Bacterial expression and one-step purification of an isotope-labeled heterotrimeric G-protein {alpha}-subunit

Energy Technology Data Exchange (ETDEWEB)

Abdulaev, Najmoutin G. [University of Maryland Biotechnology Institute, Center for Advanced Research in Biotechnology (United States); Zhang Cheng; Dinh, Andy [University of Texas Health Science Center, Center for Membrane Biology, Department of Biochemistry and Molecular Biology (United States); Ngo, Tony; Bryan, Philip N. [University of Maryland Biotechnology Institute, Center for Advanced Research in Biotechnology (United States); Brabazon, Danielle M. [Loyola College in Maryland, Department of Chemistry (United States); Marino, John P. [University of Maryland Biotechnology Institute, Center for Advanced Research in Biotechnology (United States)], E-mail: marino@carb.nist.gov; Ridge, Kevin D. [University of Texas Health Science Center, Center for Membrane Biology, Department of Biochemistry and Molecular Biology (United States)

2005-05-15

Heterologous expression systems are often employed to generate sufficient quantities of isotope-labeled proteins for high-resolution NMR studies. Recently, the interaction between the prodomain region of subtilisin and an active, mutant form of the mature enzyme has been exploited to develop a cleavable affinity tag fusion system for one-step generation and purification of full-length soluble proteins obtained by inducible prokaryotic expression. As a first step towards applying high-resolution NMR methods to study heterotrimeric G-protein {alpha}-subunit (G{sub {alpha}}) conformation and dynamics, the utility of this subtilisin prodomain fusion system for expressing and purifying an isotope-labeled G{sub {alpha}} chimera ({approx}40 kDa polypeptide) has been tested. The results show that a prodomain fused G{sub {alpha}} chimera can be expressed to levels approaching 6-8 mg/l in minimal media and that the processed, mature protein exhibits properties similar to those of G{sub {alpha}} isolated from natural sources. To assay for the functional integrity of the purified G{sub {alpha}} chimera at NMR concentrations and probe for changes in the structure and dynamics of G{sub {alpha}} that result from activation, {sup 15}N-HSQC spectra of the GDP/Mg{sup 2+} bound form of G{sub {alpha}} obtained in the absence and presence of aluminum fluoride, a well known activator of the GDP bound state, have been acquired. Comparisons of the {sup 15}N-HSQC spectra reveals a number of changes in chemical shifts of the {sup 1}HN, {sup 15}N crosspeaks that are discussed with respect to expected changes in the protein conformation associated with G{sub {alpha}} activation.

Conformational analysis of a Chlamydia-specific disaccharide {alpha}-Kdo-(2{sup {yields}}8)-{alpha}-Kdo-(2{sup {yields}}O)-allyl in aqueous solution and bound to a monoclonal antibody: Observation of intermolecular transfer NOEs

Energy Technology Data Exchange (ETDEWEB)

Sokolowski, Tobias; Haselhorst, Thomas; Scheffler, Karoline [Medizinische Universitaet, Institut fuer Chemie (Germany); Weisemann, Ruediger [Bruker Analytik GmbH, Silberstreifen (Germany); Kosma, Paul [Institut fuer Chemie der Universitaet fuer Bodenkultur Wien (Austria); Brade, Helmut; Brade, Lore [Forschungszentrum Borstel, Zentrum fuer Medizin und Biowissenschaften Parkallee 22 (Germany); Peters, Thomas [Medizinische Universitaet, Institut fuer Chemie (Germany)

1998-07-15

The disaccharide {alpha}-Kdo-(2{sup {yields}}8)-{alpha}-Kdo (Kdo: 3-deoxy-d-manno-oct-2-ulosonic acid) represents a genus-specific epitope of the lipopolysaccharide of the obligate intracellular human pathogen Chlamydia. The conformation of the synthetically derived disaccharide {alpha}-Kdo-(2{sup {yields}}8)-{alpha}-Kdo-(2{sup {yields}}O)-allyl was studied in aqueous solution, and complexed to a monoclonal antibody S25-2. Various NMR experiments based on the detection of NOEs (or transfer NOEs) and ROEs (or transfer ROEs) were performed. A major problem was the extensive overlap of almost all {sup 1}H NMR signals of {alpha}-Kdo-(2{sup {yields}}8)-{alpha}-Kdo-(2{sup {yields}}O)-allyl. To overcome this difficulty, HMQC-NOESY and HMQC-trNOESY experiments were employed. Spin diffusion effects were identified using trROESY experiments, QUIET-trNOESY experiments and MINSY experiments. It was found that protein protons contribute to the observed spin diffusion effects. At 800 MHz, intermolecular trNOEs were observed between ligand protons and aromatic protons in the antibody binding site. From NMR experiments and Metropolis Monte Carlo simulations, it was concluded that {alpha}-Kdo-(2{sup {yields}}8)-{alpha}-Kdo-(2{sup {yields}}O)-allyl in aqueous solution exists as a complex conformational mixture. Upon binding to the monoclonal antibody S25-2, only a limited range of conformations is available to {alpha}-Kdo-(2{sup {yields}}8)-{alpha}-Kdo-(2{sup {yields}}O)-allyl. These possible bound conformations were derived from a distance geometry analysis using transfer NOEs as experimental constraints. It is clear that a conformation is selected which lies within a part of the conformational space that is highly populated in solution. This conformational space also includes the conformation found in the crystal structure. Our results provide a basis for modeling studies of the antibody-disaccharide complex.

Contact replacement for NMR resonance assignment.

Science.gov (United States)

Xiong, Fei; Pandurangan, Gopal; Bailey-Kellogg, Chris

2008-07-01

Complementing its traditional role in structural studies of proteins, nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in functional studies. NMR dynamics experiments characterize motions involved in target recognition, ligand binding, etc., while NMR chemical shift perturbation experiments identify and localize protein-protein and protein-ligand interactions. The key bottleneck in these studies is to determine the backbone resonance assignment, which allows spectral peaks to be mapped to specific atoms. This article develops a novel approach to address that bottleneck, exploiting an available X-ray structure or homology model to assign the entire backbone from a set of relatively fast and cheap NMR experiments. We formulate contact replacement for resonance assignment as the problem of computing correspondences between a contact graph representing the structure and an NMR graph representing the data; the NMR graph is a significantly corrupted, ambiguous version of the contact graph. We first show that by combining connectivity and amino acid type information, and exploiting the random structure of the noise, one can provably determine unique correspondences in polynomial time with high probability, even in the presence of significant noise (a constant number of noisy edges per vertex). We then detail an efficient randomized algorithm and show that, over a variety of experimental and synthetic datasets, it is robust to typical levels of structural variation (1-2 AA), noise (250-600%) and missings (10-40%). Our algorithm achieves very good overall assignment accuracy, above 80% in alpha-helices, 70% in beta-sheets and 60% in loop regions. Our contact replacement algorithm is implemented in platform-independent Python code. The software can be freely obtained for academic use by request from the authors.

NMR techniques in the study of cardiovascular structure and functions

International Nuclear Information System (INIS)

Osbakken, M.; Haselgrove, J.

1987-01-01

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

NMR structure of navel orangeworm moth pheromone-binding protein (AtraPBP1): implications for pH-sensitive pheromone detection.

Science.gov (United States)

Xu, Xianzhong; Xu, Wei; Rayo, Josep; Ishida, Yuko; Leal, Walter S; Ames, James B

2010-02-23

The navel orangeworm, Amyelois transitella (Walker), is an agricultural insect pest that can be controlled by disrupting male-female communication with sex pheromones, a technique known as mating disruption. Insect pheromone-binding proteins (PBPs) provide fast transport of hydrophobic pheromones through the aqueous sensillar lymph and promote sensitive delivery of pheromones to receptors. Here we present the three-dimensional structure of a PBP from A. transitella (AtraPBP1) in solution at pH 4.5 determined by nuclear magnetic resonance (NMR) spectroscopy. Pulsed-field gradient NMR diffusion experiments, multiangle light scattering, and (15)N NMR relaxation analysis indicate that AtraPBP1 forms a stable monomer in solution at pH 4.5 in contrast to forming mostly dimers at pH 7. The NMR structure of AtraPBP1 at pH 4.5 contains seven alpha-helices (alpha1, L8-L23; alpha2, D27-F36; alpha3, R46-V62; alpha4, A73-M78; alpha5, D84-S100; alpha6, R107-L125; alpha7, M131-E141) that adopt an overall main-chain fold similar to that of PBPs found in Antheraea polyphemus and Bombyx mori. The AtraPBP1 structure is stabilized by three disulfide bonds formed by C19/C54, C50/C108, and C97/C117 and salt bridges formed by H69/E60, H70/E57, H80/E132, H95/E141, and H123/D40. All five His residues are cationic at pH 4.5, whereas H80 and H95 become neutral at pH 7.0. The C-terminal helix (alpha7) contains hydrophobic residues (M131, V133, V134, V135, V138, L139, and A140) that contact conserved residues (W37, L59, A73, F76, A77, I94, V111, and V115) suggested to interact with bound pheromone. Our NMR studies reveal that acid-induced formation of the C-terminal helix at pH 4.5 is triggered by a histidine protonation switch that promotes rapid release of bound pheromone under acidic conditions.

Nuclear magnetic resonance of D(-)-{alpha}-amino-benzyl penicillin; Ressonancia magnetica nuclear da D(-)-{alpha}-amino-benzil penicilina

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Monica R.M.P.; Gemal, Andre L.; San Gil, Rosane A.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Menezes, Sonia M.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

1995-12-31

The development of new drugs from penicillins has induced the study of this substances by nuclear magnetic resonance. Several samples of D(-)-{alpha}-amino-benzyl penicillin were analysed using {sup 13} C NMR techniques in aqueous solution and solid state. Spectral data of this compounds were shown and the results were presented and analysed 7 figs., 4 tabs.

Characterisation of different polymorphs of tris(8-hydroxyquinolinato)aluminium(III) using solid-state NMR and DFT calculations.

Science.gov (United States)

Goswami, Mithun; Nayak, Pabitra K; Periasamy, N; Madhu, P K

2009-11-09

Organic light emitting devices (OLED) are becoming important and characterisation of them, in terms of structure, charge distribution, and intermolecular interactions, is important. Tris(8-hydroxyquinolinato)-aluminium(III), known as Alq3, an organomettalic complex has become a reference material of great importance in OLED. It is important to elucidate the structural details of Alq3 in its various isomeric and solvated forms. Solid-state nuclear magnetic resonance (NMR) is a useful tool for this which can also complement the information obtained with X-ray diffraction studies. We report here 27Al one-dimensional (1D) and two-dimensional (2D) multiple-quantum magic-angle spinning (MQMAS) NMR studies of the meridional (alpha-phase) and the facial (delta-phase) isomeric forms of Alq3. Quadrupolar parameters are estimated from the 1D spectra under MAS and anisotropic slices of the 2D spectra and also calculated using DFT (density functional theory) quantum-chemical calculations. We have also studied solvated phase of Alq3 containing ethanol in its lattice. We show that both the XRD patterns and the quadrupolar parameters of the solvated phase are different from both the alpha-phase and the delta-phase, although the fluorescence emission shows no substantial difference between the alpha-phase and the solvated phase. Moreover, we have shown that after the removal of ethanol from the matrix the solvated Alq3 has similar XRD patterns and quadrupolar parameters to that of the alpha-phase. The 2D MQMAS experiments have shown that all the different modifications of Alq3 have 27Al in single unique crystallographic site. The quadrupolar parameters predicted using the DFT calculation under the isodensity polarisable continuum model resemble closely the experimentally obtained values. The solvated phase of Alq3 containing ethanol has structural difference from the alpha-phase of Alq3 (containing meridional isomer) from the solid-state NMR studies. Solid-state NMR can hence be

Interaction of melittin with mixed phospholipid membranes composed of dimyristoylphosphatidylcholine and dimyristoylphosphatidylserine studied by deuterium NMR

Energy Technology Data Exchange (ETDEWEB)

Dempsey, C.; Bitbol, M.; Watts, A. (Oxford Univ. (England))

1989-08-08

The interaction of bee venom melittin with mixed phospholipid bilayers composed of dimyristoylphosphatidylcholine deuterated in the {alpha}- and {beta}-methylenes of the choline head group (DMPC-d{sub 4}) and dimyristoylphosphatidylserine deuterated in the {alpha}-methylene and {beta}-CH positions of the serine head group (DMPS-d{sub 3}) was studied in ternary mixtures by using deuterium NMR spectroscopy. The changes in the deuterium quadrupole splittings of the head-group deuteriomethylenes of DMPC-d{sub 4} induced by DMPS in binary mixtures were systematically reversed by increasing concentrations of melittin, so that at a melittin concentration of 4 mol % relative to total lipid the deuterium NMR spectrum from DMPC-d{sub 4} in the ternary mixture was similar to the spectrum from pure DMPC-d{sub 4} bilayers. The absence of deuterium NMR signals arising from melittin-bound DMPS in ternary mixtures containing DMPS-d{sub 3} indicates that the reversal by melittin of the effects of DMPS on the quadrupole splittings of DMPC-d{sub 4} results from the response of the choline head group to the net surface charge rather than from phase separation of melittin-DMPS complexes. The similarity in the effects of the two cationic but otherwise dissimilar peptides indicates that the DMPS head group responds to the surface charge resulting from the presence in the bilayer of charged amphiphiles, in a manner analogous to the response of the choline head group of phosphatidylcholine to the bilayer surface charge. The presence of DMPS greatly stabilized DMPC bilayers with respect to melittin-induced micellization, indicating that the latter effect of melittin may not be important for the hemolytic activity of the peptide.

2D NMR studies of biomolecules

International Nuclear Information System (INIS)

Lamerichs, R.M.J.N.

1989-01-01

The work described in this thesis comprises two related subjects. The first part describes methods to derive high-resolution structures of proteins in solution using two-dimensional (2-D) NMR. The second part describes 2-D NMR studies on the interaction between proteins and DNA. (author). 261 refs.; 52 figs.; 23 tabs

Hyphenation of solid-phase extraction with liquid chromatography and nuclear magnetic resonance: application of HPLC-DAD-SPE-NMR to identification of constituents of Kanahia laniflora.

Science.gov (United States)

Clarkson, Cailean; Staerk, Dan; Hansen, Steen Honoré; Jaroszewski, Jerzy W

2005-06-01

The introduction of on-line solid-phase extraction (SPE) in HPLC-NMR has dramatically enhanced the sensitivity of this technique by concentration of the analytes in a small-volume NMR flow cell and by increasing the amount of the analyte by multiple peak trapping. In this study, the potential of HPLC-DAD-SPE-NMR hyphenation was demonstrated by structure determination of complex constituents of flower, leaf, root, and stem extracts of an African medicinal plant Kanahia laniflora. The technique was shown to allow acquisition of high-quality homo- and heteronuclear 2D NMR data following analytical-scale HPLC separation of extract constituents. Four flavonol glycosides [kaempferol 3-O-(6-O-alpha-l-rhamnopyranosyl)-beta-d-glucopyranoside; kaempferol 3-O-(2,6-di-O-alpha-l-rhamnopyranosyl)-beta-d-glucopyranoside; quercetin 3-O-(2,6-di-O-alpha-l-rhamnopyranosyl)-beta-d-glucopyranoside (rutin); and isorhamnetin, 3-O-(6-O-alpha-l-rhamnopyranosyl)-beta-d-glucopyranoside] and three 5alpha-cardenolides [coroglaucigenin 3-O-6-deoxy-beta-d-allopyranoside; coroglaucigenin 3-O-(4-O-beta-d-glucopyranosyl)-6-deoxy-beta-d-glucopyranoside; 3'-O-acetyl-3'-epiafroside] were identified, with complete assignments of 1H and 13C resonances based on HSQC and HMBC spectra whenever required. Confirmation of the structures was provided by HPLC-MS data. The HPLC-DAD-SPE-NMR technique therefore speeds up the dereplication of complex mixtures of natural origin significantly, by characterization of individual extract components prior to preparative isolation work.

Polymeric proanthocyanidins 13C NMR studies of procyanidins

Science.gov (United States)

Lawrence J. Porter; Roger H. Newman; Lai Yeap Foo; Herbert Wong; Richard W. Hemingway

1982-01-01

Proanthocyanidin polymers have been shown to consist entirely of flavan-3-ol units by a combination of techniques including 13C n.m.r. spectroscopy. The 13C n.m.r. spectra of the polymers and related molecules are now considered in more detail. Prior to this study UC n.m.r. data has been published of procyanidins and...

Applications of NMR to studies of tissue metabolism

International Nuclear Information System (INIS)

Avison, M.J.; Hetherington, H.P.; Shulman, R.G.

1986-01-01

From its beginnings as a tool for the elucidation of biochemical pathways and bioenergetic status in unicellular organisms, the field of NMR studie in vivo has grown to encompass not only the study of isolated perfused organs, but also the study of various aspects of the biochemistry, physiology, and pathophysiology of these same organs in the intact animal. In recent years several groups have begun to extend the techniques developed in animals to the study of clinically relevant conditions in humans. A comprehensive review of all areas of NMR studies in vivo would be either unacceptably long or very superficial. For this reason the authors have restricted this review to studies published since 1980, except where an earlier study is particularly relevant to the topic under discussion. Furthermore, they have concentrated on areas that have been extending the scope of NMR in vivo. One specific omission is review of NMR studies of tumors, since a comprehensive review has recently appeared

Sequential nearest-neighbor effects on computed {sup 13}C{sup {alpha}} chemical shifts

Energy Technology Data Exchange (ETDEWEB)

Vila, Jorge A. [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States); Serrano, Pedro; Wuethrich, Kurt [The Scripps Research Institute, Department of Molecular Biology (United States); Scheraga, Harold A., E-mail: has5@cornell.ed [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States)

2010-09-15

To evaluate sequential nearest-neighbor effects on quantum-chemical calculations of {sup 13}C{sup {alpha}} chemical shifts, we selected the structure of the nucleic acid binding (NAB) protein from the SARS coronavirus determined by NMR in solution (PDB id 2K87). NAB is a 116-residue {alpha}/{beta} protein, which contains 9 prolines and has 50% of its residues located in loops and turns. Overall, the results presented here show that sizeable nearest-neighbor effects are seen only for residues preceding proline, where Pro introduces an overestimation, on average, of 1.73 ppm in the computed {sup 13}C{sup {alpha}} chemical shifts. A new ensemble of 20 conformers representing the NMR structure of the NAB, which was calculated with an input containing backbone torsion angle constraints derived from the theoretical {sup 13}C{sup {alpha}} chemical shifts as supplementary data to the NOE distance constraints, exhibits very similar topology and comparable agreement with the NOE constraints as the published NMR structure. However, the two structures differ in the patterns of differences between observed and computed {sup 13}C{sup {alpha}} chemical shifts, {Delta}{sub ca,i}, for the individual residues along the sequence. This indicates that the {Delta}{sub ca,i} -values for the NAB protein are primarily a consequence of the limited sampling by the bundles of 20 conformers used, as in common practice, to represent the two NMR structures, rather than of local flaws in the structures.

Conductivity variations in composites of. alpha. -zirconium phosphate and alumina

Energy Technology Data Exchange (ETDEWEB)

Slade, R.C.T.; Knowles, J.A. (Dept. of Chemistry, Exeter Univ. (UK))

Composite proton-conducting solid electrolytes have been formed from {alpha}-zirconium hydrogen phosphate ({alpha}-Zr(HPO{sub 4}){sub 2}.H{sub 2}O, {alpha}-ZrP) and aluminas (Al{sub 2}O{sub 3}) in varying mole ratios. Conductivity variations as a function of temperature have been characterised and compared to that for a delaminated {alpha}-ZrP (no alumina). There are no appreciable conductivity enhancements on composite formation, but conductivity for materials ca. 50 mole% in alumina can be comparable to the delaminated materials. Differential scanning calorimetry shows the composites to have different thermal properties to simple admixtures. High resolution {sup 31}P NMR studies show reaction to form aluminium phosphate at the interface between components. (orig.).

Structural investigations of substituted indolizine derivatives by NMR studies

International Nuclear Information System (INIS)

Furdui, Bianca; Dinica, Rodica; Demeunynck, Martine; Druta, Ioan

2008-01-01

Owing to the increasing importance of indolizine heterocycles in the field of biology and pharmacology we have synthesized and investigated the obtained heterocycles by NMR techniques. In order to investigate the substituent effects on the spectroscopic properties, a series of indolizine derivatives were studied by 1 H-NMR, 13 C-NMR and 2D NMR (GCOSY, GHMBC and GHMQC spectra). (authors)

NMR studies of cerebral metabolism in vivo

International Nuclear Information System (INIS)

Prichard, J.W.

1986-01-01

The nature and extent of the potential synergism between PET and NMR methods is not yet well appreciated in the biomedical community. The long-range interest of medical neurobiology will be well served by efforts of PET and NMR scientists to follow each others' work so that opportunities for productive interchange can be efficiently exploited. Appreciation of the synergism by the rest of the biomedical community will follow naturally. PET is said by the people doing it to be still in its infancy, for they are more concerned with advancing their discipline than with admiring its already impressive achievements. On the scale of the same developmental metaphor, many NMR methods for studying the living human brain are still in utero. The best way to provide the reader a sense of the current status and future course of NMR research in medical neurobiology is by discussion of published in vivo studies. Such a discussion, adapted from another article is what follows

Structural Studies of Biological Solids Using NMR

Science.gov (United States)

Ramamoorthy, Ayyalusamy

2011-03-01

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

NMR studies of the structure of glasses

International Nuclear Information System (INIS)

Bray, P.J.; Gravina, S.J.; Stallworth, P.E.; Szu, S.P.; Jianhui Zhong

1988-01-01

Earlier continuous wave (CW) NMR studies of chemical bonding and structure in glasses are summarized. Examples are given of this use of the quadrupolar interaction and chemical shift to obtain structural information. New NMR data and analyses are presented for alkali borate and gallate glasses. Extensions to other elements (e.g. molybdenum, lanthanum) are suggested. 44 refs. (author)

Identification of a novel bile acid in swans, tree ducks, and geese: 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid.

Science.gov (United States)

Kakiyama, Genta; Iida, Takashi; Goto, Takaaki; Mano, Nariyasu; Goto, Junichi; Nambara, Toshio; Hagey, Lee R; Schteingart, Claudio D; Hofmann, Alan F

2006-07-01

By HPLC, a taurine-conjugated bile acid with a retention time different from that of taurocholate was found to be present in the bile of the black-necked swan, Cygnus melanocoryphus. The bile acid was isolated and its structure, established by (1)H and (13)C NMR and mass spectrometry, was that of the taurine N-acyl amidate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid. The compound was shown to have chromatographic and spectroscopic properties that were identical to those of the taurine conjugate of authentic 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid, previously synthesized by us from ursodeoxycholic acid. By HPLC, the taurine conjugate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid was found to be present in 6 of 6 species in the subfamily Dendrocygninae (tree ducks) and in 10 of 13 species in the subfamily Anserinae (swans and geese) but not in other subfamilies in the Anatidae family. It was also not present in species from the other two families of the order Anseriformes. 3alpha,7alpha,15alpha-Trihydroxy-5beta-cholan-24-oic acid is a new primary bile acid that is present in the biliary bile acids of swans, tree ducks, and geese and may be termed 15alpha-hydroxy-chenodeoxycholic acid.

sup 3 sup 1 P high resolution solid state NMR studies of phosphoorganic compounds of biological interest

CERN Document Server

Potrzebowski, M J; Kazmierski, S

2001-01-01

In this review several applications of sup 3 sup 1 P high resolution solid state NMR spectroscopy in structural studies of bioorganic samples is recorded. The problem of pseudopolymorphism of bis[6-O,6'-O-(1,2:3,4diisopropylidene-alpha-D-galactopyranosyl) phosphothionyl] disulfide (1) and application of sup 3 sup 1 P C/MAS experiment to investigate of this phenomenon is discussed. The influence of weak C-H--S intermolecular contacts on molecular packing of 1,6-anhydro-2-O-tosyl-4-S- (5,5-dimethyl-2-thioxa-1,3,2-dioxaphosphophorinan-2-= yl)-beta-D-glucopyranose (2) and S sub P , R sub P diastereomers of deoxyxylothymidyl-3'-O-acetylthymidyl (3',5')-O-(2-cyanoethyl) phosphorothioate (3) and their implication on sup 3 sup 1 P NMR spectra is shown. The final part of review describes the recent progress in structural studies of O-phosphorylated amino acids (serine, threonine, tyrosine), relationship between molecular structure and sup 3 sup 1 P chemical shift parameters delta sub i sub i and influence of hydrogen ...

NMR solution structure of the mitochondrial F1beta presequence from Nicotiana plumbaginifolia.

Science.gov (United States)

Moberg, Per; Nilsson, Stefan; Ståhl, Annelie; Eriksson, Anna-Carin; Glaser, Elzbieta; Mäler, Lena

2004-03-05

We have isolated, characterized and determined the three-dimensional NMR solution structure of the presequence of ATPsynthase F1beta subunit from Nicotiana plumbaginifolia. A general method for purification of presequences is presented. The method is based on overexpression of a mutant precursor containing a methionine residue introduced at the processing site, followed by CNBr-cleavage and purification of the presequence on a cation-exchange column. The F1beta presequence, 53 amino acid residues long, retained its native properties as evidenced by inhibition of in vitro mitochondrial import and processing at micromolar concentrations. CD spectroscopy revealed that the F1beta presequence formed an alpha-helical structure in membrane mimetic environments such as SDS and DPC micelles (approximately 50% alpha-helix), and in acidic phospholipid bicelles (approximately 60% alpha-helix). The NMR solution structure of the F1beta presequence in SDS micelles was determined on the basis of 518 distance and 21 torsion angle constraints. The structure was found to contain two helices, an N-terminal amphipathic alpha-helix (residues 4-15) and a C-terminal alpha-helix (residues 43-53), separated by a largely unstructured 27 residue long internal domain. The N-terminal amphipathic alpha-helix forms the putative Tom20 receptor binding site, whereas the C-terminal alpha-helix is located upstream of the mitochondrial processing peptidase cleavage site.

Isotope labeling for NMR studies of macromolecular structure and interactions

International Nuclear Information System (INIS)

Wright, P.E.

1994-01-01

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

Isotope labeling for NMR studies of macromolecular structure and interactions

Energy Technology Data Exchange (ETDEWEB)

Wright, P.E. [Scripps Research Institute, La Jolla, CA (United States)

1994-12-01

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

Application of Solution NMR Spectroscopy to Study Protein Dynamics

Directory of Open Access Journals (Sweden)

Christoph Göbl

2012-03-01

Full Text Available Recent advances in spectroscopic methods allow the identification of minute fluctuations in a protein structure. These dynamic properties have been identified as keys to some biological processes. The consequences of this structural flexibility can be far‑reaching and they add a new dimension to the structure-function relationship of biomolecules. Nuclear Magnetic Resonance (NMR spectroscopy allows the study of structure as well as dynamics of biomolecules in a very broad range of timescales at atomic level. A number of new NMR methods have been developed recently to allow the measurements of time scales and spatial fluctuations, which in turn provide the thermodynamics associated with the biological processes. Since NMR parameters reflect ensemble measurements, structural ensemble approaches in analyzing NMR data have also been developed. These new methods in some instances can even highlight previously hidden conformational features of the biomolecules. In this review we describe several solution NMR methods to study protein dynamics and discuss their impact on important biological processes.

1H and 13C NMR spectral data of new saponins from Cordia piauhiensis.

Science.gov (United States)

Santos, Renata P; Silveira, Edilberto R; Uchôa, Daniel Esdras de A; Pessoa, Otília Deusdênia L; Viana, Francisco Arnaldo; Braz-Filho, Raimundo

2007-08-01

Two new bidesmoside triterpenoid saponins were isolated from stems of Cordia piauhiensis. Their structures, characterized as 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl pomolic acid 28-O-beta-D-glucopyranosyl ester (1) and 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl ester (2), were unequivocally established after extensive NMR (1H, 13C, DEPT 135 degrees, COSY, HSQC, HMBC, TOCSY, and NOESY) studies. Copyright 2007 John Wiley & Sons, Ltd.

Protein folding on the ribosome studied using NMR spectroscopy

Science.gov (United States)

Waudby, Christopher A.; Launay, Hélène; Cabrita, Lisa D.; Christodoulou, John

2013-01-01

NMR spectroscopy is a powerful tool for the investigation of protein folding and misfolding, providing a characterization of molecular structure, dynamics and exchange processes, across a very wide range of timescales and with near atomic resolution. In recent years NMR methods have also been developed to study protein folding as it might occur within the cell, in a de novo manner, by observing the folding of nascent polypeptides in the process of emerging from the ribosome during synthesis. Despite the 2.3 MDa molecular weight of the bacterial 70S ribosome, many nascent polypeptides, and some ribosomal proteins, have sufficient local flexibility that sharp resonances may be observed in solution-state NMR spectra. In providing information on dynamic regions of the structure, NMR spectroscopy is therefore highly complementary to alternative methods such as X-ray crystallography and cryo-electron microscopy, which have successfully characterized the rigid core of the ribosome particle. However, the low working concentrations and limited sample stability associated with ribosome–nascent chain complexes means that such studies still present significant technical challenges to the NMR spectroscopist. This review will discuss the progress that has been made in this area, surveying all NMR studies that have been published to date, and with a particular focus on strategies for improving experimental sensitivity. PMID:24083462

Titration of Alanine Monitored by NMR Spectroscopy: A Biochemistry Laboratory Experiment

Science.gov (United States)

Waller, Francis J.; And Others

1977-01-01

The experiment described here involves simultaneous monitoring of pH and NMR chemical shifts during an aqueous titration of alpha- and beta-alanine. This experiment is designed for use in an undergraduate biochemistry course. (MR)

Study on the Effects of Oligo chitosan and Bioliquifert on Two Rice Mutants, NMR 151 and NMR 152

International Nuclear Information System (INIS)

Shakinah Salleh; Faiz Ahmad; Sobri Hussein

2016-01-01

Nuclear Malaysia has successfully developed two new rice mutants namely NMR 151 and NMR 152. In addition, Nuclear Malaysia has also successfully developed Oligo chitosan and liquid bio fertilizer (Bioliquifert). Oligo chitosan acts as elicitor that has been proven to be very effective in controlling disease infections and improving yield productivity. Bioliquifert on the other hand is a mixture of microbes containing major nutrient-providing microorganisms. The objective of this study is to observe the effects of Oligo chitosan and Bioliquifert on rice mutants, NMR 151 and NMR 152. The treatment was applied on 14 day old seedlings of MR 219, NMR 151 and NMR 152 sowed in 20 cm pots containing silty clay from the paddy soil of Tanjung Karang, Selangor. The seedlings were then placed in the greenhouse at Nuclear Malaysia until it reaches 110 days old. Study was conducted in a Complete Randomized Design (CRD) with 3 replications was used and each replication consisted of three plants. All treatments received compound and single dressing fertilizer as recommended by National Rice Production Package except for Treatment 2 and 3, in which Treatment 2 received Oligo chitosan and Bioliquifert while Treatment 3 only received Bioliquifert. Results on plant height, number of tiller and plant fresh weight are not significantly different for all cultivar except for seed dry weight of NMR 152 and MR 219. (author)

NMR-Metabolic Methodology in the Study of GM Foods

Science.gov (United States)

The 1H NMR methodology used in the study of genetically modified (GM) foodstuff is discussed. The study of transgenic lettuce (Lactuca sativa cv "Luxor") over-expressing the KNAT1 gene from Arabidopsis is presented as a novel study-case. The 1H NMR metabolic profiling was carried out. Twenty-two wat...

Methods of NMR structure refinement: molecular dynamics simulations improve the agreement with measured NMR data of a C-terminal peptide of GCN4-p1

Energy Technology Data Exchange (ETDEWEB)

Dolenc, Jozica [Swiss Federal Institute of Technology, Laboratory of Physical Chemistry, ETH (Switzerland); Missimer, John H.; Steinmetz, Michel O. [Paul Scherrer Institut, Biomolecular Research (Switzerland); Gunsteren, Wilfred F. van, E-mail: wfvgn@igc.phys.chem.ethz.c [Swiss Federal Institute of Technology, Laboratory of Physical Chemistry, ETH (Switzerland)

2010-07-15

The C-terminal trigger sequence is essential in the coiled-coil formation of GCN4-p1; its conformational properties are thus of importance for understanding this process at the atomic level. A solution NMR model structure of a peptide, GCN4p16-31, encompassing the GCN4-p1 trigger sequence was proposed a few years ago. Derived using a standard single-structure refinement protocol based on 172 nuclear Overhauser effect (NOE) distance restraints, 14 hydrogen-bond and 11 {phi} torsional-angle restraints, the resulting set of 20 NMR model structures exhibits regular {alpha}-helical structure. However, the set slightly violates some measured NOE bounds and does not reproduce all 15 measured {sup 3}J(H{sub N}-H{sub C{alpha}})-coupling constants, indicating that different conformers of GCN4p16-31 might be present in solution. With the aim to resolve structures compatible with all NOE upper distance bounds and {sup 3}J-coupling constants, we executed several structure refinement protocols employing unrestrained and restrained molecular dynamics (MD) simulations with two force fields. We find that only configurational ensembles obtained by applying simultaneously time-averaged NOE distance and {sup 3}J-coupling constant restraining with either force field reproduce all the experimental data. Additionally, analyses of the simulated ensembles show that the conformational variability of GCN4p16-31 in solution admitted by the available set of 187 measured NMR data is larger than represented by the set of the NMR model structures. The conformations of GCN4p16-31 in solution differ in the orientation not only of the side-chains but also of the backbone. The inconsistencies between the NMR model structures and the measured NMR data are due to the neglect of averaging effects and the inclusion of hydrogen-bond and torsional-angle restraints that have little basis in the primary, i.e. measured NMR data.

