 1H MRSI was used to investigate changes in brain metabolites in Alzheimer's disease, epilepsy, and amyotrophic lateral sclerosis. Examples of results from several ongoing clinical studies are provided. Multislice 1H MRSI of the human brain, without volume pre-selection offers considerable advantages over previously available techniques. Furthermore, MRI tissue segmentation and completely automated spectra curve fitting greatly facilitate quantitative data analysis. Future efforts will be devoted to obtaining full brain coverage and data acquisition at short spin echo times (TE less than 30 ms) for the detection of metabolites with short T2 relaxation times.

  12. Amino­silanes derived from 1H-benzimidazole-2(3H)-thione

    PubMed Central

    Palomo-Molina, Juliana; García-Báez, Efrén V.; Contreras, Rosalinda; Pineda-Urbina, Kayim; Ramos-Organillo, Angel

    2015-01-01

    Two new mol­ecular structures, namely 1,3-bis­(tri­methyl­silyl)-1H-benzimidazole-2(3H)-thione, C13H22N2SSi2, (2), and 1-tri­methyl­silyl-1H-benzimidazole-2(3H)-thione, C10H14N2SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π inter­actions between the centroid of the benzmidazole system and the SiMe3 groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R 2 2(8) rings via N—H⋯S inter­actions, along with parallel π–π inter­actions between imidazole and benzene rings. PMID:26322611

  13. Metabolomic differentiation of Cannabis sativa cultivars using 1H NMR spectroscopy and principal component analysis.

    PubMed

    Choi, Young Hae; Kim, Hye Kyong; Hazekamp, Arno; Erkelens, Cornelis; Lefeber, Alfons W M; Verpoorte, Robert

    2004-06-01

    The metabolomic analysis of 12 Cannabis sativa cultivars was carried out by 1H NMR spectroscopy and multivariate analysis techniques. Principal component analysis (PCA) of the 1H NMR spectra showed a clear discrimination between those samples by principal component 1 (PC1) and principal component 3 (PC3) in cannabinoid fraction. The loading plot of PC value obtained from all 1)H NMR signals shows that Delta9-tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) are important metabolites to differentiate the cultivars from each other. The discrimination of the cultivars could also be obtained from a water extract containing carbohydrates and amino acids. The level of sucrose, glucose, asparagine, and glutamic acid are found to be major discriminating metabolites of these cultivars. This method allows an efficient differentiation between cannabis cultivars without any prepurification steps. PMID:15217272

  14. Protein conformational exchange measured by 1H R1ρ relaxation dispersion of methyl groups.

    PubMed

    Weininger, Ulrich; Blissing, Annica T; Hennig, Janosch; Ahlner, Alexandra; Liu, Zhihong; Vogel, Hans J; Akke, Mikael; Lundström, Patrik

    2013-09-01

    Activated dynamics plays a central role in protein function, where transitions between distinct conformations often underlie the switching between active and inactive states. The characteristic time scales of these transitions typically fall in the microsecond to millisecond range, which is amenable to investigations by NMR relaxation dispersion experiments. Processes at the faster end of this range are more challenging to study, because higher RF field strengths are required to achieve refocusing of the exchanging magnetization. Here we describe a rotating-frame relaxation dispersion experiment for (1)H spins in methyl (13)CHD2 groups, which improves the characterization of fast exchange processes. The influence of (1)H-(1)H rotating-frame nuclear Overhauser effects (ROE) is shown to be negligible, based on a comparison of R 1ρ relaxation data acquired with tilt angles of 90° and 35°, in which the ROE is maximal and minimal, respectively, and on samples containing different (1)H densities surrounding the monitored methyl groups. The method was applied to ubiquitin and the apo form of calmodulin. We find that ubiquitin does not exhibit any (1)H relaxation dispersion of its methyl groups at 10 or 25 °C. By contrast, calmodulin shows significant conformational exchange of the methionine methyl groups in its C-terminal domain, as previously demonstrated by (1)H and (13)C CPMG experiments. The present R 1ρ experiment extends the relaxation dispersion profile towards higher refocusing frequencies, which improves the definition of the exchange correlation time, compared to previous results. PMID:23904100

  15. Relativistic Force Field: Parametrization of (13)C-(1)H Nuclear Spin-Spin Coupling Constants.

    PubMed

    Kutateladze, Andrei G; Mukhina, Olga A

    2015-11-01

    Previously, we reported a reliable DU8 method for natural bond orbital (NBO)-aided parametric scaling of Fermi contacts to achieve fast and accurate prediction of proton-proton spin-spin coupling constants (SSCC) in (1)H NMR. As sophisticated NMR experiments for precise measurements of carbon-proton SSCCs are becoming more user-friendly and broadly utilized by the organic chemistry community to guide and inform the process of structure determination of complex organic compounds, we have now developed a fast and accurate method for computing (13)C-(1)H SSCCs. Fermi contacts computed with the DU8 basis set are scaled using selected NBO parameters in conjunction with empirical scaling coefficients. The method is optimized for inexpensive B3LYP/6-31G(d) geometries. The parametric scaling is based on a carefully selected training set of 274 ((3)J), 193 ((2)J), and 143 ((1)J) experimental (13)C-(1)H spin-spin coupling constants reported in the literature. The DU8 basis set, optimized for computing Fermi contacts, which by design had evolved from optimization of a collection of inexpensive 3-21G*, 4-21G, and 6-31G(d) bases, offers very short computational (wall) times even for relatively large organic molecules containing 15-20 carbon atoms. The most informative SSCCs for structure determination, i.e., (3)J, were computed with an accuracy of 0.41 Hz (rmsd). The new unified approach for computing (1)H-(1)H and (13)C-(1)H SSCCs is termed "DU8c". PMID:26414291

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  17. Proton Fingerprints Portray Molecular Structures: Enhanced Description of the 1H NMR Spectra of Small Molecules

    PubMed Central

    Napolitano, José G.; Lankin, David C.; McAlpine, James B.; Niemitz, Matthias; Korhonen, Samuli-Petrus; Chen, Shao-Nong; Pauli, Guido F.

    2013-01-01

    The characteristic signals observed in NMR spectra encode essential information on the structure of small molecules. However, extracting all of this information from complex signal patterns is not trivial. This report demonstrates how computer-aided spectral analysis enables the complete interpretation of 1D 1H NMR data. The effectiveness of this approach is illustrated with a set of organic molecules, for which replicas of their 1H NMR spectra were generated. The potential impact of this methodology on organic chemistry research is discussed. PMID:24007197

  18. Fruit juice authentication by 1H NMR spectroscopy in combination with different chemometrics tools.

    PubMed

    Cuny, M; Vigneau, E; Le Gall, G; Colquhoun, I; Lees, M; Rutledge, D N

    2008-01-01

    To discriminate orange juice from grapefruit juice in a context of fraud prevention, (1)H NMR data were submitted to different treatments to extract informative variables which were then analysed using multivariate techniques. Averaging contiguous data points of the spectrum followed by logarithmic transformation improved the results of the data analysis. Moreover, supervised variable selection methods gave better rates of classification of the juices into the correct groups. Last, independent-component analysis gave better classification results than principal-component analysis. Hence, ICA may be an efficient chemometric tool to detect differences in the (1)H NMR spectra of similar samples, and so may be useful for authentication of foods. PMID:18026939

  19. Binding of Sulfonamide Antibiotics to CTABr Micelles Characterized Using (1)H NMR Spectroscopy.

    PubMed

    Sarker, Ashish K; Cashin, Patrick J; Balakrishnan, Vimal K; Exall, Kirsten; Buncel, Erwin; Brown, R Stephen

    2016-08-01

    Interactions of nine sulfonamide antibiotics (sulfadoxine, sulfathiazole, sulfamethoxazole, sulfamerazine, sulfadiazine, sulfamethazine, sulfacetamide, sulfaguanidine, and sulfanilamide) with cetyltrimethylamonium bromide (CTABr) micelles were examined using (1)H NMR spectroscopy. Seven of the nine provided a significant change in the (1)H NMR chemical shift such that the magnitude and direction (upfield vs downfield) of the chemical shift could be used to propose a locus and orientation of the sulfonamide within the micelle structure. The magnitude of the chemical shift was used to estimate the binding constant for seven sulfonamides with CTABr micelles, providing values and an overall pattern consistent with previous studies of these sulfonamides. PMID:27391918

  20. The (1) H NMR spectrum of pyrazole in a nematic phase.

    PubMed

    Provasi, Patricio; Jimeno, María Luisa; Alkorta, Ibon; Reviriego, Felipe; Elguero, José; Jokisaari, Jukka

    2016-08-01

    The experimental (1) H nuclear magnetic resonance (NMR) spectrum of 1H-pyrazole was recorded in thermotropic nematic liquid crystal N-(p-ethoxybenzylidene)-p-butylaniline (EBBA) within the temperature range of 299-308 K. Two of three observable dipolar DHH -couplings appeared to be equal at each temperature because of fast prototropic tautomerism. Analysis of the Saupe orientational order parameters using fixed geometry determined by computations and experimental dipolar couplings results in a situation in which the molecular orientation relative to the magnetic field (and the liquid crystal director) can be described exceptionally by a single parameter. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26947581

  1. Detection of hydrogen dissolved in acrylonitrile butadiene rubber by 1H nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Nishimura, Shin; Fujiwara, Hirotada

    2012-01-01

    Rubber materials, which are used for hydrogen gas seal, can dissolve hydrogen during exposure in high-pressure hydrogen gas. Dissolved hydrogen molecules were detected by solid state 1H NMR of the unfilled vulcanized acrylonitrile butadiene rubber. Two signals were observed at 4.5 ppm and 4.8 ppm, which were assignable to dissolved hydrogen, in the 1H NMR spectrum of NBR after being exposed 100 MPa hydrogen gas for 24 h at room temperature. These signals were shifted from that of gaseous hydrogen molecules. Assignment of the signals was confirmed by quantitative estimation of dissolved hydrogen and peak area of the signals.

  2. Dichloridobis{2-[(1H-1,2,4-triazol-1-yl)meth­yl]-1H-benzimidazole-κN 3}­zinc(II)

    PubMed Central

    Zhang, Wei-Peng; Zhang, Jiao-Lin; Hao, Bao-Lian; Yang, Huai-Xia

    2013-01-01

    In the title complex, [ZnCl2(C10H9N5)2], the ZnII ion is coordinated by two N atoms from two 2-[(1H-1,2,4-triazol-1-yl)meth­yl]-1H-benzimidazole (tmb) ligands and by two chloride ligands in a slightly distorted tetra­hedral geometry. In the tmb ligands, the benzimidazole rings systems are essentially planar, with maximum deviations from the mean plane of 0.021 (3) and 0.030 (3) Å, and form dihedral angles of 73.2 (2) and 83.5 (2)° with the triazole rings. In the crystal, N—H⋯N hydrogen bonds link complex mol­ecules into chains along [010]. In addition, weak C—H⋯Cl and C—H⋯N hydrogen bonds complete a three-dimensional network. Two weak intra­molecular C—H⋯Cl hydrogen bonds are also observed. PMID:23723759

  3. Hydrogen incorporation into high temperature protonic conductors: Nuclear microprobe microanalysis by means of 1H(p, p) 1H scattering

    NASA Astrophysics Data System (ADS)

    Berger, P.; Gallien, J.-P.; Khodja, H.; Daudin, L.; Berger, M.-H.; Sayir, A.

    2006-08-01

    Protonic conductivity of some solid state materials at an intermediate temperature range (400-600 °C), referred as high temperature protonic conductor (HTPC), suggests their application as electrolytes in electrochemical cells, batteries, sensors, etc. Among them, some perovskites can be protonic and electronic conductors. Several obstacles remain to achieve the full potential of these ceramic membranes, among them the lack of measurement techniques and of an unambiguous model for conductivity. A precise understanding of the transport mechanisms requires local profiling of hydrogen concentrations within the microstructure of the ceramic. We have used the nuclear microprobe of the Laboratoire Pierre SÜE to investigate quantitatively the spatial distribution of hydrogen after water heat treatment of textured perovskites, SrCe0.9Y0.1O3-δ and Sr3Ca1+xNb2-xO9-δ, x = 0.18, synthesized according to a melt-process developed at NASA GRC. A not very common method has been developed for hydrogen measurements in thin samples, 1H(p, p)1H elastic recoil coincidence spectrometry (ERCS). Early experiments have evidenced hydrogen concentration enhancement within grain boundaries.

  4. Elevated Glutamatergic Compounds in Pregenual Anterior Cingulate in Pediatric Autism Spectrum Disorder Demonstrated by 1H MRS and 1H MRSI

    PubMed Central

    Bejjani, Anthony; O'Neill, Joseph; Kim, John A.; Frew, Andrew J.; Yee, Victor W.; Ly, Ronald; Kitchen, Christina; Salamon, Noriko; McCracken, James T.; Toga, Arthur W.; Alger, Jeffry R.; Levitt, Jennifer G.

    2012-01-01

    Recent research in autism spectrum disorder (ASD) has aroused interest in anterior cingulate cortex and in the neurometabolite glutamate. We report two studies of pregenual anterior cingulate cortex (pACC) in pediatric ASD. First, we acquired in vivo single-voxel proton magnetic resonance spectroscopy (1H MRS) in 8 children with ASD and 10 typically developing controls who were well matched for age, but with fewer males and higher IQ. In the ASD group in midline pACC, we found mean 17.7% elevation of glutamate + glutamine (Glx) (p<0.05) and 21.2% (p<0.001) decrement in creatine + phosphocreatine (Cr). We then performed a larger (26 subjects with ASD, 16 controls) follow-up study in samples now matched for age, gender, and IQ using proton magnetic resonance spectroscopic imaging (1H MRSI). Higher spatial resolution enabled bilateral pACC acquisition. Significant effects were restricted to right pACC where Glx (9.5%, p<0.05), Cr (6.7%, p<0.05), and N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (10.2%, p<0.01) in the ASD sample were elevated above control. These two independent studies suggest hyperglutamatergia and other neurometabolic abnormalities in pACC in ASD, with possible right-lateralization. The hyperglutamatergic state may reflect an imbalance of excitation over inhibition in the brain as proposed in recent neurodevelopmental models of ASD. PMID:22848344

  5. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 6-Methoxy-1H-benz isoquinoline-2... New Uses for Specific Chemical Substances § 721.9078 6-Methoxy-1H-benz isoquinoline-2 -dione... substance identified generically as 6-methoxy-1H-benz isoquinoline-2 -dione derivative (PMN P-00-1205)...

  6. 32 CFR 1630.15 - Class 1-H: Registrant not subject to processing for induction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for induction. 1630.15 Section 1630.15 National Defense Other Regulations Relating to National Defense... induction. In Class 1-H shall be placed any registrant who is not eligible for Class 1-A and is not currently subject to processing for induction....

  7. NMR resonance splitting of urea in stretched hydrogels: proton exchange and (1)H/(2)H isotopologues.

    PubMed

    Kuchel, Philip W; Naumann, Christoph; Chapman, Bogdan E; Shishmarev, Dmitry; Håkansson, Pär; Bacskay, George; Hush, Noel S

    2014-10-01

    Urea at ∼12 M in concentrated gelatin gel, that was stretched, gave (1)H and (2)H NMR spectral splitting patterns that varied in a predictable way with changes in the relative proportions of (1)H2O and (2)H2O in the medium. This required consideration of the combinatorics of the two amide groups in urea that have a total of four protonation/deuteration sites giving rise to 16 different isotopologues, if all the atoms were separately identifiable. The rate constant that characterized the exchange of the protons with water was estimated by back-transformation analysis of 2D-EXSY spectra. There was no (1)H NMR spectral evidence that the chiral gelatin medium had caused in-equivalence in the protons bonded to each amide nitrogen atom. The spectral splitting patterns in (1)H and (2)H NMR spectra were accounted for by intra-molecular scalar and dipolar interactions, and quadrupolar interactions with the electric field gradients of the gelatin matrix, respectively. PMID:25241007

  8. Synthesis of 1H-Indazoles from Imidates and Nitrosobenzenes via Synergistic Rhodium/Copper Catalysis.

    PubMed

    Wang, Qiang; Li, Xingwei

    2016-05-01

    Nitrosobenzenes have been used as a convenient aminating reagent for the efficient synthesis of 1H-indazoles via rhodium and copper catalyzed C-H activation and C-N/N-N coupling. The reaction occurred under redox-neutral conditions with high efficiency and functional group tolerance. Moreover, a rhodacyclic imidate complex has been identified as a key intermediate. PMID:27082502

  9. 1H NMR determination of urinary betaine in patients with premature vascular disease and mild homocysteinemia.

    PubMed

    Lundberg, P; Dudman, N P; Kuchel, P W; Wilcken, D E

    1995-02-01

    Urinary N,N,N-trimethylglycine (betaine) and N,N-dimethylglycine (DMG) have been identified and quantified for clinical purposes by proton nuclear magnetic resonance (1H NMR) measurement in previous studies. We have assessed these procedures by using both one-dimensional (1-D) and 2-D NMR spectroscopy, together with pH titration of urinary extracts to help assign 1H NMR spectral peaks. The betaine calibration curve linearity was excellent (r = 0.997, P = 0.0001) over the concentration range 0.2-1.2 mmol/L, and CVs for replicate betaine analyses ranged from 7% (n = 10) at the lowest concentration to 1% (n = 9) at the highest. The detection limit for betaine was < 15 mumol/L. Urinary DMG concentrations were substantially lower than those of betaine. Urinary betaine and DMG concentrations measured by 1H NMR spectroscopy from 13 patients with premature vascular disease and 17 normal controls provided clinically pertinent data. We conclude that 1H NMR provides unique advantages as a research tool for determination of urinary betaine and DMG concentrations. PMID:7533065

  10. Synthesis of stereospecifically deuterated desoxypodophyllotoxins and 1H-nmr assignment of desoxypodophyllotoxin

    NASA Technical Reports Server (NTRS)

    Pullockaran, A. J.; Kingston, D. G.; Lewis, N. G.

    1989-01-01

    [4 beta- 2H1]Desoxypodophyllotoxin [3], [4 alpha- 2H1]desoxypodophyllotoxin [4], and [4, 4- 2 H2]desoxypodophyllotoxin [9] were prepared from podophyllotoxin [1] via its chloride [5]. A complete assignment of the 1H-nmr spectrum of desoxypodophyllotoxin [2] was made on the basis of the spectra of the deuterated compounds [3] and [4].

  11. Aminosilanes derived from 1H-benzimidazole-2(3H)-thione

    SciTech Connect

    Palomo-Molina, Juliana; García-Báez, Efrén V.; Pineda-Urbina, Kayim; Ramos-Organillo, Angel

    2015-08-12

    In two trimethylsilyl-substituted 1H-benzimidazole-2(3H)-thiones, noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe{sub 3} groups form helicoidal arrangements in one, and dimerization results in the formation of R{sub s} {sup 2}(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings, in the second compound. Two new molecular structures, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, C{sub 13}H{sub 22}N{sub 2}SSi{sub 2}, (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, C{sub 10}H{sub 14}N{sub 2}SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe{sub 3} groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R{sub 2}{sup 2}(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings.