Secondary structure determination of human. beta. -endorphin by /sup 1/H NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Lichtarge, O.; Jardetzky, O.; Li, C.H.

1987-09-08

The /sup 1/H NMR spectra of human ..beta..-endorphin indicate that the peptide exists in random-coil form in aqueous solution but becomes helical in mixed solvent. Thermal denaturation NMR experiments show that in water there is no transition between 24 and 75/sup 0/C, while a slow noncooperative thermal unfolding is observed in a 60% methanol-40% water mixed solvent in the same temperature range. These findings are consistent with circular dichroism studies by other workers concluding that ..beta..-endorphin is a random coil in water but that it forms 50% ..cap alpha..-helix or more in mixed solvents. The peptide in the mixed water-methanol solvent was further studied by correlated spectroscopy (COSY) and nuclear Overhauser effect spectroscopy (NOESY) experiments. These allow a complete set of assignments to be made and establish two distinct stretches over which the solvent induces formation of ..cap alpha..-helices: the first occurs between Tyr-1 and Thr-12 and the second between Leu-14 and extending to Lys-28. There is evidence that the latter is capped by a turn occurring between Lys-28 and Glu-31. These helices form at the enkephalin receptor binding site, which is at the amino terminus, and at the morphine receptor binding site, located at the carboxyl terminus. The findings suggest that these two receptors may specifically recognize ..cap alpha..-helices.

Methodology for the identification of tri-terpenes mixtures components by {sup 13} C NMR; Metodologia para identificao dos componentes de misturas de triterpenos por RMN de {sup 13} C

Energy Technology Data Exchange (ETDEWEB)

Olea, Roberto S.G.

1990-12-31

This work describes a methodology for the identification of tri terpenes complex mixtures by {sup 13} C NMR. The use of {sup 13} C NMR techniques, such as obtention of noise decoupled spectra, DEPT 135 and DEPT 90 sequences, allowed the identification of components of triterpene mixtures with identical functionality through comparison of observed {sup 13} C NMR chemical shifts with {sup 13} C NMR chemical shifts reported in the literature. The method proved to be specially helpful in the identification of triterpenes by analysis of chemical shifts assignable to doubly bonded carbons, since the particular position of such double bonds is characteristic of some triterpene skeletons. Application of this methodology indicated the presence of bauerenol, {alpha}-amyrin and {beta}-amyrin in Acmanthera latifolis Griseb. (Malpighiaceae); of germanicone, lupenone, {alpha}-amyrenone and {beta}-amyrenone in Alibertia macrophylla A. Rich. (Rubiaceae); of {alpha}-amyrin acetate, lupeol acetate and {beta}-amyrin acetate in Vernonia polyanthes Schreb. (Asteraceae); {alpha}-amyrenone, {beta}-amyrenone, boehmerone, friedelin, lupenone, {alpha}-amyrin, {beta}-amyrin and glutinol in Scoparia dulcis L. (Scrophulariaceae). (author). 37 refs., 93 figs.

Methodology for the identification of tri-terpenes mixtures components by {sup 13} C NMR; Metodologia para identificao dos componentes de misturas de triterpenos por RMN de {sup 13} C

Energy Technology Data Exchange (ETDEWEB)

Olea, Roberto S.G.

1991-12-31

This work describes a methodology for the identification of tri terpenes complex mixtures by {sup 13} C NMR. The use of {sup 13} C NMR techniques, such as obtention of noise decoupled spectra, DEPT 135 and DEPT 90 sequences, allowed the identification of components of triterpene mixtures with identical functionality through comparison of observed {sup 13} C NMR chemical shifts with {sup 13} C NMR chemical shifts reported in the literature. The method proved to be specially helpful in the identification of triterpenes by analysis of chemical shifts assignable to doubly bonded carbons, since the particular position of such double bonds is characteristic of some triterpene skeletons. Application of this methodology indicated the presence of bauerenol, {alpha}-amyrin and {beta}-amyrin in Acmanthera latifolis Griseb. (Malpighiaceae); of germanicone, lupenone, {alpha}-amyrenone and {beta}-amyrenone in Alibertia macrophylla A. Rich. (Rubiaceae); of {alpha}-amyrin acetate, lupeol acetate and {beta}-amyrin acetate in Vernonia polyanthes Schreb. (Asteraceae); {alpha}-amyrenone, {beta}-amyrenone, boehmerone, friedelin, lupenone, {alpha}-amyrin, {beta}-amyrin and glutinol in Scoparia dulcis L. (Scrophulariaceae). (author). 37 refs., 93 figs.

Determination of the pKa value of the hydroxyl group in the alpha-hydroxycarboxylates citrate, malate and lactate by 13C NMR: implications for metal coordination in biological systems.

Science.gov (United States)

Silva, Andre M N; Kong, XiaoLe; Hider, Robert C

2009-10-01

Citric acid is an important metal chelator of biological relevance. Citric acid helps solubilizing metals, increasing their bioavailability for plants and microbes and it is also thought to be a constituent of both the extracellular and cytoplasmic low molecular iron pools occurring in plants and vertebrates. Metal coordination by citric acid involves coordination both by the carboxylate and hydroxyl groups, of particular interest is its alpha-hydroxycarboxylate function. This structural feature is highly conserved in siderophores produced by evolutionarily distant species and seems to confer specificity toward Fe(III) binding. In order to understand the mechanism of metal coordination by alpha-hydroxycarboxylates and correctly evaluate the respective complex stability constants, it is essential to improve the knowledge about the ionisation of the alcohol group in these compounds. We have evaluated the hydroxyl pKa value of citric, malic and lactic acids with the objective of understanding the influence of alpha-carbon substitution. Studies at high pH values, utilizing (13)C NMR, permitted estimation of the pKa values for the three acids. The pKa (alcohol) values (14.4 for citric acid, 14.5 for malic acid, and 15.1 for lactic acid) are considerably higher than the previously reported value for citric acid (11.6) but still lower than the value of 15.5 for methanol. A comparative analysis of the three compounds indicates that different substitutions on the alpha-carbon introduce changes to the inductive effect experienced by the hydroxyl group thereby modulating its ionisation behaviour. Comparison with the siderophore rhizoferrin, which pKa (alcohol) values were confirmed to be 10 and 11.3, suggests that intra-molecular hydrogen bonding may also aid in the hydroxyl ionisation by stabilizing the resulting anion. Studies of metal coordination by alpha-hydroxycarboxylates should take these factors into account.

Studies on /sup 13/C-NMR spectroscopy of carbohydrates. Application of selective deuteration

Energy Technology Data Exchange (ETDEWEB)

Mizutani, Kenji; Kajita, Hitomi; Tashima, Takako; Tanaka, Osamu (Hiroshima Univ. (Japan). School of Medicine)

1982-10-01

Recently, Stuart et al. have reported that on heating with deuterated Raney nickel in D/sub 2/O, hexopyranosides and oligosaccharides were deuterated selectively at carbon atoms bound to a free hydroxyl group. For the application of this procedure to chemistry and biochemistry of more complex carbohydrates, further study on this reaction was conducted. On prolonged treatment with Raney nickel (24h), methyl ..cap alpha..-L-arabinopyranoside (4) and ..beta..-D-xylopyranoside (5) were partially epimerized to give (5) and methyl ..cap alpha..-L-lyxopyranoside (6) from (4), and methyl ..beta..-D-ribopyranoside (7) and (4) from (5), respectively. Methyl ..cap alpha..-L-rhamnopyranoside (8) was epimerized more slowly to yield methyl 6-deoxy-..cap alpha..-L-glucopyranoside (9). The best conditions for the deuteration under minimizing the epimerization was refluxing with W-7 type deuterated Raney nickel in D/sub 2/O-dioxane (1 : 1) or methanol-d/sub 4/-D/sub 2/O (1 : 1) for about 9h. Methyl ..beta..-sophoroside (13), methyl ..beta..-cellobioside (23) and ..beta..-sophorosyl and ..beta..-gentiobiosyl units of ginsenoside-Rb/sub 1/ (24), a Ginseng-saponin, were deuterated as expected under these conditions, while C-2 and 4 of the inner ..beta..-glucopyranosyl moiety of methyl ..beta..-laminaribioside (18) and C-4 of the inner ..beta..-glucopyranosyl moiety of methyl 2,3-di-O-..beta..-D-glucopyranosyl-..beta..-D-glucopyranoside (22) remained almost undeuterated. Deuteration of ..cap alpha..-1,6-glucan (25) proceeded rather slowly than those of mono- and oligosaccharide to obtain the expected deuteration after treatment for 24h. In the case of the deuteration of cis- and dl-trans-1, 2-cyclohexanediols (11) and ( (12), both deuteration and epimerization proceeded very fast to give an equilibrated mixture of (11-d/sub 2/) and (12-d/sub 2/) within 9h, while the isolated carbinyl carbon (C-12) of (24) was not deuterated. Further, by means of the above selective deuteration, /sup 13

NMR imaging studies of coal

Energy Technology Data Exchange (ETDEWEB)

Ma, Z.R.; Zhang, P.Z.; Ding, G.L.; Li, L.Y.; Ye, C.H. [University of Science and Technology, Beijing (China). Dept. of Chemistry

1996-06-01

The permeation transportation and swelling behavior of solvents into coal are investigated by NMR imaging using pyridine-d{sub 5} and acetone-d{sub 6}. Images of coal swollen with deuterated solvents illuminate proton distributions of mobile phases within the coal macromolecular networks. More information about the chemical and physical structure of coal can be obtained using NMR imaging techniques.

NMR study of Albemoschus esculentus characterization

International Nuclear Information System (INIS)

Bathista, A.L.B.S; Silva, E.O.; Nogueira, Jose de S.; Tavares, M.I.B.

2001-01-01

The investigation of the main compounds presented in the Albemoschus esculentus has been carried out employing nuclear magnetic resonance spectroscopy (NMR), using solution and solid state NMR when it one was necessary. The evaluation of NMR data allowed us to characterize the main type of components presented in this kind of sample. It was necessary to use a total information from solid state NMR and also the solution response. From these information we could get that four main components were presented in this sample. One in the shell, that is cellulose, another one between the shell and seeds that is a polysaccharide and in the seed two components were found one is a starch and the second one is an oil, a triacylglycerol. These components are responsible by its physical chemistry properties. (author)

NMR studies of metallic tin confined within porous matrices

International Nuclear Information System (INIS)

Charnaya, E. V.; Tien, Cheng; Lee, M. K.; Kumzerov, Yu. A.

2007-01-01

119 Sn NMR studies were carried out for metallic tin confined within synthetic opal and porous glass. Tin was embedded into nanoporous matrices in the melted state under pressure. The Knight shift for liquid confined tin was found to decrease with decreasing pore size. Correlations between NMR line shapes, Knight shift, and pore filling were observed. The melting and freezing phase transitions of tin under confinement were studied through temperature dependences of NMR signals upon warming and cooling. Melting of tin within the opal matrix agreed well with the liquid skin model suggested for small isolated particles. The influence of the pore filling on the melting process was shown

Study of some features of coordination polymerization of. cap alpha. -oxides by the example of forming U(4) alkoxyhalides

Energy Technology Data Exchange (ETDEWEB)

Khvostik, G M; Minevich, V Ya; Shupik, A N

1985-10-01

The interaction of uranium tetrachloride with ..cap alpha..-oxides in THF has been studied by NMR and conductometry methods. The opening of the oxide cycle under the action of UCl/sub 4/ is shown. The formation of the coordinational bond between the oxygen atom of the polyester clain and the catalytic centre is found to result in retardation of the reactions of the chain propagation. The general scheme of the reactions of interaction of UCl/sub 4/ with oxides is proposed.

DNA oligonucleotide conformations: high resolution NMR studies

International Nuclear Information System (INIS)

Mellema, J.-R.

1984-01-01

The present work describes a DNA double-helix model, which is well comparable with the models derived from fibre-diffraction studies. The model has a mononucleotide repeat with torsion angles in accordance with average geometries as derived from 1 H NMR studies. Special attention was paid to reduce the number of short H-H nonbonding contacts, which are abundantly present in the 'classical' fibre-diffraction models. Chapter 3 describes the first complete assignment of a 1 H NMR spectrum of a DNA tetramer, d(TAAT). Preliminary conformational data derived from the spectral parameters recorded at 27 0 C are given. A more detailed analysis employing temperature-dependence studies is given in Chapter 4. (Auth.)

NMR-Metabolic Methodology in the Study of GM Foods

Directory of Open Access Journals (Sweden)

Irene D’Amico

2010-01-01

Full Text Available The 1H-NMR methodology used in the study of genetically modified (GM foods is discussed. Transgenic lettuce (Lactuca sativa cv "Luxor" over-expressing the Arabidopsis KNAT1 gene is presented as a case study. Twenty-two water-soluble metabolites (amino acids, organic acids, sugars present in leaves of conventional and GM lettuce were monitored by NMR and quantified at two developmental stages. The NMR spectra did not reveal any difference in metabolite composition between the GM lettuce and the wild type counterpart. Statistical analyses of metabolite variables highlighted metabolism variation as a function of leaf development as well as the transgene. A main effect of the transgene was in altering sugar metabolism.

NMR study of LaPb2

International Nuclear Information System (INIS)

Ueda, K.; Kohara, T.; Yamada, Y.

1995-01-01

La and Pb NMR signals were observed in LaPb 2 with a superconducting transition temperature of about 7 K. The width of the Pb NMR spectrum with an asymmetric line shape was rather narrower than those of Er-, Gd- and Ho-Pb 2 . The spin-lattice relaxation time of Pb nuclei was twice longer than that of Pb metal. La NMR spectrum had satellites due to the electric quadrupole interaction. These results show that each local environment at La or Pb site in LaPb 2 compound is uniquely determined, compared with those in randomly substituted alloys. ((orig.))

Measurement of conformational constraints in an elastin-mimetic protein by residue-pair selected solid-state NMR

Energy Technology Data Exchange (ETDEWEB)

Hong, Mei [Iowa State University, Department of Chemistry (United States)], E-mail: mhong@iastate.edu; McMillan, R. Andrew; Conticello, Vincent P. [Emory University, Department of Chemistry (United States)

2002-02-15

We introduce a solid-state NMR technique for selective detection of a residue pair in multiply labeled proteins to obtain site-specific structural constraints. The method exploits the frequency-offset dependence of cross polarization to achieve {sup 13}CO{sub i} {sup {yields}} {sup 15}N{sub i} {sup {yields}} {sup 13}C{alpha}{sub i} transfer between two residues. A {sup 13}C, {sup 15}N-labeled elastin mimetic protein (VPGVG){sub n} is used to demonstrate the method. The technique selected the Gly3 C{alpha} signal while suppressing the Gly5 C{alpha} signal, and allowed the measurement of the Gly3 C{alpha} chemical shift anisotropy to derive information on the protein conformation. This residue-pair selection technique should simplify the study of protein structure at specific residues.

Successful Sampling Strategy Advances Laboratory Studies of NMR Logging in Unconsolidated Aquifers

Science.gov (United States)

Behroozmand, Ahmad A.; Knight, Rosemary; Müller-Petke, Mike; Auken, Esben; Barfod, Adrian A. S.; Ferré, Ty P. A.; Vilhelmsen, Troels N.; Johnson, Carole D.; Christiansen, Anders V.

2017-11-01

The nuclear magnetic resonance (NMR) technique has become popular in groundwater studies because it responds directly to the presence and mobility of water in a porous medium. There is a need to conduct laboratory experiments to aid in the development of NMR hydraulic conductivity models, as is typically done in the petroleum industry. However, the challenge has been obtaining high-quality laboratory samples from unconsolidated aquifers. At a study site in Denmark, we employed sonic drilling, which minimizes the disturbance of the surrounding material, and extracted twelve 7.6 cm diameter samples for laboratory measurements. We present a detailed comparison of the acquired laboratory and logging NMR data. The agreement observed between the laboratory and logging data suggests that the methodologies proposed in this study provide good conditions for studying NMR measurements of unconsolidated near-surface aquifers. Finally, we show how laboratory sample size and condition impact the NMR measurements.

Design of ET(B) receptor agonists: NMR spectroscopic and conformational studies of ET7-21[Leu7, Aib11, Cys(Acm)15].

Science.gov (United States)

Hewage, Chandralal M; Jiang, Lu; Parkinson, John A; Ramage, Robert; Sadler, Ian H

2002-03-01

In a previous report we have shown that the endothelin-B receptor-selective linear endothelin peptide, ET-1[Cys (Acm)1,15, Ala3, Leu7, Aib11], folds into an alpha-helical conformation in a methanol-d3/water co-solvent [Hewage et al. (1998) FEBS Lett., 425, 234-238]. To study the requirements for the structure-activity relationships, truncated analogues of this peptide were subjected to further studies. Here we report the solution conformation of ET7-21[Leu7, Aib11, Cys(Acm)15], in a methanol-d3/water co-solvent at pH 3.6, by NMR spectroscopic and molecular modelling studies. Further truncation of this short peptide results in it displaying poor agonist activity. The modelled structure shows that the peptide folds into an alpha-helical conformation between residues Lys9-His16, whereas the C-terminus prefers no fixed conformation. This truncated linear endothelin analogue is pivotal for designing endothelin-B receptor agonists.

A comparative study of bone scintigraphy and NMR for vertebral diseases

International Nuclear Information System (INIS)

Nakatani, Mariko; Sekiya, Toru; Hata, Yuichi; Mori, Yutaka; Yasuda, Masanobu; Kawakami, Kenji; Tada, Sinpei

1985-01-01

A comparative study of NMR and bone scintigraphy was performed in vertebral disorders, and the significance of both modalities was evaluated. Twelve patients with various vertebral abnormalities including ten cases of vertebral metastases, one case of cervical caries and one case of Granular cell tumor of L3, were examined. In 4 patients, NMR showed abnormalities in the same regions as the bone scintigrams. In another 3 patients. NMR did not show the disorders reported on bone scintigrams. This may be due to the low NMR sensitivity to tiny infiltration of tumor cells in the bone marrow. In 3 out of the remaining 5 patients, NMR demonstrated abnormal findings, whilst the bone scintigrams were normal. Previous bone scintigrams in these patients before treatment had shown abnormal accumulation of activity in the region of abnormal NMR findings. This may be due to the fact that NMR detects the irreversible change of bone marrow, and bone scintigram demonstrates the turn over of bone minerals. This limited experience suggests that both madalities are complementary in the evaluation of vertebral abnormalities. (author)

Rhodopsin-lipid interactions studied by NMR.

Science.gov (United States)

Soubias, Olivier; Gawrisch, Klaus

2013-01-01

The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200-nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60μm yields on the order of 500cm(2) of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated, and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. Copyright © 2013 Elsevier Inc. All rights reserved.

Structural and functional characterization of the conserved salt bridge in mammalian paneth cell alpha-defensins

DEFF Research Database (Denmark)

Rosengren, K Johan; Daly, Norelle L; Fornander, Liselotte M

2006-01-01

alpha-Defensins are mediators of mammalian innate immunity, and knowledge of their structure-function relationships is essential for understanding their mechanisms of action. We report here the NMR solution structures of the mouse Paneth cell alpha-defensin cryptdin-4 (Crp4) and a mutant (E15D)-C...

Hyperpolarized 129Xe as an NMR probe for functional studies

International Nuclear Information System (INIS)

Wolber, J.

2000-01-01

The nuclear spin polarization of 129 Xe can be enhanced by several orders of magnitude using optical pumping techniques, resulting in a dramatic enhancement of the 129 Xe Nuclear Magnetic Resonance (NMR) signal. The 'hyperpolarized' gas can be used for Magnetic Resonance Imaging (MRI) of the void spaces of the lungs after introduction of the gas into the respiratory system. Furthermore, the high solubility of xenon in blood and lipids suggests the use of 129 Xe NMR for studying blood flow, permeability, perfusion and blood volume. Hyperpolarized 129 Xe MRI has the potential of combining the high sensitivity and functional information of radioactive tracer studies with the high spatial and temporal resolution of MRI. The spin-lattice relaxation time T 1 of 129 Xe in blood determines the loss of polarization during transit from the lungs to the tissue of interest. A difference in the relaxation times of xenon in oxygenated and deoxygenated blood could be used as a contrast mechanism in functional Magnetic Resonance Imaging (fMRI). In this thesis, the hyperpolarized 129 Xe T 1 in human blood is measured in vitro as a function of blood oxygenation, and the relevant relaxation mechanisms are discussed. A new and unexpected finding is that the hyperpolarized 129 Xe NMR spectrum in blood is highly sensitive to blood oxygenation. Therefore, hyperpolarized 129 Xe NMR provides a powerful means of measuring blood oxygenation quantitatively and non-invasively. The interaction of xenon with hemoglobin is responsible for an oxygen-dependent shift of the 129 Xe NMR resonance of xenon in red blood cells. Injection delivery of hyperpolarized 129 Xe in solution could be a more efficient method of administrating the gas for functional NMR studies. For this purpose, suitable biocompatible carrier media have been studied. In particular, the use of perfluorocarbon emulsions, which are already in use as blood substitutes, as delivery media for hyperpolarized 129 Xe has been investigates

Proton NMR studies of functionalized nanoparticles in aqueous environments

Science.gov (United States)

Tataurova, Yulia Nikolaevna

Nanoscience is an emerging field that can provide potential routes towards addressing critical issues such as clean and sustainable energy, environmental remediation and human health. Specifically, porous nanomaterials, such as zeolites and mesoporous silica, are found in a wide range of applications including catalysis, drug delivery, imaging, environmental protection, and sensing. The characterization of the physical and chemical properties of nanocrystalline materials is essential to the realization of these innovative applications. The great advantage of porous nanocrystals is their increased external surface area that can control their biological, chemical and catalytic activities. Specific functional groups synthesized on the surface of nanoparticles are able to absorb heavy metals from the solution or target disease cells, such as cancer cells. In these studies, three main issues related to functionalized nanomaterials will be addressed through the application of nuclear magnetic resonance (NMR) techniques including: 1) surface composition and structure of functionalized nanocrystalline particles; 2) chemical properties of the guest molecules on the surface of nanomaterials, and 3) adsorption and reactivity of surface bound functional groups. Nuclear magnetic resonance (NMR) is one of the major spectroscopic techniques available for the characterization of molecular structure and conformational dynamics with atomic level detail. This thesis deals with the application of 1H solution state NMR to porous nanomaterial in an aqueous environment. Understanding the aqueous phase behavior of functionalized nanomaterials is a key factor in the design and development of safe nanomaterials because their interactions with living systems are always mediated through the aqueous phase. This is often due to a lack of fundamental knowledge in interfacial chemical and physical phenomena that occur on the surface of nanoparticles. The use of solution NMR spectroscopy results

NMR and optical studies of piezoelectric polymers

International Nuclear Information System (INIS)

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

1993-01-01

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

Alpha particle studies during JET DT experiments

International Nuclear Information System (INIS)

1999-01-01

The 1997 DT experiment (DTE1) at the Joint European Torus included studies of the behaviour of alpha particles in high temperature plasmas. Clear alpha particle heating was observed in a series of otherwise similar 10MW hot-ion H-modes by scanning the DT mixture from 0%T to 93%T. Maxima in central temperature and energy content were obtained which corresponded with the maximum in fusion yield. Alfven Eigenmodes (AEs) have been detected in JET, driven by NBI or ICRH fast ions. However, in agreement with theory, no AE activity was observed in DT plasmas which could be attributed to alpha particle drive, except in the afterglow of some Optimised Shear pulses. Ion Cyclotron Emission (ICE) was detected at harmonics of the alpha particle cyclotron frequency at the outer edge of the plasma. The ICE is interpreted as being close to magnetoacoustic cyclotron instability, driven by inverted alpha distributions at the plasma edge. The high-energy neutral particle spectra showed features, which are ascribed to a mixture of alphas, neutralised by helium-like impurities, and deuterons, born from elastic collisions with alpha particles and neutralised by hydrogen-like impurities. The results of all these studies are consistent with classical alpha particle trapping and slowing-down. Future DT experiments will aim to increase alpha particle pressure, so interactions with plasma instabilities can be studied. The measurement of knock-on neutral triton spectra offers a clean way to determine confined alpha densities in these future experiments. (author)

Alpha particle studies during JET DT experiments

International Nuclear Information System (INIS)

2001-01-01

The 1997 DT experiment (DTE1) at the Joint European Torus included studies of the behaviour of alpha particles in high temperature plasmas. Clear alpha particle heating was observed in a series of otherwise similar 10MW hot-ion H-modes by scanning the DT mixture from 0%T to 93%T. Maxima in central temperature and energy content were obtained which corresponded with the maximum in fusion yield. Alfven Eigenmodes (AEs) have been detected in JET, driven by NBI or ICRH fast ions. However, in agreement with theory, no AE activity was observed in DT plasmas which could be attributed to alpha particle drive, except in the afterglow of some Optimised Shear pulses. Ion Cyclotron Emission (ICE) was detected at harmonics of the alpha particle cyclotron frequency at the outer edge of the plasma. The ICE is interpreted as being close to magnetoacoustic cyclotron instability, driven by inverted alpha distributions at the plasma edge. The high-energy neutral particle spectra showed features, which are ascribed to a mixture of alphas, neutralised by helium-like impurities, and deuterons, born from elastic collisions with alpha particles and neutralised by hydrogen-like impurities. The results of all these studies are consistent with classical alpha particle trapping and slowing-down. Future DT experiments will aim to increase alpha particle pressure, so interactions with plasma instabilities can be studied. The measurement of knock-on neutral triton spectra offers a clean way to determine confined alpha densities in these future experiments. (author)

NMR studies of macroscopic and microscopic properties of liquid crystals

International Nuclear Information System (INIS)

Hughes, J.R.

1998-03-01

The work presented is concerned with studies of orientational order in liquid crystals and the behaviour of certain mesophases. The experimental technique used in common with all the work is deuterium NMR spectroscopy. Much of the work involves studies of the orientational order of deuteriated solute molecules dissolved in liquid crystal solvents. Chapter 1 gives an introduction to liquid crystals followed by a quantitative description of orientational order. Deuterium NMR in liquid crystals is described and an outline of the molecular field theory behind the orientational order of a rigid, biaxial solute in a uniaxial mesophase is given. In Chapter 2 a novel type of mesophase induction is studied using NMR, where a solute induces up to two extra phases in a discotic mesogen depending on its concentration. The purpose of this work is to try to gain an understanding into the mechanism of the phase induction involved. Chapter 3 is concerned primarily with the macroscopic behaviour of the nematic phase formed by a semi-rigid main-chain polymer in solution. Of particular interest is the study of the reorientation of the monodomain, once the director has been rotated with respect to the magnetic field of the NMR spectrometer. A mesogen which has been claimed to exhibit a biaxial nematic phase is studied in Chapter 4, in order to determine the symmetry of the phase using NMR. Finally, Chapter 5 deals with the differing behaviour of a liquid crystal monomer and its dimer dissolved in common nematic solvents in order to determine whether this agrees with molecular field theory. (author)

Novel NMR tools to study structure and dynamics of biomembranes.

Science.gov (United States)

Gawrisch, Klaus; Eldho, Nadukkudy V; Polozov, Ivan V

2002-06-01

Nuclear magnetic resonance (NMR) studies on biomembranes have benefited greatly from introduction of magic angle spinning (MAS) NMR techniques. Improvements in MAS probe technology, combined with the higher magnetic field strength of modern instruments, enables almost liquid-like resolution of lipid resonances. The cross-relaxation rates measured by nuclear Overhauser enhancement spectroscopy (NOESY) provide new insights into conformation and dynamics of lipids with atomic-scale resolution. The data reflect the tremendous motional disorder in the lipid matrix. Transfer of magnetization by spin diffusion along the proton network of lipids is of secondary relevance, even at a long NOESY mixing time of 300 ms. MAS experiments with re-coupling of anisotropic interactions, like the 13C-(1)H dipolar couplings, benefit from the excellent resolution of 13C shifts that enables assignment of the couplings to specific carbon atoms. The traditional 2H NMR experiments on deuterated lipids have higher sensitivity when conducted on oriented samples at higher magnetic field strength. A very large number of NMR parameters from lipid bilayers is now accessible, providing information about conformation and dynamics for every lipid segment. The NMR methods have the sensitivity and resolution to study lipid-protein interaction, lateral lipid organization, and the location of solvents and drugs in the lipid matrix.

Case Study - Alpha

Directory of Open Access Journals (Sweden)

Stephen Leybourne

2016-11-01

Full Text Available This case study was developed from an actual scenario by Dr. Steve Leybourne of Boston University.  The case documents the historical evolution of an organization, and has been used successfully in courses dealing with organizational and cultural change, and the utilization of ‘soft skills’ in project-based management. This is a short case, ideal for classroom use and discussion.  The issues are easily accessible to students, and there is a single wide ranging question that allows for the inclusion of many issues surrounding strategic decision-making, and behavioural and cultural change. Alpha was one of the earlier companies in the USA to invest in large, edge-of-town superstores, with plentiful free vehicle parking, selling food and related household products. Alpha was created in the 1950s as a subsidiary of a major publicly quoted retail group.  It started business by opening a string of very large discount stores in converted industrial and warehouse premises in the south of the United States. In the early days shoppers were offered a limited range of very competitively priced products. When Alpha went public in 1981 it was the fourth largest food retailer in the US, selling an ever-widening range of food and non-food products.  Its success continued to be based on high volume, low margins and good value for money, under the slogan of ‘Alpha Price.’

Conformation of glycomimetics in the free and protein-bound state: structural and binding features of the C-glycosyl analogue of the core trisaccharide alpha-D-Man-(1 --> 3)-[alpha-D-Man-(1 --> 6)]-D-Man.

Science.gov (United States)

Mikkelsen, Lise Munch; Hernáiz, María José; Martín-Pastor, M; Skrydstrup, Troels; Jiménez-Barbero, Jesús

2002-12-18

The conformational properties of the C-glycosyl analogue of the core trisaccharide alpha-D-Man-(1 --> 3)-[alpha-D-Man-(1 --> 6)]-D-Man in solution have been carefully analyzed by a combination of NMR spectroscopy and time-averaged restrained molecular dynamics. It has been found that both the alpha-1,3- and the alpha-1,6-glycosidic linkages show a major conformational averaging. Unusual Phi ca. 60 degrees orientations for both Phi torsion angles are found. Moreover, a major conformational distinction between the natural compound and the glycomimetic affects to the behavior of the omega(16) torsion angle around the alpha-1 --> 6-linkage. Despite this increased flexibility, the C-glycosyl analogue is recognized by three mannose binding lectins, as shown by NMR (line broadening, TR-NOE, and STD) and surface plasmon resonance (SPR) methods. Moreover, a process of conformational selection takes place, so that these lectins probably bind the glycomimetic similarly to the way they recognize the natural analogue. Depending upon the architecture and extension of the binding site of the lectin, loss or gain of binding affinity with respect to the natural analogue is found.

Overcoming the solubility limit with solubility-enhancement tags: successful applications in biomolecular NMR studies

International Nuclear Information System (INIS)

Zhou Pei; Wagner, Gerhard

2010-01-01

Although the rapid progress of NMR technology has significantly expanded the range of NMR-trackable systems, preparation of NMR-suitable samples that are highly soluble and stable remains a bottleneck for studies of many biological systems. The application of solubility-enhancement tags (SETs) has been highly effective in overcoming solubility and sample stability issues and has enabled structural studies of important biological systems previously deemed unapproachable by solution NMR techniques. In this review, we provide a brief survey of the development and successful applications of the SET strategy in biomolecular NMR. We also comment on the criteria for choosing optimal SETs, such as for differently charged target proteins, and recent new developments on NMR-invisible SETs.

NMR studies of Na+-anion association effects in polymer electrolytes

International Nuclear Information System (INIS)

Greenbaum, S.G.; Pak, Y.S.; Wintergill, M.C.; Fontanella, J.J.

1988-01-01

23 Na nuclear magnetic resonance (NMR) measurements on poly (propylene oxide) (PPO) and siloxane based polymer electrolytes containing various sodium salts at a single nominal concentration are reported. In addition, differential scanning calorimetry (DSC) and electrical conductivity studies were carried out on the PPO materials. The NMR-determined mobile Na + concentrations and DSC results provide evidence for ionic aggregation effects which, for some samples, result in salt precipitation at elevated temperatures. 23 Na chemical shifts observed in solid state NMR due to mobile Na + -anion interactions influence ionic transport as well as the number of available carriers. (author). 19 refs.; 7 figs

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-04-01

High field quantitative 27Al MAS NMR and temperature programmed desorption (TPD) of ethanol are used to study the surface and phase transformation of gamma-Al2O3 during calcination in the temperature range of 500 to 1300 degrees C. Following ethanol adsorption, ethylene is generated during TPD with a desorption temperature > 200 degrees C. With increasing calcination temperature prior to TPD, the amount of ethylene produced decreases monotonically. Significantly, 27Al MAS NMR reveals that the amount of penta-coordinate Al3+ ions (Lewis acid sites) also decreases with increasing calcination temperature. In fact, a strong correlation between the amount of penta-coordinate Al3+ ions and the amount of strongly adsorbed ethanol molecules (i.e., the ones that convert to ethylene during TPD) is obtained. This result indicates that the penta-coordinate aluminum sites are the catalytic active sites on alumina surfaces during ethanol dehydration reaction across the entire course of gamma- to alpha-Al2O3 phase transformations.

Applications of 1H-NMR relaxometry in experimental liver studies

International Nuclear Information System (INIS)

Holzmueller, P.

1992-01-01

Purpose of this study was to investigate applications of proton nuclear magnetic resonance ( 1 H-NMR) relaxometry in experimental medicine. Relaxometry was performed by measurements of spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation time parameters on liver biopsies up to four hours after biopsy excision. Variations of relaxation times due to species and strain, different sample handling and different liver damage models, ethionine fatty liver and paracetamol liver necrosis, were investigated. Cell integrity effects were studied on homogenized liver samples. Relaxation time parameters, especially 'main' components T 1A and T 2A of biexponential model fit, were identified to react very sensitive after tissue damages as well as to cell viability. Thus, investigation of stored liver grafts was performed in order to evaluate the possibility of a rapid liver graft viability testing method for human liver transplantation surgery by 1 H-NMR relaxometry. Another series of measurements was performed to investigate the applicability of isoflurane anesthesia for in vivo NMR experiments. This study proved the good appropriateness of isoflurane for that purpose provided that physiological monitoring and individual adjustment of anesthesia are performed. In these investigations it could be revealed that mainly T 1A and T 2A are influenced by tissue condition and that different information is inherent in these two parameters, with T 2A reflecting tissue viability and changes of tissue conditions very sensitively but rather unspecifically in respect to the damage applied. Based on these results the following future applications of 1 H-NMR relaxometry are suggested : (1) model investigations, (2) investigation of given pathologies, (3) investigation of basic requirements for in vivo NMR and (4) application in a liver graft viability testing protocol, which seems to be the most important future application of 1 H-NMR relaxometry in medicine. (author)

On-Going Bentonite Pore Water Studies by NMR and SAXS

International Nuclear Information System (INIS)

Carlsson, Torbjoern; Muurinen, Arto; Root, Andrew

2013-01-01

Compacted water-saturated MX-80 bentonite is presently being studied by SAXS and NMR in order to quantify the major pore water phases in the bentonite. The SAXS and NMR measurements gave very similar results indicating that the pore water is mainly distributed between two major phases (interlayer and non-interlayer water) and also indicate how these phases depend on the bentonite dry density. The results from the SAXS and NMR studies at VTT indicate the same thing: - The pore water in water-saturated compacted (?dry = 0.7-1.6 g/cm 3 ) bentonite is divided into two main phases: interlayer water and non-interlayer water. - The amounts of these pore water phases can be determined quantitatively with the above methods. (authors)

Multinuclear MAS NMR studies on coked zeolites H-ZSM-5

International Nuclear Information System (INIS)

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

1991-01-01

During the cracking process carbonaceous materials are deposited on the outer or inner surface of the catalyst. These deposits are in many cases the main cause of catalyst deactivation. Magic angle spinning (MAS) NMR investigations and catalytic n-hexane cracking were carried out on H-ZSM-5 zeolites after a mild hydrothermal de-alumination. By 13 C CP MAS NMR it could be shown that the enhanced catalytic activity does not enhance the coke formation and that the chemical nature of these deposits is essentially aromatic. From 1 H MAS NMR studies performed on shallow-bed activated sealed samples and 27 Al and 29 Si MAS NMR on rehydrated samples it follows that for high coke concentrations the catalyst deactivation is caused mainly by blocking of Broensted acid sites. (author). 27 refs.; 3 figs.; 2 tabs

Automated solid-state NMR resonance assignment of protein microcrystals and amyloids

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Elena [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany); Gath, Julia [ETH Zurich, Physical Chemistry (Switzerland); Habenstein, Birgit [UMR 5086 CNRS/Universite de Lyon 1, Institut de Biologie et Chimie des Proteines (France); Ravotti, Francesco; Szekely, Kathrin; Huber, Matthias [ETH Zurich, Physical Chemistry (Switzerland); Buchner, Lena [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany); Boeckmann, Anja, E-mail: a.bockmann@ibcp.fr [UMR 5086 CNRS/Universite de Lyon 1, Institut de Biologie et Chimie des Proteines (France); Meier, Beat H., E-mail: beme@ethz.ch [ETH Zurich, Physical Chemistry (Switzerland); Guentert, Peter, E-mail: guentert@em.uni-frankfurt.de [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany)

2013-07-15

Solid-state NMR is an emerging structure determination technique for crystalline and non-crystalline protein assemblies, e.g., amyloids. Resonance assignment constitutes the first and often very time-consuming step to a structure. We present ssFLYA, a generally applicable algorithm for automatic assignment of protein solid-state NMR spectra. Application to microcrystals of ubiquitin and the Ure2 prion C-terminal domain, as well as amyloids of HET-s(218-289) and {alpha}-synuclein yielded 88-97 % correctness for the backbone and side-chain assignments that are classified as self-consistent by the algorithm, and 77-90 % correctness if also assignments classified as tentative by the algorithm are included.

NMR studies of the fifth transmembrane segment of Na+,K+-ATPase reveals a non-helical ion-binding region

DEFF Research Database (Denmark)

Underhaug, Jarl; Jakobsen, Louise Odgaard; Esmann, Mikael

2006-01-01

The structure of a synthetic peptide corresponding to the fifth membrane-spanning segment (M5) in Na(+),K(+)-ATPase in sodium dodecyl sulfate (SDS) micelles was determined using liquid-state nuclear magnetic resonance (NMR) spectroscopy. The spectra reveal that this peptide is substantially less...... transmembrane element of the Ca(2+)-ATPase. Furthermore, this region spans the residues implicated in Na(+) and K(+) transport, where they are likely to offer the flexibility needed to coordinate Na(+) as well as K(+) during active transport....... alpha-helical than the corresponding M5 peptide of Ca(2+)-ATPase. A well-defined alpha-helix is shown in the C-terminal half of the peptide. Apart from a short helical stretch at the N-terminus, the N-terminal half contains a non-helical region with two proline residues and sequence similarity to a non-structured...

NMR studies of multiphase flows II

Energy Technology Data Exchange (ETDEWEB)

Altobelli, S.A.; Caprihan, A.; Fukushima, E. [Lovelace Institutes, Albuquerque, NM (United States)] [and others

1995-12-31

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

NMR spectroscopy applied to the eye: Drugs and metabolic studies

Energy Technology Data Exchange (ETDEWEB)

Saether, Oddbjoern

2005-07-01

NMR spectroscopy has been extensively applied in biomedical research during the last decades. It has proved to be an analytical tool of great value. From being mainly used in chemistry, technological developments have expanded the application of NMR spectroscopy to a great wealth of disciplines. With this method, biochemical information can be obtained by analysing tissue extracts. Moreover, NMR spectroscopy is increasingly employed for pharmacokinetic studies and analysis of biofluids. Technological progress has provided increased sensitivity and resolution in the spectra, which enable even more of the complexity of biological samples to be elucidated. With the implementation of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy in biomedicine, intact tissue samples or biopsies can be investigated. Thus, NMR spectroscopy has an ever-increasing impact in metabolic screening of human samples and in animal models, and methods are also increasingly realised in vivo. The present work, NMR spectroscopy applied to eye research, consists of two main parts. Firstly, the feasibility to monitor fluorinated ophthalmic drugs directly in the eye was assessed. Secondly, HR-MAS H1 NMR spectroscopy was applied for metabolic profiling of the anterior eye segment, specifically to analyse metabolic changes in intact corneal and lenticular samples after cataractogenic insults. This work included metabonomics with the application of pattern recognition methods to analyse HR-MAS spectra of eye tissues. Optimisation strategies were explored for F19 NMR detection of fluorinated drugs in a phantom eye. S/N gains in F19 NMR spectroscopy were achieved by implementing time-share H1 decoupling at 2.35 T. The method is advantageous for compounds displaying broad spectral coupling patterns, though detection of drugs at concentrations encountered in the anterior eye segment after topical application was not feasible. Higher magnetic fields and technological improvements could enable

NMR spectroscopy applied to the eye: Drugs and metabolic studies

International Nuclear Information System (INIS)

Saether, Oddbjoern

2005-01-01

NMR spectroscopy has been extensively applied in biomedical research during the last decades. It has proved to be an analytical tool of great value. From being mainly used in chemistry, technological developments have expanded the application of NMR spectroscopy to a great wealth of disciplines. With this method, biochemical information can be obtained by analysing tissue extracts. Moreover, NMR spectroscopy is increasingly employed for pharmacokinetic studies and analysis of biofluids. Technological progress has provided increased sensitivity and resolution in the spectra, which enable even more of the complexity of biological samples to be elucidated. With the implementation of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy in biomedicine, intact tissue samples or biopsies can be investigated. Thus, NMR spectroscopy has an ever-increasing impact in metabolic screening of human samples and in animal models, and methods are also increasingly realised in vivo. The present work, NMR spectroscopy applied to eye research, consists of two main parts. Firstly, the feasibility to monitor fluorinated ophthalmic drugs directly in the eye was assessed. Secondly, HR-MAS H1 NMR spectroscopy was applied for metabolic profiling of the anterior eye segment, specifically to analyse metabolic changes in intact corneal and lenticular samples after cataractogenic insults. This work included metabonomics with the application of pattern recognition methods to analyse HR-MAS spectra of eye tissues. Optimisation strategies were explored for F19 NMR detection of fluorinated drugs in a phantom eye. S/N gains in F19 NMR spectroscopy were achieved by implementing time-share H1 decoupling at 2.35 T. The method is advantageous for compounds displaying broad spectral coupling patterns, though detection of drugs at concentrations encountered in the anterior eye segment after topical application was not feasible. Higher magnetic fields and technological improvements could enable

NMR structural studies of peptides and proteins in membranes

Energy Technology Data Exchange (ETDEWEB)

Opella, S J [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Chemistry

1994-12-31

The use of NMR methodology in structural studies is described as applicable to larger proteins, considering that the majority of membrane proteins is constructed from a limited repertoire of structural and dynamic elements. The membrane associated domains of these proteins are made up of long hydrophobic membrane spanning helices, shorter amphipathic bridging helices in the plane of the bilayer, connecting loops with varying degrees of mobility, and mobile N- and C- terminal sections. NMR studies have been successful in identifying all of these elements and their orientations relative to each other and the membrane bilayer 19 refs., 9 figs.

NMR studies of phase behaviour in polyacrylonitrile solutions

International Nuclear Information System (INIS)

Golightly, J.A.

1998-10-01

The aim of the thesis was to study the phase behaviour of aqueous polyacrylonitrile/NaSCN solutions using a variety of nuclear magnetic resonance techniques. Polyacrylonitrile (PAN) is the basis of the acrylic fibre industry, as such fibres contain at least 85% PAN. Despite this industrial importance, the available literature describing the phase behaviour of PAN in solution is far from comprehensive. Bulk 1 H NMR relaxation measurements were carried out over a wide range of concentrations and temperatures to probe the molecular dynamics of the PAN and water molecules. The relaxation data was found to be biexponential decay for all samples, the relative amplitudes of which were shown to be equal to the ratio of PAN protons to water protons. Both species were found to be in the regime of rapid molecular motion. Bulk 1 H NMR self diffusion measurements, using the PFGSTE technique, exhibited a bi-exponential decay of the echo amplitudes. By careful selection of the observation time, Δ, it was possible to independently probe the water and PAN translational diffusion. A background gradient, resulting from inhomogeneities of the magnetic field, complicated the analysis of the data and a novel polynomial least squares fitting procedure was devised to overcome this effect. The measured attenuation of the water diffusion coefficients (D∼10 -6 -10 -5 cm 2 s -1 ) with increasing PAN volume fraction was modelled according to various theories, including free volume and scaling laws. The study of the PAN diffusion coefficient (D∼10 -7 -10 -6 cm 2 s -1 ) was limited by the experimental constraints of the NMR spectrometer. A 1 H NMR one-dimensional imaging technique was used to study the non-solvent induced phase separation (coagulation) of a PAN solution. The time dependence of the measured profiles allowed observation of the coagulation process. A diffusion model was developed to fit the experimental data using a semi-infinite diffusion framework. The fitting parameters

PVT Degradation Studies: NMR Analysis

Energy Technology Data Exchange (ETDEWEB)

Cho, Herman M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-06-06

Under certain environmental conditions, polyvinyl toluene (PVT) plastic scintillator has been observed to undergo internal fogging. Nuclear magnetic resonance spectroscopy has been used to elucidate the state of water inside the PVT. The deuterium NMR results show that water absorbed by PVT under warm, humid conditions enters several distinct environments, and when the PVT is transferred from incubation to ambient temperature and humidity the water is lost on a time scale of a few hours from these samples. Most of the deuterium NMR peaks can be assigned to bulk liquid water, but almost 35% of the detected signal intensity is contained in a resonance that resembles spectra of water contained in nanometer-scale pores in mesoporous carbon.

nmr spectroscopic study and dft calculations of giao nmr shieldings

African Journals Online (AJOL)

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3Department of Physics, Arts and Science Faculty, Dumlupinar University, Kütahya, ... 1H, 13C NMR chemical shifts and 1JCH coupling constants of .... then estimated using the corresponding TMS shieldings calculated in advance at the same.

Solid-state NMR studies of form I of atorvastatin calcium.

Science.gov (United States)

Wang, Wei David; Gao, Xudong; Strohmeier, Mark; Wang, Wei; Bai, Shi; Dybowski, Cecil

2012-03-22

Solid-state (13)C, (19)F, and (15)N magic angle spinning NMR studies of Form I of atorvastatin calcium are reported, including chemical shift tensors of all resolvable carbon sites and fluorine sites. The complete (13)C and (19)F chemical shift assignments are given based on an extensive analysis of (13)C-(1)H HETCOR and (13)C-(19)F HETCOR results. The solid-state NMR data indicate that the asymmetric unit of this material contains two atorvastatin molecules. A possible structure of Form I of atorvastatin calcium (ATC-I), derived from solid-state NMR data and density functional theory calculations of various structures, is proposed for this important active pharmaceutical ingredient (API).

27Al NMR studies of NpPd5Al2

International Nuclear Information System (INIS)

Chudo, H.; Sakai, H.; Tokunaga, Y.; Kambe, S.; Aoki, D.; Homma, Y.; Shiokawa, Y.; Haga, Y.; Ikeda, S.; Matsuda, T.D.; Onuki, Y.; Yasuoka, H.

2009-01-01

We present 27 Al NMR studies for a single crystal of the Np-based superconductor NpPd 5 Al 2 (T c =4.9K). We have observed a five-line 27 Al NMR spectrum with a center line and four satellite lines separated by first-order nuclear quadrupole splittings. The Knight shift clearly drops below T c . The temperature dependence of the 27 Al nuclear spin-lattice relaxation rate shows no coherence peak below T c , indicating that NpPd 5 Al 2 is an unconventional superconductor with an anisotropic gap. The analysis of the present NMR data provides evidence for strong-coupling d-wave superconductivity in NpPd 5 Al 2 .

[Derivative spectrophotometric and NMR spectroscopic study in pharmaceutical science].

Science.gov (United States)

Kitamura, Keisuke

2007-10-01

This review starts with an introduction of derivative spectrophotometry followed by a description on the construction of a personal computer-assisted derivative spectrophotometric (DS) system. An acquisition system for inputting digitalized absorption spectra into personal computers and a BASIC program for calculating derivative spectra were developed. Then, applications of the system to drug analyses that are difficult with traditional absorption methods are described. Following this, studies on the interactions of drugs with biological macromolecules by the DS and NMR methods were discussed. An (1)H NMR study elucidated that the small unilamellar vesicle (SUV) has a single membrane made of a phosphatidylcholine bilayer, and that chlorpromazine interacts with both the outer and inner layers. (13)C NMR revealed a reduction of the dissociation constants of phenothiazine drugs due to their interaction with SUV. The partition coefficients of phenothiazine, benzodiazepine and steroid drugs in an SUV-water system and the effects of cholesterol or amino lipids content on these partition coefficients were examined by the DS method. The binding constants of phenothiazine drugs to bovine serum albumin (BSA) and the influence of Na(+), K(+), Cl(-), Br(-), and I(-) on these binding constants were determined by DS. It was found that I(-), Br(-), Cl(-) reduce the binding constants in this order, and that Na(+) and K(+) have no effect. A (19)F NMR study revealed that triflupromazine binds to BSA and human serum albumin in two regions including Site II with different populations, and that a nonsteroidal anti-inflammatory drug, niflumic acid, binds Sites Ia and Ib.

Isotope labeling strategies for NMR studies of RNA

International Nuclear Information System (INIS)

Lu, Kun; Miyazaki, Yasuyuki; Summers, Michael F.

2010-01-01

The known biological functions of RNA have expanded in recent years and now include gene regulation, maintenance of sub-cellular structure, and catalysis, in addition to propagation of genetic information. As for proteins, RNA function is tightly correlated with structure. Unlike proteins, structural information for larger, biologically functional RNAs is relatively limited. NMR signal degeneracy, relaxation problems, and a paucity of long-range 1 H- 1 H dipolar contacts have limited the utility of traditional NMR approaches. Selective isotope labeling, including nucleotide-specific and segmental labeling strategies, may provide the best opportunities for obtaining structural information by NMR. Here we review methods that have been developed for preparing and purifying isotopically labeled RNAs, as well as NMR strategies that have been employed for signal assignment and structure determination.

CP/MAS 13C NMR characterization of the isomeric states and intermolecular packing in tris(8-hydroxyquinoline) aluminum(III) (Alq3).

Science.gov (United States)

Kaji, Hironori; Kusaka, Yasunari; Onoyama, Goro; Horii, Fumitaka

2006-04-05

The isomeric states and intermolecular packing of tris(8-hydroxyquinoline) aluminum(III) (Alq(3)) in the alpha-, gamma-, and delta-crystalline forms and in the amorphous state, which are important for understanding the light-emitting and electron-transport properties, have been analyzed by CP/MAS (13)C NMR. This simple NMR experiment shows that the isomeric state of alpha- and amorphous Alq(3) is meridional, whereas that of gamma- and delta-Alq(3) is facial. In the amorphous Alq(3), the inclusion of facial isomers has been under debate. Our experiments show that meridional isomers are dominant in the amorphous Alq(3), although the existence of facial isomers cannot be completely denied. The local structure of amorphous Alq(3) is similar to that of alpha-Alq(3) and is significantly different from those of gamma- and delta-Alq(3). Among these Alq(3) samples, the effect of intermolecular interaction is not found only for gamma-Alq(3). This finding can explain the good solvent solubility of gamma-Alq(3), compared with the other crystalline forms. It is also shown that the structures are locally disordered not only for amorphous Alq(3) but also for alpha-Alq(3), although clear X-ray diffraction peaks are observed for alpha-Alq(3). In contrast, the local structures of gamma- and delta-Alq(3) are well defined. A clear relation is found between the spectral patterns of CP/MAS (13)C NMR and the fluorescence wavelengths; the samples, which consist of facial isomers, show blue-shifted fluorescence compared with those of meridionals.

Study of molecular movements in some organic crystals by NMR

International Nuclear Information System (INIS)

Alexandre, M.

1971-01-01

After a discussion on molecular crystals (generalities, movements within molecular solids, study of movements, complexes by charge transfer) and some specific ones (molecular complexes of trinitrobenzene or TNB), this research thesis reports the use of nuclear magnetic resonance (NMR) to study molecular movements: generalities on broadband NMR, spin relaxation and strong field network, observation of the absorption signal and measurement of the second moment. The last part reports and discusses experimental results obtained on TNB-naphthalene, on TNB-azulene, on TNB-benzothiophene, and on TNB-indole

Proton NMR studies on Megaphaera elsdenii flavodoxin : structure elucidation by 2D-NMR and implications

NARCIS (Netherlands)

Mierlo, van C.

1990-01-01

¹H NMR techniques have been applied for a thorough study of the uncrystallizable Megasphaera elsdenii flavodoxin in its three redox states. The aim of the research project described in this thesis was to obtain answers regarding questions

High resolution NMR study of cellulose in solid state and in solution

International Nuclear Information System (INIS)

Saint-Germain, Jean

1983-01-01

This research thesis reports the study of native cellulose (cotton) and wood by nuclear magnetic resonance (NMR). As far as the cotton spectrum is concerned, the author assigned resonances which more specifically corresponded to amorphous or crystalline areas. Wood was studied in its bulk condition, and resonances have been determined for the different wood components. The behaviour of cellulose in solution in a solvent has been studied by liquid high resolution NMR. The solvation mechanism has been determined and a study of model components of the macromolecule allowed a conformational study of cellulose in this solvent to be performed. Bi-dimensional NMR and longitudinal relaxation time measurements highlighted the existence of an intramolecular hydrogen bond in the cellulose in solution [fr

Characterization of two minor saponins from Cordia piauhiensis by 1H and 13C NMR spectroscopy.

Science.gov (United States)

Santos, Renata P; Silveira, Edilberto R; Lemos, Telma Leda G; Viana, Francisco Arnaldo; Braz-Filho, Raimundo; Pessoa, Otília Deusdênia L

2005-06-01

A careful NMR analysis with full assignment of the 1H and 13C spectral data for two minor saponins isolated from stems of Cordia piauhiensis is reported. These saponins were isolated by high-performance liquid chromatography and characterized as 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]pomolic acid 28-O-[beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (1) and 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]oleanolic acid 28-O-[beta-D-xylopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (2). Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, NOESY, gs-HMQC and gs-HMBC) NMR techniques, electrospray ionization mass spectrometry and chemical evidence. Copyright 2005 John Wiley & Sons, Ltd.

Coincidence study of alpha particle fragmentation at E/sub alpha/ = 140 MeV

International Nuclear Information System (INIS)

Koontz, R.W.

1980-01-01

Results of an experimental study of the interaction of 140 MeV alpha particles with 90 Zr nuclei resulting in fragmentation of the alpha particle are reported. The experimental observations of the study are analyzed and are found to show that alpha particle breakup reactions leading to at least 4-body final states, composed of two charged alpha particle fragments, contribute significantly to the singles yield of charged fragments observed at a fixed forward angle. The conclusions are based on coincidence measurements where one charged fragment is detected at a small forward angle which remains fixed, while the second charged fragment is detected at a series of coplanar secondary angles. The largest coincidence charged particle yield for the multiparticle final state events results from 90 Zr(α,pp)X reactions, where both of the measured protons have energy distributions similar to the proton singles energy distributions. The second largest observed coincidence yield involving two charged fragments arises from 90 Zr(α,pd)X reactions, where the p and d fragments, as in the 90 Zr(α,pp)X reactions also have energy distribution similar to the singles energy distributions. Analysis of additional measurements, where alpha particle fragments at the fixed angle are detected in coincidence with evaporation and nonequilibrium particles at many coplanar angles, show that the alpha particle fragmentation reactions are also generally associated with large energy transfer to the target nucleus. A multiple scattering model of the fragmentation reaction is employed, in conjunction with the experimental observations, to estimate the cross sections for alpha particle fragmentation into multi-particle final states resulting in n, 2n, p, pp, d, dn, dp, t and 3 He fragments. The estimated total cross section for all fragmentation reactions is 755 mb or approximately 38% of the total reaction cross section for 140 MeV alpha particle interactions with 90 Zr

High resolution deuterium NMR studies of bacterial metabolism

Energy Technology Data Exchange (ETDEWEB)

Aguayo, J.B.; Gamcsik, M.P.; Dick, J.D.

1988-12-25

High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed.

High resolution deuterium NMR studies of bacterial metabolism

International Nuclear Information System (INIS)

Aguayo, J.B.; Gamcsik, M.P.; Dick, J.D.

1988-01-01

High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed

Solid NMR study of lithium ions accommodated in various transition metal oxides

International Nuclear Information System (INIS)

Kanzaki, Yasushi; Suzuki, Noriko

2008-01-01

Solid NMR was used to elucidate the lithium accommodation/extraction reaction in various transition metal oxides. The first study was the lithium ion exchange reaction of titanium antimonic acid (TiSbA). The effect of hydration on the selectivity of lithium ion in the solid phase was examined using 7 Li NMR. The second study was the irreversible ion exchange behavior of HNbO 3 . The selectivity for the lithium ion and the irreversible behavior were examined using 1 H and 7 Li NMR. The third study was the isotope separation between 6 Li and 7 Li in various inorganic ion exchangers. The high isotope separation coefficient was ascribed to the degree of dehydration during the ion exchange reaction. The degree of dehydration was examined by 1 H and 7 Li NMR studies. The last study was determining the mechanism of the lithium accommodation/extraction reaction of λ-MnO 2 in an aqueous solution. The different paths between the accommodation and extraction and the formation of MnO 4- during the accommodation were determined by chemical analysis. The Knight shift in the 7 Li MAS-NMR spectra of Li 0.5 MnO 2 suggested the localization of the electron density on the lithium nuclei. An XPS study also suggested the presence of an electron density on the lithium nuclei. A pH-independent redox couple was assumed to account for the accommodation/extraction reaction of lithium ions, such as Li(I)/Li(0). (author)

Chemical constituents from leaves of the Qualea grandiflora: attribution of the NMR data of two diastereoisomeric acylated flavonoid glycosides

International Nuclear Information System (INIS)

Ayres, Mariane Cruz Costa; Escorcio, Samuel Portela; Costa, Danielly Albuquerque da; Chaves, Mariana H.; Gerardo, Magela Vieira Junior; Cavalheiro, Alberto J.

2008-01-01

Phytochemical investigation from leaves of the Qualea grandiflora (Vochysiaceae) resulted in the isolation and identification of kaempferol-3-O-alpha-L-(4 - E-p-coumaroyl)-rhamnoside, kaempferol-3-O-alpha-L-(4 - Z-p-coumaroyl)-rhamnoside, squalene, phytol, lupeol, alpha-amyrin, beta-amyrin, sitosterol, sitostenone, sitosterol-3-O-beta-D-glucopyranoside, ursolic and oleanolic acids. The structures of the compounds were identified by 1D- and 2D-NMR experiments, mass and UV spectrometry and comparison with literature data. (author)

Xenon-Water Interaction in Bacterial Suspensions as Studied by NMR

DEFF Research Database (Denmark)

Rodin, V.; Ponomarev, Alexander; Gerasimov, Maxim

2017-01-01

suspensions of Escherichia coli in the presence of xenon using nuclear magnetic resonance (NMR). The work studied how the spin-lattice relaxation times of water protons in suspension change under xenon conditions. Xenon is able to form clathrate hydrates with water molecules at a temperature above the melting...... point of ice. The work studied NMR relaxation times which reflect the rotation freedom of water molecules in suspension. Lower relaxation times indicate reduced rotational freedom of water. Single exponential behavior of spin-lattice relaxation of protons in the suspensions of microorganisms has been...

Comparison of multiple crystal structures with NMR data for engrailed homeodomain

Energy Technology Data Exchange (ETDEWEB)

Religa, Tomasz L. [MRC Centre for Protein Engineering (United Kingdom)], E-mail: tlr25@mrc-lmb.cam.ac.uk

2008-03-15

Two methods are currently available to solve high resolution protein structures-X-ray crystallography and nuclear magnetic resonance (NMR). Both methods usually produce highly similar structures, but small differences between both solutions are always observed. Here the raw NMR data as well as the solved NMR structure were compared to the multiple crystal structures solved for the WT 60 residue three helix bundle engrailed homeodomain (EnHD) and single point mutants. There was excellent agreement between TALOS-predicted and crystal structure-observed dihedral angles and a good agreement for the {sup 3}J(H{sup N}H{sup {alpha}}) couplings for the multiple crystal structures. Around 1% of NOEs were violated for any crystal structure, but no NOE was inconsistent with all of the crystal structures. Violations usually occurred for surface residues or for residues for which multiple discreet conformations were observed between the crystal structures. Comparison of the disorder shown in the multiple crystal structures shows little correlation with dynamics under native conditions for this protein.

Structural Studies of Bcl-xL/ligand Complexes using {sup 19}F NMR

Energy Technology Data Exchange (ETDEWEB)

Yu Liping; Hajduk, Philip J.; Mack, Jamey; Olejniczak, Edward T. [GPRD, Abbott Laboratories, Pharmaceutical Discovery Division (United States)], E-mail: Edward.olejniczak@abbott.com

2006-04-15

Fluorine atoms are often incorporated into drug molecules as part of the lead optimization process in order to improve affinity or modify undesirable metabolic and pharmacokinetic profiles. From an NMR perspective, the abundance of fluorinated drug leads provides an exploitable niche for structural studies using {sup 19}F NMR in the drug discovery process. As {sup 19}F has no interfering background signal from biological sources, {sup 19}F NMR studies of fluorinated drugs bound to their protein receptors can yield easily interpretable and unambiguous structural constraints. {sup 19}F can also be selectively incorporated into proteins to obtain additional constraints for structural studies. Despite these advantages, {sup 19}F NMR has rarely been exploited for structural studies due to its broad lines in macromolecules and their ligand complexes, leading to weak signals in {sup 1}H/{sup 19}F heteronuclear NOE experiments. Here we demonstrate several different experimental strategies that use {sup 19}F NMR to obtain ligand-protein structural constraints for ligands bound to the anti-apoptotic protein Bcl-xL, a drug target for anti-cancer therapy. These examples indicate the applicability of these methods to typical structural problems encountered in the drug development process.

Study of β-NMR for Liquid Biological Samples

CERN Document Server

Beattie, Caitlin

2017-01-01

β-NMR is an exotic form of NMR spectroscopy that allows for the characterization of matter based on the anisotropic β-decay of radioactive probe nuclei. This has been shown to be an effective spectroscopic technique for many different compounds, but its use for liquid biological samples is relatively unexplored. The work at the VITO line of ISOLDE seeks to employ this technique to study such samples. Currently, preparations are being made for an experiment to characterize DNA G-quadruplexes and their interactions with stabilizing cations. More specifically, the work in which I engaged as a summer student focused on the experiment’s liquid handling system and the stability of the relevant biological samples under vacuum.

Solution conformation and dynamics of a tetrasaccharide related to the Lewis{sup X} antigen deduced by NMR relaxation measurements

Energy Technology Data Exchange (ETDEWEB)

Poveda, Ana [Universidad Autonoma de Madrid, Servicio Interdepartamental de Investigacion (Spain); Asensio, Juan Luis; Martin-Pastor, Manuel; Jimenez-Barbero, Jesus [Instituto de Quimica Organica, CSIC, Grupo de Carbohidratos (Spain)

1997-07-15

{sup 1}H-NMR cross-relaxation rates and nonselective longitudinal relaxation times have been obtained at two magnetic fields (7.0 and 11.8 T) and at a variety of temperatures for the branched tetrasaccharide methyl 3-O-{alpha}-N-acetyl-galactosaminyl-{beta}-galactopyranosyl-(1{sup {yields}}4)[3-O-{alpha}-fucosyl] -glucopyranoside (1), an inhibitor of astrocyte growth. In addition, {sup 13}C-NMR relaxation data have also been recorded at both fields. The {sup 1}H-NMR relaxation data have been interpreted using different motional models to obtain proton-proton correlation times. The results indicate that the GalNAc and Fuc rings display more extensive local motion than the two inner Glc and Gal moieties, since those present significantly shorter local correlation times. The{sup 13}C-NMR relaxation parameters have been interpreted in terms of the Lipari-Szabo model-free approach. Thus, order parameters and internal motion correlation times have been deduced. As obtained for the{sup 1}H-NMR relaxation data, the two outer residues possess smaller order parameters than the two inner rings. Internal correlation times are in the order of 100 ps. The hydroxymethyl groups have also different behaviour,with the exocyclic carbon on the glucopyranoside unit showing the highestS{sup 2}. Molecular dynamics simulations using a solvated system have also been performed and internal motion correlation functions have been deduced from these calculations. Order parameters and interproton distances have been compared to those inferred from the NMR measurements. The obtained results are in fair agreement with the experimental data.

Fraction of free-base nicotine in fresh smoke particulate matter from the Eclipse "cigarette" by 1H NMR spectroscopy.

Science.gov (United States)

Pankow, James F; Barsanti, Kelley C; Peyton, David H

2003-01-01

Solution 1H NMR (proton-NMR) spectroscopy was used to measure the distribution of nicotine between its free-base and protonated forms at 20 degrees C in (a) water; (b) glycerin/water mixtures; and (c) puff-averaged "smoke" particulate matter (PM) produced by the Eclipse cigarette, a so-called "harm reduction" cigarette manufactured by R. J. Reynolds (RJR) Tobacco Co. Smoke PM from the Eclipse contains glycerin, water, nicotine, and numerous other components. Smoke PM from the Eclipse yielded a signal for the three N-methyl protons on nicotine at a chemical shift of delta (ppm) = 2.79 relative to a trimethylsilane standard. With alpha fb = fraction of the total liquid nicotine in free-base form, and alpha a = fraction in the acidic, monoprotonated NicH+ form, then alpha a + alpha fb approximately 1. (The diprotonated form of nicotine was assumed negligible.) When the three types of solutions were adjusted so that alpha a approximately 1, the N-methyl protons yielded delta a = 2.82 (Eclipse smoke PM); 2.79 (35% water/65% glycerin); and 2.74 (water). When the solutions were adjusted so that alpha fb approximately 1, the N-methyl protons yielded delta fb = 2.16 (Eclipse smoke PM); 2.13 (35% water/65% glycerin); and 2.10 (water). In all of the solutions, the rate of proton exchange between NicH+ and Nic was fast relative to the 1H-NMR chemical shift difference in hertz. Each solution containing both NicH+ and Nic thus yielded a single N-methyl peak at a delta given by delta = alpha a delta a + alpha fb delta fb so that delta varied linearly between delta a and delta fb. Since alpha fb = (delta a-delta)/(delta a-delta fb), then delta = 2.79 for the unadjusted Eclipse smoke PM indicates alpha fb approximately 0.04. The effective pH of the Eclipse smoke PM at 20 degrees C may then be calculated as pHeff = 8.06 + log[alpha fb/(1-alpha fb)] = 6.69, where 8.06 is the pKa of NicH+ in water at 20 degrees C. The measurements obtained for the puff-averaged Eclipse smoke PM

TD-NMR studies on CuSO{sub 4} salt hydrates

Energy Technology Data Exchange (ETDEWEB)

Nestle, Nikolaus; Magin, Peter; Wengeler, Robert [BASF Aktiengesellschaft, Ludwigshafen (Germany); Kleinschmidt, Sebastian [Universitaet Magdeburg, FB Chemie (Germany)

2008-07-01

Despite the high concentration of paramagnetic copper ions, solid CuSO{sub 4} hydrates exhibit surprizingly narrow NMR signals. This is known since the late 1940s. Using TD-NMR methods established for polymer studies, the relaxation behaviour of CuSO{sub 4} preparations with different water content was studied at room temperature. For the water content of the pentahydrate and below, the NMR signal exhibits a pure solid-state-type magnetization decay behaviour. For slightly overstoichiometric moisture contents, a liquid-like signal is observed in addition to the solid signal. However, the relative amplitudes of the solid and the liquid signal do not mirror the stoichiometric composition of the pentahydrate and the excess water. Instead, the solid signal amplitude only accounts for four hydrate water molecules while the fifth water exhibits rapid exchange with the liquid phase and thus contributes to the liquid-type signal. This finding is in good agreement to results from investigations into the crystal structure of solid CuSO4 pentahydrate.