  12. Scalable synthesis of quaterrylene: solution-phase 1H NMR spectroscopy of its oxidative dication.

    PubMed

    Thamatam, Rajesh; Skraba, Sarah L; Johnson, Richard P

    2013-10-14

    Quaterrylene is prepared in a single reaction and high yield by Scholl-type coupling of perylene, utilizing trifluoromethanesulfonic acid as catalyst and DDQ or molecular oxygen as oxidant. Dissolution in 1 M triflic acid/dichloroethane with sonication yields the aromatic quaterrylene oxidative dication, which is characterized by its (1)H NMR spectrum. PMID:23999880

  13. Simultaneous imaging of 13C metabolism and 1H structure: technical considerations and potential applications.

    PubMed

    Gordon, Jeremy W; Fain, Sean B; Niles, David J; Ludwig, Kai D; Johnson, Kevin M; Peterson, Eric T

    2015-05-01

    Real-time imaging of (13)C metabolism in vivo has been enabled by recent advances in hyperpolarization. As a result of the inherently low natural abundance of endogenous (13)C nuclei, hyperpolarized (13)C images lack structural information that could be used to aid in motion detection and anatomical registration. Motion before or during the (13)C acquisition can therefore result in artifacts and misregistration that may obscure measures of metabolism. In this work, we demonstrate a method to simultaneously image both (1)H and (13)C nuclei using a dual-nucleus spectral-spatial radiofrequency excitation and a fully coincident readout for rapid multinuclear spectroscopic imaging. With the appropriate multinuclear hardware, and the means to simultaneously excite and receive on both channels, this technique is straightforward to implement requiring little to no increase in scan time. Phantom and in vivo experiments were performed with both Cartesian and spiral trajectories to validate and illustrate the utility of simultaneous acquisitions. Motion compensation of dynamic metabolic measurements acquired during free breathing was demonstrated using motion tracking derived from (1)H data. Simultaneous multinuclear imaging provides structural (1)H and metabolic (13)C images that are correlated both spatially and temporally, and are therefore amenable to joint (1)H and (13)C analysis and correction of structure-function images. PMID:25810146

  14. 1H NMR detection of small molecules in human urine with a deep cavitand synthetic receptor.

    PubMed

    Ryan, Daniel A; Rebek, Julius

    2013-02-21

    A water-soluble deep cavitand recognized alkylammonium salts, including the drug amantadine hydrochloride, in spiked samples of human urine. The signals of the guests are detected by (1)H NMR upfield of 0 ppm and so occur in a spectroscopic window that is outside of the normal region and distinct from the signals of the biofluid components. PMID:23304698

  15. Documentation of ice shapes on the main rotor of a UH-1H helicopter in hover

    NASA Technical Reports Server (NTRS)

    Lee, J. D.; Harding, R.; Palko, R. L.

    1984-01-01

    A helicopter icing flight test program in the hover mode was conducted with a UH-1H aircraft. The ice formations were documented after landing by means of silicone rubber molds, stereo photography and outline tracings for later use in aerodynamic analyses. The documentation techniques are described and the results presented for a typical flight.

  16. Mutation screen reveals novel variants and expands the phenotypes associated with DYNC1H1.

    PubMed

    Strickland, Alleene V; Schabhüttl, Maria; Offenbacher, Hans; Synofzik, Matthis; Hauser, Natalie S; Brunner-Krainz, Michaela; Gruber-Sedlmayr, Ursula; Moore, Steven A; Windhager, Reinhard; Bender, Benjamin; Harms, Matthew; Klebe, Stephan; Young, Peter; Kennerson, Marina; Garcia, Avencia Sanchez Mejias; Gonzalez, Michael A; Züchner, Stephan; Schule, Rebecca; Shy, Michael E; Auer-Grumbach, Michaela

    2015-09-01

    Dynein, cytoplasmic 1, heavy chain 1 (DYNC1H1) encodes a necessary subunit of the cytoplasmic dynein complex, which traffics cargo along microtubules. Dominant DYNC1H1 mutations are implicated in neural diseases, including spinal muscular atrophy with lower extremity dominance (SMA-LED), intellectual disability with neuronal migration defects, malformations of cortical development, and Charcot-Marie-Tooth disease, type 2O. We hypothesized that additional variants could be found in these and novel motoneuron and related diseases. Therefore, we analyzed our database of 1024 whole exome sequencing samples of motoneuron and related diseases for novel single nucleotide variations. We filtered these results for significant variants, which were further screened using segregation analysis in available family members. Analysis revealed six novel, rare, and highly conserved variants. Three of these are likely pathogenic and encompass a broad phenotypic spectrum with distinct disease clusters. Our findings suggest that DYNC1H1 variants can cause not only lower, but also upper motor neuron disease. It thus adds DYNC1H1 to the growing list of spastic paraplegia related genes in microtubule-dependent motor protein pathways. PMID:26100331

  17. Molecular Structures from [superscript 1]H NMR Spectra: Education Aided by Internet Programs

    ERIC Educational Resources Information Center

    Debska, Barbara; Guzowska-Swider, Barbara

    2007-01-01

    The article presents the way in which freeware Internet programs can be applied to teach [superscript 1]H NMR spectroscopy. The computer programs described in this article are part of the educational curriculum that explores spectroscopy and spectra interpretation. (Contains 6 figures.)

  18. NMR profiling of biomolecules at natural abundance using 2D 1H-15N and 1H-13C multiplicity-separated (MS) HSQC spectra

    NASA Astrophysics Data System (ADS)

    Chen, Kang; Freedberg, Darón I.; Keire, David A.

    2015-02-01

    2D NMR 1H-X (X = 15N or 13C) HSQC spectra contain cross-peaks for all XHn moieties. Multiplicity-edited1H-13C HSQC pulse sequences generate opposite signs between peaks of CH2 and CH/CH3 at a cost of lower signal-to-noise due to the 13C T2 relaxation during an additional 1/1JCH period. Such CHn-editing experiments are useful in assignment of chemical shifts and have been successfully applied to small molecules and small proteins (e.g. ubiquitin) dissolved in deuterated solvents where, generally, peak overlap is minimal. By contrast, for larger biomolecules, peak overlap in 2D HSQC spectra is unavoidable and peaks with opposite phases cancel each other out in the edited spectra. However, there is an increasing need for using NMR to profile biomolecules at natural abundance dissolved in water (e.g., protein therapeutics) where NMR experiments beyond 2D are impractical. Therefore, the existing 2D multiplicity-edited HSQC methods must be improved to acquire data on nuclei other than 13C (i.e.15N), to resolve more peaks, to reduce T2 losses and to accommodate water suppression approaches. To meet these needs, a multiplicity-separated1H-X HSQC (MS-HSQC) experiment was developed and tested on 500 and 700 MHz NMR spectrometers equipped with room temperature probes using RNase A (14 kDa) and retroviral capsid (26 kDa) proteins dissolved in 95% H2O/5% D2O. In this pulse sequence, the 1/1JXH editing-period is incorporated into the semi-constant time (semi-CT) X resonance chemical shift evolution period, which increases sensitivity, and importantly, the sum and the difference of the interleaved 1JXH-active and the 1JXH-inactive HSQC experiments yield two separate spectra for XH2 and XH/XH3. Furthermore we demonstrate improved water suppression using triple xyz-gradients instead of the more widely used z-gradient only water-suppression approach.

  19. High resolution 1H nuclear magnetic resonance of a transmembrane peptide.

    PubMed Central

    Davis, J. H.; Auger, M.; Hodges, R. S.

    1995-01-01

    Although the strong 1H-1H dipolar interaction is known to result in severe homogeneous broadening of the 1H nuclear magnetic resonance (NMR) spectra of ordered systems, in the fluid phase of biological and model membranes the rapid, axially symmetric reorientation of the molecules about the local bilayer normal projects the dipolar interaction onto the motional symmetry axis. Because the linewidth then scales as (3 cos2 theta-1)/2, where theta is the angle between the local bilayer normal and the magnetic field, the dipolar broadening has been reduced to an "inhomogeneous" broadening by the rapid axial reorientation. It is then possible to obtain high resolution 1H-NMR spectra of membrane components by using magic angle spinning (MAS). Although the rapid axial reorientation effectively eliminates the homogeneous dipolar broadening, including that due to n = 0 rotational resonances, the linewidths observed in both lipids and peptides are dominated by low frequency motions. For small peptides the most likely slow motions are either a "wobble" or reorientation of the molecular diffusion axis relative to the local bilayer normal, or the reorientation of the local bilayer normal itself through surface undulations or lateral diffusion over the curved surface. These motions render the peptide 1H-NMR lines too broad to be observed at low spinning speeds. However, the linewidths due to these slow motions are very sensitive to spinning rate, so that at higher speeds the lines become readily visible. The synthetic amphiphilic peptide K2GL20K2A-amide (peptide-20) has been incorporated into bilayers of 1,2-di-d 27-myristoyl-sn-glycero-3-phosphocholine (DMPC-d54) and studied by high speed 1H-MAS-NMR. The linewidths observed for this transbilayer peptide, although too broad to be observable at spinning rates below -5 kHz, are reduced to 68 Hz at a spinning speed of 14 kHz (at 500C). Further improvements in spinning speed and modifications in sample composition designed to reduce

  20. MTR and In-vivo 1H-MRS studies on mouse brain with parkinson's disease

    NASA Astrophysics Data System (ADS)

    Yoon, Moon-Hyun; Kim, Hyeon-Jin; Chung, Jin-Yeung; Doo, Ah-Reum; Park, Hi-Joon; Kim, Seung-Nam; Choe, Bo-Young

    2012-12-01

    The aim of this study was to investigate whether the changes in the magnetization transfer ratio (MTR) histogram are related to specific characteristics of Parkinson's disease (PD) and to investigate whether the MTR histogram parameters are associated with neurochemical dysfunction by performing in vivo proton magnetic resonance spectroscopy (1H-MRS). MTR and in vivo 1H-MRS studies were performed on control mice (n = 10) and 1-methyl-1,2,3,6-tetrahydropyridine intoxicated mice (n = 10). All the MTR and in vivo 1H-MRS experiments were performed on a 9.4 T MRI/MRS system (Bruker Biospin, Germany) using a standard head coil. The protondensity fast spin echo (FSE) images and the T2-weighted spin echo (SE) images were acquired with no gap. Outer volume suppression (OVS), combined with the ultra-short echo-time stimulated echo acquisition mode (STEAM), was used for the localized in-vivo 1H-MRS. The quantitative analysis of metabolites was performed from the 1H spectra obtained in vivo on the striatum (ST) by using jMRUI (Lyon, France). The peak height of the MTR histograms in the PD model group was significantly lower than that in the control group (p < 0.05). The midbrain MTR values for volume were lower in the PD group than the control group(p < 0.05). The complex peak (Glx: glutamine+glutamate+ GABA)/creatine (Cr) ratio of the right ST in the PD group was significantly increased as compared to that of the control group. The present study revealed that the peak height of the MTR histogram was significantly decreased in the ST and substantia nigra, and a significant increase in the Gl x /Cr ratio was found in the ST of the PD group, as compared with that of the control group. These findings could reflect the early phase of neuronal dysfunction of neurotransmitters.

  1. Translational diffusion in paramagnetic liquids by 1H NMR relaxometry: Nitroxide radicals in solution

    NASA Astrophysics Data System (ADS)

    Kruk, D.; Korpała, A.; Kubica, A.; Meier, R.; Rössler, E. A.; Moscicki, J.

    2013-01-01

    For nitroxide radicals in solution one can identify three frequency regimes in which 1H spin-lattice relaxation rate of solvent molecules depend linearly on square root of the 1H resonance frequency. Combining a recently developed theory of nuclear (proton) spin-lattice relaxation in solutions of nitroxide radicals [D. Kruk et al., J. Chem. Phys. 137, 044512 (2012)], 10.1063/1.4736854 with properties of the spectral density function associated with translational dynamics, relationships between the corresponding linear changes of the relaxation rate (for 14N spin probes) and relative translational diffusion coefficient of the solvent and solute molecules have been derived (in analogy to 15N spin probes [E. Belorizky et al., J. Phys. Chem. A 102, 3674 (1998)], 10.1021/jp980397h). This method allows a simple and straightforward determination of diffusion coefficients in spin-labeled systems, by means of 1H nuclear magnetic resonance (NMR) relaxometry. The approach has thoroughly been tested by applying to a large set of experimental data—1H spin-lattice relaxation dispersion results for solutions of different viscosity (decalin, glycerol, propylene glycol) of 14N and 15N spin probes. The experiments have been performed versus temperature (to cover a broad range of translational diffusion coefficients) using field cycling spectrometer which covers three decades in 1H resonance frequency, 10 kHz-20 MHz. The limitations of NMR relaxometry caused by the time scale of the translational dynamics as well as electron spin relaxation have been discussed. It has been shown that for spin-labeled systems NMR relaxometry gives access to considerably faster diffusion processes than for diamagnetic systems.

  2. Mutations in the tail domain of DYNC1H1 cause dominant spinal muscular atrophy

    PubMed Central

    Harms, M.B.; Ori-McKenney, K.M.; Scoto, M.; Tuck, E.P.; Bell, S.; Ma, D.; Masi, S.; Allred, P.; Al-Lozi, M.; Reilly, M.M.; Miller, L.J.; Jani-Acsadi, A.; Pestronk, A.; Shy, M.E.; Muntoni, F.; Vallee, R.B.

    2012-01-01

    Objective: To identify the gene responsible for 14q32-linked dominant spinal muscular atrophy with lower extremity predominance (SMA-LED, OMIM 158600). Methods: Target exon capture and next generation sequencing was used to analyze the 73 genes in the 14q32 linkage interval in 3 SMA-LED family members. Candidate gene sequencing in additional dominant SMA families used PCR and pooled target capture methods. Patient fibroblasts were biochemically analyzed. Results: Regional exome sequencing of all candidate genes in the 14q32 interval in the original SMA-LED family identified only one missense mutation that segregated with disease state—a mutation in the tail domain of DYNC1H1 (I584L). Sequencing of DYNC1H1 in 32 additional probands with lower extremity predominant SMA found 2 additional heterozygous tail domain mutations (K671E and Y970C), confirming that multiple different mutations in the same domain can cause a similar phenotype. Biochemical analysis of dynein purified from patient-derived fibroblasts demonstrated that the I584L mutation dominantly disrupted dynein complex stability and function. Conclusions: We demonstrate that mutations in the tail domain of the heavy chain of cytoplasmic dynein (DYNC1H1) cause spinal muscular atrophy and provide experimental evidence that a human DYNC1H1 mutation disrupts dynein complex assembly and function. DYNC1H1 mutations were recently found in a family with Charcot-Marie-Tooth disease (type 2O) and in a child with mental retardation. Both of these phenotypes show partial overlap with the spinal muscular atrophy patients described here, indicating that dynein dysfunction is associated with a range of phenotypes in humans involving neuronal development and maintenance. PMID:22459677

  3. Multiple Antiferromagnetic Spin Fluctuations and Novel Evolution of Tc in Iron-Based Superconductors LaFe(As1‑xPx)(O1‑yFy) Revealed by 31P-NMR Studies

    NASA Astrophysics Data System (ADS)

    Shiota, Takayoshi; Mukuda, Hidekazu; Uekubo, Masahiro; Engetsu, Fuko; Yashima, Mitsuharu; Kitaoka, Yoshio; Lai, Kwing To; Usui, Hidetomo; Kuroki, Kazuhiko; Miyasaka, Shigeki; Tajima, Setsuko

    2016-05-01

    We report on 31P-NMR studies of LaFe(As1‑xPx)(O1‑yFy) over wide compositions for 0 ≤ x ≤ 1 and 0 ≤ y ≤ 0.14, which provide clear evidence that antiferromagnetic spin fluctuations (AFMSFs) are one of the indispensable elements for enhancing Tc. Systematic 31P-NMR measurements revealed two types of AFMSFs in the temperature evolution, that is, one is the AFMSFs that develop rapidly down to Tc with low-energy characteristics, and the other, with relatively higher energy than the former, develops gradually upon cooling from high temperature. The low-energy AFMSFs in low y (electron doping) over a wide x (pnictogen height suppression) range are associated with the two orbitals of dxz/yz, whereas the higher-energy ones for a wide y region around low x originate from the three orbitals of dxy and dxz/yz. We remark that the nonmonotonic variation of Tc as a function of x and y in LaFe(As1‑xPx)(O1‑yFy) is attributed to these multiple AFMSFs originating from degenerated multiple 3d orbitals inherent to Fe-pnictide superconductors.

  4. Achievement of 1 H-19 F heteronuclear experiments using the conventional spectrometer with a shared single high band amplifier.

    PubMed

    Sakuma, Chiseko; Kurita, Jun-ichi; Furihata, Kazuo; Tashiro, Mitsuru

    2015-05-01

    The (1)H-(19) F heteronuclear NMR experiments were achieved using the conventional spectrometer equipped with a single high band amplifier and a (1)H/(19)F/(13) C double-tuned probe. Although double high band amplifiers are generally required to perform such experiments, a simple modification of pathway in the conventional spectrometer was capable of acquiring various (1)H-(19)F heteronuclear spectra. The efficiency of the present technique was demonstrated in an application for (19)F{(1)H} and (1)H{(19)F} saturation transfer difference experiments. PMID:25808615

  5. Crystal structures of the two salts 2-methyl-1H-imidazol-3-ium nitrate–2-methyl-1H-imidazole (1/1) and 2-methyl-1H-imidazol-3-ium nitrate

    PubMed Central

    Diop, Mouhamadou Birame; Diop, Libasse; Maris, Thierry

    2016-01-01

    The title salts, C4H7N2 +·NO3 −·C4H6N2, (I), and C4H7N2 +·NO3 −, (II), were obtained from solutions containing 2-methyl­imidazole and nitric acid in different concentrations. In the crystal structure of salt (I), one of the –NH H atoms of the imidazole ring shows half-occupancy, hence only every second mol­ecule is in its cationic form. The nitrate anion in this structure lies on a twofold rotation axis. The neutral 2-methyl­imidazole mol­ecule and the 2-methyl-1H-imidazol-3-ium cation inter­act through N—H⋯N hydrogen bonds to form [(C4H6N2)⋯(C4H7N2)+] pairs. These pairs are linked with two nitrate anions on both sides through bifurcated N—H⋯(O,O) hydrogen bonds into chains running parallel to [001]. In the crystal structure of salt (II), the C4H7N2 + cation and the NO3 − anion are both located on a mirror plane, leading to a statistical disorder of the methyl H atoms. The cations and anions again inter­act through bifurcated N—H⋯(O,O) hydrogen bonds, giving rise to the formation of chains consisting of alternating anions and cations parallel to [100]. PMID:27375869

  6. Crystal structures of the two salts 2-methyl-1H-imidazol-3-ium nitrate-2-methyl-1H-imidazole (1/1) and 2-methyl-1H-imidazol-3-ium nitrate.