NMR study of rare earth and actinide complexes

International Nuclear Information System (INIS)

Villardi de Montlaur de, G.C.

1978-01-01

Proton magnetic resonance studies of lanthanide shift reagents with olefin-transition metal complexes, monoamines and diamines as substrates are described. Shift reagents for olefins are reported: Lnsup(III)(fod) 3 can induce substantial shifts in the nmr spectra of a variety of olefins when silver 1-heptafluororobutyrate is used to complex the olefin. The preparation, properties and efficiency of such systems are described. Configurational aspects and exchange processes of Lnsup(III)(fod) 3 complexes with secondary and tertiary monoamines are analysed by means of dynamic nmr. Factors influencing the stability and the stoichiometry of these complexes and various processes such as nitrogen inversion and ligand exchange are discussed. At low temperature, ring inversion can be slow on an nmr time-scale for Lnsup(III)(fod) 3 -diamino chelates. Barriers to ring inversion in substituted ethylenediamines and propanediamines are obtained. Steric factors appear to play an important role in the stability and kinetics of these bidentate species. The synthesis of uranium-IV crown-ether and cryptate complexes is described. A conformational study of these compounds show evidence of an insertion of the paramagnetic cation as witnessed by the large induced shifts observed. The insertion of uranium in the macrocyclic ligand of a UCl 4 -dicyclohexyl-18-crown-6 complex is confirmed by an X-ray structural determination [fr

31P-NMR measurements of ATP, ADP, 2,3-diphosphoglycerate and Mg2+ in human erythrocytes.

Science.gov (United States)

Petersen, A; Kristensen, S R; Jacobsen, J P; Hørder, M

1990-08-17

Absolute 31P-NMR measurements of ATP, ADP and 2,3-diphosphoglycerate (2,3-DPG) in oxygenated and partly deoxygenated human erythrocytes, compared to measurements by standard assays after acid extraction, show that ATP is only 65% NMR visible, ADP measured by NMR is unexpectedly 400% higher than the enzymatic measurement and 2,3-DPG is fully NMR visible, regardless of the degree of oxygenation. These results show that binding to hemoglobin is unlikely to cause the decreased visibility of ATP in human erythrocytes as deoxyhemoglobin binds the phosphorylated metabolites more tightly than oxyhemoglobin. The high ADP visibility is unexplained. The levels of free Mg2+ [( Mg2+]free) in human erythrocytes are 225 mumol/l at an oxygen saturation of 98.6% and instead of the expected increase, the level decreased to 196 mumol/l at an oxygen saturation of 38.1% based on the separation between the alpha- and beta-ATP peaks. [Mg2+]free in the erythrocytes decreased to 104 mumol/l at a high 2,3-DPG concentration of 25.4 mmol/l red blood cells (RBC) and a normal ATP concentration of 2.05 mmol/l RBC. By increasing the ATP concentration to 3.57 mmol/l RBC, and with a high 2,3-DPG concentration of 24.7 mmol/l RBC, the 31P-NMR measured [Mg2+]free decreased to 61 mumol/l. These results indicate, that the 31P-NMR determined [Mg2+]free in human erythrocytes, based solely on the separation of the alpha- and beta-ATP peaks, does not give a true measure of intracellular free Mg2+ changes with different oxygen saturation levels. Furthermore the measurement is influenced by the concentration of the Mg2+ binding metabolites ATP and 2,3-DPG. Failure to take these factors into account when interpreting 31P-NMR data from human erythrocytes may explain some discrepancies in the literature regarding [Mg2+]free.

NMR Studies of Polymer Nanocomposites

National Research Council Canada - National Science Library

Greenbaum, Steve

2001-01-01

.... The primary tool is pulsed field gradient NMR. A static field gradient method was developed which makes possible variable pressure diffusion measurement, and the application to the important fuel cell membrane NAFION constitute the first results...

NMR

International Nuclear Information System (INIS)

Kneeland, J.B.; Lee, B.C.P.; Whalen, J.P.; Knowles, R.J.R.; Cahill, P.T.

1984-01-01

Although still quite new, NMR imaging has already emerged as a safe, noninvasive, painless, and effective diagnostic modality requiring no ionizing radiation. Also, NMR appears already to have established itself as the method of choice for the examination of the brain spinal cord (excluding herniated disks). Another area in which NMR excels is in the examination of the pelvis. The use of surface coils offers the promise of visualizing structures with resolution unobtainable by any other means. In addition, NMR, with its superb visualization of vascular structures and potential ability to measure flow, may soon revolutionize the diagnosis of cardiovascular disease. Finally, NMR, through biochemically and physiologically based T/sub 1/ and T/sub 2/ indices or through spectroscopy, may provide a means of monitoring therapeutic response so as to permit tailoring of treatment to the individual patient. In short, NMR is today probably at the same stage as the x-ray was in Roentgen's day

Ultrastructural studies of human and rabbit alpha-M-globulins.

Science.gov (United States)

Bloth, B; Chesebro, B; Svehag, S E

1968-04-01

Electron micrographs of isolated human alpha(2)M-molecules, obtained by the negative contrast technique, revealed morphologically homogenous structures resembling a graceful monogram of the two letters H and I. The modal values for the length and width of the alpha(2)M particles were 170 A and 100 A, respectively. Purified rabbit alphamacroglobulins contained about 80% alpha(1)M- and 20% alpha(2)M-globulins. The isolated rabbit alpha(1)M- and alpha(2)M-molecules were morphologically indistinguishable from one another and from human alpha(2)M-molecules. Preliminary immunoprecipitation studies demonstrated that the two rabbit alphaM-globulins were antigenically different. Sedimentation constant determinations gave s(20, w) values of 18.8 and 18.2 for rabbit alpha(1)M and alpha(2)M, respectively.

Theoretical and experimental NMR studies on muscimol from fly agaric mushroom (Amanita muscaria)

Science.gov (United States)

Kupka, Teobald; Wieczorek, Piotr P.

2016-01-01

In this article we report results of combined theoretical and experimental NMR studies on muscimol, the bioactive alkaloid from fly agaric mushroom (Amanita muscaria). The assignment of 1H and 13C NMR spectra of muscimol in DMSO-d6 was supported by additional two-dimensional heteronuclear correlated spectra (2D NMR) and gauge independent atomic orbital (GIAO) NMR calculations using density functional theory (DFT). The effect of solvent in theoretical calculations was included via polarized continuum model (PCM) and the hybrid three-parameter B3LYP density functional in combination with 6-311++G(3df,2pd) basis set enabled calculation of reliable structures of non-ionized (neutral) molecule and its NH and zwitterionic forms in the gas phase, chloroform, DMSO and water. GIAO NMR calculations, using equilibrium and rovibrationally averaged geometry, at B3LYP/6-31G* and B3LYP/aug-cc-pVTZ-J levels of theory provided muscimol nuclear magnetic shieldings. The theoretical proton and carbon chemical shifts were critically compared with experimental NMR spectra measured in DMSO. Our results provide useful information on its structure in solution. We believe that such data could improve the understanding of basic features of muscimol at atomistic level and provide another tool in studies related to GABA analogs.

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

Science.gov (United States)

Paik, Younkee

Electrolytic manganese dioxide (EMD) is used world wide as the cathode materials in both lithium and alkaline primary (non-rechargeable) batteries. We have developed deuterium and lithium MAS NMR techniques to study EMD and related manganese oxides and hydroxides, where diffraction techniques are of limited value due to a highly defective nature of the structures. Deuterons in EMD, manganite, groutite, and deuterium-intercalated pyrolusite and ramsdellite were detected by NMR, for the first time, and their locations and motions in the structures were analyzed by applying variable temperature NMR techniques. Discharge mechanisms of EMD in alkaline (aqueous) electrolytes were studied, in conjunction with step potential electrochemical spectroscopic (SPECS) method, and five distinctive discharge processes were proposed. EMD is usually heat-treated at about 300--400°C to remove water to be used in lithium batteries. Details of the effects of heat-treatment, such as structural and compositional changes as a function of heat-treatment temperature, were studied by a combination of MAS NMR, XRD, and thermogravimetric analysis. Lithium local environments in heat-treated EMD (HEMD) that were discharged in lithium cells, were described in terms of related environments found in model compounds pyrolusite and ramsdellite where specific Li + sites were detected by MAS NMR and the hyperfine shift scale method of Grey et al. Acid-leaching of Li2MnO3 represents an approach for synthesizing new or modified manganese oxide electrode materials for lithium rechargeable batteries. Progressive removal of lithium from specific crystallographic sites, followed by a gradual change of the crystal structure, was monitored by a combination of NMR and XRD techniques.

Dynamic NMR Study of Model CMP Slurry Containing Silica Particles as Abrasives

Science.gov (United States)

Odeh, F.; Al-Bawab, A.; Li, Y.

2018-02-01

Chemical mechanical planarization (CMP) should provide a good surface planarity with minimal surface defectivity. Since CMP slurries are multi-component systems, it is very important to understand the various processes and interactions taking place in such slurries. Several techniques have been employed for such task, however, most of them lack the molecular recognition to investigate molecular interactions without adding probes which in turn increase complexity and might alter the microenvironment of the slurry. Nuclear magnetic resonance (NMR) is a powerful technique that can be employed in such study. The longitudinal relaxation times (T1) of the different components of CMP slurries were measured using Spin Echo-NMR (SE-NMR) at a constant temperature. The fact that NMR is non-invasive and gives information on the molecular level gives more advantage to the technique. The model CMP slurry was prepared in D2O to enable monitoring of T1 for the various components' protons. SE-NMR provide a very powerful tool to study the various interactions and adsorption processes that take place in a model CMP silica based slurry which contains BTA and/or glycine and/or Cu+2 ions. It was found that BTA is very competitive towards complexation with Cu+2 ions and BTA-Cu complex adsorbs on silica surface.

Methods of NMR structure refinement: molecular dynamics simulations improve the agreement with measured NMR data of a C-terminal peptide of GCN4-p1.

Science.gov (United States)

Dolenc, Jozica; Missimer, John H; Steinmetz, Michel O; van Gunsteren, Wilfred F

2010-07-01

The C-terminal trigger sequence is essential in the coiled-coil formation of GCN4-p1; its conformational properties are thus of importance for understanding this process at the atomic level. A solution NMR model structure of a peptide, GCN4p16-31, encompassing the GCN4-p1 trigger sequence was proposed a few years ago. Derived using a standard single-structure refinement protocol based on 172 nuclear Overhauser effect (NOE) distance restraints, 14 hydrogen-bond and 11 phi torsional-angle restraints, the resulting set of 20 NMR model structures exhibits regular alpha-helical structure. However, the set slightly violates some measured NOE bounds and does not reproduce all 15 measured (3)J(H(N)-H(Calpha))-coupling constants, indicating that different conformers of GCN4p16-31 might be present in solution. With the aim to resolve structures compatible with all NOE upper distance bounds and (3)J-coupling constants, we executed several structure refinement protocols employing unrestrained and restrained molecular dynamics (MD) simulations with two force fields. We find that only configurational ensembles obtained by applying simultaneously time-averaged NOE distance and (3)J-coupling constant restraining with either force field reproduce all the experimental data. Additionally, analyses of the simulated ensembles show that the conformational variability of GCN4p16-31 in solution admitted by the available set of 187 measured NMR data is larger than represented by the set of the NMR model structures. The conformations of GCN4p16-31 in solution differ in the orientation not only of the side-chains but also of the backbone. The inconsistencies between the NMR model structures and the measured NMR data are due to the neglect of averaging effects and the inclusion of hydrogen-bond and torsional-angle restraints that have little basis in the primary, i.e. measured NMR data.

Reduced dimensionality (3,2)D NMR experiments and their automated analysis: implications to high-throughput structural studies on proteins.

Science.gov (United States)

Reddy, Jithender G; Kumar, Dinesh; Hosur, Ramakrishna V

2015-02-01

Protein NMR spectroscopy has expanded dramatically over the last decade into a powerful tool for the study of their structure, dynamics, and interactions. The primary requirement for all such investigations is sequence-specific resonance assignment. The demand now is to obtain this information as rapidly as possible and in all types of protein systems, stable/unstable, soluble/insoluble, small/big, structured/unstructured, and so on. In this context, we introduce here two reduced dimensionality experiments – (3,2)D-hNCOcanH and (3,2)D-hNcoCAnH – which enhance the previously described 2D NMR-based assignment methods quite significantly. Both the experiments can be recorded in just about 2-3 h each and hence would be of immense value for high-throughput structural proteomics and drug discovery research. The applicability of the method has been demonstrated using alpha-helical bovine apo calbindin-D9k P43M mutant (75 aa) protein. Automated assignment of this data using AUTOBA has been presented, which enhances the utility of these experiments. The backbone resonance assignments so derived are utilized to estimate secondary structures and the backbone fold using Web-based algorithms. Taken together, we believe that the method and the protocol proposed here can be used for routine high-throughput structural studies of proteins. Copyright © 2014 John Wiley & Sons, Ltd.

31P-NMR study of human pyrimidine 5'-nucleotidase deficient erythrocytes

International Nuclear Information System (INIS)

Higaki, Tsuyoshi; Kagimoto, Tadashi; Nagata, Koichi; Tanase, Sumio; Morino, Yoshimasa; Takatsuki, Kiyoshi

1982-01-01

Metabolic disorder of nucleotides in human pyrimidine 5'-nucleotidase (P5N) deficient erythrocytes was studied by 31 P-NMR with high resolution. Identification by combination of high-speed liquid chromatography revealed two-fold increases from the normal in the spectra in the α-, β- and γ-zones of nucleoside triphosphates of P5N deficient erythrocytes, 2,3-diphosphoglycerate shifted to the 0.3 ppm low magnetic field and signals of NAD and UDP-sugars(s) in the diphosphodiester zone. These results were obtained from the 31 P-NMR spectrum about one hour after blood sampling, indicating the high utility of this NMR for the diagnosis of P5N deficiency. (Chiba, N.)

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

Science.gov (United States)

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

2012-12-01

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

Advanced NMR technology for bioscience and biotechnology

Energy Technology Data Exchange (ETDEWEB)

Hammel, P.C.; Hernandez, G.; Trewhella, J.; Unkefer, C.J. [Los Alamos National Lab., NM (US); Boumenthal, D.K. [Univ. of Utah, Salt Lake City, UT (US); Kennedy, M.A. [Pacific Northwest National Lab., Richland, WA (US); Moore, G.J. [Wayne State Univ., Detroit, MI (US)

1998-11-01

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

NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

International Nuclear Information System (INIS)

Foerland, Kjersti

2005-01-01

In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41

NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

Energy Technology Data Exchange (ETDEWEB)

Foerland, Kjersti

2005-07-01

In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41.

Thermal stability of chicken brain {alpha}-spectrin repeat 17: a spectroscopic study

Energy Technology Data Exchange (ETDEWEB)

Brenner, Annette K. [University of Bergen, Department of Chemistry (Norway); Kieffer, Bruno [Ecole Superieure de Biotechnologie de Strasbourg, IGBMC Biomolecular NMR Group, CNRS UMR 7104 (France); Trave, Gilles [Ecole Superieure de Biotechnologie de Strasbourg, Equipe Oncoproteines, IREBS, UMR 7242 (France); Froystein, Nils Age [University of Bergen, Department of Chemistry (Norway); Raae, Arnt J., E-mail: arnt.raae@mbi.uib.no [University of Bergen, Department of Molecular Biology (Norway)

2012-06-15

Spectrin is a rod-like multi-modular protein that is mainly composed of triple-helical repeats. These repeats show very similar 3D-structures but variable conformational and thermodynamical stabilities, which may be of great importance for the flexibility and dynamic behaviour of spectrin in the cell. For instance, repeat 17 (R17) of the chicken brain spectrin {alpha}-chain is four times less stable than neighbouring repeat 16 (R16) in terms of Increment G. The structure of spectrin repeats has mainly been investigated by X-ray crystallography, but the structures of a few repeats, e.g. R16, have also been determined by NMR spectroscopy. Here, we undertook a detailed characterization of the neighbouring R17 by NMR spectroscopy. We assigned most backbone resonances and observed NOE restraints, relaxation values and coupling constants that all indicated that the fold of R17 is highly similar to that of R16, in agreement with previous X-ray analysis of a tandem repeat of the two domains. However, {sup 15}N heteronuclear NMR spectra measured at different temperatures revealed particular features of the R17 domain that might contribute to its lower stability. Conformational exchange appeared to alter the linker connecting R17 to R16 as well as the BC-loop in close proximity. In addition, heat-induced splitting was observed for backbone resonances of a few spatially related residues including V99 of helix C, which in R16 is replaced by the larger hydrophobic tryptophan residue that is relatively conserved among other spectrin repeats. These data support the view that the substitution of tryptophan by valine at this position may contribute to the lower stability of R17.

Automated sample preparation station for studying self-diffusion in porous solids with NMR spectroscopy

Science.gov (United States)

Hedin, Niklas; DeMartin, Gregory J.; Reyes, Sebastián C.

2006-03-01

In studies of gas diffusion in porous solids with nuclear magnetic resonance (NMR) spectroscopy the sample preparation procedure becomes very important. An apparatus is presented here that pretreats the sample ex situ and accurately sets the desired pressure and temperature within the NMR tube prior to its introduction in the spectrometer. The gas manifold that supplies the NMR tube is also connected to a microbalance containing another portion of the same sample, which is kept at the same temperature as the sample in the NMR tube. This arrangement permits the simultaneous measurement of the adsorption loading on the sample, which is required for the interpretation of the NMR diffusion experiments. Furthermore, to ensure a good seal of the NMR tube, a hybrid valve design composed of titanium, a Teflon® seat, and Kalrez® O-rings is utilized. A computer controlled algorithm ensures the accuracy and reproducibility of all the procedures, enabling the NMR diffusion experiments to be performed at well controlled conditions of pressure, temperature, and amount of gas adsorbed on the porous sample.

NMR studies of transmembrane electron transport in human erythrocytes

International Nuclear Information System (INIS)

Kennett, E.C.; Bubb, W.A.; Kuchel, P.W.

2002-01-01

Full text: Electron transport systems exist in the plasma membranes of all cells. These systems appear to play a role in cell growth and proliferation, intracellular signalling, hormone responses, apoptotic events, cell defence and perhaps most importantly they enable the cell to respond to changes in the redox state of both the intra- and extracellular environments. Previously, 13 C NMR has been used to study transmembrane electron transport in human erythrocytes, specifically the reduction of extracellular 13 C-ferricyanide. NMR is a particularly useful tool for studying such systems as changes in the metabolic state of the cell can be observed concomitantly with extracellular reductase activity. We investigated the oxidation of extracellular NADH by human erythrocytes using 1 H and 31 P NMR spectroscopy. Recent results for glucose-starved human erythrocytes indicate that, under these conditions, extracellular NADH can be oxidised at the plasma membrane with the electron transfer across the membrane resulting in reduction of intracellular NAD + . The activity is inhibited by known trans-plasma membrane electron transport inhibitors (capsaicin and atebrin) and is unaffected by inhibition of the erythrocyte Band 3 anion transporter. These results suggest that electron import from extracellular NADH allows the cell to re-establish a reducing environment after the normal redox balance is disturbed

Broad line NMR study of modified polypropylene fibres

International Nuclear Information System (INIS)

Olcak, D.; Sevcovic, L.; Mucha, L.

1999-01-01

Study of drawn fibres prepared from an isostatic polypropylene modified by an ethylene aminoalkylacrylate copolymer has been done using the broad line of 1 H NMR. NMR spectra were measured on the set of fibres prepared with a draw ratio λ from 1 to 5.5 at two temperatures, one of them corresponding to the onset of segmental motion and the other one is the minddle of the temperature interval as determined by decrease of the second moment M 2 . Decomposition of the spectra into elementary components related to the amorphous, intermediate and crystalline regions of partially crystalline polymers has been made. The drawing of the fibres was found to enhance the chain mobility in the amorphous region and to restrain the molecular motion in the intermediate region. Such behaviour well supports conclusions predicted in the earlier study based on the spin-lattice relaxation time T 1 and dynamic mechanical data treated using the WLF theory. (Authors)

NMR studies concerning base-base interactions in oligonucleotides

International Nuclear Information System (INIS)

Hoogen, Y.T. van den.

1988-01-01

Two main subjects are treated in the present thesis. The firsst part principally deals with the base-base interactions in single-stranded oligoribonucleotides. The second part presents NMR and model-building studies of DNA and RNA duplexes containing an unpaired base. (author). 242 refs.; 26 figs.; 24 tabs

Solid-state NMR studies of nucleic acid components

Czech Academy of Sciences Publication Activity Database

Dračínský, Martin; Hodgkinson, P.

2015-01-01

Roč. 5, č. 16 (2015), s. 12300-12310 ISSN 2046-2069 R&D Projects: GA ČR GA13-24880S Institutional support: RVO:61388963 Keywords : NMR spectroscopy * nucleic acid s * solid-state NMR Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.289, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/ra/c4ra14404j

1H-NMR/13C-NMR studies of branched structures in PVC obtained at atmospheric pressure

International Nuclear Information System (INIS)

Braun, D.; Holzer, G.; Hjertberg, T.

1981-01-01

The 1 H-NMR-spectra of raw poly (vinyl cloride) obtained at atmospheric pressure (U-PVC) have revealed the presence of high concentrations of branches. The content of labile chlorine was determined by reaction with phenole in order to estimate the branch points with tertiary chlorine. The branch length of reductively dehalogenated U-PVC by 13 C-NMR analysis have provided evidence for both short chain branches including chloromethyl groups and 2.4-dichloro-n-butyl groups and long chain branching. For a number of U-polymers the total amount of branching ranges from 7.5 to 13.5/1000 C. The 13 C-NMR measurements point to a ratio of methyl/butyl branches of 1:1 and short chains/long chains of 6:1. (orig.)

11B nutation NMR study of powdered borosilicates

International Nuclear Information System (INIS)

Woo, Ae Ja; Yang, Kyung Hwa; Han, Duk Young

1998-01-01

In this work, we applied the 1D 11 B nutation NMR method for the analysis of the local structural environments in powdered borosilicates (SiO 2 -B 2 O 3 ). Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density matrix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D 11 B nutation NMR experiment. The 11 B NMR parameters, quadrupole coupling constants (e 2 qQ/h) and asymmetry parameters (η), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed

15N NMR relaxation studies of calcium-loaded parvalbumin show tight dynamics compared to those of other EF-hand proteins

DEFF Research Database (Denmark)

Baldellon, C; Alattia, J R; Strub, M P

1998-01-01

Dynamics of the rat alpha-parvalbumin calcium-loaded form have been determined by measurement of 15N nuclear relaxation using proton-detected heteronuclear NMR spectroscopy. The relaxation data were analyzed using spectral density functions and the Lipari-Szabo formalism. The major dynamic features...... for the rat alpha-parvalbumin calcium-loaded form are (1) the extreme rigidity of the helix-loop-helix EF-hand motifs and the linker segment connecting them, (2) the N and C termini of the protein being restricted in their mobility, (3) a conformational exchange occurring at the kink of helix D, and (4...... properties which are conserved in the EF-hand domains from different members of this superfamily: (1) a tendency toward higher mobility of NH vectors at relative position 2 in the Ca2+-binding loop, (2) a restricted mobility for the other residues in the binding loop, and (3) an overall rigidity...

Note: Commercial SQUID magnetometer-compatible NMR probe and its application for studying a quantum magnet.

Science.gov (United States)

Vennemann, T; Jeong, M; Yoon, D; Magrez, A; Berger, H; Yang, L; Živković, I; Babkevich, P; Rønnow, H M

2018-04-01

We present a compact nuclear magnetic resonance (NMR) probe which is compatible with a magnet of a commercial superconducting quantum interference device magnetometer and demonstrate its application to the study of a quantum magnet. We employ trimmer chip capacitors to construct an NMR tank circuit for low temperature measurements. Using a magnetic insulator MoOPO 4 with S = 1/2 (Mo 5+ ) as an example, we show that the T-dependence of the circuit is weak enough to allow the ligand-ion NMR study of magnetic systems. Our 31 P NMR results are compatible with previous bulk susceptibility and neutron scattering experiments and furthermore reveal unconventional spin dynamics.

Note: Commercial SQUID magnetometer-compatible NMR probe and its application for studying a quantum magnet

Science.gov (United States)

Vennemann, T.; Jeong, M.; Yoon, D.; Magrez, A.; Berger, H.; Yang, L.; Živković, I.; Babkevich, P.; Rønnow, H. M.

2018-04-01

We present a compact nuclear magnetic resonance (NMR) probe which is compatible with a magnet of a commercial superconducting quantum interference device magnetometer and demonstrate its application to the study of a quantum magnet. We employ trimmer chip capacitors to construct an NMR tank circuit for low temperature measurements. Using a magnetic insulator MoOPO4 with S = 1/2 (Mo5+) as an example, we show that the T-dependence of the circuit is weak enough to allow the ligand-ion NMR study of magnetic systems. Our 31P NMR results are compatible with previous bulk susceptibility and neutron scattering experiments and furthermore reveal unconventional spin dynamics.

Contribution to the study of alpha-alpha interaction; Contribution a l'etude de l'interaction alpha - alpha

Energy Technology Data Exchange (ETDEWEB)

Darriulai, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-03-01

Two sets of measurements of the {alpha}-{alpha} elastic scattering differential cross section are presented. The first set - angular distributions from 50 up to 120 MeV - shows two new resonances, 6{sup +} and 8{sup +}, at 25 and 57 MeV. Complex phase shifts are extracted from the data and a phenomenological potential is given. A description of the 3 {alpha}-particle 0{sup +} states in C{sup 12} is made with this interaction potential. The second set - excitation curves between 20 and 50 MeV - allows investigation of the Be{sup 8} level structure within this energy range - It identifies the 16.6 and 16.9 MeV states as 2{sup +}, but the rise of inelastic processes at higher energies makes further identification of spins and parities more and more difficult. (author) [French] Deux series de mesures de la section efficace differentielle de diffusion {alpha}-{alpha} sont presentees. La premiere - distributions angulaires entre 50 et 120 MeV - fait apparaitre deux nouvelles resonances, 6{sup +} et 8{sup +}, a 25 et 57 MeV d'excitation. Des dephasages complexes en sont extraits et un potentiel phenomenologique est presente. Une etude des etats 0{sup +} a parentage (3{alpha}) de {sup 12}C est faite a partir de ce potentiel. La seconde - courbes d'excitation s'etendant de 20 a 50 MeV - met en evidence la structure de {sup 8}Be dans cette region. Elle montre que les niveaux a 16,6 et 16,9 MeV sont des 2{sup +} mais l'importance des processus inelastiques rend difficile l'identification des niveaux d'excitation plus elevee. (auteur)

NMR studies of the helical antiferromagnetic compound EuCo2P2

Science.gov (United States)

Higa, N.; Ding, Q.-P.; Kubota, F.; Uehara, H.; Yogi, M.; Furukawa, Y.; Sangeetha, N. S.; Johnston, D. C.; Nakamura, A.; Hedo, M.; Nakama, T.; Ōnuki, Y.

2018-05-01

In EuCo2P2, 4f electron spins of Eu2+ ions order antiferromagnetically below a Néel temperature TN = 66.5 K . The magnetic structure below TN was reported to be helical with the helix axis along the c-axis from the neutron diffraction study. We report the results of 153Eu, 59Co and 31P nuclear magnetic resonance (NMR) measurements on EuCo2P2 using a single crystal and a powdered sample. In the antiferromagnetic (AFM) state, we succeeded in observing 153Eu, 59Co and 31P NMR spectra in zero magnetic field. The sharp 153Eu zero field NMR (ZF NMR) lines indicate homogeneous Eu ordered moment. The 59Co and 31P ZF NMR spectra showed an asymmetric spectral shape, indicating a distribution of the internal magnetic induction at each nuclear position. The AFM propagation vector k characterizing the helical AFM state can be determined from the internal magnetic induction at Co site. We have determined the model-independent value of the AFM propagation vector k distributed from (0, 0, 0.86)2π/c to (0, 0, 0.73)2π/c, where c is the lattice parameter.

Radial-velocity variations in Alpha Ori, Alpha Sco, and Alpha Her

International Nuclear Information System (INIS)

Smith, M.A.; Patten, B.M.; Goldberg, L.

1989-01-01

Radial-velocity observations of Alpha Ori, Alpha Sco A, and Alpha Her A are used to study radial-velocity periodicities in M supergiants. The data refer to several metallic lines in the H-alpha region and to H-alpha itself. It is shown that Alpha Ori and Alpha Sco A have cycle lengths of about 1 yr and semiamplitudes of 2 km/s. It is suggested that many semiregular red supergiant varibles such as Alpha Ori may be heading toward chaos. All three stars show short-term stochastic flucutations with an amplitude of 1-2 km/s. It is found that the long-term variability of H-alpha velocities may be a consequence of intermittent failed ejections. 58 refs

Solid-state NMR of inorganic semiconductors.

Science.gov (United States)

Yesinowski, James P

2012-01-01

Studies of inorganic semiconductors by solid-state NMR vary widely in terms of the nature of the samples investigated, the techniques employed to observe the NMR signal, and the types of information obtained. Compared with the NMR of diamagnetic non-semiconducting substances, important differences often result from the presence of electron or hole carriers that are the hallmark of semiconductors, and whose theoretical interpretation can be involved. This review aims to provide a broad perspective on the topic for the non-expert by providing: (1) a basic introduction to semiconductor physical concepts relevant to NMR, including common crystal structures and the various methods of making samples; (2) discussions of the NMR spin Hamiltonian, details of some of the NMR techniques and strategies used to make measurements and theoretically predict NMR parameters, and examples of how each of the terms in the Hamiltonian has provided useful information in bulk semiconductors; (3) a discussion of the additional considerations needed to interpret the NMR of nanoscale semiconductors, with selected examples. The area of semiconductor NMR is being revitalized by this interest in nanoscale semiconductors, the great improvements in NMR detection sensitivity and resolution that have occurred, and the current interest in optical pumping and spintronics-related studies. Promising directions for future research will be noted throughout.

Local environments and lithium adsorption on the iron oxyhydroxides lepidocrocite (gamma-FeOOH) and goethite (alpha-FeOOH): A ²H-2 and ⁷Li solid-state MAS NMR study

DEFF Research Database (Denmark)

Nielsen, Ulla Gro; Grey, Clare P.; Paik, Jonkim

2008-01-01

2H and 7LiMAS NMR spectroscopy techniques were applied to study the local surface and bulk environments of iron oxyhydroxide lepiclocrocite (gamma-FeOOH). 2H variable-temperature (VT) MAS NMR experiments were performed, showing the presence of short-range, strong antiferromagnetic correlations......, even at temperatures above the Neel temperature, TN, 77 K. The formation of a Li+ inner-sphere complex on the surface of lepiclocrocite was confirmed by the observation of a signal with a large 7Li hyperfine shift in the 7Li  MAS NMR spectrum. The effect of pH and relative humidity (RH...

Contrast-enhanced NMR imaging: animal studies using gadolinium-DTPA complex

International Nuclear Information System (INIS)

Brasch, R.C.; Weinmann, H.J.; Wesbey, G.E.

1984-01-01

Gadolinium (Gd)-DTPA complex was assessed as a nuclear magnetic resonance (NMR) contrast-enhancing agent by experimentally imaging normal and diseased animals. After intravenous injection, Gd-DTPA, a strongly paramagnetic complex by virtue of unpaired electrons, was rapidly excreted into the urine of rats, producing an easily observable contrast enhancement on NMR images in kidney parenchyma and urine. Sterile soft-tissue abscesses demonstrated an obvious rim pattern of enhancement. A focus of radiation-induced brain damage in a canine model was only faintly detectable on spin-echo NMR images before contrast administration; after 0.5 mmol/kg Gd-DTPA administration, the lesion intensity increased from 3867 to 5590. In comparison, the normal brain with an intact blood-brain barrier remained unchanged in NMR characterization. Gd-DTPA is a promising new NMR contrast enhancer for the clinical assessment of renal function, of inflammatory lesions, and of focal disruption of the blood-brain barrier

Moessbauer and NMR study of novel Tin(IV)-lactames

Energy Technology Data Exchange (ETDEWEB)

Kuzmann, Erno; Szalay, Roland; Homonnay, Zoltan, E-mail: homonnay@ludens.elte.hu; Nagy, Sandor [Eoetvoes Lorand University, Institute of Chemistry (Hungary)

2012-03-15

N-tributylstannylated 2-pyrrolidinone was reacted with tributyltin triflate in different molar ratios and the complex formation monitored using {sup 1}H-NMR, {sup 13}C-NMR and {sup 119}Sn Moessbauer spectroscopy. Comparing the carbon NMR and tin Moessbauer results, a reaction scheme is suggested for the complexation which assumes the formation of a simultaneously O- and N-tributylstannylated pyrrolidinone cation. The formation of the only O-stannylated pyrrolidinone is also assumed to account for the non-constant Moessbauer parameters of the two tin environments in the distannylated pyrrolidinone cation when the ratio of tributyltin triflate is increased in the reaction.

A study on alpha particles range in Cr-39

International Nuclear Information System (INIS)

Ibrahim, Z.A.; Talaat, T.M.; Abdel-Aziz, Kh.M.A.; El-Asser, M.R.

2000-01-01

Cr-39 plastic nuclear track detector has been used in range determination of alpha particles. A set of experiments was carried out for studying alpha energy and track diameter relationships. This work was done under the optimum conditions of Cr-39 etching in 6.25 N NaOH at 70 degree C for various etching times. Determination of alpha range in Cr-39 recorders was studied at different energy values using the over etched track profile technique. Data are discussed within the framework of track formation theory in plastic foils, comparison between experimental and theoretical values of alpha range is included

11B NMR study of calcium-hexaborides

International Nuclear Information System (INIS)

Mean, B.J.; Lee, K.H.; Kang, K.H.; Lee, Moohee; Rhee, J.S.; Cho, B.K.

2005-01-01

We have performed 11 B nuclear magnetic resonance (NMR) measurements to look for microscopic evidence of the ferromagnetic state in several CaB 6 single crystals. A number of 11 B NMR resonance peaks are observed with the frequency and intensity of those peaks distinctively changing depending on the angle between the crystalline axis and a magnetic field. Analyzing this behavior, we find that the electric field gradient tensor at the boron has its principal axis perpendicular to the six cubic faces with a quadrupole resonance frequency ν Q ∼600kHz. However, the satellite resonances are found to be made of two peaks. Detailed analysis of the four composite satellite peaks confirms that there are two different boron sites with slightly different ν Q 's. This suggests that the boron octahedron cages are locally distorted. However, this distortion is not directly related to ferromagnetism. Even though the magnetization data highlight the ferromagnetic hysteresis, 11 B NMR linewidth and shift data show no clear microscopic evidence of the ferromagnetic state in several different compositions of CaB 6 single crystals

Recent Advances in Targeted and Untargeted Metabolomics by NMR and MS/NMR Methods

Energy Technology Data Exchange (ETDEWEB)

Bingol, Kerem

2018-04-18

Metabolomics has made significant progress in multiple fronts in the last 18 months. This minireview aimed to give an overview of these advancements in the light of their contribution to targeted and untargeted metabolomics. New computational approaches have emerged to overcome manual absolute quantitation step of metabolites in 1D 1H NMR spectra. This provides more consistency between inter-laboratory comparisons. Integration of 2D NMR metabolomics databases under a unified web server allowed very accurate identification of the metabolites that have been catalogued in these databases. For the remaining uncatalogued and unknown metabolites, new cheminformatics approaches have been developed by combining NMR and mass spectrometry. These hybrid NMR/MS approaches accelerated the identification of unknowns in untargeted studies, and now they are allowing to profile ever larger number of metabolites in application studies.

A comparison study of PET, NMR, and CT imaging in cerebral ischemia

International Nuclear Information System (INIS)

Babikian, V.L.; Ford, C.S.; Buonanno, F.S.; Kistler, J.P.; Ackerman, R.H.; Alpert, N.M.; Correia, J.A.; Johnson, K.A.; Buxton, R.B.

1987-01-01

Whether ischemia without infarction produces recognizable changes in relaxation times of ischemic but viable brain is an important, unresolved issue. Therefore, a study was initiated of patients with cerebral ischemia, using positron emission tomography (PET), NMR, and computed tomography (CT) to compare and contrast the pathophysiologic information provided by each and to study the issue of whether cerebral ischemia without infarction can be appreciated by proton NMR imaging. Here the initial results are reported. 4 refs.; 2 figs.; 1 table

NMR data-driven structure determination using NMR-I-TASSER in the CASD-NMR experiment

Energy Technology Data Exchange (ETDEWEB)

Jang, Richard [Huazhong University of Science and Technology, School of Software Engineering (China); Wang, Yan [Huazhong University of Science and Technology, School of Life Science and Technology (China); Xue, Zhidong, E-mail: zdxue@hust.edu.cn [Huazhong University of Science and Technology, School of Software Engineering (China); Zhang, Yang, E-mail: zhng@umich.edu [University of Michigan, Department of Computational Medicine and Bioinformatics (United States)

2015-08-15

NMR-I-TASSER, an adaption of the I-TASSER algorithm combining NMR data for protein structure determination, recently joined the second round of the CASD-NMR experiment. Unlike many molecular dynamics-based methods, NMR-I-TASSER takes a molecular replacement-like approach to the problem by first threading the target through the PDB to identify structural templates which are then used for iterative NOE assignments and fragment structure assembly refinements. The employment of multiple templates allows NMR-I-TASSER to sample different topologies while convergence to a single structure is not required. Retroactive and blind tests of the CASD-NMR targets from Rounds 1 and 2 demonstrate that even without using NOE peak lists I-TASSER can generate correct structure topology with 15 of 20 targets having a TM-score above 0.5. With the addition of NOE-based distance restraints, NMR-I-TASSER significantly improved the I-TASSER models with all models having the TM-score above 0.5. The average RMSD was reduced from 5.29 to 2.14 Å in Round 1 and 3.18 to 1.71 Å in Round 2. There is no obvious difference in the modeling results with using raw and refined peak lists, indicating robustness of the pipeline to the NOE assignment errors. Overall, despite the low-resolution modeling the current NMR-I-TASSER pipeline provides a coarse-grained structure folding approach complementary to traditional molecular dynamics simulations, which can produce fast near-native frameworks for atomic-level structural refinement.

Studies on Photodarkening Effect in Glassy As2S3 Using High Field NMR

Science.gov (United States)

Hari, Parameswar; Su, Tining; Taylor, Craig; Reyes, Arneil; Kuhns, Phil; Moulton, William; Sullivan, N. S.

2001-03-01

Photodarkening, or the shift of the optical absorption edge to smaller energies after excitation with light whose energy is near that of the optical band edge, has been studied in many chalcogenide glasses for many years. Recently we have conducted nuclear magnetic resonance (NMR) studies of 75As in glassy As2S3 at 17T . We compared the 75As NMR lineshape in glassy As2S3 before and after irradiation at 77K. After irradiation at 514.5 nm for 230 hours with 170 mW/cm2 there is a subtle change in the NMR lineshape. This change is reversible on annealing at 200 C for 1.75 hours. We will discuss the implications of this result based on NMR lineshape analysis using an exact solution of the spin 3/2 Hamiltonian

Direct Comparison of 19F qNMR and 1H qNMR by Characterizing Atorvastatin Calcium Content

Directory of Open Access Journals (Sweden)

Yang Liu

2016-01-01

Full Text Available Quantitative nuclear magnetic resonance (qNMR is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR (1H qNMR and only a few fluorine qNMR (19F qNMR were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both 19F and 1H qNMR were performed to characterize the content of atorvastatin calcium with the same internal standard. Linearity, precision, and results from two methods were compared. Results showed that 19F qNMR has similar precision and sensitivity to 1H qNMR. Both methods generate similar results compared to mass balance method. Major advantage from 19F qNMR is that the analyte signal is with less or no interference from impurities. 19F qNMR is an excellent approach to quantify fluorine-containing analytes.

Study of ({alpha}, {sup 3}He) and ({alpha}, t) reactions on {sup 28}Si at 45 MeV

Energy Technology Data Exchange (ETDEWEB)

Darshan, V.P.; Sathyavathiamma, M.P.; Ramaswamy, C.R.; Raja Rao, M.; Puttaswamy, N.G.; Banerjee, S.R.; Chintalapudi, S.N. [Dept. of Phys., Bangalore Univ. (India)

1995-03-01

The {sup 28}Si({alpha}, {sup 3}He){sup 29}Si, {sup 28}Si({alpha}, t){sup 29}P and Si({alpha}, {alpha})Si reactions were studied at E{sub {alpha}} = 45 MeV. Exact finite-range (EFR) DWBA analysis was carried out for the transitions to the ground state and to five excited states in {sup 29}Si and {sup 29}P. Spectroscopic strengths G were extracted for all the states and were compared with the predictions from shell-model and quasi-particle core-coupling calculations. Similar EFR-DWBA analyses were carried out from available (unpublished) data for the {sup 28}Si({alpha}, {sup 3}He){sup 29}Si reaction at E{sub {alpha}} = 64.9 and 120 MeV, and for the {sup 28}Si({alpha}, t){sup 29}P reaction at E{sub {alpha}} = 50 and 64.9 MeV. The comparison of experimental and theoretical values of G are provided. (author)

A Field Study of NMR Logging to Quantify Petroleum Contamination in Subsurface Sediments

Science.gov (United States)

Fay, E. L.; Knight, R. J.; Grunewald, E. D.

2016-12-01

Nuclear magnetic resonance (NMR) measurements are directly sensitive to hydrogen-bearing fluids including water and petroleum products. NMR logging tools can be used to detect and quantify petroleum hydrocarbon contamination in the sediments surrounding a well or borehole. An advantage of the NMR method is that data can be collected in both cased and uncased holes. In order to estimate the volume of in-situ hydrocarbon, there must be sufficient contrast between either the relaxation times (T2) or the diffusion coefficients (D) of water and the contaminant. In a field study conducted in Pine Ridge, South Dakota, NMR logging measurements were used to investigate an area of hydrocarbon contamination from leaking underground storage tanks. A contaminant sample recovered from a monitoring well at the site was found to be consistent with a mixture of gasoline and diesel fuel. NMR measurements were collected in two PVC-cased monitoring wells; D and T2 measurements were used together to detect and quantify contaminant in the sediments above and below the water table at both of the wells. While the contrast in D between the fluids was found to be inadequate for fluid typing, the T2 contrast between the contaminant and water in silt enabled the estimation of the water and contaminant volumes. This study shows that NMR logging can be used to detect and quantify in-situ contamination, but also highlights the importance of sediment and contaminant properties that lead to a sufficiently large contrast in T2 or D.

'In vivo' and high resolution spectroscopy in solids by NMR: an instrument for transgenic plants study

International Nuclear Information System (INIS)

Colnago, L.A.; Herrmann, P.S.P.; Bernardes Filho, R.

1995-01-01

This work has developed a study on transgenic plants using two different techniques of nuclear magnetic resonance, in vivo NMR and high resolution NMR. In order to understand the gene mutations and characterize the plants constituents, NMR spectral data were analysed and discussed, then the results were presented

High resolution NMR spectroscopy of synthetic polymers in bulk

International Nuclear Information System (INIS)

Komorski, R.A.

1986-01-01

The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

NMR study of structure of lanthanide complexes in solution

International Nuclear Information System (INIS)

Choppin, G.R.

1976-01-01

The diagnostic value PMR studies of diamagnetic lanthanide complexes to define the nature of the species in the lanthanide-pyruvate system is discussed. The use of NMR spectra of both diamagnetic and paramagnetic lanthanide complexes to obtain detailed structural information is reviewed

Alpha shift correlation (ASC) method. Sensitivity of B-11 NMR shifts to halogen substitution in the ten-vertex nido and arachno series of boron clusters. Linear behavior of NMR effects

Czech Academy of Sciences Publication Activity Database

Štíbr, Bohumil

2018-01-01

Roč. 471, FEB (2018), s. 615-619 ISSN 0020-1693 R&D Projects: GA ČR(CZ) GA16-01618S Institutional support: RVO:61388980 Keywords : Boranes * Dicarbaboranes * NMR shifts- B NMR correlation 11 * Sensitivity factors * Substitution effects Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 2.002, year: 2016

1D AND 2D NMR STUDIES OF BENZYL O–VANILLIN

Directory of Open Access Journals (Sweden)

Mohammed Hadi Al–Douh

2010-06-01

Full Text Available The reaction of o-vanillin A with benzyl bromide B2 in acetone as the solvent and K2CO3 as a base in the presence of tetra-n-butylammonium iodide (TBAI as catalyst formed benzyl o-vanillin, C. The complete assignments of C using PROTON, APT, DEPT-135, COSY, NOESY, HMQC and HMBC NMR in both CDCl3 and acetone-d6 are discussed, and the coupling constants J are reported in Hertz (Hz.     Keywords: 1H NMR; 13C NMR; 2D NMR; Benzyl o-Vanillin

Two dimensional solid state NMR

International Nuclear Information System (INIS)

Kentgens, A.P.M.

1987-01-01

This thesis illustrates, by discussing some existing and newly developed 2D solid state experiments, that two-dimensional NMR of solids is a useful and important extension of NMR techniques. Chapter 1 gives an overview of spin interactions and averaging techniques important in solid state NMR. As 2D NMR is already an established technique in solutions, only the basics of two dimensional NMR are presented in chapter 2, with an emphasis on the aspects important for solid spectra. The following chapters discuss the theoretical background and applications of specific 2D solid state experiments. An application of 2D-J resolved NMR, analogous to J-resolved spectroscopy in solutions, to natural rubber is given in chapter 3. In chapter 4 the anisotropic chemical shift is mapped out against the heteronuclear dipolar interaction to obtain information about the orientation of the shielding tensor in poly-(oxymethylene). Chapter 5 concentrates on the study of super-slow molecular motions in polymers using a variant of the 2D exchange experiment developed by us. Finally chapter 6 discusses a new experiment, 2D nutation NMR, which makes it possible to study the quadrupole interaction of half-integer spins. 230 refs.; 48 figs.; 8 tabs

A combined NMR and XRD study of AFI and AEL type molecular sieves

NARCIS (Netherlands)

Peeters, M.P.J.; Ven, van de L.J.M.; Haan, de J.W.; Hooff, van J.H.C.

1993-01-01

Calcined dehydrated AlPO4-5 was studied by x-ray powder diffraction, 31P MAS, and 27Al double-resonance (DOR) NMR. Three crystallog. different sites can be distinguished in the structure of dehydrated AlPO4-5 in the ratio 1:1:1. The obsd. splitting of the NMR spectra is correlated to the line width

53Cr NMR study of CuCrO2 multiferroic

Science.gov (United States)

Smol'nikov, A. G.; Ogloblichev, V. V.; Verkhovskii, S. V.; Mikhalev, K. N.; Yakubovskii, A. Yu.; Kumagai, K.; Furukawa, Y.; Sadykov, A. F.; Piskunov, Yu. V.; Gerashchenko, A. P.; Barilo, S. N.; Shiryaev, S. V.

2015-11-01

The magnetically ordered phase of the CuCrO2 single crystal has been studied by the nuclear magnetic resonance (NMR) method on 53Cr nuclei in the absence of an external magnetic field. The 53Cr NMR spectrum is observed in the frequency range νres = 61-66 MHz. The shape of the spectrum depends on the delay tdel between pulses in the pulse sequence τπ/2- t del-τπ- t del-echo. The spin-spin and spin-lattice relaxation times have been measured. Components of the electric field gradient, hyperfine fields, and the magnetic moment on chromium atoms have been estimated.

Two- and three-dimensional proton NMR studies of apo-neocarzinostatin

International Nuclear Information System (INIS)

Xiaolian Gao; Burkhart, W.

1991-01-01

Neocarzinostatin (NCS) is an antitumor protein from Streptomyces carzinostaticus that is identical in apo-protein sequence with mitomalcin (MMC) from Streptomyces malayensis. The authors describe the use of apo-NCS as a model system for applying combined two-and three-dimensional (2D and 3D) proton NMR spectroscopy to the structure determination of proteins without isotope labeling. Strategies aimed at accurately assigning overlapped 2D cross-peaks by using semiautomated combined 2D and 3D data analysis are developed. Using this approach, they have assigned 99% of the protons, including those of the side chains, and identified about 1,270 intra- and interresidue proton-proton interactions (fixed distances are not included) in apo-NCS. Comparing these results with those reported recently on 2D NMR studies of apo-NCS demonstrated advantages of proton 3D NMR spectroscopy in protein spectral assignments. They are able to obtain more complete proton resonance and secondary structural assignments and find several misassignments in the earlier report. Strategies utilized in this work should be useful for developing automation procedures for spectral assignments

NMR studies of stock process water and reaction pathways in hydrothermal carbonization of furfural residue

Directory of Open Access Journals (Sweden)

Fen Yue

2018-04-01

Full Text Available Hydrothermal carbonization (HTC is a valuable approach to convert furfural residue (FR into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains to be studied in detail. Herein, a NMR study of the main components in stock process water generated at different HTC reaction conditions was reported. Various qualitative and quantitative NMR techniques (1H and 13C NMR, 1H–1H COSY and 1H13C HSQC etc. especially 1D selective gradient total correlation spectroscopy (TOCSY NMR were strategically applied in the analysis of HTC stock process water. Without separation and purification, it was demonstrated that the main detectable compounds are 5-hydroxymethylfurfural, formic acid, methanol, acetic acid, levulinic acid, glycerol, hydroxyacetone and acetaldehyde in this complicate mixture. Furthermore, the relationship between the concentration of major products and the reaction conditions (180–240 °C at 8 h, and 1–24 h at 240 °C was established. Finally, reasonable reaction pathways for hydrothermal conversion of FR were proposed based on this result and our previously obtained characteristics of biochars. The routine and challenging NMR methods utilized here would be an alternative other than HPLC or GC for biomass conversion research and can be extended to more studies. Keywords: NMR, Hydrothermal carbonization, Furfural residue, Stock process water

Impact of opal nanoconfinement on electronic properties of sodium particles: NMR studies

Energy Technology Data Exchange (ETDEWEB)

Charnaya, E.V., E-mail: charnaya@live.com [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); Institute of Physics, St. Petersburg State University, St. Petersburg, 198504 (Russian Federation); Lee, M.K. [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); MoST Instrument Center at NCKU, Tainan, 70101 Taiwan (China); Chang, L.J. [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); Kumzerov, Yu.A.; Fokin, A.V. [A.F. Ioffe Physico-Technical Institute RAS, St. Petersburg, 194021 (Russian Federation); Samoylovich, M.I. [Moscow Institute of Physics and Technology, Moscow, 141700 (Russian Federation); Bugaev, A.S. [CSR Institute of Technology “Technomash”, Moscow, 121108 (Russian Federation)

2015-03-20

The {sup 23}Na Knight shift of NMR line which is highly correlated with the electron spin susceptibility and density of states at the Fermi level was studied for the sodium loaded opal. The measurements were carried out within a temperature range from 100 to 400 K for solid and melted confined sodium nanoparticles. The NMR line below 305 K was a singlet with the Knight shift reduced compared to that in bulk. Above this temperature the NMR line split reproducibly into two components with opposite trends in the Knight shift temperature dependences which evidenced a nanoconfinement-induced transformation and heterogeneity in the electron system. The findings were suggested to be related to changes in the topology of the Fermi surface.

Synergistic Applications of MD and NMR for the Study of Biological Systems

Directory of Open Access Journals (Sweden)

Olivier Fisette

2012-01-01

same time, theoretical and computational approaches gain in reliability and their field of application widens. In this short paper, we discuss recent advances in the areas of solution nuclear magnetic resonance (NMR spectroscopy and molecular dynamics (MD simulations that were made possible by the combination of both methods, that is, through their synergistic use. We present the main NMR observables and parameters that can be computed from simulations, and how they are used in a variety of complementary applications, including dynamics studies, model-free analysis, force field validation, and structural studies.

Synthesis of N-(4-bromo-2-trifluoromethylphenyl)-1-(2-fluorophenyl)-O,O-dialkyl-alpha-aminophosphonates under ultrasonic irradiation.

Science.gov (United States)

Song, Bao-An; Zhang, Guo-Ping; Yang, Song; Hu, De-Yu; Jin, Lin-Hong

2006-02-01

Boron trifluoride diethyl etherate catalyzes the Mannich-type reaction of 2-trifluoromethyl-4-bromoaniline and O,O-dialkylphosphite with 2-fluorobenzoaldehyde under ultrasonic irradiation to synthesize the corresponding product alpha-aminophosphonate. The advantages of the procedure include short reaction period, high yield and simple working up. Their structures were clearly established by IR, (1)H NMR, (13)C NMR and elemental analysis. The bioassay tests showed that the title compounds exhibit moderate antitumor activity in vitro by MTT method.

Molecular motion of micellar solutes: a 13C NMR relaxation study

International Nuclear Information System (INIS)

Stark, R.E.; Kasakevich, M.L.; Granger, J.W.

1982-01-01

A series of simple NMR relaxation experiments have been performed on nitrobenzene and aniline dissolved in the ionic detergents sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB). Using 13 C relaxation rates at various molecular sites, and comparing data obtained in organic media with those for micellar solutions, the viscosity at the solubilization site was estimated and a detailed picture of motional restrictions imposed by the micellar enviroment was derived. Viscosities of 8 to 17 cp indicate a rather fluid environment for solubilized nitrobenzene; both additives exhibit altered motional preferences in CTAB solutions only. As an aid in interpretation of the NMR data, quasi-elastic light scattering and other physical techniques have been used to evaluate the influence of organic solutes on micellar size and shape. The NMR methods are examined critically in terms of their general usefulness for studies of solubilization in detergent micelles. 48 references

CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis

International Nuclear Information System (INIS)

Skinner, Simon P.; Fogh, Rasmus H.; Boucher, Wayne; Ragan, Timothy J.; Mureddu, Luca G.; Vuister, Geerten W.

2016-01-01

NMR spectroscopy is an indispensably powerful technique for the analysis of biomolecules under ambient conditions, both for structural- and functional studies. However, in practice the complexity of the technique has often frustrated its application by non-specialists. In this paper, we present CcpNmr version-3, the latest software release from the Collaborative Computational Project for NMR, for all aspects of NMR data analysis, including liquid- and solid-state NMR data. This software has been designed to be simple, functional and flexible, and aims to ensure that routine tasks can be performed in a straightforward manner. We have designed the software according to modern software engineering principles and leveraged the capabilities of modern graphics libraries to simplify a variety of data analysis tasks. We describe the process of backbone assignment as an example of the flexibility and simplicity of implementing workflows, as well as the toolkit used to create the necessary graphics for this workflow. The package can be downloaded from www.ccpn.ac.uk/v3-software/downloads http://www.ccpn.ac.uk/v3-software/downloads and is freely available to all non-profit organisations.

CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis

Energy Technology Data Exchange (ETDEWEB)

Skinner, Simon P.; Fogh, Rasmus H. [University of Leicester, Department of Molecular and Cell Biology, Leicester Institute for Structural- and Chemical Biology (United Kingdom); Boucher, Wayne [University of Cambridge, Department of Biochemistry (United Kingdom); Ragan, Timothy J.; Mureddu, Luca G.; Vuister, Geerten W., E-mail: gv29@le.ac.uk [University of Leicester, Department of Molecular and Cell Biology, Leicester Institute for Structural- and Chemical Biology (United Kingdom)

2016-10-15

NMR spectroscopy is an indispensably powerful technique for the analysis of biomolecules under ambient conditions, both for structural- and functional studies. However, in practice the complexity of the technique has often frustrated its application by non-specialists. In this paper, we present CcpNmr version-3, the latest software release from the Collaborative Computational Project for NMR, for all aspects of NMR data analysis, including liquid- and solid-state NMR data. This software has been designed to be simple, functional and flexible, and aims to ensure that routine tasks can be performed in a straightforward manner. We have designed the software according to modern software engineering principles and leveraged the capabilities of modern graphics libraries to simplify a variety of data analysis tasks. We describe the process of backbone assignment as an example of the flexibility and simplicity of implementing workflows, as well as the toolkit used to create the necessary graphics for this workflow. The package can be downloaded from www.ccpn.ac.uk/v3-software/downloads http://www.ccpn.ac.uk/v3-software/downloads and is freely available to all non-profit organisations.

15N NMR studies of layered nitride superconductor LixZrNCl

International Nuclear Information System (INIS)

Tou, H.; Oshiro, S.; Kotegawa, H.; Taguchi, Y.; Kishiume, Y.; Kasahara, Y.; Iwasa, Y.

2010-01-01

NMR measurements were carried out on pristine ZrNCl and Li x ZrNCl. From the 15 N-Knight shift study, the isotropic Knight shift, the traceless chemical (orbital) shift tensor and the traceless Knight shift tensor were determined as K iso = -71 ppm, (σ 1 , σ 2 , σ 3 ) = (-55, -55, 110) ppm and (K 1 , K 2 , K 3 ) = (48, 48, -96) ppm, respectively. In the superconducting state, the fractional change of the 15 N NMR shift for H-parallel ab was observed, evidencing that the pairing symmetry is a spin-singlet state.

An NMR Protonation Study of Metal Diethylenetriaminepentaacetic Acid Complexes.

Science.gov (United States)

Letkeman, Peter

1979-01-01

This experiment is suitable for an integrated laboratory course for senior chemistry majors. It introduces the student to a study of the relative basicity of different proton accepting sites. It serves as an opportunity to learn about nmr techniques and could extend to infrared, as well. (BB)

Structural studies of SpoIIAA using NMR

International Nuclear Information System (INIS)

Comfort, D.M.

1998-01-01

The protein SpoIIAA participates, via phosphorylation and dephosphorylation, in the four-component system that regulates the sporulation sigma factor e. Differential gene expression depends on specialised transcription factors called sigma factors, which direct the RNA polymerase to transcribe specific genes in one or other of the two chambers at various stages of sporulation. The first sporulation-specific sigma factor to be activated is 4 transcription that depends on σ F is essential for the remaining sigma factors to become active in turn. Early in sporulation SpoIIAA is in the phosphorylated state (SpoIIAA-P), as a result of the activity of the ATP-dependent protein kinase, SpoIIAB. About 80 minutes after the initiation of sporulation a specific phosphatase, SpoIIE, begins to hydrolyse SpoIIAA-P, and the resulting SpoIIAA again becomes a substrate for SpoIIAB. SpoIIAB is also an anti-sigma factor which in its free form inhibits a F by binding to it. Competition by SpoIIAA (the anti-anti-sigma factor) for binding to SpoIIAB releases e activity. The three-dimensional structure of SpoIIAA has been determined using high resolution NMR. SpoIIAA has a novel fold, composed of a-helices and P-strand elements. The structural differences between SpoIIAA and its inactive form, SpoIIAA-P, were also investigated by NMR. Tentative evidence points to the observation that phosphorylation of SpoIIAA results in a minor conformational change near the site of phosphorylation, which interferes with the hydrophobic interaction between SpoIIAA and SpoIIAB. Further NMR studies helped to predict the location of SpoIIAA-, GTP-, and ATP-binding sites on the SpoIIAA structure. In addition, the automated iterative NOE assignment algorithm, ARIA, was used to obtain additional NOE-based distance constraints and to calculate a refined structure. (author)

Structural studies of SpoIIAA using NMR

Energy Technology Data Exchange (ETDEWEB)

Comfort, D.M

1998-07-01

The protein SpoIIAA participates, via phosphorylation and dephosphorylation, in the four-component system that regulates the sporulation sigma factor e. Differential gene expression depends on specialised transcription factors called sigma factors, which direct the RNA polymerase to transcribe specific genes in one or other of the two chambers at various stages of sporulation. The first sporulation-specific sigma factor to be activated is 4 transcription that depends on {sigma}{sup F} is essential for the remaining sigma factors to become active in turn. Early in sporulation SpoIIAA is in the phosphorylated state (SpoIIAA-P), as a result of the activity of the ATP-dependent protein kinase, SpoIIAB. About 80 minutes after the initiation of sporulation a specific phosphatase, SpoIIE, begins to hydrolyse SpoIIAA-P, and the resulting SpoIIAA again becomes a substrate for SpoIIAB. SpoIIAB is also an anti-sigma factor which in its free form inhibits a F by binding to it. Competition by SpoIIAA (the anti-anti-sigma factor) for binding to SpoIIAB releases e activity. The three-dimensional structure of SpoIIAA has been determined using high resolution NMR. SpoIIAA has a novel fold, composed of a-helices and P-strand elements. The structural differences between SpoIIAA and its inactive form, SpoIIAA-P, were also investigated by NMR. Tentative evidence points to the observation that phosphorylation of SpoIIAA results in a minor conformational change near the site of phosphorylation, which interferes with the hydrophobic interaction between SpoIIAA and SpoIIAB. Further NMR studies helped to predict the location of SpoIIAA-, GTP-, and ATP-binding sites on the SpoIIAA structure. In addition, the automated iterative NOE assignment algorithm, ARIA, was used to obtain additional NOE-based distance constraints and to calculate a refined structure. (author)

1H NMR and SPME-GC/MS study of hydrolysis, oxidation and other reactions occurring during in vitro digestion of non-oxidized and oxidized sunflower oil. Formation of hydroxy-octadecadienoates.

Science.gov (United States)

Nieva-Echevarría, Bárbara; Goicoechea, Encarnación; Manzanos, María J; Guillén, María D

2017-01-01

Both fresh and slightly oxidized sunflower oils, as models of omega-6 rich lipids, were submitted to in vitro gastrointestinal digestion and studied by 1 H NMR and SPME-GC/MS. Changes in lipolysis degree, lipid composition and oxidative level were studied by 1 H NMR. Three quantitative approaches were used and several equations were newly developed. In oxidized oil digestates slightly lower hydrolysis and a higher advance of oxidation took place during digestion. This latter was evidenced by a greater decrease of lipid unsaturation degree and enhanced generation of oxidation products (cis,trans-hydroperoxy-octadecadienoates, cis,trans- and trans,trans-hydroxy-octadecadienoates). For the first time, the generation of hydroxy-octadecadienoates during in vitro digestion is reported. Furthermore, SPME-GC/MS study of non-digested and digested samples headspaces confirmed that lipid oxidation occurred: abundances of volatile markers increased (including potentially toxic alpha,beta-unsaturated aldehydes), especially in oxidized oils digestates. Markers of Maillard-type and esterification reactions were also detected in the digestates. Copyright © 2016 Elsevier Ltd. All rights reserved.

NMR study of hyper-polarized 129Xe and applications to liquid-phase NMR experiments

International Nuclear Information System (INIS)

Marion, D.

2008-07-01

In liquid samples where both nuclear polarization and spin density are strong, the magnetization dynamics, which can be analysed by NMR (nuclear magnetic resonance) methods, is deeply influenced by the internal couplings induced by local dipolar fields. The present thesis describes some of the many consequences associated to the presence in the sample of concentrated xenon hyper-polarized by an optical pumping process. First, we deal with the induced modifications in frequency and line width of the proton and xenon spectra, then we present the results of SPIDER, a coherent polarization transfer experiment designed to enhance the polarization of protons, in order to increase their NMR signal level. A third part is dedicated to the description of the apparition of repeated chaotic maser emissions by un unstable xenon magnetization coupled to the detection coil tuned at the xenon Larmor frequency (here 138 MHz). In the last part, we present a new method allowing a better tuning of any NMR detection probe and resulting in sensible gains in terms of sensitivity and signal shaping. Finally, we conclude with a partial questioning of the classical relaxation theory in the specific field of highly polarized and concentrated spin systems in a liquid phase. (author)

Three-residue turns in alpha/beta-peptides and their application in the design of tertiary structures.

Science.gov (United States)

Sharma, Gangavaram V M; Nagendar, Pendem; Ramakrishna, Kallaganti V S; Chandramouli, Nagula; Choudhary, Madavi; Kunwar, Ajit C

2008-06-02

A new three-residue turn was serendipitously discovered in alpha/beta hybrid peptides derived from alternating C-linked carbo-beta-amino acids (beta-Caa) and L-Ala residues. The three-residue beta-alpha-beta turn at the C termini, nucleated by a helix at the N termini, resulted in helix-turn (HT) supersecondary structures in these peptides. The turn in the HT motif is stabilized by two H bonds-CO(i-2)-NH(i), with a seven-membered pseudoring (gamma turn) in the backward direction, and NH(i-2)-CO(i), with a 13-membered pseudoring in the forward direction (i being the last residue)--at the C termini. The study was extended to generalize the new three-residue turn (beta-alpha-beta) by using different alpha- and beta-amino acids. Furthermore, the HT motifs were efficiently converted, by an extension with helical oligomers at the C termini, into peptides with novel helix-turn-helix (HTH) tertiary structures. However, this resulted in the destabilization of the beta-alpha-beta turn with the concomitant nucleation of another three-residue turn, alpha-beta-beta, which is stabilized by 11- and 15-membered bifurcated H bonds. Extensive NMR spectroscopic studies were carried out to delineate the secondary and tertiary structures in these peptides, which are further supported by molecular dynamics (MD) investigations.

Optical pumping and xenon NMR

International Nuclear Information System (INIS)

Raftery, M.D.

1991-11-01

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

NMR spectroscopic studies of membrane-bound biological systems

International Nuclear Information System (INIS)

Hohlweg, W.