    PubMed

    Diop, Mouhamadou Birame; Diop, Libasse; Maris, Thierry

    2016-04-01

    The title salts, C4H7N2 (+)·NO3 (-)·C4H6N2, (I), and C4H7N2 (+)·NO3 (-), (II), were obtained from solutions containing 2-methyl-imidazole and nitric acid in different concentrations. In the crystal structure of salt (I), one of the -NH H atoms of the imidazole ring shows half-occupancy, hence only every second mol-ecule is in its cationic form. The nitrate anion in this structure lies on a twofold rotation axis. The neutral 2-methyl-imidazole mol-ecule and the 2-methyl-1H-imidazol-3-ium cation inter-act through N-H⋯N hydrogen bonds to form [(C4H6N2)⋯(C4H7N2)(+)] pairs. These pairs are linked with two nitrate anions on both sides through bifurcated N-H⋯(O,O) hydrogen bonds into chains running parallel to [001]. In the crystal structure of salt (II), the C4H7N2 (+) cation and the NO3 (-) anion are both located on a mirror plane, leading to a statistical disorder of the methyl H atoms. The cations and anions again inter-act through bifurcated N-H⋯(O,O) hydrogen bonds, giving rise to the formation of chains consisting of alternating anions and cations parallel to [100]. PMID:27375869

  7. Prospective Motion Correction for Single-Voxel 1H MR Spectroscopy

    PubMed Central

    Keating, Brian; Deng, Weiran; Roddey, J. Cooper; White, Nathan; Dale, Anders; Stenger, V. Andrew; Ernst, Thomas

    2010-01-01

    Head motion during 1H MR spectroscopy (MRS) acquisitions may compromise the quality and reliability of in vivo metabolite measurements. Therefore, a 3-plane image-based motion tracking module was integrated into a single-voxel 1H MRS (PRESS) sequence. A series of 3 orthogonal spiral navigator images were acquired immediately prior to the MRS water suppression module in order to estimate head motion. By applying the appropriate rotations and translations, the MRS voxel position can be updated such that it remains stationary with respect to the brain. Frequency and phase corrections were applied during post-processing to reduce line-width and restore coherent averaging. Spectra acquired during intentional head motion in 11 volunteers demonstrate reduced lipid contamination and increased spectral reproducibility when motion correction is applied. PMID:20806374

  8. Improved Carbohydrate Structure Generalization Scheme for (1)H and (13)C NMR Simulations.

    PubMed

    Kapaev, Roman R; Toukach, Philip V

    2015-07-21

    The improved Carbohydrate Structure Generalization Scheme has been developed for the simulation of (13)C and (1)H NMR spectra of oligo- and polysaccharides and their derivatives, including those containing noncarbohydrate constituents found in natural glycans. Besides adding the (1)H NMR calculations, we improved the accuracy and performance of prediction and optimized the mathematical model of the precision estimation. This new approach outperformed other methods of chemical shift simulation, including database-driven, neural net-based, and purely empirical methods and quantum-mechanical calculations at high theory levels. It can process structures with rarely occurring and noncarbohydrate constituents unsupported by the other methods. The algorithm is transparent to users and allows tracking used reference NMR data to original publications. It was implemented in the Glycan-Optimized Dual Empirical Spectrum Simulation (GODESS) web service, which is freely available at the platform of the Carbohydrate Structure Database (CSDB) project ( http://csdb.glycoscience.ru). PMID:26087011

  9. 1H NMR profiling as an approach to differentiate conventionally and organically grown tomatoes.

    PubMed

    Hohmann, Monika; Christoph, Norbert; Wachter, Helmut; Holzgrabe, Ulrike

    2014-08-20

    This study describes the approach of (1)H NMR profiling for the authentication of organically produced tomatoes (Solanum lycopersicum). Overall, 361 tomato samples of two different cultivars and four different producers were regularly analyzed during a 7 month period. The results of principal component analysis showed a significant trend for the separation between organically and conventionally produced tomatoes (p < 0.001 using the t test). Linear discriminant analysis demonstrated good discrimination between the growing regimens, and external validation showed 100% correctly classified tomato samples. Further validation studies, however, also disclosed unexpected differences between individual producers, which interfere with the aim of predicting the cultivation method, yet the results indicate significant differences between (1)H NMR spectra of organically and conventionally grown tomatoes. PMID:25066078

  10. Exploring the 3-piperidin-4-yl-1H-indole scaffold as a novel antimalarial chemotype.

    PubMed

    Santos, Sofia A; Lukens, Amanda K; Coelho, Lis; Nogueira, Fátima; Wirth, Dyann F; Mazitschek, Ralph; Moreira, Rui; Paulo, Alexandra

    2015-09-18

    A series of 3-piperidin-4-yl-1H-indoles with building block diversity was synthesized based on a hit derived from an HTS whole-cell screen against Plasmodium falciparum. Thirty-eight compounds were obtained following a three-step synthetic approach and evaluated for anti-parasitic activity. The SAR shows that 3-piperidin-4-yl-1H-indole is intolerant to most N-piperidinyl modifications. Nevertheless, we were able to identify a new compound (10d) with lead-like properties (MW = 305; cLogP = 2.42), showing antimalarial activity against drug-resistant and sensitive strains (EC50 values ∼ 3 μM), selectivity for malaria parasite and no cross-resistance with chloroquine, thus representing a potential new chemotype for further optimization towards novel and affordable antimalarial drugs. PMID:26295174

  11. Generation of heteronuclear 13C 1H chemical-shift correlations using soft pulses

    NASA Astrophysics Data System (ADS)

    Doddrell, David M.; Brooks, William; Field, James; Lynden-Bell, R. M.

    Two multipulse sequences are analyzed which can be used to generate heteronuclear 13C, 1H chemical-shift correlations without 2D NMR techniques. Both sequences utilize polarization-transfer techniques and generate the required chemical-shift correlation using a single soft proton pulse. The most useful technique is an extension of the DEPT method of polarization transfer since not only are the chemical-shift correlations generated in an easy to interpret form, but depending on the specific form of the pulse train used, the method can be employed to obtain information on the CH n group multiplicity. The methods are illustrated by applying them to generate 13C, 1H chemical-shift correlation spectra for menthol and cholesterol.

  12. Evaluation of saffron (Crocus sativus L.) adulteration with plant adulterants by (1)H NMR metabolite fingerprinting.

    PubMed

    Petrakis, Eleftherios A; Cagliani, Laura R; Polissiou, Moschos G; Consonni, Roberto

    2015-04-15

    In the present work, a preliminary study for the detection of adulterated saffron and the identification of the adulterant used by means of (1)H NMR and chemometrics is reported. Authentic Greek saffron and four typical plant-derived materials utilised as bulking agents in saffron, i.e., Crocus sativus stamens, safflower, turmeric, and gardenia were investigated. A two-step approach, relied on the application of both OPLS-DA and O2PLS-DA models to the (1)H NMR data, was adopted to perform authentication and prediction of authentic and adulterated saffron. Taking into account the deficiency of established methodologies to detect saffron adulteration with plant adulterants, the method developed resulted reliable in assessing the type of adulteration and could be viable for dealing with extensive saffron frauds at a minimum level of 20% (w/w). PMID:25466103

  13. Efficient dipolar double quantum filtering under magic angle spinning without a 1H decoupling field

    NASA Astrophysics Data System (ADS)

    Courtney, Joseph M.; Rienstra, Chad M.

    2016-08-01

    We present a systematic study of dipolar double quantum (DQ) filtering in 13C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n ⩾ 7, provided that the 13C nutation frequency is on the order of 100 kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between 13C and 1H fields. For 13C nutation frequencies greater than 75 kHz, optimal performance is observed without an applied 1H field. At spinning rates exceeding 20 kHz, symmetry conditions as low as n = 3 were found to perform adequately.

  14. Total (1)H NMR assignment of 3β-acetoxypregna-5,16-dien-20-one.

    PubMed

    Becerra-Martinez, Elvia; Ramírez-Gualito, Karla E; Pérez-Hernández, Nury; Joseph-Nathan, Pedro

    2015-12-01

    This work describes the total and unambiguous assignment of the 750 MHz (1)H NMR spectrum of 3β-acetoxypregna-5,16-dien-20-one or 16-DPA (1), the well-known intermediate utilized in the synthesis of biological important commercial steroids. The task was accomplished by extracting the coupling constant values in the overlapped spectrum region by HSQC, and using these values in the (1)H iterative full spin analysis integrated in the PERCH NMR software. Comparison of the experimental vicinal coupling constants of 1 with the values calculated using Altona provides an excellent correlation. The same procedure, when applied to the published data of progesterone (2) and testosterone (3), afforded an acceptable correlation for 2 and a poor correlation for 3. In the last case, this suggested the reassignment of all four vicinal coupling constants for the methylene signals at the C-15 and C-16 positions, demonstrating the utility of this methodology. PMID:26476187

  15. Study on 1H-NMR fingerprinting of Rhodiolae Crenulatae Radix et Rhizoma.

    PubMed

    Wen, Shi-yuan; Zhou, Jiang-tao; Chen, Yan-yan; Ding, Li-qin; Jiang, Miao-miao

    2015-07-01

    Nuclear magnetic resonance (1H-NMR) fingerprint of Rhodiola rosea medicinal materials was established, and used to distinguish the quality of raw materials from different sources. Pulse sequence for water peak inhibition was employed to acquire 1H-NMR spectra with the temperature at 298 K and spectrometer frequency of 400.13 MHz. Through subsection integral method, the obtained NMR data was subjected to similarity analysis and principal component analysis (PCA). 10 batches raw materials of Rhodiola rosea from different origins were successfully distinguished by PCA. The statistical results indicated that rhodiola glucoside, butyl alcohol, maleic acid and alanine were the main differential ingredients. This method provides an auxiliary method of Chinese quality approach to evaluate the quality of Rhodiola crenulata without using natural reference substances. PMID:26697690

  16. Digital NMR Profiles as Building Blocks: Assembling 1H Fingerprints of Steviol Glycosides

    PubMed Central

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

    2015-01-01

    This report describes a fragment-based approach to the examination of congeneric organic compounds by NMR spectroscopy. The method combines the classic interpretation of 1D- and 2D-NMR data sets with contemporary computer-assisted NMR analysis. Characteristic NMR profiles of key structural motifs were generated by 1H iterative full spin analysis and then joined together as building blocks to recreate the 1H NMR spectra of increasingly complex molecules. To illustrate the methodology described, a comprehensive analysis of steviol (1), seven steviol glycosides (2–8) and two structurally related isosteviol compounds (9, 10) was carried out. The study also assessed the potential impact of this method on relevant aspects of natural product research including structural verification, chemical dereplication, and mixture analysis. PMID:25714117

  17. Sequential acquisition of multi-dimensional heteronuclear chemical shift correlation spectra with 1H detection

    PubMed Central

    Bellstedt, Peter; Ihle, Yvonne; Wiedemann, Christoph; Kirschstein, Anika; Herbst, Christian; Görlach, Matthias; Ramachandran, Ramadurai

    2014-01-01

    RF pulse schemes for the simultaneous acquisition of heteronuclear multi-dimensional chemical shift correlation spectra, such as {HA(CA)NH & HA(CACO)NH}, {HA(CA)NH & H(N)CAHA} and {H(N)CAHA & H(CC)NH}, that are commonly employed in the study of moderately-sized protein molecules, have been implemented using dual sequential 1H acquisitions in the direct dimension. Such an approach is not only beneficial in terms of the reduction of experimental time as compared to data collection via two separate experiments but also facilitates the unambiguous sequential linking of the backbone amino acid residues. The potential of sequential 1H data acquisition procedure in the study of RNA is also demonstrated here. PMID:24671105

  18. Nonvortical Rashba Spin Structure on a Surface with C1 h Symmetry

    NASA Astrophysics Data System (ADS)

    Annese, Emilia; Kuzumaki, Takuya; Müller, Beate; Yamamoto, Yuta; Nakano, Hiroto; Kato, Haruki; Araki, Atsushi; Ohtaka, Minoru; Aoki, Takashi; Ishikawa, Hirotaka; Hayashida, Takashi; Osiecki, Jacek R.; Miyamoto, Koji; Takeichi, Yasuo; Harasawa, Ayumi; Yaji, Koichiro; Shirasawa, Tetsuroh; Nittoh, Koh-ichi; Yang, Wooil; Miki, Kazushi; Oda, Tatsuki; Yeom, Han Woong; Sakamoto, Kazuyuki

    2016-07-01

    A totally anisotropic peculiar Rashba-Bychkov (RB) splitting of electronic bands was found on the Tl /Si (110 )-(1 ×1 ) surface with C1 h symmetry by angle- and spin-resolved photoelectron spectroscopy and first-principles theoretical calculation. The constant energy contour of the upper branch of the RB split band has a warped elliptical shape centered at a k point located between Γ ¯ and the edge of the surface Brillouin zone, i.e., at a point without time-reversal symmetry. The spin-polarization vector of this state is in-plane and points almost the same direction along the whole elliptic contour. This novel nonvortical RB spin structure is confirmed as a general phenomenon originating from the C1 h symmetry of the surface.

  19. Nonvortical Rashba Spin Structure on a Surface with C_{1h} Symmetry.

    PubMed

    Annese, Emilia; Kuzumaki, Takuya; Müller, Beate; Yamamoto, Yuta; Nakano, Hiroto; Kato, Haruki; Araki, Atsushi; Ohtaka, Minoru; Aoki, Takashi; Ishikawa, Hirotaka; Hayashida, Takashi; Osiecki, Jacek R; Miyamoto, Koji; Takeichi, Yasuo; Harasawa, Ayumi; Yaji, Koichiro; Shirasawa, Tetsuroh; Nittoh, Koh-Ichi; Yang, Wooil; Miki, Kazushi; Oda, Tatsuki; Yeom, Han Woong; Sakamoto, Kazuyuki

    2016-07-01

    A totally anisotropic peculiar Rashba-Bychkov (RB) splitting of electronic bands was found on the Tl/Si(110)-(1×1) surface with C_{1h} symmetry by angle- and spin-resolved photoelectron spectroscopy and first-principles theoretical calculation. The constant energy contour of the upper branch of the RB split band has a warped elliptical shape centered at a k point located between Γ[over ¯] and the edge of the surface Brillouin zone, i.e., at a point without time-reversal symmetry. The spin-polarization vector of this state is in-plane and points almost the same direction along the whole elliptic contour. This novel nonvortical RB spin structure is confirmed as a general phenomenon originating from the C_{1h} symmetry of the surface. PMID:27419582

  20. A mathematical force and moment model of a UH-1H helicopter for flight dynamics simulations

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Corliss, L. D.

    1977-01-01

    A model of a UH-1H helicopter was developed to support flight simulations and for developmental work on an avionics system known as V/STOLAND system. Equations and numerical values of constants used to represent the helicopter are presented. Responses to stop inputs of the cyclic and collective controls are shown and compared with flight test data for a UH-1H. The model coefficients were adjusted in an attempt to get a consistant match with the flight time histories at hover and 60 knots. Response matching was obtained at 60 knots, but the matching at hover was not as successful. Pilot evaluations of the model, both fixed and moving base, were made.

  1. Shaft Sinking at the Nevada Test Site, U1h Shaft Project

    SciTech Connect

    B. Briggs; R. Musick

    2001-03-01

    The U1h Shaft Project is a design/build subcontract to construct one 6.1 meter (m) (20 feet (ft)) finished diameter shaft to a depth of 321.6 m (1,055 ft.) at the Nevada Test Site. Atkinson Construction was subcontracted by Bechtel Nevada to construct the U1h Shaft for the U.S. Department of Energy. The project consists of furnishing and installing the sinking plant, construction of the 321.6 m (1,055 ft.) of concrete lined shaft, development of a shaft station at a depth of 297.5 m (976 ft.), and construction of a loading pocket at the station. The outfitting of the shaft and installation of a new hoist may be incorporated into the project at a later date. This paper will describe the design phase, the excavation and lining operation, shaft station construction and the contractual challenges encountered on this project.

  2. (1)H-NMR-based discrimination of thermal and vinegar treated ginseng roots.

    PubMed

    Kim, So-Hyun; Hyun, Sun-Hee; Yang, Seung-Ok; Choi, Hyung-Kyoon; Lee, Boo-Yong

    2010-08-01

    To investigate the changes in nonvolatile metabolites of thermal and/or vinegar treated ginseng (TVG), samples prepared using various treatment conditions were analyzed using an (1)H-NMR-based metabolomics technique. The processing conditions of the ginseng in this study were 100, 140, and 180 degrees C with and without vinegar and the duration of exposure to each temperature was 10, 30, and 50 min, respectively. There was a clear separation in the score plots among various treatment conditions. Major compounds contributing to the separation of 50% methanol extracts of TVG with various process conditions were valine, lactate, alanine, arginine, glucose, fructose, and sucrose. As temperature increased, valine, arginine, glucose, fructose, and sucrose concentrations decreased, whereas lactate, glucose, and fructose increased in the vinegar-treated samples compared to non-vinegar-treated samples. The present study suggests the usefulness of an (1)H-NMR-based metabolomics approach to discriminate TVG samples, subjected to different processing conditions. PMID:20722913

  3. Efficient dipolar double quantum filtering under magic angle spinning without a (1)H decoupling field.

    PubMed

    Courtney, Joseph M; Rienstra, Chad M

    2016-08-01

    We present a systematic study of dipolar double quantum (DQ) filtering in (13)C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n⩾7, provided that the (13)C nutation frequency is on the order of 100kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between (13)C and (1)H fields. For (13)C nutation frequencies greater than 75kHz, optimal performance is observed without an applied (1)H field. At spinning rates exceeding 20kHz, symmetry conditions as low as n=3 were found to perform adequately. PMID:27314744

  4. Aromatic derivatives of 2,3-dihydro-1H-1,5-benzodiazepine

    SciTech Connect

    Orlov, V.D.; Desenko, S.M.; Kiroga, Kh.

    1987-09-01

    The formation of 2,2,4-trisubstituted 2,3-dihydro-1H-1,5-benzodiazepines in the reactions of acetylarenes with 4-ethoxy- and 3,5-dimethyl-1,2-phenylenediamine was studied. The effect of the substituents on the individual stages of the reactions is discussed. A quantum-chemical calculation of the relative nucleophilicity of 1,2-phenylenediamine, 2,3-diaminopyridine, and 3,4-diaminofurazan was undertaken.

  5. Quantitative 1H MRI and MRS Microscopy of Individual V79 Lung Tumor Spheroids

    NASA Astrophysics Data System (ADS)

    Minard, Kevin R.; Guo, Xiuling; Wind, Robert A.

    1998-08-01

    In this Communication1H MRI and MRS microscopy experiments of individual V79 lung tumor spheroids with diameters between 550 and 650 μm are reported. The results have been used to determine theT1,T2, andDvalues as well as the concentrations of water, total choline, creatine/phosphocreatine, and mobile lipids in the viable rims and in the necrotic centers.

  6. Direct phosphonation of quinoxalin-2(1H)-ones under transition-metal-free conditions.

    PubMed

    Gao, Ming; Li, Yi; Xie, Lijuan; Chauvin, Remi; Cui, Xiuling

    2016-02-01

    A direct C-H bond phosphonation of quinoxalin-2(1H)-ones with H-phosphonates, H-phosphinates or H-phosphine oxides has been developed. A wide variety of heteroaryl phosphonates were obtained in up to 92% yield for 20 examples under transition-metal-free conditions. This protocol tolerates a broad scope of substrates and features practicality, high efficiency, environmental friendliness and atom economy. PMID:26779573

  7. 1H and 13C spectral assignment of symmetrical bis[(4-aminosubstituted)quinolinium] derivatives.

    PubMed

    Campos, Joaquín M; Sánchez-Martín, Rosario M; Cruz-López, Olga; Conejo-García, Ana; Gallo, Miguel A; Espinosa, Antonio

    2005-12-01

    1H and 13C NMR spectroscopic data of both the quinolinium ring and the spacers for 32 symmetrical bisquinolinium compounds were assigned by a combination of one- and two-dimensional experiments (DEPT, HMBC, HMQC). The compounds have electron-releasing groups at position 4 of the quinolinium ring, with several arylalkyl linkers such as the 3,3'-, 4,4'-bis(methylene)biphenyl and 4,4'-bis(methylene)bibenzyl moieties. PMID:16114103

  8. Application of 1H-NMR metabolomic profiling for reef-building corals.

    PubMed

    Sogin, Emilia M; Anderson, Paul; Williams, Philip; Chen, Chii-Shiarng; Gates, Ruth D

    2014-01-01

    In light of global reef decline new methods to accurately, cheaply, and quickly evaluate coral metabolic states are needed to assess reef health. Metabolomic profiling can describe the response of individuals to disturbance (i.e., shifts in environmental conditions) across biological models and is a powerful approach for characterizing and comparing coral metabolism. For the first time, we assess the utility of a proton-nuclear magnetic resonance spectroscopy (1H-NMR)-based metabolomics approach in characterizing coral metabolite profiles by 1) investigating technical, intra-, and inter-sample variation, 2) evaluating the ability to recover targeted metabolite spikes, and 3) assessing the potential for this method to differentiate among coral species. Our results indicate 1H-NMR profiling of Porites compressa corals is highly reproducible and exhibits low levels of variability within and among colonies. The spiking experiments validate the sensitivity of our methods and showcase the capacity of orthogonal partial least squares discriminate analysis (OPLS-DA) to distinguish between profiles spiked with varying metabolite concentrations (0 mM, 0.1 mM, and 10 mM). Finally, 1H-NMR metabolomics coupled with OPLS-DA, revealed species-specific patterns in metabolite profiles among four reef-building corals (Pocillopora damicornis, Porites lobata, Montipora aequituberculata, and Seriatopora hystrix). Collectively, these data indicate that 1H-NMR metabolomic techniques can profile reef-building coral metabolomes and have the potential to provide an integrated picture of the coral phenotype in response to environmental change. PMID:25354140

  9. Application of 1H-NMR Metabolomic Profiling for Reef-Building Corals

    PubMed Central

    Sogin, Emilia M.; Anderson, Paul; Williams, Philip; Chen, Chii-Shiarng; Gates, Ruth D.

    2014-01-01

    In light of global reef decline new methods to accurately, cheaply, and quickly evaluate coral metabolic states are needed to assess reef health. Metabolomic profiling can describe the response of individuals to disturbance (i.e., shifts in environmental conditions) across biological models and is a powerful approach for characterizing and comparing coral metabolism. For the first time, we assess the utility of a proton-nuclear magnetic resonance spectroscopy (1H-NMR)-based metabolomics approach in characterizing coral metabolite profiles by 1) investigating technical, intra-, and inter-sample variation, 2) evaluating the ability to recover targeted metabolite spikes, and 3) assessing the potential for this method to differentiate among coral species. Our results indicate 1H-NMR profiling of Porites compressa corals is highly reproducible and exhibits low levels of variability within and among colonies. The spiking experiments validate the sensitivity of our methods and showcase the capacity of orthogonal partial least squares discriminate analysis (OPLS-DA) to distinguish between profiles spiked with varying metabolite concentrations (0 mM, 0.1 mM, and 10 mM). Finally, 1H-NMR metabolomics coupled with OPLS-DA, revealed species-specific patterns in metabolite profiles among four reef-building corals (Pocillopora damicornis, Porites lobata, Montipora aequituberculata, and Seriatopora hystrix). Collectively, these data indicate that 1H-NMR metabolomic techniques can profile reef-building coral metabolomes and have the potential to provide an integrated picture of the coral phenotype in response to environmental change. PMID:25354140

  10. Parallel NMR spectroscopy with simultaneous detection of (1) H and (19) F nuclei.

    PubMed

    Kovacs, Helena; Kupče, Ēriks

    2016-07-01

    Recording NMR signals of several nuclear species simultaneously by using parallel receivers provides more information from a single measurement and at the same time increases the measurement sensitivity per unit time. Here we present a comprehensive series of the most frequently used NMR experiments modified for simultaneous direct detection of two of the most sensitive NMR nuclei - (1) H and (19) F. We hope that the presented material will stimulate interest in and further development of this technique. PMID:27021630

  11. High remission rate in T-cell prolymphocytic leukemia with CAMPATH-1H.

    PubMed

    Dearden, C E; Matutes, E; Cazin, B; Tjønnfjord, G E; Parreira, A; Nomdedeu, B; Leoni, P; Clark, F J; Radia, D; Rassam, S M; Roques, T; Ketterer, N; Brito-Babapulle, V; Dyer, M J; Catovsky, D

    2001-09-15

    T-cell prolymphocytic leukemia (T-PLL) is a chemotherapy-resistant malignancy with a median survival of 7.5 months. Preliminary results indicated a high remission induction rate with the human CD52 antibody, CAMPATH-1H. This study reports results in 39 patients with T-PLL treated with CAMPATH-1H between March 1993 and May 2000. All but 2 patients had received prior therapy with a variety of agents, including 30 with pentostatin; none achieved complete remission (CR). CAMPATH-1H (30 mg) was administered intravenously 3 times weekly until maximal response. The overall response rate was 76% with 60% CR and 16% partial remission (PR). These responses were durable with a median disease-free interval of 7 months (range, 4-45 months). Survival was significantly prolonged in patients achieving CR compared to PR or no response (NR), including one patient who survived 54 months. Nine patients remain alive up to 29 months after completing therapy. Seven patients received high-dose therapy with autologous stem cell support, 3 of whom remain alive in CR 5, 7, and 15 months after autograft. Stem cell harvests in these patients were uncontaminated with T-PLL cells as demonstrated by dual-color flow cytometry and polymerase chain reaction. Four patients had allogeneic stem cell transplants, 3 from siblings and 1 from a matched unrelated donor. Two had nonmyeloablative conditioning. Three are alive in CR up to 24 months after allograft. The conclusion is that CAMPATH-1H is an effective therapy in T-PLL, producing remissions in more than two thirds of patients. The use of stem cell transplantation to consolidate responses merits further study. PMID:11535503

  12. Resolution enhancement in spectra of natural products dissolved in weakly orienting media with the help of 1H homonuclear dipolar decoupling during acquisition: Application to 1H- 13C dipolar couplings measurements

    NASA Astrophysics Data System (ADS)

    Farjon, Jonathan; Bermel, Wolfgang; Griesinger, Christian

    2006-05-01

    In weakly orienting media such as poly-γ-benzyl- L-glutamate (PBLG) a polymer that forms a chiral liquid crystal in organic solvents, the spectral resolution for embedded molecules is usually poor because of numerous 1H, 1H dipolar couplings that generally broaden proton spectra. Therefore 1H, 13C dipolar couplings are difficult or impossible to measure. Here, we incorporate Flip-Flop decoupling during detection into an HSQC experiment. Flip-Flop removes the 1H, 1H dipolar couplings and scales the chemical shifts of the protons as well as the 1H, 13C dipolar couplings during detection. A resolution gain by a factor 1.5-4.2 and improved signal intensity by an average factor of 1.6-1.7 have been obtained. This technique is demonstrated on (+)-menthol dissolved in a PBLG/CDCl 3 phase.

  13. An efficient spectra processing method for metabolite identification from 1H-NMR metabolomics data.

    PubMed

    Jacob, Daniel; Deborde, Catherine; Moing, Annick

    2013-06-01

    The spectra processing step is crucial in metabolomics approaches, especially for proton NMR metabolomics profiling. During this step, noise reduction, baseline correction, peak alignment and reduction of the 1D (1)H-NMR spectral data are required in order to allow biological information to be highlighted through further statistical analyses. Above all, data reduction (binning or bucketing) strongly impacts subsequent statistical data analysis and potential biomarker discovery. Here, we propose an efficient spectra processing method which also provides helpful support for compound identification using a new data reduction algorithm that produces relevant variables, called buckets. These buckets are the result of the extraction of all relevant peaks contained in the complex mixture spectra, rid of any non-significant signal. Taking advantage of the concentration variability of each compound in a series of samples and based on significant correlations that link these buckets together into clusters, the method further proposes automatic assignment of metabolites by matching these clusters with the spectra of reference compounds from the Human Metabolome Database or a home-made database. This new method is applied to a set of simulated (1)H-NMR spectra to determine the effect of some processing parameters and, as a proof of concept, to a tomato (1)H-NMR dataset to test its ability to recover the fruit extract compositions. The implementation code for both clustering and matching steps is available upon request to the corresponding author. PMID:23525538

  14. Non-invasive detection of cocaine dissolved in wine bottles by (1) H magnetic resonance spectroscopy.

    PubMed

    Gambarota, Giulio; Perazzolo, Chiara; Leimgruber, Antoine; Meuli, Reto; Mangin, Patrice; Augsburger, Marc; Grabherr, Silke

    2011-09-01

    Recently, a number of cases of smuggling dissolved cocaine in wine bottles have been reported. The aim of the present study was to determine whether cocaine dissolved in wine can be detected by proton magnetic resonance spectroscopy ((1) H MRS) on a standard clinical MR scanner, in intact (i.e. unopened) wine bottles. (1) H MRS experiments were performed with a 3 Tesla clinical scanner on wine phantoms with or without cocaine contamination. The aromatic protons of cocaine displayed resonance peaks in the 7-8 ppm region of the spectrum, where no overlapping resonances of wine were present. Additional cocaine resonances were detected in the 2-3 ppm region of the spectrum, between the resonances of ethanol and other wine constituents. Detection of cocaine in wine (at 5 mM, i.e. ∼1.5 g/L) was feasible in a scan time of 1 min. We conclude that dissolved cocaine can be detected in intact wine bottles, on a standard clinical MR scanner. Thus, (1) H MRS is the technique of choice to examine this type of suspicious cargo, since it allows for a non-destructive and rapid content characterization. PMID:20886462

  15. A Comprehensive Review of the 1H-MRS Metabolite Spectrum in Autism Spectrum Disorder

    PubMed Central

    Ford, Talitha C.; Crewther, David P.

    2016-01-01

    Neuroimaging studies of neuropsychiatric behavior biomarkers across spectrum disorders are typically based on diagnosis, thus failing to account for the heterogeneity of multi-dimensional spectrum disorders such as autism (ASD). Control group trait phenotypes are also seldom reported. Proton magnetic resonance spectroscopy (1H-MRS) measures the abundance of neurochemicals such as neurotransmitters and metabolites and hence can probe disorder phenotypes at clinical and sub-clinical levels. This detailed review summarizes and critiques the current 1H-MRS research in ASD. The literature reports reduced N-acetylaspartate (NAA), glutamate and glutamine (Glx), γ-aminobutyric acid (GABA), creatine and choline, and increased glutamate for children with ASD. Adult studies are few and results are inconclusive. Overall, the literature has several limitations arising from differences in 1H-MRS methodology and sample demographics. We argue that more consistent methods and greater emphasis on phenotype studies will advance understanding of underlying cortical metabolite disturbance in ASD, and the detection, diagnosis, and treatment of ASD and other multi-dimensional psychiatric disorders. PMID:27013964

  16. {sup 1}H NMR spectroscopic studies establish that heparanase is a retaining glycosidase

    SciTech Connect

    Wilson, Jennifer C.; Laloo, Andrew Elohim; Singh, Sanjesh; Ferro, Vito

    2014-01-03

    Highlights: •{sup 1}H and {sup 13}C NMR chemical shifts of fondaparinux were fully assigned by 1D and 2D NMR techniques. •Hydrolysis of fondaparinux by heparanase was monitored by {sup 1}H NMR spectroscopy. •Heparanase is established to be a retaining glycosidase. -- Abstract: Heparanase is an endo-β-glucuronidase that cleaves heparan sulfate side chains of proteoglycans in basement membranes and the extracellular matrix (ECM). Heparanase is implicated in several diverse pathological processes associated with ECM degradation such as metastasis, inflammation and angiogenesis and is thus an important target for anti-cancer and anti-inflammatory drug discovery. Heparanase has been classed as belonging to the clan A glycoside hydrolase family 79 based on sequence analysis, secondary structure predictions and mutagenic analysis, and thus it has been inferred that it is a retaining glycosidase. However, there has been no direct experimental evidence to support this conclusion. Herein we describe {sup 1}H NMR spectroscopic studies of the hydrolysis of the pentasaccharide substrate fondaparinux by heparanase, and provide conclusive evidence that heparanase hydrolyses its substrate with retention of configuration and is thus established as a retaining glycosidase. Knowledge of the mechanism of hydrolysis may have implications for future design of inhibitors for this important drug target.

  17. Improved analysis of 1H-MR spectra in the presence of mobile lipids.

    PubMed

    Auer, D P; Gössl, C; Schirmer, T; Czisch, M

    2001-09-01

    Focal brain lesions can be associated with proton magnetic resonance spectra (1H-MRS)-detectable mobile lipids, reflecting severe tissue degradation and necrosis. However, advanced fitting procedures, such as the LCModel, fail to adequately fit spectra in the presence of lipid resonances. To overcome this, different approaches to generate lipid model spectra were compared using a phantom, real in vivo data, and simulated data. Twenty-six in vivo short-echo time (TE) 1H-MRS from 21 malignant gliomas, four infections, and one ischemia were analyzed to evaluate the performance of the modified LCModel fit. Adding simulated aliphatic resonances at 1.3 and 0.9 ppm improved the overall fitting quality remarkably and allowed good separation of lactate and alanine. Also, a better differentiation of glioblastomas and anaplastic gliomas was achieved. In conclusion, we propose a simple way to efficiently include lipid resonances in the LCModel, allowing a better fit of in vivo short-TE 1H-MRS, and demonstrate the diagnostic potential of quantitative assessment of mobile lipids in brain tumors. PMID:11550257

  18. 1H relaxation enhancement induced by nanoparticles in solutions: influence of magnetic properties and diffusion.

    PubMed

    Kruk, D; Korpała, A; Taheri, S Mehdizadeh; Kozłowski, A; Förster, S; Rössler, E A

    2014-05-01

    Magnetic nanoparticles that induce nuclear relaxation are the most promising materials to enhance the sensitivity in Magnetic Resonance Imaging. In order to provide a comprehensive understanding of the magnetic field dependence of the relaxation enhancement in solutions, Nuclear Magnetic Resonance (1)H spin-lattice relaxation for decalin and toluene solutions of various Fe2O3 nanoparticles was investigated. The relaxation experiments were performed in a frequency range of 10 kHz-20 MHz by applying Field Cycling method, and in the temperature range of 257-298 K, using nanoparticles differing in size and shape: spherical--5 nm diameter, cubic--6.5 nm diameter, and cubic--9 nm diameter. The relaxation dispersion data were interpreted in terms of a theory of nuclear relaxation induced by magnetic crystals in solution. The approach was tested with respect to its applicability depending on the magnetic characteristics of the nanocrystals and the time-scale of translational diffusion of the solvent. The role of Curie relaxation and the contributions to the overall (1)H spin-lattice relaxation associated with the electronic spin-lattice and spin-spin relaxation was thoroughly discussed. It was demonstrated that the approach leads to consistent results providing information on the magnetic (electronic) properties of the nanocrystals, i.e., effective electron spin and relaxation times. In addition, features of the (1)H spin-lattice relaxation resulting from the electronic properties of the crystals and the solvent diffusion were explained. PMID:24811643

  19. Serum metabolic signature of minimal hepatic encephalopathy by (1)H-nuclear magnetic resonance.

    PubMed

    Jiménez, Beatriz; Montoliu, Carmina; MacIntyre, David A; Serra, Miguel A; Wassel, Abdallah; Jover, María; Romero-Gomez, Manuel; Rodrigo, Jose M; Pineda-Lucena, Antonio; Felipo, Vicente

    2010-10-01

    Minimal hepatic encephalopathy (MHE) reduces quality of life of cirrhotic patients, predicts overt hepatic encephalopathy, and is associated with poor prognosis. We hypothesized that MHE arises once metabolic alterations derived from the liver reach a particular threshold. Our aim was to assess whether metabolic profiling of serum samples by high-field (1)H-nuclear magnetic resonance spectroscopy ((1)H NMR) and subsequent multivariate analyses would be useful to characterize metabolic perturbations associated with MHE and to identify potential metabolic biomarkers. Metabolic serum profiles from controls (n = 69) and cirrhotic patients without MHE (n = 62) and with MHE (n = 39) were acquired using high field NMR. Supervised modeling of the data provided perfect discrimination between healthy controls and cirrhotic patients and allowed the generation of a predictive model displaying strong discrimination between patients with and without MHE (R(2)Y = 0.68, Q(2)Y = 0.63). MHE patients displayed increased serum concentrations of glucose, lactate, methionine, TMAO, and glycerol, as well as decreased levels of choline, branch amino acids, alanine, glycine, acetoacetate, NAC, and lipid moieties. Serum metabonomics by (1)H NMR offers a useful approach for characterizing underlying metabolic differences between patients with and without MHE. This procedure shows great potential as a diagnostic tool of MHE as it objectively reflects measurable biochemical differences between the patient groups and may facilitate monitoring of both disease progression and effects of therapeutic treatments. PMID:20690770

  20. A Comprehensive Review of the (1)H-MRS Metabolite Spectrum in Autism Spectrum Disorder.

    PubMed

    Ford, Talitha C; Crewther, David P

    2016-01-01

    Neuroimaging studies of neuropsychiatric behavior biomarkers across spectrum disorders are typically based on diagnosis, thus failing to account for the heterogeneity of multi-dimensional spectrum disorders such as autism (ASD). Control group trait phenotypes are also seldom reported. Proton magnetic resonance spectroscopy ((1)H-MRS) measures the abundance of neurochemicals such as neurotransmitters and metabolites and hence can probe disorder phenotypes at clinical and sub-clinical levels. This detailed review summarizes and critiques the current (1)H-MRS research in ASD. The literature reports reduced N-acetylaspartate (NAA), glutamate and glutamine (Glx), γ-aminobutyric acid (GABA), creatine and choline, and increased glutamate for children with ASD. Adult studies are few and results are inconclusive. Overall, the literature has several limitations arising from differences in (1)H-MRS methodology and sample demographics. We argue that more consistent methods and greater emphasis on phenotype studies will advance understanding of underlying cortical metabolite disturbance in ASD, and the detection, diagnosis, and treatment of ASD and other multi-dimensional psychiatric disorders. PMID:27013964

  1. Effect of biological factors on successful measurements with skeletal-muscle 1H-MRS

    PubMed Central

    Isobe, Tomonori; Okamoto, Yoshikazu; Hirano, Yuji; Ando, Hiroki; Takada, Kenta; Sato, Eisuke; Shinoda, Kazuya; Tadano, Kiichi; Takei, Hideyuki; Kamizawa, Satoshi; Mori, Yutaro; Suzuki, Hiroaki

    2016-01-01

    Background Our purpose in this study was to clarify whether differences in subject group attributes could affect data acquisition in proton magnetic resonance spectroscopy (1H-MRS). Methods Subjects without diabetes mellitus (DM) were divided into two groups (group A, in their 20s; group B, 30–60 years old). Subjects with DM formed group C (30–60 years old). The numbers of subjects were 19, 27, and 22 for group A, B, and C respectively. For all subjects, 1H-MRS measurements were taken of the soleus muscle (SOL) and the anterior tibial muscle (AT). We defined the success of the measurements by the detection of intramyocellular lipids. Moreover, we also measured the full width at half maximum of the water peaks for all subjects. Results The success rate was significantly higher for the AT (100%) than for the SOL (81.6%) (P<0.01). For the SOL, the success rate was 100% in group A, 85.2% in group B, and 77.3% in group C. There was a significant difference (P<0.05) between groups A and B, as well as between groups A and C. In all subjects, there was a significant difference (P<0.01) in the full width at half maximum (Hz) of the water peak between the AT and SOL measurements. Conclusion We conclude that differences in the age and DM history of subjects could affect the probability of successful 1H-MRS data acquisition. PMID:27499626