2013-01-01

In the course of this thesis, biological NMR spectroscopy was employed in studying membrane-bound peptides and proteins, for which structural information is still comparatively hard to obtain. Initial work focused on various model peptides bound to membrane-mimicking micelles, studying the protonation state of arginine in a membrane environment. Strong evidence for a cation-π complex was found in TM7, a peptide which forms the seventh transmembrane helix of subunit a of the vacuolar-type H+-ATPase (V-ATPase). V-ATPase is a physiologically highly relevant proton pump, which is present in intracellular membranes of all eukaryotic organisms, as well as the plasma membrane of several specialized cells. Loss of functional V-ATPase is associated with human diseases such as osteopetrosis, distal renal tubular acidosis or the spreading of cancer. V-ATPase is considered a potential drug target in the treatment of osteoporosis and cancer, or in the development of novel contraceptives. Results from NMR solution structure determination, NMR titration experiments, paramagnetic relaxation enhancement experiments and tryptophan fluorescence spectroscopy confirm the existence of a buried cation-? complex formed between arginine residue R735, which is essential for proton transport, and neighbouring tryptophan and tyrosine residues. In vivo experiments in the yeast Saccharomyces cerevisiae using selective growth tests and fluorescence microscopy showed that formation of the cation-π complex is essential for V-ATPase function. Deletion of both aromatic residues, as well as only the one tryptophan residue leads to growth defects and inability to maintain vacuolar pH homeostasis. These findings shine new light on the still elusive mechanism of proton transport in V-ATPase, and show that arginine R735 may be directly involved in proton transfer across the membrane. (author) [de

Studies of metal-biomolecule systems in liquids with beta-detected NMR

CERN Document Server

Walczak, Michal

2017-01-01

My internship took place within a small research team funded via the European Research Council (ERC Starting Grant: Beta-Drop NMR) at ISOLDE. It was devoted to laser spin-polarization and beta-detected NMR techniques and their future applications in chemistry and biology. I was involved in the design and tests of the beta-NMR spectrometer which will be used in the upcoming experiments. In this way I have been exposed to many topics in physics (atomic and nuclear physics), experimental techniques (vacuum technology, lasers, beta detectors, electronics, DAQ software), as well as chemistry and biology (NMR on metal ions, metal ion binding to biomolecules, quantum chemistry calculations).

1H-NMR, 1H-NMR T2-edited, and 2D-NMR in bipolar disorder metabolic profiling.

Science.gov (United States)

Sethi, Sumit; Pedrini, Mariana; Rizzo, Lucas B; Zeni-Graiff, Maiara; Mas, Caroline Dal; Cassinelli, Ana Cláudia; Noto, Mariane N; Asevedo, Elson; Cordeiro, Quirino; Pontes, João G M; Brasil, Antonio J M; Lacerda, Acioly; Hayashi, Mirian A F; Poppi, Ronei; Tasic, Ljubica; Brietzke, Elisa

2017-12-01

The objective of this study was to identify molecular alterations in the human blood serum related to bipolar disorder, using nuclear magnetic resonance (NMR) spectroscopy and chemometrics. Metabolomic profiling, employing 1 H-NMR, 1 H-NMR T 2 -edited, and 2D-NMR spectroscopy and chemometrics of human blood serum samples from patients with bipolar disorder (n = 26) compared with healthy volunteers (n = 50) was performed. The investigated groups presented distinct metabolic profiles, in which the main differential metabolites found in the serum sample of bipolar disorder patients compared with those from controls were lipids, lipid metabolism-related molecules (choline, myo-inositol), and some amino acids (N-acetyl-L-phenyl alanine, N-acetyl-L-aspartyl-L-glutamic acid, L-glutamine). In addition, amygdalin, α-ketoglutaric acid, and lipoamide, among other compounds, were also present or were significantly altered in the serum of bipolar disorder patients. The data presented herein suggest that some of these metabolites differentially distributed between the groups studied may be directly related to the bipolar disorder pathophysiology. The strategy employed here showed significant potential for exploring pathophysiological features and molecular pathways involved in bipolar disorder. Thus, our findings may contribute to pave the way for future studies aiming at identifying important potential biomarkers for bipolar disorder diagnosis or progression follow-up.

Positron annihilation and 129Xe NMR studies of free volume in polymers

International Nuclear Information System (INIS)

Nagasaka, Bunsow; Eguchi, Taro; Nakayama, Hirokazu; Nakamura, Nobuo; Ito, Yasuo

2000-01-01

The existence and the average size of free volume in bisphenol-A polycarbonate (PC), low-density polyethylene (LDPE), poly (2,6-dimethyl-phenylene oxide)(PPO), and polytetrafluoroethylene (PTFE) were studied by positron annihilation and 129 Xe NMR measurements. The 129 Xe NMR chemical shifts for xenon adsorbed in the polymers indicated that the average pore size of the free volume increased in the following order: PC, LDPE, PPO, and PTFE. This order of the pore size of the free volume agrees well with that estimated from the longest lifetime (τ 3 ) of ortho-positronium formed in the polymers. The unique correlation that δ -1 ∝ r is established between the 129 Xe NMR chemical shift (δ) and the pore size (r), which is deduced from the positron annihilation measurements.

NMR-based milk metabolomics

DEFF Research Database (Denmark)

Sundekilde, Ulrik; Larsen, Lotte Bach; Bertram, Hanne Christine S.

2013-01-01

and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR)-based metabolomics trends in milk research, including applications linking...... compounds. Furthermore, metabolomics applications elucidating how the differential regulated genes affects milk composition are also reported. This review will highlight the recent advances in NMR-based metabolomics on milk, as well as give a brief summary of when NMR spectroscopy can be useful for gaining...

Crystalline anhydrous {alpha},{alpha}-trehalose (polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose: A calorimetric study

Energy Technology Data Exchange (ETDEWEB)

Pinto, Susana S. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: susanapinto@ist.utl.pt; Diogo, Herminio P. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: hdiogo@ist.utl.pt; Moura-Ramos, Joaquim J. [Centro de Quimica-Fisica Molecular, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: mouraramos@ist.utl.pt

2006-09-15

The mean values of the standard massic energy of combustion of crystalline anhydrous {alpha},{alpha}-trehalose (C{sub 12}H{sub 22}O{sub 11}, polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose (C{sub 12}H{sub 26}O{sub 13}) measured by static-bomb combustion calorimetry in oxygen, at the temperature T=298.15K, are {delta}{sub c}u{sup o}=-(16434.05+/-4.50)J.g{sup -1} and {delta}{sub c}u{sup o}=-(14816.05+/-3.52)J.g{sup -1}, respectively. The standard (p{sup o}=0.1MPa) molar enthalpy of formation of these compounds were derived from the corresponding standard molar enthalpies of combustion, respectively, {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 22}O{sub 11},cr)=-(2240.9+/-3.9)kJ.mol{sup -1}, and {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 26}O{sub 13},cr)=-(2832.6+/-3.6)kJ.mol{sup -1}. The values of the standard enthalpies of formation obtained in this work, together with data on enthalpies of solution at infinite dilution ({delta}{sub sol}H{sup {approx}}) for crystalline dihydrate and amorphous anhydrous trehalose, allow a better insight on the thermodynamic description of the trehalose system which can provide, together with the future research on the subject, a contribution for understanding the metabolism in several organisms, as well as the phase transition between the different polymorphs.

Solid state NMR study of cumbaru flour

International Nuclear Information System (INIS)

Nogueira, Jose S.; Bathista, Andre L.B.S.; Silva, Emerson O.; Priante Filho, Nicolau; Tavares, Maria I.B.

2001-01-01

The polysaccharide obtained by seed of Dipteryx alata Vog, has been characterised by 13 C solid state, using the basic routine techniques, like MAS and CPMAS and by the proton spin-lattice relaxation time in the rotating frame parameter (T 1 H ρ). Knowing that the chemical structure and molecular dynamic are extremely necessary route to obtain information on the polysaccharides, this work contributes to the classification of the seed containing in the cumbaru fruit to get response on its application. To obtain the initial responses for our purposes some solid state NMR techniques were chosen. The CPMAS 13 C NMR spectrum of the polysaccharide was investigated to know if it has some crystallinity. The MAS 13 C NMR spectrum showed the presence of domains with distinct molecular mobility, because these domains will differ basically in the distribution size and chain packing. The variable contact time experiment was used to analyse the distribution form of 13 C decays, which give us more information about sample heterogeneity. The T 1 H ρHr values were obtained from the variable contact time and by delayed contact time experiment, because these parameter indicate the order of polysaccharides. From the values of this parameter, we found that this polysaccharide is completely non-ordered. (author)

Two-dimensional NMR studies of allyl palladium complexes of ...

Indian Academy of Sciences (India)

Administrator

h3-Allyl complexes are intermediates in organic synthetic reactions such as allylic alkylation and amination. There is growing interest in understanding the structures of chiral h3-allyl intermediates as this would help to unravel the mechanism of enantioselective C–C bond forming reactions. Two-dimensional NMR study is a.

Conformational, vibrational, NMR and DFT studies of N-methylacetanilide.

Science.gov (United States)

Arjunan, V; Santhanam, R; Rani, T; Rosi, H; Mohan, S

2013-03-01

A detailed conformational, vibrational, NMR and DFT studies of N-methylacetanilide have been carried out. In DFT, B3LYP method have been used with 6-31G(**), 6-311++G(**) and cc-pVTZ basis sets. The vibrational frequencies were calculated resulting in IR and Raman frequencies together with intensities and Raman depolarisation ratios. The dipole moment derivatives were computed analytically. Owing to the complexity of the molecule, the potential energy distributions of the vibrational modes of the compound are also calculated. Isoelectronic molecular electrostatic potential surface (MEP) and electron density surface were examined. (1)H and (13)C NMR isotropic chemical shifts were calculated and the assignments made are compared with the experimental values. The energies of important MO's of the compound were also determined from TD-DFT method. Copyright © 2012 Elsevier B.V. All rights reserved.

sup(1)H-NMR study of restricted rotation in dithiophosphoromethyl acetanilides

International Nuclear Information System (INIS)

Kovacs, Zs.

1985-01-01

sup(1)H-NMR spectra of a series of dithiophosphoromethyl acetanilide derivatives were investigated. The presence of an ortho substituted aryl group bonded to the nitrogen atom of the amide group allowed the observation of restricted internal rotation around the aryl-nitrogen bond. Coalescence temperature and the values of the free energy of activation were determined from the temperature dependent NMR behaviour of these molecules. The possibility of cis-trans isomerism about the nitrogen carbonyl bond was also studied, and the assignment of the conformation of the existing isomer was also made using the aromatic solvent induced shift. (author)

Mössbauer and NMR study of novel Tin(IV)-lactames

International Nuclear Information System (INIS)

Kuzmann, Erno; Szalay, Roland; Homonnay, Zoltan; Nagy, Sandor

2012-01-01

N-tributylstannylated 2-pyrrolidinone was reacted with tributyltin triflate in different molar ratios and the complex formation monitored using 1 H-NMR, 13 C-NMR and 119 Sn Mössbauer spectroscopy. Comparing the carbon NMR and tin Mössbauer results, a reaction scheme is suggested for the complexation which assumes the formation of a simultaneously O- and N-tributylstannylated pyrrolidinone cation. The formation of the only O-stannylated pyrrolidinone is also assumed to account for the non-constant Mössbauer parameters of the two tin environments in the distannylated pyrrolidinone cation when the ratio of tributyltin triflate is increased in the reaction.

Correlation between protein kinase C alpha activity and membrane phase behavior.

Science.gov (United States)

Micol, V; Sánchez-Piñera, P; Villalaín, J; de Godos, A; Gómez-Fernández, J C

1999-02-01

Lipid activation of protein kinase C alpha (PKC alpha) was studied by using a model mixture containing 1, 2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1, 2-dimyristoyl-sn-glycero-3-phosphoserine (DMPS), and 1, 2-dimyristoyl-sn-glycerol (1,2-DMG). This lipid mixture was physically characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and 31P-nuclear magnetic resonance (31P-NMR). Based on these techniques, a phase diagram was constructed by keeping a constant DMPC/DMPS molar ratio of 4:1 and changing the concentration of 1,2-DMG. This phase diagram displayed three regions and two compounds: compound 1 (C1), with 45 mol% 1,2-DMG, and compound 2 (C2), with 60 mol% 1,2-DMG. When the phase diagram was elaborated in the presence of Ca2+ and Mg2+, at concentrations similar to those used in the PKC alpha activity assay, the boundaries between the regions changed slightly and C1 had 35 mol% 1,2-DMG. The activity of PKC alpha was studied at several temperatures and at different concentrations of 1,2-DMG, with a maximum of activity reached at 30 mol% 1,2-DMG and lower values at higher concentrations. In the presence of Ca2+ and Mg2+, maximum PKC alpha activity occurred at concentrations of 1,2-DMG that were close to the boundary in the phase diagram between region 1, where compound C1 and the pure phospholipid coexisted in the gel phase, and region 2, where compounds C1 and C2 coexisted. These results suggest that the membrane structure corresponding to a mixture of 1,2-DMG/phospholipid complex and free phospholipid is better able to support the activity of PKC alpha than the 1,2-DMG/phospholipid complex alone.

NMR imaging of cerebral infarction

International Nuclear Information System (INIS)

Takusagawa, Yoshihiko; Yamaoka, Naoki; Doi, Kazuaki; Okada, Keisei

1987-01-01

One hundred and five patients with cerebral infarction were studied by nuclear magnetic resonance (NMR) CT (resistive type of magnet with strength of 0.1 tesla) and X-ray CT. Pulse sequences used saturation recovery (Tr = 600 mSec), Inversion recovery (Tr = 500 mSec, Td = 300 mSec) and spin echo (Tr = 1500 mSec, Te = 40, 80, 120, 160 mSec). Fifteen cases were examined by NMR-CT within 24 hours from onset. Proton NMR imaging could not detect cerebral ischemia as early as 2 hours after onset, but except could detect the lesions in Se image the area of cerebral infarct 3 hours after onset. After 5 hours from onset image changes in SE were evident and corresponded to the area of cerebral infarct, but image changes in IR could not fully delineate the infarcted area. NMR images of 41 year-old woman with cerebral embolism by MCA trunck occlusion associated with mitral stenosis were presented, and NMR-CT was examined 10 hours, 9th and 43th days after episode of MCA occlusion. Sixty patents (64 times) with lacunar infarction were studied by NMR-CT and X-ray CT. The inversion recovery images were used mainly for detection of lesions and comparison with X-ray CT. In 160 lesions which were detected by NMR-CT or X-ray CT, could 156 lesions be detected by NMR-CT and 78 lesions by X-ray CT. Inversion recovery images were more useful for detection of lacunes than X-ray CT. Calculated T1 and T2 values prolonged with time course from onset. (author)

Bentonite pore structure based on SAXS, chloride exclusion and NMR studies

International Nuclear Information System (INIS)

Muurinen, A.; Carlsson, T.

2013-11-01

Water-saturated bentonite is planned to be used in many countries as an important barrier component in high-level nuclear waste (HLW) repositories. Knowledge about the microstructure of the bentonite and the distribution of water between interlayer and non-interlayer pores is important for modelling of long-term processes. In this work the microstructure of water-saturated samples prepared from Na montmorillonite, Ca-montmorillonite, sodium bentonite MX-80 and calcium bentonite Deponit CaN were studied with nuclear magnetic resonance (NMR) and small-angle xray scattering spectroscopy (SAXS). The sample dry densities ranged between 0.3 and 1.6 g/cm 3 . The NMR technique was used to get information about the volumes of different water types in the bentonite samples. The results were obtained using 1H NMR spin-lattice T 1ρ relaxation time measurements using the short inter-pulse method. The interpretation of the NMR results was made by fitting distributions of exponentials to observed decay curves. The SAXS measurements were used to get information about the size distribution of the interlayer distance of montmorillonite. The chloride porosity measurements and Donnan exclusion calculations were used together with the SAXS results for evaluation of the bentonite microstructure. The NMR studies and SAXS studies coupled with Cl porosity measurements provided very similar pictures of how the porewater is divided in interlayer and non-interlayer water in MX-80 bentonite. In the case where MX-80 of a dry density 1.6 g/cm 3 was equilibrated with 0.1 M NaCl solution, the results indicated an interlayer porosity of 30 % and non-interlayer porosity of 12 %. The interlayer space mainly contained two water layers but also spaces with more water layers were present. The average size of the non-interlayer pores was evaluated to be 120 - 150 A. From the montmorillonite surface area 98 % was interlayer and 2 % non-interlayer. Evaluation of the interlayer and non

Proton NMR study of α-MnH 0.06

Science.gov (United States)

Soloninin, A. V.; Skripov, A. V.; Buzlukov, A. L.; Antonov, V. E.; Antonova, T. E.

2004-07-01

Proton nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates for the solid solution α-MnH 0.06 have been measured over the temperature range 11-297 K and the resonance frequency range 20-90 MHz. A considerable shift and broadening of the proton NMR line and a sharp peak of the spin-lattice relaxation rate are observed near 130 K. These effects are attributed to the onset of antiferromagnetic ordering below the Néel temperature TN≈130 K. The proton NMR line does not disappear in the antiferromagnetic phase; this suggests a small magnitude of the local magnetic fields at H-sites in α-MnH 0.06. The spin-lattice relaxation rate in the paramagnetic phase is dominated by the effects of spin fluctuations.

Non-polymeric asymmetric binary glass-formers. II. Secondary relaxation studied by dielectric, 2H NMR, and 31P NMR spectroscopy

Science.gov (United States)

Pötzschner, B.; Mohamed, F.; Bächer, C.; Wagner, E.; Lichtinger, A.; Bock, D.; Kreger, K.; Schmidt, H.-W.; Rössler, E. A.

2017-04-01

We investigate the secondary (β-) relaxations of an asymmetric binary glass former consisting of a spirobichroman derivative (SBC; Tg = 356 K) as the high-Tg component and the low-Tg component tripropyl phosphate (TPP; Tg = 134 K). The main relaxations are studied in Paper I [B. Pötzschner et al., J. Chem. Phys. 146, 164503 (2017)]. A high Tg contrast of ΔTg = 222 K is put into effect in a non-polymeric system. Component-selective studies are carried out by combining results from dielectric spectroscopy (DS) for mass concentrations cTPP ≥ 60% and those from different methods of 2H and 31P NMR spectroscopy. In the case of NMR, the full concentration range (10% ≤ cTPP ≤ 100%) is covered. The neat components exhibit a β-relaxation (β1 (SBC) and β2 (TPP)). The latter is rediscovered by DS in the mixtures for all concentrations with unchanged time constants. NMR spectroscopy identifies the β-relaxations as being alike to those in neat glasses. A spatially highly restricted motion with angular displacement below ±10° encompassing all molecules is involved. In the low temperature range, where TPP shows the typical 31P NMR echo spectra of the β2-process, very similar spectral features are observed for the (deuterated) SBC component by 2H NMR, in addition to its "own" β1-process observed at high temperatures. Apparently, the small TPP molecules enslave the large SBC molecules to perform a common hindered reorientation. The temperature dependence of the spin-lattice relaxation time of both components is the same and reveals an angular displacement of the SBC molecules somewhat smaller than that of TPP, though the time constants τβ2 are the same. Furthermore, T1(T) of TPP in the temperature region of the β2-process is absolutely the same as in the mixture TPP/polystyrene investigated previously. It appears that the manifestations of the β-process introduced by one component are essentially independent of the second component. Finally, at cTPP ≤ 20% one

Some nitrogen-14 NMR studies in solids

International Nuclear Information System (INIS)

Pratum, T.K.

1983-11-01

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

NMR-based metabonomic study of the sub-acute toxicity of titanium dioxide nanoparticles in rats after oral administration

Energy Technology Data Exchange (ETDEWEB)

Bu Qian; Lin Hongjun; Xu Youzhi; Cao Zhixing; Zhou Tian; Zhao Yinglan [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Yan Guangyan; Cen Xiaobo [National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Deng Pengchi [Analytical and Testing Center, Sichuan University, Chengdu 610041 (China); Peng Feng [Department of Thoracic Oncology of Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Xue Aiqin [Institute of Bioengineering, Zhejiang Sci-Tech University Road 2, Xiasha, Hangzhou 310018 (China); Wang Yanli, E-mail: alancenxb@sina.com [Tianjin Children' s Hospital, Tianjin 300074 (China)

2010-03-26

As titanium dioxide nanoparticles (TiO{sub 2} NPs) are widely used commercially, their potential toxicity on human health has attracted particular attention. In the present study, the oral toxicological effects of TiO{sub 2} NPs (dosed at 0.16, 0.4 and 1 g kg{sup -1}, respectively) were investigated using conventional approaches and metabonomic analysis in Wistar rats. Serum chemistry, hematology and histopathology examinations were performed. The urine and serum were investigated by {sup 1}H nuclear magnetic resonance (NMR) using principal components and partial least squares discriminant analysis. The metabolic signature of urinalysis in TiO{sub 2} NP-treated rats showed increases in the levels of taurine, citrate, hippurate, histidine, trimethylamine-N-oxide (TMAO), citrulline, {alpha}-ketoglutarate, phenylacetylglycine (PAG) and acetate; moreover, decreases in the levels of lactate, betaine, methionine, threonine, pyruvate, 3-D-hydroxybutyrate (3-D-HB), choline and leucine were observed. The metabonomics analysis of serum showed increases in TMAO, choline, creatine, phosphocholine and 3-D-HB as well as decreases in glutamine, pyruvate, glutamate, acetoacetate, glutathione and methionine after TiO{sub 2} NP treatment. Aspartate aminotransferase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH) were elevated and mitochondrial swelling in heart tissue was observed in TiO{sub 2} NP-treated rats. These findings indicate that disturbances in energy and amino acid metabolism and the gut microflora environment may be attributable to the slight injury to the liver and heart caused by TiO{sub 2} NPs. Moreover, the NMR-based metabolomic approach is a reliable and sensitive method to study the biochemical effects of nanomaterials.

Studies of Superfluid 3He Confined to a Regular Submicron Slab Geometry, Using SQUID NMR

International Nuclear Information System (INIS)

Casey, Andrew; Corcoles, Antonio; Lusher, Chris; Cowan, Brian; Saunders, John

2006-01-01

The effect on the superfluid ground state of confining p-wave superfluid 3He in regular geometries of characteristic size comparable to the diameter of the Cooper pair remains relatively unexplored, in part because of the demands placed by experiments on the sensitivity of the measuring technique. In this paper we report preliminary experiments aimed at the study of 3He confined to a slab geometry. The NMR response of a series of superfluid samples has been investigated using a SQUID NMR amplifier. The sensitivity of this NMR spectrometer enables samples of order 1017 spins, with low filling factor, to be studied with good resolution

13C-NMR assignment, structure, and dynamics of deoxyoligonucleotides

International Nuclear Information System (INIS)

Zanatta, N.; Borer, P.N.; Levy, G.C.

1986-01-01

The unique spectral properties of 13 C-NMR for studying nucleic acids and some of the important features of 13 C-NMR in oligonucleotide studies are demostrated. The main difficulty in studying oligonucleotides by 13 C-NMR and recent improvements in NMR instrumentation and advances in oligonucleotide synthesis are presented. The high resolution 13 C-NMR spectra, T 1 relaxation times and NOEs were measured for duplex of the self-complementary oligo-DNAs: d(CG) 3 and d(GGTATACC) are studied. The target of this study is to developed a systematic 13 C-NMR spectral assignment and to investigate the structure and dynamics of these two sequences by this techniques. (M.J.C.) [pt

NMR: its application to the experimental study of hydrocephalus and brain edema

Energy Technology Data Exchange (ETDEWEB)

Asato, R; Murata, T; Mori, K; Handa, H [Kyoto Univ. (Japan). Faculty of Medicine

1981-06-01

The pulsed NMR technique is very sensitive to molecular movement because its observation frequency is in the range of the rates of molecular movement. Furthermore it makes it possible to study the interested molecules in the biological tissues physically and noninvasively. In this report we have investigated the experimental brain edema and hydrocephalus, in both of which the tissue fluid changes are main pathology, through /sup 1/H-NMR relaxation study of water molecule in the brain tissues. The longitudinal (T/sub 1/) and the transverse (T/sub 2/) relaxation times were measured with Varian-HR-220 spectrometer modified with Nicolet-TT-100 PFT system. The experimental materials were the adult male Wister rats suffering from cold injury edema and the adult canines suffering from kaolin hydrocephalus. The study showed firstly that in brain edema no particular changes were found for relaxation times in the white matter, whereas in the gray matter, discrepancy between the changes of T/sub 1/ and T/sub 2/ was observed. That is to say, there were 2 components of T/sub 2/ in contrast with single T/sub 1/ value in the same sample of the edematous gray matter, which indicates the existence of 2 fractions of tissue water, not exchanging on an NMR time scale. Secondary, a good correlation between the longitudinal (T/sub 1/) relaxation time and the tissue water content was found for the dog brains, which suggests that we can analyse the NMR relaxation data of the dog brains based on the two-fraction fast-exchange model.

'Boomerang'-like insertion of a fusogenic peptide in a lipid membrane revealed by solid-state 19F NMR.

Science.gov (United States)

Afonin, Sergii; Dürr, Ulrich H N; Glaser, Ralf W; Ulrich, Anne S

2004-02-01

Solid state (19)F NMR revealed the conformation and alignment of the fusogenic peptide sequence B18 from the sea urchin fertilization protein bindin embedded in flat phospholipid bilayers. Single (19)F labels were introduced into nine distinct positions along the wild-type sequence by substituting each hydrophobic amino acid, one by one, with L-4-fluorophenylglycine. Their anisotropic chemical shifts were measured in uniaxially oriented membrane samples and used as orientational constraints to model the peptide structure in the membrane-bound state. Previous (1)H NMR studies of B18 in 30% TFE and in detergent micelles had shown that the peptide structure consists of two alpha-helical segments that are connected by a flexible hinge. This helix-break-helix motif was confirmed here by the solid-state (19)F NMR data, while no other secondary structure (beta-sheet, 3(10)-helix) was compatible with the set of orientational constraints. For both alpha-helical segments we found that the helical conformation extends all the way to the respective N- and C-termini of the peptide. Analysis of the corresponding tilt and azimuthal rotation angles showed that the N-terminal helix of B18 is immersed obliquely into the bilayer (at a tilt angle tau approximately 54 degrees), whereas the C-terminus is peripherally aligned (tau approximately 91 degrees). The azimuthal orientation of the two segments is consistent with the amphiphilic distribution of side-chains. The observed 'boomerang'-like mode of insertion into the membrane may thus explain how peptide binding leads to lipid dehydration and acyl chain perturbation as a prerequisite for bilayer fusion to occur. Copyright 2004 John Wiley & Sons, Ltd.

Continuous Flow 1H and 13C NMR Spectroscopy in Microfluidic Stripline NMR Chips

NARCIS (Netherlands)

Oosthoek-de Vries, Anna Jo; Bart, Jacob; Tiggelaar, Roald M.; Janssen, Johannes W.G.; van Bentum, Jan (P.J.M.); Gardeniers, Han J.G.E.; Kentgens, Arno P.M.

2017-01-01

Microfluidic stripline NMR technology not only allows for NMR experiments to be performed on small sample volumes in the submicroliter range, but also experiments can easily be performed in continuous flow because of the stripline's favorable geometry. In this study we demonstrate the possibility of

NMR studies of electrophoretic mobility in surfactant systems

International Nuclear Information System (INIS)

Conveney, F.M.; Strange, J.H.; Smith, A.L.; Smith, E.G.

1989-01-01

An experimental technique is described in which the flow of electrically charged micelles is measured in the presence of an applied electric field using an NMR technique. The method is used to determine the electrophoretic mobility at ambient temperature of a 5% aqueous solution of sodium dodecyl sulphate and is shown to provide a new technique for the study of electrophoresis in surfactant solutions. (author). 8 refs.; 4 figs

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes.

Science.gov (United States)

Adam, Christian; Beele, Björn B; Geist, Andreas; Müllich, Udo; Kaden, Peter; Panak, Petra J

2015-02-01

C5-BPP is a highly efficient N-donor ligand for the separation of trivalent actinides, An(iii), from trivalent lanthanides, Ln(iii). The molecular origin of the selectivity of C5-BPP and many other N-donor ligands of the BTP-type is still not entirely understood. We present here the first NMR studies on C5-BPP Ln(iii) and An(iii) complexes. C5-BPP is synthesized with 10% 15 N labeling and characterized by NMR and LIFDI-MS methods. 15 N NMR spectroscopy gives a detailed insight into the bonding of C5-BPP with lanthanides and Am(iii) as a representative for trivalent actinide cations, revealing significant differences in 15 N chemical shift for coordinating nitrogen atoms compared to Ln(iii) complexes. The temperature dependence of NMR chemical shifts observed for the Am(iii) complex indicates a weak paramagnetism. This as well as the observed large chemical shift for coordinating nitrogen atoms show that metal-ligand bonding in Am(C5-BPP) 3 has a larger share of covalence than in lanthanide complexes, confirming earlier studies. The Am(C5-BPP) 3 NMR sample is furthermore spiked with Cm(iii) and characterized by time-resolved laser fluorescence spectroscopy (TRLFS), yielding important information on the speciation of trace amounts of minor complex species.

NMR study of local diamagnetic properties of carbon structures with multiwalled nanotubes

International Nuclear Information System (INIS)

Nikolaev, E.G.; Omel'yanovsky, O.E.; Prudkovsky, V.S.; Sadakov, A.V.; Tsebro, V.I.

2009-01-01

The reasons for the high diamagnetic susceptibility of carbon columns, which are covered with a nanotube mesh, from the interior part of cathode deposits have been studied by means of NMR. A comparative study is made of the 13 C NMR spectra and the magnetic susceptibility of carbon columns before and after ultrasonic processing as well as of finely dispersed material, obtained as a result of such processing, enriched with multilayer nanotubes. The strong diamagnetism of the carbon columns is apparently associated with a quite dense conglomerate of graphite particles, nanotubes, and multilayer polyhedral particles present in their core and not with the surface mesh of multilayer nanotubes. To make a more accurate determination of the character of the anisotropy of the magnetic susceptibility of multilayer carbon nanotubes, the form of the 13 C NMR spectra of samples enriched with multilayer nanotubes, where the nanotubes are either not oriented or only partially oriented, is analyzed. It is shown that the diamagnetic susceptibility of multilayer carbon nanotubes is highest when the magnetic field is oriented perpendicular to their axis

Heteronuclear multidimensional NMR and homology modelling studies of the C-terminal nucleotide-binding domain of the human mitochondrial ABC transporter ABCB6

Energy Technology Data Exchange (ETDEWEB)

Kurashima-Ito, Kaori [RIKEN, Cellular and Molecular Biology Laboratory (Japan); Ikeya, Teppei [National Institute of Advanced Industrial Science and Technology (AIST), (Japan); Senbongi, Hiroshi [Mitochondrial Diseases Group, MRC Dunn Human NutritionUnit (United Kingdom); Tochio, Hidehito [International Graduate School of Arts and Sciences, Supramolecular Biology, Yokohama City University, Molecular Biophysics Laboratory (Japan); Mikawa, Tsutomu [RIKEN, Cellular and Molecular Biology Laboratory (Japan); Shibata, Takehiko [RIKEN, Shibata Distinguished Senior Scientist Laboratory (Japan); Ito, Yutaka [RIKEN, Cellular and Molecular Biology Laboratory (Japan)], E-mail: ito-yutaka@center.tmu.ac.jp

2006-05-15

Human ATP-binding cassette, sub-family B, member 6 (ABCB6) is a mitochondrial ABC transporter, and presumably contributes to iron homeostasis. Aimed at understanding the structural basis for the conformational changes accompanying the substrate-transportation cycle, we have studied the C-terminal nucleotide-binding domain of ABCB6 (ABCB6-C) in both the nucleotide-free and ADP-bound states by heteronuclear multidimensional NMR and homology modelling. A non-linear sampling scheme was utilised for indirectly acquired {sup 13}C and {sup 15}N dimensions of all 3D triple-resonance NMR experiments, in order to overcome the instability and the low solubility of ABCB6-C. The backbone resonances for approximately 25% of non-proline residues, which are mostly distributed around the functionally important loops and in the Helical domain, were not observed for nucleotide-free form of ABCB6-C. From the pH, temperature and magnetic field strength dependencies of the resonance intensities, we concluded that this incompleteness in the assignments is mainly due to the exchange between multiple conformations at an intermediate rate on the NMR timescale. These localised conformational dynamics remained in ADP-bound ABCB6-C except for the loops responsible for adenine base and {alpha}/{beta}-phosphate binding. These results revealed that the localised dynamic cooperativity, which was recently proposed for a prokaryotic ABC MJ1267, also exists in a higher eukaryotic ABC, and is presumably shared by all members of the ABC family. Since the Helical domain is the putative interface to the transmembrane domain, this cooperativity may explain the coupled functions between domains in the substrate-transportation cycle.

Ligand-receptor Interactions by NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Novak. P.

2008-04-01

Full Text Available Today NMR spectroscopy is a method of choice for elucidation of interactions between biomolecules and the potential ligands. Knowledge on these interactions is an essential prerequisite for the rational drug design. The most important contribution of NMR to drug design a few years ago was the 3D structure determination of proteins. Besides delivering the 3D structures of the free proteins as a raw material for the modeling studies on ligand binding, NMR can directly yield valuable experimental data on the biologically important protein-ligand complexes. In addition to X-ray diffraction, NMR spectroscopy can provide information on the internal protein dynamics ordynamics of intermolecular interactions. Changes in NMR parameters allow us to detect ("SAR by NMR" and quantitatively determine binding affinities (titration, diffusion NMR experiments, etc. of potential ligands. Also, it is possible to determine the binding site and conformations of ligands, receptors and receptor-ligand complexes with the help of NMR methods such as tr-NOESY. Epitopes or functional groups responsible for binding of ligands to the receptor can be identified by employing STD or WaterLOGSY experiments. In this review are described some of the most frequent NMR methods for the characterization of the interactions between biomolecules and ligands, together with their advantages and disadvantages.