  2. Anti-Toxoplasma Activity of 2-(Naphthalene-2-γlthiol)-1H Indole

    PubMed Central

    ASGARI, Qasem; KESHAVARZ, Hossein; REZAEIAN, Mostafa; SADEGHPOUR, Hossein; MIRI, Ramin; MOTAZEDIAN, Mohammad Hossein

    2015-01-01

    Background: This study was undertaken to evaluate the viability, infectivity and immunity of Toxoplasma gondii tachyzoites exposed to 2-(naphthalene-2-ylthio)-1H-indole. Methods: Tachyzoites of RH strain were incubated in various concentrations of 2-(naphthalene-2-ylthio)-1H-indole (25–800 μM) for 1.5 hours. Then, they were stained by PI and analyzed by Fluorescence-activated cell sorting (FACS). To evaluate the infectivity, the tachyzoites exposed to the different concentrations of the compound were inoculated to 10 BALB/c mice groups. For Control, parasites exposed to DMSO (0.2% v/v) were also intraperitoneally inoculated into two groups of mice. The immunity of the exposed tachyzoites was evaluated by inoculation of the naïve parasite to the survived mice. Results: The LD50 of 2-(naphthalene-2-ylthio)-1H-indole was 57 μmol. The longevity of mice was dose dependent. Five mice out of group 400μmol and 3 out of group 800μmol showed immunization to the parasite. Conclusion: Our findings demonstrated the toxoplasmocidal activity of the compound. The presence of a well-organized transporter mechanism for indole compounds within the parasite in conjunction with several effective mechanisms of these compounds on Toxoplasma viability would open a window for production of new drugs and vaccines. PMID:26246814

  3. Clinical Relevance of Single-Voxel 1H MRS Metabolites in Discriminating Suprasellar Tumors

    PubMed Central

    Virani, Rahul A

    2016-01-01

    Introdution Spatially resolved metabolic data obtained from Proton Magnetic Resonance Spectroscopy (1H MRS) provides information which increases the diagnostic accuracy of imaging sequences in predicting the histology of suprasellar tumors. Aim To evaluate the role of 1H MRS in the diagnosis of various suprasellar tumors. Materials and Methods Sixty cases of various suprasellar, hypothalamic and third ventricular neoplasms were investigated with long-echo single voxel 1H -MRS using 1.5 Tesla clinical imager. Single-voxel spectroscopic examinations were guided by T1-weighted or T2-weighted images. Statistical analysis was carried out using IBM SPSS software version 19. Results We observed that whenever brain tissue was damaged or replaced by any process, NAA was markedly reduced. Extra-axial lesions which do not infiltrate brain or contain neuroglial tissue, didn’t demonstrate any NAA resonances. Cr was used as an internal standard for semi-quantitative evaluation of metabolic changes of other brain metabolites. Increased Cho was seen in processes with elevated cell-membrane turnover. Conclusion Spectra obtained from different tumors exhibit reproducible differences while histologically similar tumors yield characteristic spectra with only minor differences. Pituitary tumors were typically characterized by significant reduction of NAA, Cr peak and moderate elevation of Cho peak. Gliomas were typically characterized by decrease of NAA and Cr peaks and increase of Cho peak. Craniopharyngiomas were typically characterized by significant decrease of all metabolites.

  4. A 1H NMR assay for measuring the photostationary States of photoswitchable ligands.

    PubMed

    Banghart, Matthew R; Trauner, Dirk

    2013-01-01

    Incorporation of photoisomerizable chromophores into small molecule ligands represents a general approach for reversibly controlling protein function with light. Illumination at different wavelengths produces photostationary states (PSSs) consisting of different ratios of photoisomers. Thus optimal implementation of photoswitchable ligands requires knowledge of their wavelength sensitivity. Using an azobenzene-based ion channel blocker as an example, this protocol describes a (1)H NMR assay that can be used to precisely determine the isomeric content of photostationary states (PSSs) as a function of illumination wavelength. Samples of the photoswitchable ligand are dissolved in deuterated water and analyzed by UV/VIS spectroscopy to identify the range of illumination wavelengths that produce PSSs. The PSSs produced by these wavelengths are quantified using (1)H NMR spectroscopy under continuous irradiation through a monochromator-coupled fiber-optic cable. Because aromatic protons of azobenzene trans and cis isomers exhibit sufficiently different chemical shifts, their relative abundances at each PSS can be readily determined by peak integration. Constant illumination during spectrum acquisition is essential to accurately determine PSSs from molecules that thermally relax on the timescale of minutes or faster. This general protocol can be readily applied to any photoswitch that exhibits distinct (1)H NMR signals in each photoisomeric state. PMID:23494375

  5. Mechanochemical and solution synthesis, X-ray structure and IR and 31P solid state NMR spectroscopic studies of copper(I) thiocyanate adducts with bulky monodentate tertiary phosphine ligands.

    PubMed

    Bowmaker, Graham A; Hanna, John V; Hart, Robert D; Healy, Peter C; King, Scott P; Marchetti, Fabio; Pettinari, Claudio; Skelton, Brian W; Tabacaru, Aurel; White, Allan H

    2012-07-01

    A number of adducts of copper(I) thiocyanate with bulky tertiary phosphine ligands, and some nitrogen-base solvates, were synthesized and structurally and spectroscopically characterised. CuSCN:PCy3 (1:2), as crystallized from pyridine, is shown by a single crystal X-ray study to be a one-dimensional polymer ...(Cy3P)2CuSCN(Cy3P)2CuSCN... (1) with the four-coordinate copper atoms linked end-on by S-SCN-N bridging thiocyanate groups. A second form (2), obtained from acetonitrile, was also identified and shown by IR and 31P CPMAS NMR spectroscopy to be mononuclear, with the magnitude of the dν(Cu) parameter measured from the 31P CPMAS and the ν(CN) value from the IR clearly establishing this compound as three-coordinate [(Cy3P)2CuNCS]. Two further CuSCN/PCy3 compounds CuSCN:PCy3 (1:1) (3), and CuSCN:PCy3:py (1:1:1) (4) were also characterized spectroscopically, with the dν(Cu) parameters indicating three- and four-coordinate copper sites, respectively. Attempts to obtain a 1:2 adduct with tri-t-butylphosphine have yielded, from pyridine, the 1:1 adduct as a dimer [(Bu(t)3P)((SCN)(NCS))Cu(PBu(t)3)] (5), while similar attempts with tri-o-tolylphosphine (from acetonitrile and pyridine (= L)) resulted in solvated 1:1:1 CuSCN:P(o-tol)3:L forms as dimeric [{(o-tol)3P}LCu((SCN)(NCS))CuL{P(o-tol)3}] (6 and 8). The solvent-free 1:1 CuSCN:P(o-tol)3 adduct (7), obtained by desolvation of 6, was characterized spectroscopically and dν(Cu) measurements from the 31P CPMAS NMR data are consistent with the decrease in coordination number of the copper atom from four (for 6) (P,N(MeCN)Cu,S,N) to three (for 7) (PCuS,N) upon loss of the acetonitrile of solvation. These results are compared with those previously reported for mononuclear and binuclear PPh3 adducts which demonstrate a clear tendency for the copper centre to remain four-coordinate. The IR spectroscopic measurements on these compounds show that bands in the far-IR spectra provide a much more definitive criterion for

  6. Mechanistic Assessment of PD-1H Coinhibitory Receptor-Induced T-Cell Tolerance to Allogeneic Antigens1

    PubMed Central

    Flies, Dallas B.; Higuchi, Tomoe; Chen, Lieping

    2015-01-01

    PD-1H is a recently identified cell surface co-inhibitory molecule of the B7/CD28 immune modulatory gene family. We showed previously that single injection of a PD-1H agonistic monoclonal antibody (mAb) protected mice from graft versus host disease (GVHD). We report here two distinct mechanisms operate in PD-1H-induced T cell tolerance. First, signaling via PD-1H co-inhibitory receptor potently arrests allo-reactive donor T cells from activation and expansion in the initiation phase. Second, donor regulatory T cells are subsequently expanded to maintain long-term tolerance and GVHD suppression. Our study reveals the crucial function of PD-1H as a co-inhibitory receptor on allo-reactive T cells and its function in the regulation of T cell tolerance. Therefore, PD-1H may be a target for the modulation of allo-reactive T cells in GVHD and transplantation. PMID:25917101

  7. Electrochemical lithiation/delithiation of SnP2O7 observed by in situ XRD and ex situ(7)Li/(31)P NMR, and (119)Sn Mössbauer spectroscopy.

    PubMed

    Bezza, Ilham; Kaus, Maximilian; Riekehr, Lars; Pfaffmann, Lukas; Doyle, Stephen; Indris, Sylvio; Ehrenberg, Helmut; Solhy, Abderrahim; Saadoune, Ismael

    2016-04-21

    SnP2O7 was prepared by a sol-gel route. The structural changes of tin pyrophosphate during the electrochemical lithiation were followed by using in situ XRD measurements that reveal the existence of a crystalline phase at the beginning of the discharge process. Nevertheless, it becomes amorphous after the full discharge as a result of a conversion reaction leading to the formation of LixSny alloys. The electrochemical tests show a high capacity with high retention upon cycling. To better understand the reaction mechanism of SnP2O7 with Li, several techniques were applied, such as ex situ(119)Sn Mössbauer and ex situ(7)Li and (31)P NMR spectroscopies with which we can follow the changes in the local environment of each element during cycling. PMID:27029601

  8. Localization of two X-linked mental retardation (XLMR) genes to Xp: MRX37 gene at Xp22.31-p22.32 and a putative MRX gene on Xp22.11-p22.2

    SciTech Connect

    Bar-David, S.; Lerer, I.; Sarfaty, C.K.

    1996-07-12

    MRX genes of 2 families with X-linked mental retardation (XLMR) were localized by linkage analysis. In family A, the gene was mapped to Xp22.31-p22.32, with significant LOD scores to various Xp22 markers within a distance of 6 Mb between DXS1223 and DXS1224. The MRX gene of this family was designated MRX37. In a mentally retarded female who is a carrier of the MRX37 gene, a random pattern of X inactivation was demonstrated. In family B, a positive LOD score, although not significant (<+2), was found with the marker DXS1202 at Xp22.11-p22.2. 15 refs., 4 figs., 2 tabs.

  9. 31P MAS-NMR study of flux-grown rare-earth element orthophosphate (monazite/xenotime) solid solutions: Evidence of random cation distribution from paramagnetically shifted NMR resonances

    SciTech Connect

    Palke, A. C.; Stebbins, J. F.; Boatner, Lynn A

    2013-01-01

    We present 31P magic angle spinning nuclear magnetic resonance (MAS-NMR) spectra of flux-grown solid solutions of La1-xCexPO4 ( x between 0.027 and 0.32) having the monoclinic monazite structure, and of Y1-xMxPO4 (M = Vn+, Ce3+, Nd3+, x between 0.001 and 0.014) having the tetragonal zircon structure. Paramagnetically shifted NMR resonances are observed in all samples due to the presence of paramagnetic Vn+, Ce3+, and Nd3+ in the diamagnetic LaPO4 or YPO4. As a first-order observation, the number and relative intensity of these peaks is related to the symmetry and structure of the diamagnetic host phase. The presence of paramagnetic shifts allows for increased resolution between NMR resonances for distinct atomic species which leads to the observation of low intensity peaks related to PO4 species having more than one paramagnetic neighbor two or four atomic bonds away. Through careful analysis of peak areas and comparison with predictions for simple models, it was determined that solid solutions in the systems examined here are characterized by complete disorder (random distribution) of diamagnetic La3+ or Y3+ with the paramagnetic substitutional species Ce3+ and Nd3+. The increased resolution given by the paramagnetic interactions also leads to the observation of splitting of specific resonances in the 31P NMR spectra that may be caused by local, small-scale distortions from the substitution of ions having dissimilar ionic radii.

  10. 31P magic angle spinning NMR study of flux-grown rare-earth element orthophosphate (monazite/xenotime) solid solutions: evidence of random cation distribution from paramagnetically shifted NMR resonances.

    PubMed

    Palke, Aaron C; Stebbins, Jonathan F; Boatner, Lynn A

    2013-11-01

    We present (31)P magic angle spinning nuclear magnetic resonance spectra of flux-grown solid solutions of La(1-x)Ce(x)PO4 (x between 0.027 and 0.32) having the monoclinic monazite structure, and of Y(1-x)M(x)PO4 (M = V(n+), Ce(3+), Nd(3+), x between 0.001 and 0.014) having the tetragonal zircon structure. Paramagnetically shifted NMR resonances are observed in all samples due to the presence of paramagnetic V(n+), Ce(3+), and Nd(3+) in the diamagnetic LaPO4 or YPO4. As a first-order observation, the number and relative intensities of these peaks are related to the symmetry and structure of the diamagnetic host phase. The presence of paramagnetic shifts allows for increased resolution between NMR resonances for distinct atomic species which leads to the observation of low intensity peaks related to PO4 species having more than one paramagnetic neighbor two or four atomic bonds away. Through careful analysis of peak areas and comparison with predictions for simple models, it was determined that solid solutions in the systems examined here are characterized by complete disorder (random distribution) of diamagnetic La(3+) or Y(3+) with the paramagnetic substitutional species Ce(3+) and Nd(3+). The increased resolution given by the paramagnetic interactions also leads to the observation of splitting of specific resonances in the (31)P NMR spectra that may be caused by local, small-scale distortions from the substitution of ions having dissimilar ionic radii. PMID:24131129

  11. The Effect of a C-Terminal Peptide of Surfactant Protein B (SP-B) on Oriented Lipid Bilayers, Characterized by Solid-State 2H- and 31P-NMR

    PubMed Central

    Yang, Tran-Chin; McDonald, Mark; Morrow, Michael R.; Booth, Valerie

    2009-01-01

    SP-BCTERM, a cationic, helical peptide based on the essential lung surfactant protein B (SP-B), retains a significant fraction of the function of the full-length protein. Solid-state 2H- and 31P-NMR were used to examine the effects of SP-BCTERM on mechanically oriented lipid bilayer samples. SP-BCTERM modified the multilayer structure of bilayers composed of POPC, POPG, POPC/POPG, or bovine lipid extract surfactant (BLES), even at relatively low peptide concentrations. The 31P spectra of BLES, which contains ∼1% SP-B, and POPC/POPG with 1% SP-BCTERM, look very similar, supporting a similarity in lipid interactions of SP-BCTERM and its parent protein, full-length SP-B. In the model systems, although the peptide interacted with both the oriented and unoriented fractions of the lipids, it interacted differently with the two fractions, as demonstrated by differences in lipid headgroup structure induced by the peptide. On the other hand, although SP-BCTERM induced similar disruptions in overall bilayer orientation in BLES, there was no evidence of lipid headgroup conformational changes in either the oriented or the unoriented fractions of the BLES samples. Notably, in the model lipid systems the peptide did not induce the formation of small, rapidly tumbling lipid structures, such as micelles, or of hexagonal phases, the observation of which would have provided support for functional mechanisms involving peptide-induced lipid flip-flop or stabilization of curved lipid structures, respectively. PMID:19413982

  12. 1H and 13C resonance designation of antimycin A1 by two-dimensional NMR spectroscopy

    USGS Publications Warehouse

    Abidi, S.L.; Adams, B.R.

    1987-01-01

    Complete 1H and 13C resonance assignments of antimycin A1 were accomplished by two-dimensional NMR techniques, viz. 1H homonuclear COSY correlation, heteronuclear 13C-1H chemical shift correlation and long-range heteronuclear 13C-1H COLOC correlation. Antimycin A1 was found to consist of two isomeric components in a 2:1 ratio based on NMR spectroscopic evidence. The structure of the major component was newly assigned as the 8-isopentanoic acid ester. The spectra of the minor component were consistent with the known structure of antimycin A1.

  13. Identification of Metastasis-Associated Metabolic Profiles of Tumors by (1)H-HR-MAS-MRS.

    PubMed

    Gorad, Saurabh S; Ellingsen, Christine; Bathen, Tone F; Mathiesen, Berit S; Moestue, Siver A; Rofstad, Einar K

    2015-10-01

    Tumors develop an abnormal microenvironment during growth, and similar to the metastatic phenotype, the metabolic phenotype of cancer cells is tightly linked to characteristics of the tumor microenvironment (TME). In this study, we explored relationships between metabolic profile, metastatic propensity, and hypoxia in experimental tumors in an attempt to identify metastasis-associated metabolic profiles. Two human melanoma xenograft lines (A-07, R-18) showing different TMEs were used as cancer models. Metabolic profile was assessed by proton high resolution magic angle spinning magnetic resonance spectroscopy ((1)H-HR-MAS-MRS). Tumor hypoxia was detected in immunostained histological preparations by using pimonidazole as a hypoxia marker. Twenty-four samples from 10 A-07 tumors and 28 samples from 10 R-18 tumors were analyzed. Metastasis was associated with hypoxia in both A-07 and R-18 tumors, and (1)H-HR-MAS-MRS discriminated between tissue samples with and tissue samples without hypoxic regions in both models, primarily because hypoxia was associated with high lactate resonance peaks in A-07 tumors and with low lactate resonance peaks in R-18 tumors. Similarly, metastatic and non-metastatic R-18 tumors showed significantly different metabolic profiles, but not metastatic and non-metastatic A-07 tumors, probably because some samples from the metastatic A-07 tumors were derived from tumor regions without hypoxic tissue. This study suggests that (1)H-HR-MAS-MRS may be a valuable tool for evaluating the role of hypoxia and lactate in tumor metastasis as well as for identification of metastasis-associated metabolic profiles. PMID:26585232

  14. {sup 1}H relaxation enhancement induced by nanoparticles in solutions: Influence of magnetic properties and diffusion

    SciTech Connect

    Kruk, D.; Korpała, A.; Taheri, S. Mehdizadeh; Förster, S.; Kozłowski, A.; Rössler, E. A.

    2014-05-07

    Magnetic nanoparticles that induce nuclear relaxation are the most promising materials to enhance the sensitivity in Magnetic Resonance Imaging. In order to provide a comprehensive understanding of the magnetic field dependence of the relaxation enhancement in solutions, Nuclear Magnetic Resonance {sup 1}H spin-lattice relaxation for decalin and toluene solutions of various Fe{sub 2}O{sub 3} nanoparticles was investigated. The relaxation experiments were performed in a frequency range of 10 kHz–20 MHz by applying Field Cycling method, and in the temperature range of 257–298 K, using nanoparticles differing in size and shape: spherical – 5 nm diameter, cubic – 6.5 nm diameter, and cubic – 9 nm diameter. The relaxation dispersion data were interpreted in terms of a theory of nuclear relaxation induced by magnetic crystals in solution. The approach was tested with respect to its applicability depending on the magnetic characteristics of the nanocrystals and the time-scale of translational diffusion of the solvent. The role of Curie relaxation and the contributions to the overall {sup 1}H spin-lattice relaxation associated with the electronic spin-lattice and spin-spin relaxation was thoroughly discussed. It was demonstrated that the approach leads to consistent results providing information on the magnetic (electronic) properties of the nanocrystals, i.e., effective electron spin and relaxation times. In addition, features of the {sup 1}H spin-lattice relaxation resulting from the electronic properties of the crystals and the solvent diffusion were explained.

  15. MfERG waveform characteristics in the RS1h mouse model featuring a 'negative' ERG.

    PubMed

    Seeliger, Mathias W; Weber, Bernhard H F; Besch, Dorothea; Zrenner, Eberhard; Schrewe, Heinrich; Mayser, Helmut

    2003-07-01

    Several retinal disorders lead to a relatively greater attenuation of the b-wave compared to the a-wave of the electroretinogram (ERG), a constellation called 'negative' ERG. To determine the waveform characteristics of multifocal ERGs (mfERGs) and their dependence on recording parameters in such a case, we studied the Rs1h(-/Y) mouse, the model for x-linked juvenile retinoschisis. mfERGs were recorded with a VERIS 4 system connected to a piggyback stimulator prototype that added the stimulus to the optical pathway of a HRA scanning-laser ophthalmoscope (SLO) by means of a wavelength-sensitive mirror. Real-time fundus visualization was achieved with the infrared laser of the SLO (835 nm). High-pass filter settings and the time interval used by the 'artefact removal' feature were varied to study their influence on the waveform. The mfERG in the Rs1h(-/Y) mouse had a 'negative' shape. However, the high-pass filter setting had to be lowered from the usual 10 Hz down to about 2 Hz in order to obtain that result, otherwise the negative shape was lost and mainly a positive peak remained. Similarly, a short time interval used by the 'artefact removal' feature also removed the negative shape. The Rs1h(-/Y) mouse was found to be a valuable model of diseases with a 'negative' waveform shape also in mfERG. Our results underline the importance of a lower high-pass filter cutoff frequency when recording mfERGs in such disorders. In addition, if the 'artefact removal' feature is used, it should be verified that it doesn't distort the waveform shape. PMID:12906120

  16. Identifying metabolites related to nitrogen mineralisation using 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    . T McDonald, Noeleen; Graham, Stewart; Watson, Catherine; Gordon, Alan; Lalor, Stan; Laughlin, Ronnie; Elliott, Chris; . P Wall, David

    2015-04-01

    Exploring new analysis techniques to enhance our knowledge of the various metabolites within our soil systems is imperative. Principally, this knowledge would allow us to link key metabolites with functional influences on critical nutrient processes, such as the nitrogen (N) mineralisation in soils. Currently there are few studies that utilize proton nuclear magnetic resonance spectroscopy (1H NMR) to characterize multiple metabolites within a soil sample. The aim of this research study was to examine the effectiveness of 1H NMR for isolating multiple metabolites that are related to the mineralizable N (MN) capacity across a range of 35 Irish grassland soils. Soils were measured for MN using the standard seven day anaerobic incubation (AI-7). Additionally, soils were also analysed for a range of physio-chemical properties [e.g. total N, total C, mineral N, texture and soil organic matter (SOM)]. Proton NMR analysis was carried on these soils by extracting with 40% methanol:water, lyophilizing and reconstituting in deuterium oxide and recording the NMR spectra on a 400MHz Bruker AVANCE III spectrometer. Once the NMR data were spectrally processed and analysed using multivariate statistical analysis, seven metabolites were identified as having significant relationships with MN (glucose, trimethylamine, glutamic acid, serine, aspartic acid, 4-aminohippuirc acid and citric acid). Following quantification, glucose was shown to explain the largest percentage variability in MN (72%). These outcomes suggest that sources of labile carbon are essential in regulating N mineralisation and the capacity of plant available N derived from SOM-N pools in these soils. Although, smaller in concentration, the amino acids; 4-aminohippuirc acid, glutamic acid and serine also significantly (P<0.05) explained 43%, 27% and 19% of the variability in MN, respectively. This novel study highlights the effectiveness of using 1H NMR as a practical approach to profile multiple metabolites in

  17. Advanced Fuel Cycle Initiative AFC-1D, AFC-1G and AFC-1H Irradiation Report

    SciTech Connect

    Debra J. Utterbeck; Gray Chang

    2005-09-01

    The U. S. Advanced Fuel Cycle Initiative (AFCI) seeks to develop and demonstrate the technologies needed to transmute the long-lived transuranic actinide isotopes contained in spent nuclear fuel into shorter-lived fission products, thereby dramatically decreasing the volume of material requiring disposition and the long-term radiotoxity and heat load of high-level waste sent to a geologic repository. The AFC-1 irradiation experiments on transmutation fuels are expected to provide irradiation performance data on non-fertile and low-fertile fuel forms specifically, irradiation growth and swelling, helium production, fission gas release, fission product and fuel constituent migration, fuel phase equilibria, and fuel-cladding chemical interaction. Contained in this report are the to-date physics evaluations performed on three of the AFC-1 experiments; AFC-1D, AFC-1G and AFC-1H. The AFC-1D irradiation experiment consists of metallic non-fertile fuel compositions with minor actinides for potential use in accelerator driven systems and AFC-1G and AFC-1H irradiation experiments are part of the fast neutron reactor fuel development effort. These experiments are high burnup analogs to previously irradiated experiments and are to be irradiated to = 20 atom % burnup. Results of the evaluations show that AFC-1D will remain in the ATR for approximately 100 additional effective full power days (EFPDs), and AFC-1G and AFC-1H for approximately 300 additional EFPDs in order to reach the desired programmatic burnup. The specific irradiation schedule for these tests will be determined based on future physics evaluations and all results will be documented in subsequent reports.

  18. Preparation of the UNDERC 200 MHz /sup 1/H NMR spectral catalog, Volume II

    SciTech Connect

    Gaides, G.E.; Farnum, S.A.; Wolfson, A.C.; Farnum, B.W.

    1984-01-01

    High resolution 200 MHz /sup 1/H NMR is used extensively to identify the components of complex low-rank coal-derived materials. We have compiled a catalog of 302 spectra of standards: (1) and are compiling a second, similar volume of 125 additional spectra. Many of these new compounds have only recently become available from commercial suppliers, or by synthesis. Like the previous catalog, Volume II is divided into two sections: a tabular section of all the compounds with their correct names, structure, and a line list of the chemical shifts, and a section which contains the actual spectra. Each section is arranged by functional group, for example, alkanes, phenols, etc. in order of their chromatographic elution. There is also an appendix which lists the suppliers of all the compounds in the catalog. Volume II contains several features not incorporated in the original catalog. We have added an alphabetical listing of all the compounds in both NMR catalogs, as well as formula and molecular weight indices. An added feature of this volume is the expanded coverage of nitrogen-containing compounds. Though there are many /sup 1/H NMR spectral catalogs in print, there are none that contain spectra run on 200 MHz spectrometers. Many spectra that appear complex at 60 MHz become first order at 200 MHz, facilitating their interpretation. At the UNDERC the majority of our samples are extremely complex mixtures. The simplification of the spectra of the individual components is necessary to characterize these coal-derived liquids. Another advantage of /sup 1/H NMR spectra run at 200 MHz is the greater than eleven-fold increase in sensitivity over those run at 60 MHz (2). Smaller, or more dilute samples may therefore be utilized. 2 references, 1 figure.

  19. 1H NMR structure of the heme pocket of HNO-myoglobin.

    PubMed

    Sulc, Filip; Fleischer, Everly; Farmer, Patrick J; Ma, Dejian; La Mar, Gerd N

    2003-02-01

    The unique (1)H NMR signal of nitrosyl hydride at 14.8 ppm is used to obtain a solution structure of the distal pocket of Mb-HNO, a rare nitroxyl adduct with a half-life of several months at room temperature. (1)H NMR, NOESY and TOCSY data were obtained under identical experimental conditions on solutions of the diamagnetic HNO and CO complexes of equine Mb, allowing direct comparison of NMR data to a crystallographically characterized structure. Twenty NOEs between the nitrosyl hydride and protein and heme-based signals were observed. The HNO orientation obtained by modeling the experimental (1)H NMR NOESY data yielded an orientation of ca. -104 degrees referenced to the N-Fe-N vector between alpha and beta mesoprotons. An essentially identical orientation was obtained by simple energy minimization of the HNO adduct using ESFF potentials, suggesting steric control of the orientation. Differences in chemical shifts are seen for protons on residues Phe43(CD1) and Val68(E11), but both exhibit virtually identical NOESY contacts to other residues, and thus are attributed to small movements of ca. 0.1 A within the strong ring current. The most significant differences are seen in the NOESY peak intensities and chemical shifts for the ring non-labile protons of the distal His64(E7). The orientation of the His64(E7) in Mb-HNO was analyzed on the basis of the NOESY cross-peak changes and chemical shift changes, predicting a ca. 20 degrees rotation about the beta-gamma bond. The deduced HNO and His64(E7) orientations result in geometry where the His64(E7) ring can serve as the donor for a significant H-bond to the oxygen atom of the bound HNO. PMID:12589571

  20. Co(III)-Carbene Radical Approach to Substituted 1H-Indenes.

    PubMed

    Das, Braja Gopal; Chirila, Andrei; Tromp, Moniek; Reek, Joost N H; Bruin, Bas de

    2016-07-20

    A new strategy for the catalytic synthesis of substituted 1H-indenes via metalloradical activation of o-cinnamyl N-tosyl hydrazones is presented, taking advantage of the intrinsic reactivity of a Co(III) carbene radical intermediate. The reaction uses readily available starting materials and is operationally simple, thus representing a practical method for the construction of functionalized 1H-indene derivatives. The cheap and easy to prepare low spin cobalt(II) complex [Co(II)(MeTAA)] (MeTAA = tetramethyltetraaza[14]annulene) proved to be the most active catalyst among those investigated, which demonstrates catalytic carbene radical reactivity for a nonporphyrin cobalt(II) complex, and for the first time catalytic activity of [Co(II)(MeTAA)] in general. The methodology has been successfully applied to a broad range of substrates, producing 1H-indenes in good to excellent yields. The metallo-radical catalyzed indene synthesis in this paper represents a unique example of a net (formal) intramolecular carbene insertion reaction into a vinylic C(sp(2))-H bond, made possible by a controlled radical ring-closure process of the carbene radical intermediate involved. The mechanism was investigated computationally, and the results were confirmed by a series of supporting experimental reactions. Density functional theory calculations reveal a stepwise process involving activation of the diazo compound leading to formation of a Co(III)-carbene radical, followed by radical ring-closure to produce an indanyl/benzyl radical intermediate. Subsequent indene product elimination involving a 1,2-hydrogen transfer step regenerates the catalyst. Trapping experiments using 2,2,6,6-tetra-methylpiperidine-1-oxyl (TEMPO) radical or dibenzoylperoxide (DBPO) confirm the involvement of cobalt(III) carbene radical intermediates. Electron paramagnetic resonance spectroscopic spin-trapping experiments using phenyl N-tert-butylnitrone (PBN) reveal the radical nature of the reaction. PMID

  1. Experimental design and environmental parameters affect Rhodospirillum rubrum S1H response to space flight.

    PubMed

    Mastroleo, Felice; Van Houdt, Rob; Leroy, Baptiste; Benotmane, M Abderrafi; Janssen, Ann; Mergeay, Max; Vanhavere, Filip; Hendrickx, Larissa; Wattiez, Ruddy; Leys, Natalie

    2009-12-01

    In view of long-haul space exploration missions, the European Space Agency initiated the Micro-Ecological Life Support System Alternative (MELiSSA) project targeting the total recycling of organic waste produced by the astronauts into oxygen, water and food using a loop of bacterial and higher plant bioreactors. In that purpose, the alpha-proteobacterium, Rhodospirillum rubrum S1H, was sent twice to the International Space Station and was analyzed post-flight using a newly developed R. rubrum whole genome oligonucleotide microarray and high throughput gel-free proteomics with Isotope-Coded Protein Label technology. Moreover, in an effort to identify a specific response of R. rubrum S1H to space flight, simulation of microgravity and space-ionizing radiation were performed on Earth under identical culture set-up and growth conditions as encountered during the actual space journeys. Transcriptomic and proteomic data were integrated and permitted to put forward the importance of medium composition and culture set-up on the response of the bacterium to space flight-related environmental conditions. In addition, we showed for the first time that a low dose of ionizing radiation (2 mGy) can induce a significant response at the transcriptomic level, although no change in cell viability and only a few significant differentially expressed proteins were observed. From the MELiSSA perspective, we could argue the effect of microgravity to be minimized, whereas R. rubrum S1H could be more sensitive to ionizing radiation during long-term space exploration mission. PMID:19571896

  2. Identification of fucans from four species of sea cucumber by high temperature 1H NMR

    NASA Astrophysics Data System (ADS)

    Wu, Nian; Chen, Shiguo; Ye, Xingqian; Li, Guoyun; Yin, Li'ang; Xue, Changhu

    2014-10-01

    Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei ( Pg) from Indo-Pacific, Holothuria vagabunda ( Hv) from Norwegian Coast, Stichopus tremulu ( St) from Western Indian Ocean, and Isostichopus badionotu ( Ib) from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans (SC-Fucs). The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer (NMR) and room temperature 13C NMR. The results indicated that Fuc- Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc- Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc- St from the frigid zone and Fuc- Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.

  3. (1)H MRS: a potential biomarker of in utero placental function.

    PubMed

    Macnaught, Gillian; Gray, Calum; Walker, Jane; Simpson, Mary; Norman, Jane; Semple, Scott; Denison, Fiona

    2015-10-01

    The placenta is a temporary organ that is essential for a healthy pregnancy. It performs several important functions, including the transport of nutrients, the removal of waste products and the metabolism of certain substances. Placental disorders have been found to account for over 50% of stillbirths. Despite this, there are currently no methods available to directly and non-invasively assess placental function in utero. The primary aim of this pilot study was to investigate the use of (1)H MRS for this purpose. (1)H MRS offers the possibility to detect several placental metabolites, including choline, lipids and the amino acids glutamine and glutamate (Glx), which are vital to fetal development and placental function. Here, in utero placental spectra were acquired from nine small for gestational age (SGA) pregnancies, a cohort who are at increased risk of perinatal morbidity and mortality, and from nine healthy gestation-matched pregnancies. All subjects were between 26 and 39 weeks of gestation. Placenta Glx, choline and lipids at 1.3 and 0.9 ppm were quantified as amplitude ratios to that of intrinsic H2O. Wilcoxon signed rank tests indicated a significant difference in Glx/H2O (p = 0.024) between the two groups, but not in choline/H2O (p = 0.722) or in either lipid/H2O ratio (1.3 ppm, p = 0.813; 0.9 ppm, p = 0.058). This study has demonstrated that (1)H MRS has potential for the detection of placental metabolites in utero. This warrants further investigation as a tool for the monitoring of placental function. PMID:26313636

  4. Crystal structure of 2-methyl-1H-imidazol-3-ium hydrogen oxalate dihydrate.

    PubMed

    Diop, Mouhamadou Birame; Diop, Libasse; Plasseraud, Laurent; Cattey, Hélène

    2016-08-01

    Single crystals of the title mol-ecular salt, C4H7N2 (+)·HC2O4 (-)·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N-H⋯(O,O) hydrogen bonds. The water mol-ecules of crystallization link the chains into (10-1) bilayers, with the methyl groups of the cations organized in an isotactic manner. PMID:27536393

  5. In vivo localized 1H NMR spectroscopy at 11.7 Tesla

    NASA Astrophysics Data System (ADS)

    Crozier, Stuart; Field, James; Brereton, Ian M.; Moxon, Leith N.; Shannon, Gerald F.; Doddrell, David M.

    The SPACE volume-selection technique has been used to acquire high-resolution 1H spectra from the brain of neonate mice at 11.7 T (500 MHz). Spectra were acquired from voxels smaller than 20 μl. The spectra display elevated intensities of resonances arising from taurine and reduced intensities of those arising from N-acetylaspartate, when compared to those of mature animals, correlating well with in vitro studies. An integrated probe design consisting of separate transmission and reception RF coils and linear gradient coils is described. Comments are made concerning the advantages and disadvantages of performing gradient-encoded localized spectroscopy at this field strength.

  6. Determination of metabolite profiles in tropical wines by 1H NMR spectroscopy and chemometrics.

    PubMed

    da Silva Neto, Humberto G; da Silva, João B P; Pereira, Giuliano E; Hallwass, Fernando

    2009-12-01

    Traditionally, wines are produced in temperate climate zones, with one harvest per year. Tropical wines are a new concept of vitiviniculture that is being developed, principally in Brazil. The new Brazilian frontier is located in the northeast region (São Francisco River Valley) in Pernambuco State, close to the equator, between 8 and 9 degrees S. Compared with other Brazilian and worldwide vineyards, the grapes of this region possess peculiar characteristics. The aim of this work is a preliminary study of commercial São Francisco River Valley wines, analyzing their metabolite profiles by (1)H NMR and chemometric methods. PMID:19810052

  7. 1H NMR investigation of self-association of vanillin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Bogdan, Mircea; Floare, Calin G.; Pîrnau, Adrian

    2009-08-01

    A self-association of vanillin have been studied by 1H NMR spectroscopy using the analysis of proton chemical shifts changes in aqueous solution as a function of concentration. The experimental results have been analysed using indefinite non-cooperative and cooperative models of molecular self-association, enabling the determination of equilibrium constants, parameters of cooperativity and the limiting values of vanillin proton chemical shifts in the complex. It was found that the dimer formation creates energetically favourable conditions for subsequent molecular association.

  8. Cucurbitacins from Cayaponia racemosa: isolation and total assignment of 1H and 13C NMR spectra.

    PubMed

    Chaves, Davina C; Assunção, João Carlos C; Braz-Filho, Raimundo; Lemos, Telma L G; Monte, Francisco J Q

    2007-05-01

    Two new cucurbitane-type triterpenoids, 2beta,3beta,16alpha,20(R),25-pentahydroxy-9-methyl-19-norlanost-5-en-7,22-dione and 2beta,3beta,16alpha,20(R),25-pentahydroxy-9-methyl-19-norlanost-5-en-7,11,22-trione, were isolated from fruits of Cayaponia racemosa. The total (1)H and (13)C chemical shift assignment of these two closely related compounds is described, making use of one- and two-dimensional NMR techniques. PMID:17372957

  9. Identification of Gastric Cancer Biomarkers Using 1H Nuclear Magnetic Resonance Spectrometry.

    PubMed

    Ramachandran, Gokula Krishnan; Yong, Wei Peng; Yeow, Chen Hua

    2016-01-01

    Existing gastric cancer diagnosing methods were invasive, hence, a reliable non-invasive gastric cancer diagnosing method is needed. As a starting point, we used 1H NMR for identifying gastric cancer biomarkers using a panel of gastric cancer spheroids and normal gastric spheroids. We were able to identify 8 chemical shift biomarkers for gastric cancer spheroids. Our data suggests that the cancerous and non-cancerous spheroids significantly differ in the lipid composition and energy metabolism. These results encourage the translation of these biomarkers into in-vivo gastric cancer detection methodology using MRI-MS. PMID:27611679

  10. {sup 1}H nuclear magnetic resonance study of hydrated water dynamics in perfluorosulfonic acid ionomer Nafion

    SciTech Connect

    Han, Jun Hee; Lee, Kyu Won; Jeon, G. W.; Lee, Cheol Eui; Park, W. K.; Choi, E. H.

    2015-01-12

    We have studied the dynamics of hydrated water molecules in the proton exchange membrane of Nafion by means of high-resolution {sup 1}H nuclear magnetic resonance (NMR) measurements. “Bound” and “free” states of hydrated water clusters as well as the exchange protons were identified from the NMR chemical shift measurements, and their activation energies were obtained from the temperature-dependent laboratory- and rotating-frame spin-lattice relaxation measurements. Besides, a peculiar motional transition in the ultralow frequency region was observed at 373 K for the “free” hydrated water from the rotating-frame NMR spin-lattice relaxation time measurements.

  11. Determination of the delta(2H/1H)of Water: RSIL Lab Code 1574

    USGS Publications Warehouse

    Revesz, Kinga; Coplen, Tyler B.