Structural characterization of supramolecular assemblies by {sup 13}C spin dilution and 3D solid-state NMR

Energy Technology Data Exchange (ETDEWEB)

Habenstein, Birgit; Loquet, Antoine; Giller, Karin; Becker, Stefan; Lange, Adam, E-mail: adla@nmr.mpibpc.mpg.de [Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology (Germany)

2013-01-15

{sup 13}C spin diluted protein samples can be produced using [1-{sup 13}C] and [2-{sup 13}C]-glucose (Glc) carbon sources in the bacterial growth medium. The {sup 13}C spin dilution results in favorable {sup 13}C spectral resolution and polarization transfer behavior. We recently reported the combined use of [1-{sup 13}C]- and [2-{sup 13}C]-Glc labeling to facilitate the structural analysis of insoluble and non-crystalline biological systems by solid-state NMR (ssNMR), including sequential assignment, detection of long-range contacts and structure determination of macromolecular assemblies. In solution NMR the beneficial properties of sparsely labeled samples using [2-{sup 13}C]-glycerol ({sup 13}C labeled C{alpha} sites on a {sup 12}C diluted background) have recently been exploited to provide a bi-directional assignment method (Takeuchi et al. in J Biomol NMR 49(1):17-26, 2011 ). Inspired by this approach and our own recent results using [2-{sup 13}C]-Glc as carbon sources for the simplification of ssNMR spectra, we present a strategy for a bi-directional sequential assignment of solid-state NMR resonances and additionally the detection of long-range contacts using the combination of {sup 13}C spin dilution and 3D NMR spectroscopy. We illustrate our results with the sequential assignment and the collection of distance restraints on an insoluble and non-crystalline supramolecular assembly, the Salmonella typhimurium type III secretion system needle.

Lateral interactions in the photoreceptor membrane: a NMR study

International Nuclear Information System (INIS)

Mollevanger, L.C.P.J.

1987-01-01

The photoreceptor membrane has an exceptionally high content of polyunsaturated fatty acyl chains combined with a high amount of phosphatidyl ethanolamine. It is situated in a cell organelle, the rod outer segment, with a high biological activity in which controlable trans-membrane currents of different ions play an important role. These characteristics make it a very interesting biological membrane to search for the existence of non-bilayer structures. Therefore in this thesis a detailed study of the polymorphic phase behaviour of the rod outer segment photoreceptor lipids was undertaken, concerning modulation of the polymorphic phase behaviour of photoreceptor membrane lipids by divalent cations and temperature, polymorphism of the individual phospholipid classes phosphatidylethanolamine and phosphatidylserine and effects of cholesterol, bilayer stabilization by (rhod)opsin. Morphologically intact rod outer segment possesses a large magnetic anisotropy. This property is used to obtain 31 P-NMR of oriented photoreceptor membranes which allows spectral analysis and identification of individual phospholipid classes, and allows to study lateral lipid diffusion in intact disk membranes. The power of high resolution solid state 13 C-NMR to study the conformation of the chromophore in rhodopsin is demonstrated. (Auth.)

NMR characterization of hydrocarbon adsorption on calcite surfaces: A first principles study

Energy Technology Data Exchange (ETDEWEB)

Bevilaqua, Rochele C. A.; Miranda, Caetano R. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC, Santo André, SP (Brazil); Rigo, Vagner A. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC, Santo André, SP (Brazil); Universidade Tecnológica Federal do Paraná, UTFPR, Cornélio Procópio, PR (Brazil); Veríssimo-Alves, Marcos [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC, Santo André, SP (Brazil); Departamento de Física, ICEx, Universidade Federal Fluminense, UFF, Volta Redonda, RJ (Brazil)

2014-11-28

The electronic and coordination environment of minerals surfaces, as calcite, are very difficult to characterize experimentally. This is mainly due to the fact that there are relatively few spectroscopic techniques able to detect Ca{sup 2+}. Since calcite is a major constituent of sedimentary rocks in oil reservoir, a more detailed characterization of the interaction between hydrocarbon molecules and mineral surfaces is highly desirable. Here we perform a first principles study on the adsorption of hydrocarbon molecules on calcite surface (CaCO{sub 3} (101{sup ¯}4)). The simulations were based on Density Functional Theory with Solid State Nuclear Magnetic Resonance (SS-NMR) calculations. The Gauge-Including Projector Augmented Wave method was used to compute mainly SS-NMR parameters for {sup 43}Ca, {sup 13}C, and {sup 17}O in calcite surface. It was possible to assign the peaks in the theoretical NMR spectra for all structures studied. Besides showing different chemical shifts for atoms located on different environments (bulk and surface) for calcite, the results also display changes on the chemical shift, mainly for Ca sites, when the hydrocarbon molecules are present. Even though the interaction of the benzene molecule with the calcite surface is weak, there is a clearly distinguishable displacement of the signal of the Ca sites over which the hydrocarbon molecule is located. A similar effect is also observed for hexane adsorption. Through NMR spectroscopy, we show that aromatic and alkane hydrocarbon molecules adsorbed on carbonate surfaces can be differentiated.

Unraveling double stranded alpha-helical coiled coils: an x-ray diffraction study on hard alpha-keratin fibers.

Science.gov (United States)

Kreplak, L; Doucet, J; Briki, F

2001-04-15

Transformations of proteins secondary and tertiary structures are generally studied in globular proteins in solution. In fibrous proteins, such as hard alpha-keratin, that contain long and well-defined double stranded alpha-helical coiled coil domains, such study can be directly done on the native fibrous tissue. In order to assess the structural behavior of the coiled coil domains under an axial mechanical stress, wide angle x-ray scattering and small angle x-ray scattering experiments have been carried out on stretched horse hair fibers at relative humidity around 30%. Our observations of the three major axial spacings as a function of the applied macroscopic strain have shown two rates. Up to 4% macroscopic strain the coiled coils were slightly distorted but retained their overall conformation. Above 4% the proportion of coiled coil domains progressively decreased. The main and new result of our study is the observation of the transition from alpha-helical coiled coils to disordered chains instead of the alpha-helical coiled coil to beta-sheet transition that occurs in wet fibers.

NMR spectroscopy and drug development

International Nuclear Information System (INIS)

Craik, D.; Munro, S.

1990-01-01

The use of nuclear magnetic resonance (NMR) spectroscopy for structural and conformational studies on drug molecules, the three-dimensional investigation of proteins structure and their interactions with ligands are discussed. In-vivo NMR studies of the effects of drugs on metabolism in perfused organs and whole animals are also briefly presented. 5 refs., ills

Part I. Generation of tailored radio-frequency pulses for NMR. Part II. Deuterium NMR studies of oriented DNA, and its interaction with water

International Nuclear Information System (INIS)

Brandes, R.

1988-01-01

A novel method for generating tailored radio-frequency pulses for use in NMR is presented. For this purpose, an inexpensive device based on analog audio filters was built. As an application, the superior selectivity of this method is shown by comparing it with a soft pulse excitation. The theoretical response of the magnetization to these tailored rf pulses is also calculated. Deuterium NMR line shapes of 2 H-labeled purine bases in solid, uniaxially oriented Li- and Na-DNA have been obtained. The spectral densities of motion were determined for the Li-DNA samples to test a model for uncorrelated, restricted base motion. For the first time, a 2 H spectrum is reported for 2 H labeled DNA in the liquid crystalline state. A procedure is outlined to separate the base motion from the DNA axis motion. In addition to the studies of DNA itself, the interaction of water (D 2 O) with samples of uniaxially oriented Na- and Li-DNA have been studied by high resolution 2 H NMR

Comparative NMR study of nPrBTP and iPrBTP

Energy Technology Data Exchange (ETDEWEB)

Adam, C.; Muellich, U.; Geist, A.; Geckeis, H. [Karlsruhe Institute of Technology - KIT, Institute for Nuclear Waste Disposal - INE, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rohde, V. [Fraunhofer Institute for Chemical Technology - ICT, Environmental Engineering, Joseph-von-Fraunhofer-Str. 7, 76327 Pfinztal (Germany); Kaden, P. [Helmholtz-Zentrum Dresden - Rossendorf e. V., Institute of Resource Ecology, Bautzner Landstrasse 400, 01328 Dresden (Germany); Panak, P.J. [Karlsruhe Institute of Technology - KIT, Institute for Nuclear Waste Disposal - INE, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); University of Heidelberg, Department of Physical Chemistry, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany)

2016-07-01

Bis-triazinyl-pyridine type ligands are important extracting agents for separating trivalent actinide ions from trivalent lanthanides. The alkyl substituents on the lateral triazine rings have a significant effect on the stability of the ligand against hydrolysis and radiolysis. Furthermore they influence solubility, extraction behaviour and selectivity. TRLFS and extraction studies suggest differences in complexation and extraction behaviour of BTP ligands bearing iso-propyl or n-propyl substituents, respectively. As NMR studies allow insight into the metal-ligand bonding, we conducted NMR studies on a range of {sup 15}N-labelled nPrBTP and iPrBTP Ln(III) and Am(III) complexes. Our results show that no strong change in the metal-ligand bonding occurs, thus excluding electronic reasons for differences in complexation behaviour, extraction kinetics and selectivity. This supports mechanistic reasons for the observed differences. (authors)

Nitrogen Use Efficiency and Carbon Isotope Discrimination Study on NMR151 and NMR152 Mutant Lines Rice at Field Under Different Nitrogen Rates and Water Potentials

International Nuclear Information System (INIS)

Ahmad Nazrul Abdul Wahid; Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Latiffah Nordin; Abdul Razak Ruslan; Hazlina Abdullah; Khairuddin Abdul Rahim

2016-01-01

This study was conducted to evaluate the nitrogen use efficiency and "1"3C isotope discrimination of rice mutant lines viz. NMR151 and NMR152. Both cultivars are developed under rice radiation mutagenesis programme for adaptability to aerobic conditions. In the present study, NMR151 and NMR152 were grown under conditions of varying water potentials and nitrogen levels in a field. Two water potentials and three nitrogen rates in a completely randomized design with three replications were carried out. The rice mutants were grown for 110 days under two water potentials, (i) Field capacity from 0 to 110 DAS [FC], and (ii) Field capacity from 0 to 40 DAS and 30 % dry of field capacity from 41 to 110 DAS [SS] and three nitrogen rates, (i) 0 kg N/ ha (0N), (ii) 60 kg N/ ha (60N), and (iii) 120 kg N/ ha (120N). "1"5N isotopic tracer technique was used in this study, whereby the "1"5N labeled urea fertilizer 5.20 % atom excess (a.e) was utilized as a tracer for nitrogen use efficiency (NUE) study. "1"5N isotope presence in the samples was determined using emission spectrometry and percentage of total nitrogen was determined by the Kjeldahl method. "1"5N a.e values of the samples were used in the determination of the NUE. The value of "1"3C isotope discrimination (Δ"1"3C) in the sample was determined using isotope ratio mass spectrometry (IRMS). The "1"3C isotope discrimination technique was used as a tool to identify drought resistance rice cultivars with improves water use efficiency. The growth and agronomy data, viz. plant height, number of tillers, grain yield, straw yield, and 1000 grain weight also were recorded. Results from this study showed nitrogen rates imparted significant effects on yield (grain and straw) plant height, number of tillers and 1000 grain weight. Water potentials had significant effects only on 1000 grain weight and Δ"1"3C. The NUE for both mutant lines rice showed no significant different between treatments. Both Rice mutant lines rice NMR151

Some nitrogen-14 NMR studies in solids

Energy Technology Data Exchange (ETDEWEB)

Pratum, T.K.

1983-11-01

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

β-NMR sample optimization

CERN Document Server

Zakoucka, Eva

2013-01-01

During my summer student programme I was working on sample optimization for a new β-NMR project at the ISOLDE facility. The β-NMR technique is well-established in solid-state physics and just recently it is being introduced for applications in biochemistry and life sciences. The β-NMR collaboration will be applying for beam time to the INTC committee in September for three nuclei: Cu, Zn and Mg. Sample optimization for Mg was already performed last year during the summer student programme. Therefore sample optimization for Cu and Zn had to be completed as well for the project proposal. My part in the project was to perform thorough literature research on techniques studying Cu and Zn complexes in native conditions, search for relevant binding candidates for Cu and Zn applicable for ß-NMR and eventually evaluate selected binding candidates using UV-VIS spectrometry.

NMR imaging

International Nuclear Information System (INIS)

Andrew, E.R.

1983-01-01

Since hydrogen is the most abundant element in all living organisms, proton NMR lends itself well as a method of investigation in biology and medicine. NMR imaging has some special advantages as a diagnostic tool: no ionizing radiation is used, it is noninvasive; it provides a safer means of imaging than the use of x-rays, gamma rays, positrons, or heavy ions. In contrast with ultrasound, the radiation penetrates the bony structures without attenuation. In additional to morphological information, NMR imaging provides additional diagnostic insights through relaxation parameters, which are not available from other imaging methods. In the decade since the first primitive NMR images were obtained, the quality of images now obtained approaches those from CT x-ray scanners. Prototype instruments are being constructed for clinical evaluation and the first whole-body scanners are beginning to appear on the market at costs comparable to CT scanners. Primary differences in equipment for conventional NMR and NMR imaging are the much larger aperture magnets that are required for the examination of human subjects and the addition of coils to generate field gradients and facilities for manipulating the gradients. Early results from clinical trials in many parts of the world are encouraging, and in a few years, the usefuleness of this modality of medical imaging to the medical profession in diagnosis and treatment of disease will be defined. 10 figures

Fundamentals of Protein NMR Spectroscopy

CERN Document Server

Rule, Gordon S

2006-01-01

NMR spectroscopy has proven to be a powerful technique to study the structure and dynamics of biological macromolecules. Fundamentals of Protein NMR Spectroscopy is a comprehensive textbook that guides the reader from a basic understanding of the phenomenological properties of magnetic resonance to the application and interpretation of modern multi-dimensional NMR experiments on 15N/13C-labeled proteins. Beginning with elementary quantum mechanics, a set of practical rules is presented and used to describe many commonly employed multi-dimensional, multi-nuclear NMR pulse sequences. A modular analysis of NMR pulse sequence building blocks also provides a basis for understanding and developing novel pulse programs. This text not only covers topics from chemical shift assignment to protein structure refinement, as well as the analysis of protein dynamics and chemical kinetics, but also provides a practical guide to many aspects of modern spectrometer hardware, sample preparation, experimental set-up, and data pr...

Morphological study of chitin from Xiphopenaeus kroyeri exoskeletons by using atomic force microscopy (AFM) and CPMAS {sup 13} C NMR; Estudo morfologico de quitina da exocuticula de Xiphopenaeus kroyeri por AFM e por CPMAS {sup 13} C NMR

Energy Technology Data Exchange (ETDEWEB)

Silva, K.M.; Tavares, M.I.; Andrade, C.T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas; Simao, R.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Metalurgica e de Materiais

1999-07-01

A sample of {alpha} chitin was isolated from exoskeletons of Xiphopenaeus kroyeri. This sample ws dissolved in phosphoric acid and recovered as a fibrous precipitate. Atomic force microscopy was used in noncontact mode to obtain images of the native chitin sample. Different morphological features were observed, including rigid rod crystals 200-300 nm wide. Solid state {sup 13} C NMR techniques were used to investigate chitin samples, and revealed molecular order in both samples. The differences observed in the proton spin-lattice relaxation times in the rotating frame, T{sup H1}{sub p} were attributed to the formation of hydrogen bonds in preferential sites in the samples. (author)

Oriented solid-state NMR spectrosocpy

DEFF Research Database (Denmark)

Bertelsen, Kresten

This thesis is concerned with driving forward oriented solid-state NMR spectroscopy as a viable technique for studying peptides in membrane bilayers. I will show that structural heterogeneity is an intrinsic part of the peptide/lipid system and that NMR can be used to characterize static...... and dynamic structural features of the peptides and its local surroundings. In fact one need to take into account the dynamical features of the system in order to correctly predict the structure from oriented solid-state NMR spectra.      ...

NMR-CT scanner

International Nuclear Information System (INIS)

Kose, Katsumi; Sato, Kozo; Sugimoto, Hiroshi; Sato, Masataka.

1983-01-01

A brief explanation is made on the imaging methods for a practical diagnostic NMR-CT scanner : A whole-body NMR-CT scanner utilizing a resistive magnet has been developed by Toshiba in cooperation with the Institute for Solid State Physics, the University of Tokyo. Typical NMR-CT images of volunteers and patients obtained in the clinical experiments using this device are presented. Detailed specifications are also shown about the practical NMR-CTs which are to be put on the market after obtaining the government approval. (author)

Solid-State NMR Study of New Copolymers as Solid Polymer Electrolytes

Directory of Open Access Journals (Sweden)

Jean-Christophe Daigle

2018-01-01

Full Text Available We report the analysis of comb-like polymers by solid-state NMR. The polymers were previously evaluated as solid-polymer-electrolytes (SPE for lithium-polymer-metal batteries that have suitable ionic conductivity at 60 °C. We propose to develop a correlation between 13C solid-state NMR measurements and phase segregation. 13C solid-state NMR is a perfect tool for differentiating polymer phases with fast or slow motions. 7Li was used to monitor the motion of lithium ions in the polymer, and activation energies were calculated.

Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

CERN Document Server

Fujiwara, M.C.; Bertsche, W.; Bowe, P.D.; Bray, C.C.; Butler, E.; Cesar, C.L.; Chapman, S.; Charlton, M.; Fajans, J.; Funakoshi, R.; Gill, D.R.; Hangst, J.S.; Hardy, W.N.; Hayano, R.S.; Hayden, M.E.; Humphries, A.J.; Hydomako, R.; Jenkins, M.J.; Jorgensen, L.V.; Kurchaninov, L.; Lai, W.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seif El Nasr, S.; Silveira, D.M.; Storey, J.W.; Thompson, R.I.; van der Werf, D.P.; Wasilenko, L.; Wurtele, J.S.; Yamazaki, Y.

2008-01-01

We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.

NMR studies of defects created by irradiation in metals

International Nuclear Information System (INIS)

Minier, M.; Minier, C.

1983-06-01

Nuclear Magnetic Resonance has been rarely used to study point defects created by irradiation in metals. Information obtained in this field using N.M.R. are shown. Some results are also described: characterization of migrating defects in electron irradiated copper; mobility of the complex interstitial-impurity in Al with 150 ppm of chromium; interstitial structure in irradiated aluminum and autodiffusion in metals [fr

Solution NMR Spectroscopy in Target-Based Drug Discovery.

Science.gov (United States)

Li, Yan; Kang, Congbao

2017-08-23

Solution NMR spectroscopy is a powerful tool to study protein structures and dynamics under physiological conditions. This technique is particularly useful in target-based drug discovery projects as it provides protein-ligand binding information in solution. Accumulated studies have shown that NMR will play more and more important roles in multiple steps of the drug discovery process. In a fragment-based drug discovery process, ligand-observed and protein-observed NMR spectroscopy can be applied to screen fragments with low binding affinities. The screened fragments can be further optimized into drug-like molecules. In combination with other biophysical techniques, NMR will guide structure-based drug discovery. In this review, we describe the possible roles of NMR spectroscopy in drug discovery. We also illustrate the challenges encountered in the drug discovery process. We include several examples demonstrating the roles of NMR in target-based drug discoveries such as hit identification, ranking ligand binding affinities, and mapping the ligand binding site. We also speculate the possible roles of NMR in target engagement based on recent processes in in-cell NMR spectroscopy.

NMR of lignins

Science.gov (United States)

John Ralph; Larry L. Landucci

2010-01-01

This chapter will consider the basic aspects and findings of several forms of NMR spectroscopy, including separate discussions of proton, carbon, heteronuclear, and multidimensional NMR. Enhanced focus will be on 13C NMR, because of its qualitative and quantitative importance, followed by NMR’s contributions to our understanding of lignin...

Pulse radiolytic study of alpha-tocopherol radical mechanisms in ethanolic solution

International Nuclear Information System (INIS)

Jore, D.; Patterson, L.K.; Ferradini, C.

1986-01-01

Pulse radiolytic studies of alpha-tocopherol (alpha TH) oxidation-reduction processes were carried out with low doses (5 Gy) of high-energy electrons in O 2 -, N 2 -, and air-saturated ethanolic solutions. Depending on the concentration of oxygen in solution, two different radicals, A . and B ., were observed. The first, A ., was obtained under N 2 and results from alpha TH reaction with solvated electron (k alpha TH + e-solv = 3.4 X 10(8) mol-1 liter s-1) and with H 3 C-CH-OH, (R.) (k alpha TH + R. = 5 X 10(5) mol-1 liter s-1). B., observed under O 2 , is produced by alpha TH reaction with RO 2 . peroxyl radicals (k alpha TH + RO 2 . = 9.5 X 10(4) mol-1 liter s-1)

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

International Nuclear Information System (INIS)

Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G.; Boffo, Elisangela F.; Figueira, Glyn M.

2012-01-01

The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, 1 H HR-MAS NMR and 1 H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

Annual reports on NMR spectroscopy

CERN Document Server

Webb, Graham A; McCarthy, M J

1995-01-01

Over recent years, no other technique has grown to such importance as that of NMR spectroscopy. It is used in all branches of science where precise structural determination is required and where the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a means for the specialist and non-specialist alike to become familiar with new applications of the technique in all branches of chemistry, including biochemistry, and pharmaceutics. This volume focuses on theoretical aspects of NMR nuclear shielding and on applications of

NMR spectroscopy study of agar-based polymers electrolytes

Energy Technology Data Exchange (ETDEWEB)

Mattos, R.I.; Tambelli, C.E. [Universidade de Sao Paulo (USP), Pirassununga, SP (Brazil). Fac. de Zootecnia e Engenharia de Alimentos; Raphael, E. [Universidade Federal de Sao Joao del-Rey (UFSJ), MG (Brazil). Dept. de Ciencias Naturais; Silva, I.D.A.; Magon, C.J.; Donoso, J.P. [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica

2012-07-01

Full text: This communication presents the results of preparation and characterization of transparent films obtained from agar and acetic acid. The films were characterized by electrochemical impedance spectroscopy (EIS) and nuclear magnetic resonance (NMR). The film formed by agar (Sigma Aldrich) was dispersed in water and kept under stirring and heating at 100 deg C. Next, glycerol, formaldehyde and different quantities of acetic acid (25 and 50 wt%) were added to this solution. The obtained solution was placed on a glass plate and left to dry for 48 hours in oven at 50 deg C to obtain the films, which were kept under vacuum before characterization. The ionic conductivity of the films display an Arrhenius behavior with activation energy E{sub a} = 78 (25 wt% of acetic acid) and E{sub a} = 87 kJ/mol (50 wt% of acetic acid). The conductivity values were 3:0 X 10{sup -6} and 1:2 X 10{sup -4} S/cm at room temperature and 4:4 X 10{sup -4} and 1:5 X 10{sup -3}S/cm at 70 deg C, for the 25 and 50 wt% of acetic acid respectively. To investigate the mechanism of protonic conduction in the polymer proton conductor proton NMR measurements were performed in the temperature range 200-370 K. The {sup 1}H-NMR results exhibit the qualitative feature associated with the proton mobility, namely the presence of well defined {sup 1}H spin-lattice relaxation maxima at 300 K. Activation energy of the order of 40 kJ/mol was obtained from the {sup 1}H-NMR line narrowing data. The ionic conductivity of the film combined with their transparency, flexibility, homogeneity and good adhesion to the glasses or metals indicate that agar-based SPEs are promising materials for used on optoelectronic applications. (author)

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

International Nuclear Information System (INIS)

Matwiyoff, N.A.

1983-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Matwiyoff, N.A.

1983-01-01

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

Studying the molecular determinants of potassium channel structure and function in membranes by solid-state NMR

NARCIS (Netherlands)

van der Cruijsen, Elwin

2014-01-01

Solid-state Nuclear Magnetic Resonance (ssNMR) has made remarkable progress in the structural characterization of membrane proteins systems at atomic resolution. Such studies can be further aided by the use of molecular dynamic simulations. Moreover, ssNMR data can be directly compared to functional

KUJIRA, a package of integrated modules for systematic and interactive analysis of NMR data directed to high-throughput NMR structure studies

International Nuclear Information System (INIS)

Kobayashi, Naohiro; Iwahara, Junji; Koshiba, Seizo; Tomizawa, Tadashi; Tochio, Naoya; Guentert, Peter; Kigawa, Takanori; Yokoyama, Shigeyuki

2007-01-01

The recent expansion of structural genomics has increased the demands for quick and accurate protein structure determination by NMR spectroscopy. The conventional strategy without an automated protocol can no longer satisfy the needs of high-throughput application to a large number of proteins, with each data set including many NMR spectra, chemical shifts, NOE assignments, and calculated structures. We have developed the new software KUJIRA, a package of integrated modules for the systematic and interactive analysis of NMR data, which is designed to reduce the tediousness of organizing and manipulating a large number of NMR data sets. In combination with CYANA, the program for automated NOE assignment and structure determination, we have established a robust and highly optimized strategy for comprehensive protein structure analysis. An application of KUJIRA in accordance with our new strategy was carried out by a non-expert in NMR structure analysis, demonstrating that the accurate assignment of the chemical shifts and a high-quality structure of a small protein can be completed in a few weeks. The high completeness of the chemical shift assignment and the NOE assignment achieved by the systematic analysis using KUJIRA and CYANA led, in practice, to increased reliability of the determined structure

NMR studies of interfaces, strain and anisotropy in Co/Cu multilayers

International Nuclear Information System (INIS)

Thomson, T.; Riedi, P.C.

1999-01-01

59 Co NMR studies of multilayers are able to give three direct pieces of information: (i) the crystal phase of Co, fcc (217.4 MHz), hcp (220-228 MHz) and in exotic cases bcc (198 MHz) for films measured at T= 4.2 K, (ii) the nature of the interfaces from low frequency satellite lines, and (iii) the strain state deduced from small changes in the line positions. Extensive studies of Co/Cu multilayer interfacial structures as a function of deposition technique, layer thickness, substrate/buffer layer structure and annealing temperature have been undertaken. This work has shed new light on the relationship between interfacial structure and magnetoresistance and in particular has demonstrated that flat, atomic scale, interfaces lead to greater magnetoresistance. The difference between the Co and Cu lattice constant results in an extensive, tensile in-plane strain developing in Co layers provided that some epitaxial registry is present. Information on strain effects can be obtained from the position and width of the NMR lines. The magnetic anisotropy field can be determined by measuring the field dependence of the enhancement effect due to electronic magnetisation. This provides unique insight into the distribution of magnetic anisotropy within the Co layers, as the enhancement can be investigated independently for each NMR line and, hence, provides environment specific information on magnetic anisotropy at the interfaces and in the interior of the layers

Degree of Biomimicry of Artificial Spider Silk Spinning Assessed by NMR Spectroscopy.

Science.gov (United States)

Otikovs, Martins; Andersson, Marlene; Jia, Qiupin; Nordling, Kerstin; Meng, Qing; Andreas, Loren B; Pintacuda, Guido; Johansson, Jan; Rising, Anna; Jaudzems, Kristaps

2017-10-02

Biomimetic spinning of artificial spider silk requires that the terminal domains of designed minispidroins undergo specific structural changes in concert with the β-sheet conversion of the repetitive region. Herein, we combine solution and solid-state NMR methods to probe domain-specific structural changes in the NT2RepCT minispidroin, which allows us to assess the degree of biomimicry of artificial silk spinning. In addition, we show that the structural effects of post-spinning procedures can be examined. By studying the impact of NT2RepCT fiber drying, we observed a reversible beta-to-alpha conversion. We think that this approach will be useful for guiding the optimization of artificial spider silk fibers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Push-through Direction Injectin NMR Automation

Science.gov (United States)

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

Experimental and theoretical NMR studies of interaction between phenylalanine derivative and egg yolk lecithin.

Science.gov (United States)

Wałęsa, Roksana; Ptak, Tomasz; Siodłak, Dawid; Kupka, Teobald; Broda, Małgorzata A

2014-06-01

The interaction of phenylalanine diamide (Ac-Phe-NHMe) with egg yolk lecithin (EYL) in chloroform was studied by (1)H and (13)C NMR. Six complexes EYL-Ac-Phe-NHMe, stabilized by N-H···O or/and C-H···O hydrogen bonds, were optimized at M06-2X/6-31G(d,p) level. The assignment of EYL and Ac-Phe-NHMe NMR signals was supported using GIAO (gauge including atomic orbital) NMR calculations at VSXC and B3LYP level of theory combined with STO-3Gmag basis set. Results of our study indicate that the interaction of peptides with lecithin occurs mainly in the polar 'head' of the lecithin. Additionally, the most probable lecithin site of H-bond interaction with Ac-Phe-NHMe is the negatively charged oxygen in phosphate group that acts as proton acceptor. Copyright © 2014 John Wiley & Sons, Ltd.

1H Nuclear Magnetic Resonance (NMR) metabonomic study of breast cancer in Indian population

International Nuclear Information System (INIS)

Sonkar, Kanchan; Sinha, Neeraj; Arshad, Farah

2012-01-01

Breast cancer is the most common cancer diagnosed in women worldwide with over 1.3 million new cases per year. Recently it has been observed that breast cancer is increasing very rapidly in low income countries including India. Lipids not only play very important and vital role of prime structural component in human body they are also important functional components in cellular metabolism. Transformation from benign to malignant tissue involves several biochemical processes and understanding these processes provides very useful insight related to cancer prognosis. Thus study of lipids becomes very important and NMR spectroscopy is one of the techniques which can be utilized to identifying all lipid components simultaneously. The tissue specimens (35, benign 20 and malignant 15; patient age group 47 yrs) were collected after breast surgeries and were snap frozen in liquid nitrogen. Part of all tissues was sent for routine histopathology. Lipid extraction was performed by Folch method (Folch, 1957) using cholesterol and methanol (2:1 ratio). The NMR spectra of the extracted lipids were recorded immediately after the sample preparation. All NMR experiments were performed on a Bruker Avance 800 MHz spectrometer. 1 H NMR analysis of lipid extract of breast tissue in Indian population shows there is significant elevation of phosphotidycholine, plasmalogen and esterified cholesterol with decrease in triacylglycerol in cancer breast compared to benign tissue implying that their metabolism is definitely altered during carcinogenesis. This study analyzes the role of NMR as an additional diagnostic tool on the basis of examination of lipid extract. (author)

High resolution NMR theory and chemical applications

CERN Document Server

Becker, Edwin D

1999-01-01

High Resolution NMR provides a broad treatment of the principles and theory of nuclear magnetic resonance (NMR) as it is used in the chemical sciences. It is written at an "intermediate" level, with mathematics used to augment, rather than replace, clear verbal descriptions of the phenomena. The book is intended to allow a graduate student, advanced undergraduate, or researcher to understand NMR at a fundamental level, and to see illustrations of the applications of NMR to the determination of the structure of small organic molecules and macromolecules, including proteins. Emphasis is on the study of NMR in liquids, but the treatment also includes high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. Careful attention is given to developing and interrelating four approaches - steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The presentation is based on the assumption that the reader has an acquaintan...

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

Energy Technology Data Exchange (ETDEWEB)

Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Boffo, Elisangela F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Figueira, Glyn M., E-mail: maiarassantos@yahoo.com.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

2012-07-01

The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, {sup 1}H HR-MAS NMR and {sup 1}H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

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

Directory of Open Access Journals (Sweden)

Maiara S. Santos

2012-01-01

Full Text Available The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as "quebra-pedras" in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques.

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

Energy Technology Data Exchange (ETDEWEB)

Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Boffo, Elisangela F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Figueira, Glyn M., E-mail: maiarassantos@yahoo.com.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

2012-07-01

The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, {sup 1}H HR-MAS NMR and {sup 1}H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

Rapid Determination of Total Thujone in Absinthe Using 1H NMR Spectroscopy

OpenAIRE

Yulia B. Monakhova; Thomas Kuballa; Dirk W. Lachenmeier

2011-01-01

1H NMR spectroscopy is utilized to quantify total thujone (sum of alpha- and beta-isomers) in absinthe. For sample preparation, a simple dilution with buffer is required. Thujone produces a distinct peak of the CH2 group in the cyclopentanone moiety in the 2.13–2.11 ppm range. No overlap with other typical constituents such as anethole or fenchone occurs. The detection limit of 0.3 mg/L is adequate to control the EU maximum limit. The relative standard deviation was 6%, and linearity was obse...

{sup 11}B-NMR spectroscopic study on the interaction of epinephrine and p-BPA

Energy Technology Data Exchange (ETDEWEB)

Ichihara, K.; Yoshino, K. [Shinshu Univ., Department of Chemistry, Matsumoto, Nagano (Japan)

2000-10-01

It is studied that p-BPA (p-bronophenylalanine) which formed complex with catechol functional group has interaction with epinephrine by {sup 11}B-NMR. Two {sup 11}B-NMR resonance signals were observed at pH 7.0. The signal at 29.6 ppm is assigned to p-BPA and at 10.8 ppm is assigned to that of complex. We can determine complex formation constants (logK') in various pH. (author)

An introduction to biological NMR spectroscopy

International Nuclear Information System (INIS)

Marion, Dominique

2013-01-01

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

N7- and N9-substituted purine derivatives: a N-15 NMR study

Czech Academy of Sciences Publication Activity Database

Marek, R.; Brus, Jiří; Toušek, J.; Kovács, L.; Hocková, Dana

2002-01-01

Roč. 40, č. 5 (2002), s. 353-360 ISSN 0749-1581 R&D Projects: GA ČR GA203/98/P026; GA MŠk LN00A016 Institutional research plan: CEZ:AV0Z4050913 Keywords : NMR * H-1 NMR * N-15 NMR Subject RIV: CE - Biochemistry Impact factor: 0.994, year: 2002

Rapid measurement of 3J(H N-H alpha) and 3J(N-H beta) coupling constants in polypeptides.