    2008-01-01

    Reston Stable Isotope Laboratory (RSIL) lab code 1574 describes a method used to determine the relative hydrogen isotope-ratio delta(2H,1H), abbreviated hereafter as d2H of water. The d2H measurement of water also is a component of the National Water Quality Laboratory (NWQL) schedules 1142 and 1172. The water is collected unfiltered in a 60-mL glass bottle and capped with a Polyseal cap. In the laboratory, the water sample is equilibrated with gaseous hydrogen using a platinum catalyst (Horita, 1988; Horita and others, 1989; Coplen and others, 1991). The reaction for the exchange of one hydrogen atom is shown in equation 1.

  12. 1H nuclear magnetic resonance study of distinct interstitial hydrogen dynamics in ZnO

    NASA Astrophysics Data System (ADS)

    Kue Park, Jun; Won Lee, Kyu; Eui Lee, Cheol

    2013-07-01

    A comprehensive 1H nuclear magnetic resonance (NMR) study has been carried out for hydrogen dynamics in a sol-gel-prepared ZnO system. The temperature-dependent linewidth and chemical shift measurements sensitively reflected the proton motions and changes in the local environment. Besides, two types of interstitial proton (Hi+) motions were distinguished from the spin-spin relaxation time measurements, one of them with an activation energy of 0.16 eV and the other with that of 0.33 eV depending on the temperature ranges.

  13. 3-Acetyl-5-phenyl-1-p-tolyl-1H-pyrazole-4-carbonitrile

    PubMed Central

    Abdel-Aziz, Hatem A.; Ghabbour, Hazem A.; Chantrapromma, Suchada; Fun, Hoong-Kun

    2012-01-01

    In the title pyrazole derivative, C19H15N3O, the central pyrazole ring makes dihedral angles of 42.71 (9) and 61.34 (9)°, respectively, with the phenyl and p-tolyl rings. The dihedral angle between the phenyl and p-tolyl rings is 58.22 (9)°. The 3-acetyl-1H-pyrazole-4-carbonitrile unit is essentially planar, with an r.m.s. deviation of 0.0295 (1) Å for the ten non-H atoms. PMID:22606111

  14. Crystal structure of 2-methyl-1H-imidazol-3-ium hydrogen oxalate dihydrate

    PubMed Central

    Diop, Mouhamadou Birame; Diop, Libasse; Plasseraud, Laurent; Cattey, Hélène

    2016-01-01

    Single crystals of the title mol­ecular salt, C4H7N2 +·HC2O4 −·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N—H⋯(O,O) hydrogen bonds. The water mol­ecules of crystallization link the chains into (10-1) bilayers, with the methyl groups of the cations organized in an isotactic manner. PMID:27536393

  15. 1H-NMR study of the spin dynamics of fine superparamagnetic nanoparticles

    SciTech Connect

    Bordonali, L.; Furukawa, Y.; Kraken, M.; Litterst, F.J.; Sangregorio, C.; Casula, M.F.; Lascialfari, A.

    2012-05-25

    We report a broadband 1H-NMR study of the temperature spin dynamics of nearly monodisperse dextran-coated γ-Fe2O3 magnetic nanoparticles. We observed a maximum in T1−1(T) that decreases in amplitude and shifts toward higher temperatures with increasing field. We suggest that this is related to the progressive superparamagnetic spin blocking of the ferrite core. The data can be explained by assuming a single electronic spin-spin correlation time and introducing a field-dependent distribution of anisotropy energy barriers.

  16. Simultaneous 19F-1H medium resolution NMR spectroscopy for online reaction monitoring

    NASA Astrophysics Data System (ADS)

    Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Kraume, Matthias; Guthausen, Gisela; Maiwald, Michael

    2014-12-01

    Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions. Within this study, a simple 1/16″ fluorinated ethylene propylene (FEP) tube with an ID of 0.04″ (1.02 mm) was used as a flow cell in combination with a 5 mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a 1H Larmor frequency of 43.32 MHz and 40.68 MHz for 19F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating 19F and 1H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500 MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra. Finally, the performance of 1/16″ FEP tube set-up with an ID of 1.02 mm was characterised regarding the limit of detection (LOQ (1H) = 0.335 mol L-1 and LOQ (19F) = 0.130 mol L-1 for trifluoroethanol in

  17. Development of tricyclic hydroxy-1H-pyrrolopyridine-trione containing HIV-1 integrase inhibitors.

    PubMed

    Zhao, Xue Zhi; Maddali, Kasthuraiah; Metifiot, Mathieu; Smith, Steven J; Vu, B Christie; Marchand, Christophe; Hughes, Stephen H; Pommier, Yves; Burke, Terrence R

    2011-05-15

    New tricyclic HIV-1 integrase (IN) inhibitors were prepared that combined structural features of bicyclic pyrimidinones with recently disclosed 4,5-dihydroxy-1H-isoindole-1,3(2H)-diones. This combination resulted in the introduction of a nitrogen into the aryl ring and the addition of a fused third ring to our previously described inhibitors. The resulting analogues showed low micromolar inhibitory potency in in vitro HIV-1 integrase assays, with good selectivity for strand transfer relative to 3'-processing. PMID:21493066

  18. Polymorphism of HF (beta 1H-globulin) in three Asian populations (Bangladeshis, Tibetans and Indonesians).

    PubMed

    Kido, Akira; Susukida, Rie; Oya, Masakazu; Fujitani, Noboru; Kimura, Hiroshi; Hara, Masaaki

    2003-03-01

    The polymorphism of HF (beta 1H-globulin) was investigated in three Asian populations (Bangladeshis, Tibetans and Indonesians) by means of isoelectric focusing and immunoblotting. Phenotypes associated with three common alleles (HF*A, HF*B and HF*Q0) and a rare allele HF*A1 were identified. The observed numbers of phenotypes were in accordance with the numbers expected under the Hardy-Weinberg equilibrium. HF*A1 seems to be a unique allele of the East-Asian Mongoloids including Tibetans and Indonesians. PMID:12712773

  19. 4-Amino-1H-1,2,4-triazol-1-ium nitrate

    PubMed Central

    Matulková, Irena; Císařová, Ivana; Němec, Ivan

    2011-01-01

    The non-centrosymmetric crystal structure of the novel semi-organic title compound, C2H5N4 +·NO3 −, is based on alternating layers of 4-amino-1H-1,2,4-triazolinium cations (formed by parallel chains of cations mediated by weak C—H⋯N hydrogen bonds) and nitrate anions inter­connected via linear and bifurcated N—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds. N—H⋯N hydrogen bonds link the anions and cations. PMID:21522685

  20. V/STOL AND digital avionics system for UH-1H

    NASA Technical Reports Server (NTRS)

    Liden, S.

    1978-01-01

    A hardware and software system for the Bell UH-1H helicopter was developed that provides sophisticated navigation, guidance, control, display, and data acquisition capabilities for performing terminal area navigation, guidance and control research. Two Sperry 1819B general purpose digital computers were used. One contains the development software that performs all the specified system flight computations. The second computer is available to NASA for experimental programs that run simultaneously with the other computer programs and which may, at the push of a button, replace selected computer computations. Other features that provide research flexibility include keyboard selectable gains and parameters and software generated alphanumeric and CRT displays.

  1. A possible detection of Jupiter's northern auroral S1(1) H2 quadrupole line emission

    NASA Technical Reports Server (NTRS)

    Trafton, L.; Carr, J.; Lester, D.; Harvey, P.

    1988-01-01

    An upper limit is presently determined for the mean intensity of the Jupiter northern Auroral UV/thermal hot spot's S1(1) H2 quadrupole emission, over an 8 sq arcsec illuminated beam; the value obtained is 4.2 X 10 to the -6th W/sq m per sr. It is suggested that the nonradiative deexitation of the H2 molecules via collisions with H may have been underestimated by Kim and Maguire (1986), due to uncertainties concerning auroral H density.

  2. Functional integrals and 1/h expansion in the boson-fermion model

    NASA Astrophysics Data System (ADS)

    Yan, Jun

    2016-06-01

    The effective action of boson-fermion model is derived by means of the functional integrals method and Popov-Faddeev canonical transformations. The energy gap equation and excitation spectrum equation are obtained from first order and second order perturbation expansions of functional determinant. In the long wave approximation, some analytical expressions of excitation spectrum are calculated by using the 1/h expansion technique, the results showed that analytical calculation is in good agreement with the numerical calculation. Moreover, the Nambu sum rules of Higgs bosons are analyzed and discussed.

  3. Simultaneous (19)F-(1)H medium resolution NMR spectroscopy for online reaction monitoring.

    PubMed

    Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Kraume, Matthias; Guthausen, Gisela; Maiwald, Michael

    2014-10-18

    Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions. Within this study, a simple 1/16″ fluorinated ethylene propylene (FEP) tube with an ID of 0.04″ (1.02mm) was used as a flow cell in combination with a 5mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a (1)H Larmor frequency of 43.32MHz and 40.68MHz for (19)F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating (19)F and (1)H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra. Finally, the performance of 1/16″ FEP tube set-up with an ID of 1.02mm was characterised regarding the limit of detection (LOQ ((1)H)=0.335molL(-1) and LOQ ((19)F)=0.130molL(-1) for trifluoroethanol

  4. Investigation of the exclusive 3He(e,e' pn)1H reaction.

    PubMed

    Middleton, D G; Annand, J R M; Antelo, M Ases; Ayerbe, C; Barneo, P; Baumann, D; Bermuth, J; Bernauer, J; Blok, H P; Böhm, R; Bosnar, D; Ding, M; Distler, M O; Friedrich, J; Llongo, J García; Glazier, D I; Golak, J; Glöckle, W; Grabmayr, P; Hehl, T; Heim, J; Hesselink, W H A; Jans, E; Kamada, H; Mañas, G Jover; Kohl, M; Lapikás, L; MacGregor, I J D; Martin, I; McGeorge, J C; Merkel, H; Merle, P; Monstad, K; Moschini, F; Müller, U; Nogga, A; Pérez-Benito, R; Pospischil, Th; Potokar, M; Rosner, G; Seimetz, M; Skibiński, R; de Vries, H; Walcher, Th; Watts, D P; Weinriefer, M; Weiss, M; Witała, H; Zihlmann, B

    2009-10-01

    Cross sections for the 3He(e,e' pn)1H reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming smaller at higher recoil proton momentum. PMID:19905628

  5. An improved technique for the 2H/1H analysis of urines from diabetic volunteers

    USGS Publications Warehouse

    Coplen, T.B.; Harper, I.T.

    1994-01-01

    The H2-H2O ambient-temperature equilibration technique for the determination of 2H/1H ratios in urinary waters from diabetic subjects provides improved accuracy over the conventional Zn reduction technique. The standard deviation, ~ 1-2???, is at least a factor of three better than that of the Zn reduction technique on urinary waters from diabetic volunteers. Experiments with pure water and solutions containing glucose, urea and albumen indicate that there is no measurable bias in the hydrogen equilibration technique.The H2-H2O ambient-temperature equilibration technique for the determination of 2H/1H ratios in urinary waters from diabetic subjects provides improved accuracy over the conventional Zn reduction technique. The standard deviation, approximately 1-2%, is at least a factor of three better than that of the Zn reduction technique on urinary waters from diabetic volunteers. Experiments with pure water and solutions containing glucose, urea and albumen indicate that there is no measurable bias in the hydrogen equilibration technique.

  6. Strategies for rapid in vivo 1H and hyperpolarized 13C MR spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Nelson, Sarah J.; Ozhinsky, Eugene; Li, Yan; Park, Il woo; Crane, Jason

    2013-04-01

    In vivo MRSI is an important imaging modality that has been shown in numerous research studies to give biologically relevant information for assessing the underlying mechanisms of disease and for monitoring response to therapy. The increasing availability of high field scanners and multichannel radiofrequency coils has provided the opportunity to acquire in vivo data with significant improvements in sensitivity and signal to noise ratio. These capabilities may be used to shorten acquisition time and provide increased coverage. The ability to acquire rapid, volumetric MRSI data is critical for examining heterogeneity in metabolic profiles and for relating serial changes in metabolism within the same individual during the course of the disease. In this review we discuss the implementation of strategies that use alternative k-space sampling trajectories and parallel imaging methods in order to speed up data acquisition. The impact of such methods is demonstrated using three recent examples of how these methods have been applied. These are to the acquisition of robust 3D 1H MRSI data within 5-10 min at a field strength of 3 T, to obtaining higher sensitivity for 1H MRSI at 7 T and to using ultrafast volumetric and dynamic 13C MRSI for monitoring the changes in signals that occur following the injection of hyperpolarized 13C agents.

  7. Strategies for rapid in vivo 1H and hyperpolarized 13C MR spectroscopic imaging.

    PubMed

    Nelson, Sarah J; Ozhinsky, Eugene; Li, Yan; Park, Il woo; Crane, Jason

    2013-04-01

    In vivo MRSI is an important imaging modality that has been shown in numerous research studies to give biologically relevant information for assessing the underlying mechanisms of disease and for monitoring response to therapy. The increasing availability of high field scanners and multichannel radiofrequency coils has provided the opportunity to acquire in vivo data with significant improvements in sensitivity and signal to noise ratio. These capabilities may be used to shorten acquisition time and provide increased coverage. The ability to acquire rapid, volumetric MRSI data is critical for examining heterogeneity in metabolic profiles and for relating serial changes in metabolism within the same individual during the course of the disease. In this review we discuss the implementation of strategies that use alternative k-space sampling trajectories and parallel imaging methods in order to speed up data acquisition. The impact of such methods is demonstrated using three recent examples of how these methods have been applied. These are to the acquisition of robust 3D (1)H MRSI data within 5-10 min at a field strength of 3 T, to obtaining higher sensitivity for (1)H MRSI at 7 T and to using ultrafast volumetric and dynamic (13)C MRSI for monitoring the changes in signals that occur following the injection of hyperpolarized (13)C agents. PMID:23453759

  8. Investigating brain metabolism at high fields using localized 13C NMR spectroscopy without 1H decoupling.

    PubMed

    Deelchand, Dinesh Kumar; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2006-02-01

    Most in vivo 13C NMR spectroscopy studies in the brain have been performed using 1H decoupling during acquisition. Decoupling imposes significant constraints on the experimental setup (particularly for human studies at high magnetic field) in order to stay within safety limits for power deposition. We show here that incorporation of the 13C label from 13C-labeled glucose into brain amino acids can be monitored accurately using localized 13C NMR spectroscopy without the application of 1H decoupling. Using LCModel quantification with prior knowledge of one-bond and multiple-bond J(CH) coupling constants, the uncertainty on metabolites concentrations was only 35% to 91% higher (depending on the carbon resonance of interest) in undecoupled spectra compared to decoupled spectra in the rat brain at 9.4 Tesla. Although less sensitive, 13C NMR without decoupling dramatically reduces experimental constraints on coil setup and pulse sequence design required to keep power deposition within safety guidelines. This opens the prospect of safely measuring 13C NMR spectra in humans at varied brain locations (not only the occipital lobe) and at very high magnetic fields above 4 Tesla. PMID:16345037

  9. Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

    PubMed Central

    2013-01-01

    Background Biodiesel production has increased dramatically over the last decade, raising the need for new rapid and non-destructive analytical tools and technologies. 1H Low Field Nuclear Magnetic Resonance (LF-NMR) applications, which offer great potential to the field of biodiesel, have been developed by the Phyto Lipid Biotechnology Lab research team in the last few years. Results Supervised and un-supervised chemometric tools are suggested for screening new alternative biodiesel feedstocks according to oil content and viscosity. The tools allowed assignment into viscosity groups of biodiesel-petrodiesel samples whose viscosity is unknown, and uncovered biodiesel samples that have residues of unreacted acylglycerol and/or methanol, and poorly separated and cleaned glycerol and water. In the case of composite materials, relaxation time distribution, and cross-correlation methods were successfully applied to differentiate components. Continuous distributed methods were also applied to calculate the yield of the transesterification reaction, and thus monitor the progress of the common and in-situ transesterification reactions, offering a tool for optimization of reaction parameters. Conclusions Comprehensive applied tools are detailed for the characterization of new alternative biodiesel resources in their whole conformation, monitoring of the biodiesel transesterification reaction, and quality evaluation of the final product, using a non-invasive and non-destructive technology that is new to the biodiesel research area. A new integrated computational-experimental approach for analysis of 1H LF-NMR relaxometry data is also presented, suggesting improved solution stability and peak resolution. PMID:23590829

  10. Effect of Exercise on the Creatine Resonances in 1H MR Spectra of Human Skeletal Muscle

    NASA Astrophysics Data System (ADS)

    Kreis, R.; Jung, B.; Slotboom, J.; Felblinger, J.; Boesch, C.

    1999-04-01

    1H MR spectra of human muscles were recorded before, during, and after fatiguing exercise. In contrast to expectations, it was found that the spectral contributions of creatine/phosphocreatine (Cr/PCr) were subject to change as a function of exercise. In particular, the dipolar-coupled methylene protons of Cr/PCr were found to be reduced in intensity in proportion to the co-registered PCr levels. Recovery after exercise and behavior under ischemic conditions provide further evidence to suggest that the contributions of the CH2protons of Cr/PCr to1H MR spectra of human musclein vivoreflect PCr rather than Cr levels. Variation of experimental parameters showed that this effect is not due to a trivial change in relaxation times. At present it can only be speculated about why the Cr resonances have reduced NMR visibility. If temporary binding to macromolecules should be involved, the free Cr concentration-important for equilibrium calculations of the creatine kinase reaction-might be different from what was previously assumed.

  11. Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy.

    PubMed

    Jakes, W; Gerdova, A; Defernez, M; Watson, A D; McCallum, C; Limer, E; Colquhoun, I J; Williamson, D C; Kemsley, E K

    2015-05-15

    This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz (1)H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional "authentic" beef region (p=0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze-thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz (1)H NMR represents a feasible high-throughput approach for screening raw meat. PMID:25577043

  12. Metabolic characterization of natural and cultured Ophicordyceps sinensis from different origins by 1H NMR spectroscopy.

    PubMed

    Zhang, Jianshuang; Zhong, Xin; Li, Shaosong; Zhang, Guren; Liu, Xin

    2015-11-10

    Ophicordyceps sinensis is a well-known traditional Chinese medicine and cultured mycelium is a substitute for wild O. sinensis. Metabolic profiles of wild O. sinensis from three geographical locations and cultivated mycelia derived from three origins were investigated using (1)H nuclear magnetic resonance (NMR) analysis combined with multivariate statistical analysis. A total of 56 primary metabolites were identified and quantified from O. sinensis samples. The principle component analysis (PCA) showed significant differences between natural O. sinensis and fermentation mycelia. Seven metabolites responsible for differentiation were screened out by orthogonal partial least squares discriminant analysis (OPLS-DA). The concentrations of mannitol, trehalose, arginine, trans-4-hydroxyproline, alanine and glucitol were significantly different between wild and cultured groups. The variation in metabolic profiling among artificial mycelia was greater than that among wild O. sinensis. Furthermore, wild samples from different origins were clearly distinguished by the levels of mannitol, trehalose and some amino acids. This study indicates that (1)H NMR-based metabolomics is useful for fingerprinting and discriminating O. sinensis of different geographical regions and cultivated mycelia of different strains. The present study provided an efficient approach for investigating chemical compositions and evaluating the quality of medicine and health food derived from O. sinensis. PMID:26279370

  13. High-resolution magic angle spinning 1H MRS in prostate cancer.

    PubMed

    Decelle, Emily A; Cheng, Leo L

    2014-01-01

    Prostate cancer (PCa) is the most frequently diagnosed malignancy in men worldwide, largely as a result of the increased use of the annual serum prostate-specific antigen (PSA) screening test for detection. PSA screening has saved lives, but it has also resulted in the overtreatment of many patients with PCa because of a limited ability to accurately localize and characterize PCa lesions through imaging. High-resolution magic angle spinning (HRMAS) (1)H MRS has proven to be a strong potential clinical tool for PCa diagnosis and prognosis. The HRMAS technique allows valuable metabolic information to be obtained from ex vivo intact tissue samples and also enables the performance of histopathology on the same tissue specimens. Studies have found that the quantification of individual metabolite levels and metabolite ratios, as well as metabolomic profiles, shows strong potential to improve accuracy in PCa detection, diagnosis and monitoring. Ex vivo HRMAS is also a valuable tool for the interpretation of in vivo results, including the localization of tumors, and thus has the potential to improve in vivo diagnostic tests used in the clinic. Here, we primarily review publications of HRMAS (1)H MRS and its use for the study of intact human prostate tissue. PMID:23529951

  14. Towards high resolution ^1H NMR spectra of tannin colloidal aggregates

    NASA Astrophysics Data System (ADS)

    Mirabel, M.; Glories, Y.; Pianet, I.; Dufourc, E. J.

    1999-10-01

    The time dependent colloidal formation of tannins in hydro-alcoholic medium has been studied by 1H-NMR. Line broadening observed with time can be cancelled by making use of magic angle sample spinning (MASS) thus yielding sharp lines that allow structural studies. We used as an example catechin, a constitutive monomer of Bordeaux young red wine tannins. Chemical shift variations of polyphenol protons allow monitoring the time course of aggregation. La formation de tanins colloïdaux au cours du temps, en milieu hydroalcoolique, a été suivie par RMN-^1H. Un élargissement marqué des résonances est observé et peut être supprimé par la rotation de l'échantillon à l'angle magique ce qui ouvre tout un champ d'études structurales sur ces composés colloïdaux. L'exemple proposé est celui de la catéchine, monomère constitutif de tannins présents en grande quantité dans les vins rouges jeunes de Bordeaux. Des variations du déplacement chimique de certains protons polyphénoliques permettent de suivre l'évolution temporelle de l'agrégation.

  15. Spatially localized sup 1 H NMR spectra of metabolites in the human brain

    SciTech Connect

    Hanstock, C.C. ); Rothman, D.L.; Jue, T.; Shulman, R.G. ); Prichard, J.W. )

    1988-03-01

    Using a surface coil, the authors have obtained {sup 1}H NMR spectra from metabolites in the human brain. Localization was achieved by combining depth pulses with image-selected in vivo spectroscopy magnetic field gradient methods. {sup 1}H spectra in which total creatine (3.03 ppm) has a signal/noise ratio of 95:1 were obtained in 4 min from 14 ml of brain. A resonance at 2.02 ppm consisting predominantly of N-acetylaspartate was measured relative to the creatine peak in gray and white matter, and the ratio was lower in the white matter. The spin-spin relaxation times of N-acetylaspartate and creatine were measured in white and gray matter and while creatine relaxation times were the same in both, the N-acetylaspartate relaxation time was longer in white matter. Lactate was detected in the normoxic brain and the average of three measurements was {approx}0.5 mM from comparison with the creatine plus phosphocreatine peak, which was assumed to be 10.5 mM.

  16. 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

  17. Methodology of 1H NMR Spectroscopy of the Human Brain at Very High Magnetic Fields

    PubMed Central

    Tkáč, I.; Gruetter, R.

    2009-01-01

    An ultrashort-echo-time stimulated echo-acquisition mode (STEAM) pulse sequence with interleaved outer volume suppression and VAPOR (variable power and optimized relaxation delays) water suppression was redesigned and optimized for human applications at 4 and 7 T, taking into account the specific requirements for spectroscopy at high magnetic fields and limitations of currently available hardware. In combination with automatic shimming, automated parameter adjustments and data processing, this method provided a user-friendly tool for routine 1H nuclear magnetic resonance (NMR) spectroscopy of the human brain at very high magnetic fields. Effects of first- and second-order shimming, single-scan averaging, frequency and phase corrections, and eddy currents were described. LCModel analysis of an in vivo 1H NMR spectrum measured from the human brain at 7 T allowed reliable quantification of more than fifteen metabolites noninvasively, illustrating the potential of high-field NMR spectroscopy. Examples of spectroscopic studies performed at 4 and 7 T demonstrated the high reproducibility of acquired spectra quality. PMID:20179773

  18. Toxicity assessment of Arisaematis Rhizoma in rats by a (1)H NMR-based metabolomics approach.

    PubMed

    Dong, Ge; Wang, Junsong; Guo, Pingping; Wei, Dandan; Yang, Minghua; Kong, Lingyi

    2015-02-01

    Arisaematis Rhizoma (AR), a famous traditional Chinese medicine, has been widely used in Asia over thousands of years. Documented with noticeable toxicity in ancient books, AR has been used to treat various diseases in the clinic. Therefore, it is important to assess the toxicity of AR dynamically and holistically. In this study, a (1)H NMR-based metabolomics approach complemented with serum chemistry and histopathology has been applied to investigate the toxicity of AR. Rats were intragastrically administered with AR (0, 0.5 and 1 g kg(-1) body weight) for 30 days, and serum and urine samples were collected. Their (1)H NMR profiles were analyzed by multivariate pattern recognition techniques to denote metabolic variations induced by AR, and 13 metabolites in urine and 6 metabolites in serum were significantly altered, which suggested that disturbances in energy metabolism, perturbation of the gut microflora environment, membrane damage, folate deficiency and injury of kidneys are produced by AR. Histopathology showed a slight vacuolization of the glomerular matrix and edema of renal tubular epithelial cells in kidneys of AR administered rats, which were evidenced by increased levels of blood urea nitrogen and creatinine in serum chemistry. Our results indicated that oral administration of crude AR was found to induce slight renal toxicity. Therefore, precautions should be made to monitor the potential nephrotoxicity of AR in clinical use. The metabolomics approach provided a promising tool for the study and better understanding of TCM-induced toxicity dynamically and holistically. PMID:25407163

  19. Broad identification of bacterial type in urinary tract infection using (1)h NMR spectroscopy.

    PubMed

    Gupta, Ashish; Dwivedi, Mayank; Mahdi, Abbas Ali; Khetrapal, Chunni Lal; Bhandari, Mahendra

    2012-03-01

    To address the shortcomings of urine culture for the rapid identification of urinary tract infection (UTI), we applied (1)H-nuclear magnetic resonance (NMR) spectroscopy as a surrogate method for fast screening of microorganisms. Study includes 682 urine samples from suspected UTI patients, 50 healthy volunteers, and commercially available standard strains of gram negative bacilli (GNB) (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Enterobacter, Acinetobacter, Proteus mirabilis, Citrobacter frundii) and gram positive cocci (GPC) (Enterococcus faecalis, Streptococcus group B, Staphylococcus saprophyticus). Acetate, lactate, ethanol, succinate, creatinine, trimethylamine (TMA), citrate, trimethylamin-N-oxide, glycine, urea, and hippurate were measured by (1)H NMR spectroscopy. All urine specimens were evaluated with culture method. Multivariate discriminant function analysis (DFA) reveals that acetate, lactate, succinate, and formate were able to differentiate, with high accuracy (99.5%), healthy controls from UTI patients. This statistical analysis was also able to classify GNB to GPC infected urine samples with high accuracy (96%). This technique appears to be a promising, rapid, and noninvasive approach to probing GNB and GPC infected urine specimens with its distinguishing metabolic profile. The determination of infection will be very important for rapidly and efficiently measuring the efficacy of a tailored treatment, leading to prompt and appropriate care of UTI patients. PMID:22292465

  20. UV-visible and (1)H-(15)N NMR spectroscopic studies of colorimetric thiosemicarbazide anion sensors.

    PubMed

    Farrugia, Kristina N; Makuc, Damjan; Podborska, Agnieszka; Szaciłowski, Konrad; Plavec, Janez; Magri, David C

    2015-02-14

    Four model thiosemicarbazide anion chemosensors containing three N-H bonds, substituted with phenyl and/or 4-nitrophenyl units, were synthesised and studied for their anion binding abilities with hydroxide, fluoride, acetate, dihydrogen phosphate and chloride. The anion binding properties were studied in DMSO and 9 : 1 DMSO-H2O by UV-visible absorption and (1)H/(13)C/(15)N NMR spectroscopic techniques and corroborated with DFT studies. Significant changes were observed in the UV-visible absorption spectra with all anions, except for chloride, accompanied by dramatic colour changes visible to the naked eye. These changes were determined to be due to the deprotonation of the central N-H proton and not due to hydrogen bonding based on (1)H/(15)N NMR titration studies with acetate in DMSO-d6-0.5% water. Direct evidence for deprotonation was confirmed by the disappearance of the central thiourea proton and the formation of acetic acid. DFT and charge distribution calculations suggest that for all four compounds the central N-H proton is the most acidic. Hence, the anion chemosensors operate by a deprotonation mechanism of the central N-H proton rather than by hydrogen bonding as is often reported. PMID:25451865

  1. Binding of thiocyanate to lactoperoxidase: 1H and 15N nuclear magnetic resonance studies

    SciTech Connect

    Modi, S.; Behere, D.V.; Mitra, S. )

    1989-05-30

    The binding of thiocyanate to lactoperoxidase (LPO) has been investigated by 1H and 15N NMR spectroscopy. 1H NMR of LPO shows that the major broad heme methyl proton resonance at about 61 ppm is shifted upfield by addition of the thiocyanate, indicating binding of the thiocyanate to the enzyme. The pH dependence of line width of 15N resonance of SC15N- in the presence of the enzyme has revealed that the binding of the thiocyanate to the enzyme is facilitated by protonation of an ionizable group (with pKa of 6.4), which is presumably distal histidine. Dissociation constants (KD) of SC15N-/LPO, SC15N-/LPO/I-, and SC15N-/LPO/CN- equilibria have been determined by 15N T1 measurements and found to be 90 +/- 5, 173 +/- 20, and 83 +/- 6 mM, respectively. On the basis of these values of KD, it is suggested that the iodide ion inhibits the binding of the thiocyanate but cyanide ion does not. The thiocyanate is shown to bind at the same site of LPO as iodide does, but the binding is considerably weaker and is away from the ferric ion. The distance of 15N of the bound thiocyanate ion from the iron is determined to be 7.2 +/- 0.2 A from the 15N T1 measurements.

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

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

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

  3. Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy

    PubMed Central

    Jakes, W.; Gerdova, A.; Defernez, M.; Watson, A.D.; McCallum, C.; Limer, E.; Colquhoun, I.J.; Williamson, D.C.; Kemsley, E.K.

    2015-01-01

    This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz 1H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional “authentic” beef region (p = 0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze–thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz 1H NMR represents a feasible high-throughput approach for screening raw meat. PMID:25577043

  4. Wastewater Colloidal Organic Carbon: Characterization of Filtration Fractions Using 1H NMR.

    PubMed

    McPhedran, Kerry N; Seth, Rajesh

    2016-04-01

    The current study separates colloidal organic carbon (COC) of municipal wastewater using membrane and ultrafiltration filters followed by characterization using 1H nuclear magnetic resonance (NMR) and UV absorbance with the goal of determination of size-specific characteristics, which may be used to correlate contaminant partitioning to natural COC. Passing fractions included 49.7, 44.8, 39.3, and 33.1 mg/L COC for filter sizes 1.5 μm, 0.45 μm, 100 kDa, and 1 kDa, respectively. The methodology used for processing COC prior to 1H NMR characterization was novel and successful in concentrating COC without modification of structures, which is the general drawback of other separation techniques such as resin extractions. This concentration technique is quite simple (i.e., not dependent on specialized instrumentation) and allows much shorter NMR experimental durations saving time and cost of analysis. Further work using NMR techniques will allow for greater understanding of COC molecular characteristics and be valuable for use in predictive modeling improvements. PMID:27131054

  5. Molecular structures of 2-arylaminomethyl-1H-benzimidazole: Spectral, electrochemical, DFT and biological studies

    NASA Astrophysics Data System (ADS)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.

    2012-06-01

    In the present work, structural studies on (1H-benzimidazol-2-ylmethyl)-N-(4-chloro-phenyl)-amine (L1) and (1H-benzimidazol-2-ylmethyl)-N-(4-iodo-phenyl)-amine (L2) have been done extensively by a variety of physico-chemical techniques. Optimized geometrical structures, harmonic vibrational frequencies, natural bonding orbital (NBO) analysis, and Frontier molecular orbitals (FMO) were obtained by DFT/B3LYP method. TD-DFT calculations help to assign the electronic transitions. The polarizable continuum model (PCM) fails to describe the experimental chemical shift associated with the NH protons as calculated by applying Gauge-invariant atomic orbital (GIAO) method, but a very good correlation between the theoretical and experimental values was achieved by taking into account the specific solute-solvent interactions. DFT calculations showed a good agreement between the theoretical and observed results. These compounds exhibited a high biological activity through the inhibition of the metabolic growth of the investigated bacteria.

  6. Antimalarial 4(1H)-pyridones bind to the Qi site of cytochrome bc1

    PubMed Central

    Capper, Michael J.; O’Neill, Paul M.; Fisher, Nicholas; Strange, Richard W.; Moss, Darren; Ward, Stephen A.; Berry, Neil G.; Lawrenson, Alexandre S.; Hasnain, S. Samar; Biagini, Giancarlo A.; Antonyuk, Svetlana V.

    2015-01-01

    Cytochrome bc1 is a proven drug target in the prevention and treatment of malaria. The rise in drug-resistant strains of Plasmodium falciparum, the organism responsible for malaria, has generated a global effort in designing new classes of drugs. Much of the design/redesign work on overcoming this resistance has been focused on compounds that are presumed to bind the Qo site (one of two potential binding sites within cytochrome bc1) using the known crystal structure of this large membrane-bound macromolecular complex via in silico modeling. Cocrystallization of the cytochrome bc1 complex with the 4(1H)-pyridone class of inhibitors, GSK932121 and GW844520, that have been shown to be potent antimalarial agents in vivo, revealed that these inhibitors do not bind at the Qo site but bind at the Qi site. The discovery that these compounds bind at the Qi site may provide a molecular explanation for the cardiotoxicity and eventual failure of GSK932121 in phase-1 clinical trial and highlight the need for direct experimental observation of a compound bound to a target site before chemical optimization and development for clinical trials. The binding of the 4(1H)-pyridone class of inhibitors to Qi also explains the ability of this class to overcome parasite Qo-based atovaquone resistance and provides critical structural information for future design of new selective compounds with improved safety profiles. PMID:25564664

  7. (1)H NMR Spectroscopy of Fecal Extracts Enables Detection of Advanced Colorectal Neoplasia.

    PubMed

    Amiot, Aurelien; Dona, Anthony C; Wijeyesekera, Anisha; Tournigand, Christophe; Baumgaertner, Isabelle; Lebaleur, Yann; Sobhani, Iradj; Holmes, Elaine

    2015-09-01

    Colorectal cancer (CRC) is a growing cause of mortality in developing countries, warranting investigation into its etiopathogenesis and earlier diagnosis. Here, we investigated the fecal metabolic phenotype of patients with advanced colorectal neoplasia and controls using (1)H-nuclear magnetic resonance (NMR) spectroscopy and multivariate modeling. The fecal microbiota composition was assessed by quantitative real-time PCR as well as Wif-1 methylation levels in stools, serum, and urine and correlated to the metabolic profile of each patient. The predictivity of the model was 0.507 (Q(2)Y), and the explained variance was 0.755 (R(2)Y). Patients with advanced colorectal neoplasia demonstrated increased fecal concentrations of four short-chain fatty acids (valerate, acetate, propionate, and butyrate) and decreased signals relating to β-glucose, glutamine, and glutamate. The predictive accuracy of the multivariate (1)H NMR model was higher than that of the guaiac-fecal occult blood test and the Wif-1 methylation test for predicting advanced colorectal neoplasia. Correlation analysis between fecal metabolites and bacterial profiles revealed strong associations between Faecalibacterium prausnitzii and Clostridium leptum species with short-chain fatty acids concentration and inverse correlation between Faecalibacterium prausnitzii and glucose. These preliminary results suggest that fecal metabonomics may potentially have a future role in a noninvasive colorectal screening program and may contribute to our understanding of the role of these dysregulated molecules in the cross-talk between the host and its bacterial microbiota. PMID:26211820

  8. Low Temperature 1H MAS NMR Spectroscopy Studies of Proton Motion in Zeolite

    SciTech Connect

    Huo, H.; Peng, L; Grey, C

    2009-01-01

    Low temperature {sup 1}H MAS NMR spectroscopy is used to study protonic motion in zeolite HZSM-5 in both samples that have been dried using procedures that are standard in the literature and samples that have been more carefully dehydrated. A significant enhancement of proton mobility is seen for the ''standard'' dehydrated HZSM-5 sample in comparison to that seen for the much drier sample. This is ascribed to a vehicle-hopping mechanism involving the residual water that is present in these zeolites. A gradual change of the framework structure is observed on cooling to approximately 213 K, as monitored via the change in {sup 1}H chemical shift values of the Broensted acid resonances and by X-ray diffraction. A more sudden change in structure is seen by differential scanning calorimetry and NMR at approximately 220?230 K, which is associated with changes in both the mobility and the modes of binding of the residual water to the Broensted acid sites and the zeolite framework.

  9. Two-dimensional /sup 1/H NMR studies on cyclophilin, a cytosolic cyclosporin A binding protein

    SciTech Connect

    Dalgarno, D.C.; Harding, M.W.; Lazarides, A.; Handschumacher, R.E.; Armitage, I.M.

    1986-05-01

    Cyclophilin (CyP) is a specific cytosolic cyclosporin A (CsA) binding protein (163 residues) that has been implicated in the pharmacological action of this potent immunosuppressant. One and two-dimensional /sup 1/H NMR methods are being employed to elucidate the solution structural properties of CyP particularly as they relate to the binding site of CsA. The focal point for these studies is the single Trp (residue number120) in CyP which, in the 1:1 CyP:CsA complex (K/sub d/approx.2 x 10/sup -7/M), shows a 2 fold enhancement in its intrinsic fluorescence. Using 2D /sup 1/H NMR methods, a low resolution structure has been derived for a very hydrophobic domain containing the Trp residue using interresidue n.O.e. data between assigned spin systems and a distance geometry algorithm. The structure of this hydrophobic domain will be discussed in relation to the predicted ..cap alpha../..beta.. secondary structure of this protein and comparisons made between its structure in the drug free and complexed form of the protein.

  10. Response to the Letter to the Editor regarding "Determination of the fatty acid profile by 1H-NMR spectroscopy."

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In expansion of previous work (G. Knothe, J.A. Kenar, Determination of the fatty acid profile by 1H-NMR spectroscopy, Eur. J. Lipid Sci. Technol. 2004, 106, 88-96), an additional approach is discussed for quantitating saturated fatty acids in the fatty acid profiles of common vegetable oils by 1H-NM...

  11. 40 CFR 721.4468 - 1H-Imidazole, 2-ethyl-4,5-dihydro-4-methyl-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1H-Imidazole, 2-ethyl-4,5-dihydro-4... Specific Chemical Substances § 721.4468 1H-Imidazole, 2-ethyl-4,5-dihydro-4-methyl-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as...

  12. 40 CFR 721