Science.gov (United States)

Barnwal, Ravi Pratap; Rout, Ashok K; Chary, Kandala V R; Atreya, Hanudatta S

2007-12-01

We present two NMR experiments, (3,2)D HNHA and (3,2)D HNHB, for rapid and accurate measurement of 3J(H N-H alpha) and 3J(N-H beta) coupling constants in polypeptides based on the principle of G-matrix Fourier transform NMR spectroscopy and quantitative J-correlation. These experiments, which facilitate fast acquisition of three-dimensional data with high spectral/digital resolution and chemical shift dispersion, will provide renewed opportunities to utilize them for sequence specific resonance assignments, estimation/characterization of secondary structure with/without prior knowledge of resonance assignments, stereospecific assignment of prochiral groups and 3D structure determination, refinement and validation. Taken together, these experiments have a wide range of applications from structural genomics projects to studying structure and folding in polypeptides.

Is Low-field NMR a Complementary Tool to GC-MS in Quality Control of Essential Oils? A Case Study

NARCIS (Netherlands)

Krause, Andre; Wu, Yu; Tian, Runtao; Beek, van Teris A.

2018-01-01

High-field NMR is an expensive and important quality control technique. In recent years, cheaper and simpler low-field NMR has become available as a new quality control technique. In this study, 60 MHz 1 H-NMR was compared with GC-MS and refractometry for the detection of adulteration of essential

NMR studies of liquid crystals and molecules dissolved in liquid crystal solvents

Energy Technology Data Exchange (ETDEWEB)

Drobny, Gary Peter [Univ. of California, Berkeley, CA (United States)

1982-11-01

This thesis describes several studies in which nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure, orientation and dynamics of liquid crystal mesogens and molecules dissolved in liquid crystalline phases. In addition, a modern high field nmr spectrometer is described which has been used to perform such nmr studies. Chapter 1 introduces the quantum mechanical formalisms used throughout this thesis and briefly reviews the fundamentals of nuclear spin physics and pulsed nmr spectroscopy. First the density operator is described and a specific form for the canonical ensemble is derived. Then Clebsch-Gordon coefficients, Wigner rotation matrices, and irreducible tensor operators are reviewed. An expression for the equilibrium (Curie) magnetization is obtained and the linear response of a spin system to a strong pulsed r.f. irradiation is described. Finally, the spin interaction Hamiltonians relevant to this work are reviewed together with their truncated forms. Chapter 2 is a deuterium magnetic resonance study of two 'nom' liquid crystals which possess several low temperature mesomorphic phases. Specifically, deuterium quadrupolar echo spectroscopy is used to determine the orientation of the liquid crystal molecules in smectic phases, the changes in molecular orientation and motion that occur at smectic-smectic phase transitions, and the order of the phase transitions. For both compounds, the phase sequence is determined to be isotropic, nematic, smectic A, smectic C, smectic B_A, smectic B_C, and crystalline. The structure of the smectic A phase is found to be consistent with the well-known model of a two dimensional liquid in which molecules are rapidly rotating about their long axes and oriented at right angles to the plane of the layers. Molecules in the smectic C phase are found to have their long axes tilted with respect to the layer normal, and the tilt angle is temperature dependent, increasing from

Standardizing the experimental conditions for using urine in NMR-based metabolomic studies with a particular focus on diagnostic studies: a review

KAUST Repository

Emwas, Abdul-Hamid M.

2014-11-21

The metabolic composition of human biofluids can provide important diagnostic and prognostic information. Among the biofluids most commonly analyzed in metabolomic studies, urine appears to be particularly useful. It is abundant, readily available, easily stored and can be collected by simple, noninvasive techniques. Moreover, given its chemical complexity, urine is particularly rich in potential disease biomarkers. This makes it an ideal biofluid for detecting or monitoring disease processes. Among the metabolomic tools available for urine analysis, NMR spectroscopy has proven to be particularly well-suited, because the technique is highly reproducible and requires minimal sample handling. As it permits the identification and quantification of a wide range of compounds, independent of their chemical properties, NMR spectroscopy has been frequently used to detect or discover disease fingerprints and biomarkers in urine. Although protocols for NMR data acquisition and processing have been standardized, no consensus on protocols for urine sample selection, collection, storage and preparation in NMR-based metabolomic studies have been developed. This lack of consensus may be leading to spurious biomarkers being reported and may account for a general lack of reproducibility between laboratories. Here, we review a large number of published studies on NMR-based urine metabolic profiling with the aim of identifying key variables that may affect the results of metabolomics studies. From this survey, we identify a number of issues that require either standardization or careful accounting in experimental design and provide some recommendations for urine collection, sample preparation and data acquisition.

Standardizing the experimental conditions for using urine in NMR-based metabolomic studies with a particular focus on diagnostic studies: a review

KAUST Repository

Emwas, Abdul-Hamid M.; Luchinat, Claudio; Turano, Paola; Tenori, Leonardo; Roy, Raja; Salek, Reza M.; Ryan, Danielle; Merzaban, Jasmeen; Kaddurah-Daouk, Rima; Zeri, Ana Carolina; Nagana Gowda, G. A.; Raftery, Daniel; Wang, Yulan; Brennan, Lorraine; Wishart, David S.

2014-01-01

The metabolic composition of human biofluids can provide important diagnostic and prognostic information. Among the biofluids most commonly analyzed in metabolomic studies, urine appears to be particularly useful. It is abundant, readily available, easily stored and can be collected by simple, noninvasive techniques. Moreover, given its chemical complexity, urine is particularly rich in potential disease biomarkers. This makes it an ideal biofluid for detecting or monitoring disease processes. Among the metabolomic tools available for urine analysis, NMR spectroscopy has proven to be particularly well-suited, because the technique is highly reproducible and requires minimal sample handling. As it permits the identification and quantification of a wide range of compounds, independent of their chemical properties, NMR spectroscopy has been frequently used to detect or discover disease fingerprints and biomarkers in urine. Although protocols for NMR data acquisition and processing have been standardized, no consensus on protocols for urine sample selection, collection, storage and preparation in NMR-based metabolomic studies have been developed. This lack of consensus may be leading to spurious biomarkers being reported and may account for a general lack of reproducibility between laboratories. Here, we review a large number of published studies on NMR-based urine metabolic profiling with the aim of identifying key variables that may affect the results of metabolomics studies. From this survey, we identify a number of issues that require either standardization or careful accounting in experimental design and provide some recommendations for urine collection, sample preparation and data acquisition.

Standardizing the experimental conditions for using urine in NMR-based metabolomic studies with a particular focus on diagnostic studies: a review.

Science.gov (United States)

Emwas, Abdul-Hamid; Luchinat, Claudio; Turano, Paola; Tenori, Leonardo; Roy, Raja; Salek, Reza M; Ryan, Danielle; Merzaban, Jasmeen S; Kaddurah-Daouk, Rima; Zeri, Ana Carolina; Nagana Gowda, G A; Raftery, Daniel; Wang, Yulan; Brennan, Lorraine; Wishart, David S

The metabolic composition of human biofluids can provide important diagnostic and prognostic information. Among the biofluids most commonly analyzed in metabolomic studies, urine appears to be particularly useful. It is abundant, readily available, easily stored and can be collected by simple, noninvasive techniques. Moreover, given its chemical complexity, urine is particularly rich in potential disease biomarkers. This makes it an ideal biofluid for detecting or monitoring disease processes. Among the metabolomic tools available for urine analysis, NMR spectroscopy has proven to be particularly well-suited, because the technique is highly reproducible and requires minimal sample handling. As it permits the identification and quantification of a wide range of compounds, independent of their chemical properties, NMR spectroscopy has been frequently used to detect or discover disease fingerprints and biomarkers in urine. Although protocols for NMR data acquisition and processing have been standardized, no consensus on protocols for urine sample selection, collection, storage and preparation in NMR-based metabolomic studies have been developed. This lack of consensus may be leading to spurious biomarkers being reported and may account for a general lack of reproducibility between laboratories. Here, we review a large number of published studies on NMR-based urine metabolic profiling with the aim of identifying key variables that may affect the results of metabolomics studies. From this survey, we identify a number of issues that require either standardization or careful accounting in experimental design and provide some recommendations for urine collection, sample preparation and data acquisition.

Solution NMR study of the yeast cytochrome c peroxidase: cytochrome c interaction

Energy Technology Data Exchange (ETDEWEB)

Volkov, Alexander N., E-mail: ovolkov@vub.ac.be; Nuland, Nico A. J. van [Vrije Universiteit Brussel, Jean Jeener NMR Centre, Structural Biology Brussels (Belgium)

2013-07-15

Here we present a solution NMR study of the complex between yeast cytochrome c (Cc) and cytochrome c peroxidase (CcP), a paradigm for understanding the biological electron transfer. Performed for the first time, the CcP-observed heteronuclear NMR experiments were used to probe the Cc binding in solution. Combining the Cc- and CcP-detected experiments, the binding interface on both proteins was mapped out, confirming that the X-ray structure of the complex is maintained in solution. Using NMR titrations and chemical shift perturbation analysis, we show that the interaction is independent of the CcP spin-state and is only weakly affected by the Cc redox state. Based on these findings, we argue that the complex of the ferrous Cc and the cyanide-bound CcP is a good mimic of the catalytically-active Cc-CcP compound I species. Finally, no chemical shift perturbations due to the Cc binding at the low-affinity CcP site were observed at low ionic strength. We discuss possible reasons for the absence of the effects and outline future research directions.

ECG gated NMR-CT for cardiovascular diseases

International Nuclear Information System (INIS)

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

1984-01-01

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

In situ NMR and modeling studies of nitroxide mediated copolymerization of styrene and n-butyl acrylate

NARCIS (Netherlands)

Hlalele, L.; Klumperman, L.

2011-01-01

The combination of in situ1H NMR and in situ31P NMR was used to study the nitroxide mediated copolymerization of styrene and n-butyl acrylate. The alkoxyamine MAMA-DEPN was employed to initiate and mediate the copolymerization. The nature of the ultimate/terminal monomer units of dormant polymer

NMR imaging and pharmaceutical sciences

International Nuclear Information System (INIS)

Beall, P.T.; Good, W.R.

1986-01-01

Described is the technique of NMR-imaging in diagnostic medicine. Proton and phosphorus NMR in diagnosis of abnormal tissue pathology. Discussed is the value of NMR to the pharmaceutical sciences. NMR may play an important role in monitoring the response of tissues to drugs, determining the localization of drugs, performing real time pharmacokinetics and testing the use of NMR contrast pharmaceuticals

13C NMR Chemical Shifts of the Triclinic and Monoclinic Crystal forms of Valinomycin

International Nuclear Information System (INIS)

Kameda, Tsunenori; McGeorge, Gary; Orendt, Anita M.; Grant, David M.

2004-01-01

Two different crystalline polymorphs of valinomycin, the triclinic and monoclinic forms, have been studied by high resolution, solid state 13 C CP-MAS NMR spectroscopy. Although the two polymorphs of the crystal are remarkably similar, there are distinct differences in the isotropic chemical shifts between the two spectra. For the triclinic form, the carbon chemical shift tensor components for the alpha carbons adjacent to oxygen in the lactic acid and hydroxyisovaleric acid residues and the ester carbonyls of the valine residue were obtained using the FIREMAT experiment. From the measured components, it was found that the behavior of the isotropic chemical shift, δ iso , for valine residue ester carbonyl carbons is predominately influenced by the intermediate component, δ 22 . Additionally it was found that the smallest shift component, δ 33 , for the L-lactic acid (L-Lac) and D-α-hydroxyisovaleric acid (D-Hyi) C α -O carbon was significantly displaced depending upon the nature of individual amino acid residues, and it is the δ 33 component that governs the behavior of δ iso in these alpha carbons

Alpha decay studies on Po isotopes using different versions of nuclear potentials

Energy Technology Data Exchange (ETDEWEB)

Santhosh, K.P.; Sukumaran, Indu [Kannur University, School of Pure and Applied Physics, Payyanur, Kerala (India)

2017-12-15

The alpha decays from {sup 186-224}Po isotopes have been studied using 25 different versions of nuclear potentials so as to select a suitable nuclear potential for alpha decay studies. The computed standard deviation of the calculated half-lives in comparison with the experimental data suggested that proximity 2003-I is the apt form of nuclear potential for alpha decay studies as it possesses the least standard deviation, σ = 0.620. Among the different proximity potentials, proximity 1966 (σ = 0.630) and proximity 1977 (σ = 0.636), are also found to work well in alpha decay studies with low deviation. Among other versions of nuclear potentials (other than proximity potentials), Bass 1980 is suggested to be a significant form of nuclear potential because of its good predictive power. However, while the other forms of potentials are able to reproduce the experimental data to some extent, these potentials cannot be considered as apposite potentials for alpha decay studies in their present form. Since the experimental correlation of the models is noticed to be satisfying, the alpha decay half-lives of certain Po isotopes that are not detected experimentally yet have been predicted. (orig.)

Double rotation NMR studies of zeolites and aluminophosphate molecular sieves

Energy Technology Data Exchange (ETDEWEB)

Jelinek, Raz [Univ. of California, Berkeley, CA (United States)

1993-07-01

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

Study of a Conformational Equilibrium of Lisinopril by HPLC, NMR, and DFT

Directory of Open Access Journals (Sweden)

Sondes Bouabdallah

2014-01-01

Full Text Available The isomerization of lisinopril has been investigated using chromatographic, NMR spectroscopic, and theoretical calculations. The NMR data, particularly the NOEDIFF experiments, show that the major species that was eluted first is the trans form. The proportion was 77% and 23% for the trans and cis, respectively. The thermodynamic parameters (ΔH, ΔS, and ΔG were determined by varying the temperature in the NMR experiments. The interpretations of the experimental data were further supported by DFT/B3LYP calculations.

Some double resonance and multiple quantum NMR studies in solids

International Nuclear Information System (INIS)

Wemmer, D.E.

1978-08-01

The first section of this work presents the theory and experimental applications to analysis of molecular motion of chemical shielding lineshapes obtained with high resolution double resonance NMR techniques. Analysis of 13 C powder lineshapes in hexamethylbenzene (HMB) and decamethylferrocene (DMFe) show that these molecules reorient in a jumping manner about the symmetry axis. Analysis of proton chemical shielding lineshapes of residual protons in heavy ice (D 2 O) show that protons are exchanged among the tetrahedral positions of neighboring oxygen atoms, consistent with motion expected from defect migration. The second section describes the application of Fourier Transform Double Quantum NMR to measurement of chemical shielding of deuterium in powder samples. Studies of partially deuterated benzene and ferrocene give equal shielding anisotropies, Δsigma = -6.5 ppM. Theoretical predictions and experimental measurements of dipolar couplings between deuterons using FTDQ NMR are presented. Crystals of BaClO 3 .D 2 O, α,β d-2 HMB and α,β,γ d-3 HMB were studied, as were powders of d-2 HMB and anisic acid. The third section discusses general multiple quantum spectroscopy in dipolar coupled spin systems. Theoretical description is made for creation and detection of coherences between states without quantum number selection rules Δm = +-1. Descriptions of techniques for partial selectivity of order in preparation and detection of multiple quantum coherences are made. The effects on selectivity and resolution of echo pulses during multiple quantum experiments are discussed. Experimental observation of coherences up to order 6 have been made in a sample of benzene dissolved in a liquid crystal. Experimental verifications of order selection and echo generation have been made

Carbon-13 NMR spectroscopy of biological systems

CERN Document Server

Beckmann, Nicolau

1995-01-01

This book is intended to provide an in-depth understanding of 13C NMR as a tool in biological research. 13C NMR has provided unique information concerning complex biological systems, from proteins and nucleic acids to animals and humans. The subjects addressed include multidimensional heteronuclear techniques for structural studies of molecules in the liquid and solid states, the investigation of interactions in model membranes, the elucidation of metabolic pathwaysin vitro and in vivo on animals, and noninvasive metabolic studies performed on humans. The book is a unique mix of NMR methods and biological applications which makes it a convenient reference for those interested in research in this interdisciplinary area of physics, chemistry, biology, and medicine.Key Features* An interdisciplinary text with emphasis on both 13C NMR methodology and the relevant biological and biomedical issues* State-of-the-art 13C NMR techniques are described; Whenever possible, their advantages over other approaches are empha...

Structural variation study of cobalt nanoparticles synthesized by co-precipitation method using 59Co NMR

Science.gov (United States)

Manjunatha, M.; Kumar, Rajeev; B. M., Siddesh; Sahoo, Balaram; Damle, R.; Ramesh, K. P.

2018-04-01

We have synthesized cobalt nanoparticles using co-precipitation method. Further, the two phases of the cobalt is monitored by varying the synthesis parameters. 59Co NMR and XRD are used as characterization tools to study the phase variation in the cobalt samples. XRD and NMR results show a remarkable correlation in the two samples (Co-1 and Co-2). Co-2 has predominant fcc and hcp phases, whereas, Co-1 has fcc phase with lower amount of hcp. Both the samples show same saturation magnetization (Ms) but there is a remarkable difference in the phase composition. Thus, 59Co NMR appears to be a good tool to identify the phase purity of the ferromagnetic cobalt samples.

Theory of NMR probe design

International Nuclear Information System (INIS)

Schnall, M.D.

1988-01-01

The NMR probe is the intrinsic part of the NMR system which allows transmission of a stimulus to a sample and the reception of a resulting signal from a sample. NMR probes are used in both imaging and spectroscopy. Optimal probe design is important to the production of adequate signal/moise. It is important for anyone using NMR techniques to understand how NMR probes work and how to optimize probe design

$\\beta$-NMR of copper isotopes in ionic liquids

CERN Multimedia

We propose to test the feasibility of spin-polarization and $\\beta$-NMR studies on several short-lived copper isotopes, $^{58}$ Cu, $^{74}$Cu and $^{75}$Cu in crystals and liquids. The motivation is given by biological studies of Cu with $\\beta$-NMR in liquid samples, since Cu is present in a large number of enzymes involved in electron transfer and activation of oxygen. The technique is based on spin-polarization via optical pumping in the new VITO beamline. We will use the existing lasers, NMR magnet and NMR chambers and we will prepare a new optical pumping system. The studies will be devoted to tests of achieved $\\beta$-asymmetry in solid hosts, the behaviour of asymmetry when increasing vacuum, and finally NMR scans in ionic liquids. The achieved spin polarization will be also relevant for the plans to measure with high precision the magnetic moments of neutron-rich Cu isotopes.

NMR studies of myocardial energy metabolism and ionic homeostasis during ischemia and reperfusion

International Nuclear Information System (INIS)

Kirkels, J.H.

1989-01-01

In this study several aspects of myocardial energy metabolism and ionic homeostasis during ischemia and reperfusion were investigated in isolated perfused rat hearts, regionally ischemic rabbit hearts, and ex vivo human donor hearts during long term hypothermic cardioplegia. Phosphorus-31 nuclear magnetic resonance ( 31 P NMR) spectroscopy was used as a powerful tool to non-destructively follow the time course in changes in intracellular high-energy phosphates, (creatine phosphate and ATP), inorganic phosphate, and pH. In addition, changes in intracellular free magnesium were followed during ischemia and reperfusion. Sodium-23 ( 23 Na) NMR spectroscopy was used to study intracellular sodium during ischemia and reperfusion and during calcium-free perfusion. (author). 495 refs.; 33 figs.; 11 tabs

Quantum tunneling of magnetization in molecular nanomagnet Fe8 studied by NMR

International Nuclear Information System (INIS)

Maegawa, Satoru; Ueda, Miki

2003-01-01

Magnetization and NMR measurements have been performed for single crystals of molecular magnet Fe8. The field and temperature dependences of magnetization below 25 K are well described in terms of the isolated clusters with the total spin S=10. The stepwise recoveries of 1 H-NMR signals at the level crossing fields caused by the resonant quantum tunneling of magnetization were observed below 400 mK. The recovery of the NMR signals are explained by the fluctuation caused by the transition between the energy states of Fe magnetizations governed by Landau-Zener quantum transitions

Structural study of the membrane protein MscL using cell-free expression and solid-state NMR

Science.gov (United States)

Abdine, Alaa; Verhoeven, Michiel A.; Park, Kyu-Ho; Ghazi, Alexandre; Guittet, Eric; Berrier, Catherine; Van Heijenoort, Carine; Warschawski, Dror E.

2010-05-01

High-resolution structures of membrane proteins have so far been obtained mostly by X-ray crystallography, on samples where the protein is surrounded by detergent. Recent developments of solid-state NMR have opened the way to a new approach for the study of integral membrane proteins inside a membrane. At the same time, the extension of cell-free expression to the production of membrane proteins allows for the production of proteins tailor made for NMR. We present here an in situ solid-state NMR study of a membrane protein selectively labeled through the use of cell-free expression. The sample consists of MscL (mechano-sensitive channel of large conductance), a 75 kDa pentameric α-helical ion channel from Escherichia coli, reconstituted in a hydrated lipid bilayer. Compared to a uniformly labeled protein sample, the spectral crowding is greatly reduced in the cell-free expressed protein sample. This approach may be a decisive step required for spectral assignment and structure determination of membrane proteins by solid-state NMR.

NMR and computational study of Ba8CuxGe46-x clathrate semiconductors

International Nuclear Information System (INIS)

Chen, Jing-Han; Sirusi Arvij, Ali; Zheng, Xiang; Rodriguez, Sergio Y.; Ross, Joseph H.

2014-01-01

Highlights: • Quadrupole NMR with first-principles calculations probes local site preferences. • Cu/Ge ratio is clarified vs. the ideal Zintl composition. • Modified Becke–Johnson exchange potential agrees well with NMR Knight shifts. - Abstract: Ba 8 Cu x Ge 46-x is a type-I clathrate material that forms as a semiconductor in a narrow composition range corresponding to the electron-balanced Zintl composition, with x = 5.3. We use NMR spectroscopy combined with ab initio electronic structure calculations to probe the electronic and structural behavior of these materials. Computational results based on a superstructure model for the atomic configuration of the alloy provide good agreement with the electric quadrupole-broadened NMR lineshapes. Modeling using the modified Becke–Johnson (TB-mBJ) exchange potential is also shown to agree well with experimental NMR Knight shifts. The results indicate that the Cu–Ge balance is the main factor determining the carrier density, within a narrow stability range near the ideal Zintl composition

Studies on supramolecular gel formation using DOSY NMR

Czech Academy of Sciences Publication Activity Database

Nonappa, N.; Šaman, David; Kolehmainen, E.

2015-01-01

Roč. 53, č. 4 (2015), s. 256-260 ISSN 0749-1581 Institutional support: RVO:61388963 Keywords : DOSY * VT NMR * gel * diffusion coefficients Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.226, year: 2015

Petrophysical properties of greensand as predicted from NMR measurements

DEFF Research Database (Denmark)

Hossain, Zakir; Grattoni, Carlos A.; Solymar, Mikael

2011-01-01

ABSTRACT: Nuclear magnetic resonance (NMR) is a useful tool in reservoir evaluation. The objective of this study is to predict petrophysical properties from NMR T2 distributions. A series of laboratory experiments including core analysis, capillary pressure measurements, NMR T2 measurements...... with macro-pores. Permeability may be predicted from NMR by using Kozeny's equation when surface relaxivity is known. Capillary pressure drainage curves may be predicted from NMR T2 distribution when pore size distribution within a sample is homogeneous....

Local electronic structure of TM-based alloys: a pulsed NMR study

International Nuclear Information System (INIS)

Guerra, D.A.

1984-01-01

A pulsed NMR study on several transition metal + metalloid amorphous alloys is reported. The analisis of Knight shifts and nuclear spin-lattice relaxation of metalloids indicates a dominant contribution of p-electrons in the Fermi level density of state, supporting the existence of a p-d hibridization. (author) [pt

nmrML: A Community Supported Open Data Standard for the Description, Storage, and Exchange of NMR Data.

Science.gov (United States)

Schober, Daniel; Jacob, Daniel; Wilson, Michael; Cruz, Joseph A; Marcu, Ana; Grant, Jason R; Moing, Annick; Deborde, Catherine; de Figueiredo, Luis F; Haug, Kenneth; Rocca-Serra, Philippe; Easton, John; Ebbels, Timothy M D; Hao, Jie; Ludwig, Christian; Günther, Ulrich L; Rosato, Antonio; Klein, Matthias S; Lewis, Ian A; Luchinat, Claudio; Jones, Andrew R; Grauslys, Arturas; Larralde, Martin; Yokochi, Masashi; Kobayashi, Naohiro; Porzel, Andrea; Griffin, Julian L; Viant, Mark R; Wishart, David S; Steinbeck, Christoph; Salek, Reza M; Neumann, Steffen

2018-01-02

NMR is a widely used analytical technique with a growing number of repositories available. As a result, demands for a vendor-agnostic, open data format for long-term archiving of NMR data have emerged with the aim to ease and encourage sharing, comparison, and reuse of NMR data. Here we present nmrML, an open XML-based exchange and storage format for NMR spectral data. The nmrML format is intended to be fully compatible with existing NMR data for chemical, biochemical, and metabolomics experiments. nmrML can capture raw NMR data, spectral data acquisition parameters, and where available spectral metadata, such as chemical structures associated with spectral assignments. The nmrML format is compatible with pure-compound NMR data for reference spectral libraries as well as NMR data from complex biomixtures, i.e., metabolomics experiments. To facilitate format conversions, we provide nmrML converters for Bruker, JEOL and Agilent/Varian vendor formats. In addition, easy-to-use Web-based spectral viewing, processing, and spectral assignment tools that read and write nmrML have been developed. Software libraries and Web services for data validation are available for tool developers and end-users. The nmrML format has already been adopted for capturing and disseminating NMR data for small molecules by several open source data processing tools and metabolomics reference spectral libraries, e.g., serving as storage format for the MetaboLights data repository. The nmrML open access data standard has been endorsed by the Metabolomics Standards Initiative (MSI), and we here encourage user participation and feedback to increase usability and make it a successful standard.

Selected topics from recent NMR studies of organolithium compounds

Directory of Open Access Journals (Sweden)

Günther Harald

1999-01-01

Full Text Available After a short introduction to NMR spectroscopy of alkali and alkaline earth metals the review concentrates on NMR investigations of organolithium compounds. The isotopic fingerprint method, which rests on deuterium-induced isotope shifts for 6Li resonances, is introduced and exemplified with applications from the aggregation behavior of cyclopropyllithium systems and mixed aggregate formation between methyllithium and lithium salts. In the following chapter, one- and two-dimensional pulse experiments, both for homo- and for heteronuclear spin systems are discussed. Finally, the structural aspects associated with benzyllithium are outlined and the formation of polylithium systems by lithium reduction of biphenylenes is described.

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR.

Science.gov (United States)

van der Schot, Gijs; Bonvin, Alexandre M J J

2015-08-01

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665-1674, 2005b, doi: 10.1021/ja047109h). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27-35, 2013, doi: 10.1007/s10858-013-9762-6), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution.

Alpha Anisotropy Studies of Near-Spherical and Deformed Nuclei

CERN Multimedia

Van Duppen, P

2002-01-01

% IS329 \\\\ \\\\ Although it was the first decay mode to be discovered, the process of $\\alpha$-particle emission is still poorly understood. A few years ago the first systematic study of anisotropic $\\alpha$-decay triggered renewed theoretical interest. Nevertheless, today the theories are still not adequate enough and more experimental data are urgently needed. We therefore measure the $\\alpha$-anisotropies of the favoured transitions of a number of near-spherical Rn and At isotopes, and of deformed nuclei near A=220. As the different models yield contradictory predictions for the transitions that are investigated, the measurements will allow to discern on their validity. They will at the same time provide the necessary basis for further theoretical developments.

Nuclear magnetic resonance (NMR) tomography

International Nuclear Information System (INIS)

Skalpe, I.O.

1984-01-01

A brief survey of the working principle of the NMR technique in diagnostical medicine is given. Its clinical usefulness for locating tumors, diagnosing various other diseases, such as some mental illnesses and multiple sclerosis, and its possibilities for studying biochemical processes in vivo are mentioned. The price of NMR image scanners and the problems of the strong magnetic field around the machines are mentioned

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

NARCIS (Netherlands)

Van Der Schot, Gijs; Bonvin, Alexandre M J J

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on

Derivatives of 16alpha-hydroxy-dehydroepiandrosterone with an additional 7-oxo or 7-hydroxy substituent: synthesis and gas chromatography/mass spectrometry analysis.

Science.gov (United States)

Pouzar, Vladimír; Cerný, Ivan; Hill, Martin; Bicíková, Marie; Hampl, Richard

2005-10-01

Derivatives of 16alpha-hydroxy-dehydroepiandrosterone, which have an additional oxygen substituent at position 7 (oxo or hydroxy group), were synthesized. Firstly, 17,17-dimethoxyandrost-5-ene-3beta,16alpha-diyl diacetate was prepared and then oxidized with a complex of chromium(VI) oxide and 2,5-dimethylpyrazole to the respective 7-oxo derivative. This key intermediate was both deprotected or reduced by l-Selectride or sodium borohydride in the presence of cerium(III) chloride and then deprotected to give 7-oxo, 7alpha-hydroxy and 7beta-hydroxy derivatives of 16alpha-hydroxy-dehydroepiandrosterone. The target compounds were characterized by (1)H and (13)C NMR spectra and in the form of O-methyloxime-trimethylsilyl derivatives, by gas chromatography/mass spectrometry methods.

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

Energy Technology Data Exchange (ETDEWEB)

Schot, Gijs van der [Uppsala University, Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology (Sweden); Bonvin, Alexandre M. J. J., E-mail: a.m.j.j.bonvin@uu.nl [Utrecht University, Faculty of Science – Chemistry, Bijvoet Center for Biomolecular Research (Netherlands)

2015-08-15

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665–1674, 2005b, doi: 10.1021/ja047109h 10.1021/ja047109h ). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27–35, 2013, doi: 10.1007/s10858-013-9762-6 10.1007/s10858-013-9762-6 ), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution.

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

International Nuclear Information System (INIS)

Schot, Gijs van der; Bonvin, Alexandre M. J. J.

2015-01-01

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665–1674, 2005b, doi: 10.1021/ja047109h 10.1021/ja047109h ). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27–35, 2013, doi: 10.1007/s10858-013-9762-6 10.1007/s10858-013-9762-6 ), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution

Interaction of charged amphiphilic drugs with phosphatidylcholine vesicles studied by NMR

International Nuclear Information System (INIS)

Eriksson, L.E.G.

1987-01-01

Small unilamellar vesicles from egg phosphatidylcholine in NaCl solutions were exposed to some amphiphilic pharmaca. The aromatic drugs (chlorpromazine, dibucaine, tetracaine, imipramine and propranolol) were in their cationic form of the amines. By 1 H- and 31 P-NMR the membrane signals were observed. In particular, the N-methyl choline proton signals were followed upon drug addition. The intrinsic chemical shift difference (0.02 ppm) between the inner (upfield) and outer choline signals was influenced by the drug concentration. Packing properties of the lipid head groups and ring current shift probably contributed. At very high drug concentration, the vesicles are destroyed. A transformation into a micellar state with a high sample viscosity took place in a narrow concentration range of drug. The anion effects of Cl - were studied from the 35 Cl-NMR linewidth at 9.8 and 39.1 MHz. A continuous increase in the signal linewidth followed upon drug addition to the vesicles. Only chlorpromazine produced a broadening in the absence of vesicles (NaCl blank). The linewidth reflected a critical micelle concentration of this drug around 7 mM in 0.1 M NaCl. The 35 Cl-NMR experiments demonstrated the existence of an anionic counterion effect. This phenomenon should be accounted for when quantitatively analysing drug-membrane interactions in electrostatic terms. (Auth.)

Molecular basis for nondeletion alpha-thalassemia in American blacks. Alpha 2(116GAG----UAG).

OpenAIRE

Liebhaber, S A; Coleman, M B; Adams, J G; Cash, F E; Steinberg, M H

1987-01-01

An American black woman was found to have the phenotype of moderately severe alpha-thalassemia normally associated with the loss of two to three alpha-globin genes despite an alpha-globin gene map that demonstrated the loss of only a single alpha-globin gene (-alpha/alpha alpha). Several individuals in her kindred with normal alpha-globin gene mapping studies (alpha alpha/alpha alpha) had mild alpha-thalassemia hematologic values consistent with the loss of one to two alpha-globin genes. Thes...

Exciton Coupling in Circular Dichroic Spectroscopy as a Tool for Establishing the Absolute Configuration of alpha,beta-Unsaturated Esters of Allylic Alcohols

DEFF Research Database (Denmark)

Lauridsen, A.; Cornett, Claus; Christensen, S. B.

1991-01-01

alpha-beta-Unsaturated esters of allylic alcohols have been shown to exhibit exciton coupling by circular dichroic spectroscopy. This coupling permits the establishment of the absolute configuration. The method was used to prove the absolute configuration at C-2 of archangelolide. Detailed NMR sp...

Dynamic pulsed-field-gradient NMR

CERN Document Server

Sørland, Geir Humborstad

2014-01-01

Dealing with the basics, theory and applications of dynamic pulsed-field-gradient NMR NMR (PFG NMR), this book describes the essential theory behind diffusion in heterogeneous media that can be combined with NMR measurements to extract important information of the system being investigated. This information could be the surface to volume ratio, droplet size distribution in emulsions, brine profiles, fat content in food stuff, permeability/connectivity in porous materials and medical applications currently being developed. Besides theory and applications it will provide the readers with background knowledge on the experimental set-ups, and most important, deal with the pitfalls that are numerously present in work with PFG-NMR. How to analyze the NMR data and some important basic knowledge on the hardware will be explained, too.

Single crystal NMR studies of high temperature superconductors

International Nuclear Information System (INIS)

Pennington, C.H.; Durand, D.J.; Zax, D.B.; Slichter, C.P.; Rice, J.P.; Bukowski, E.D.; Ginsberg, D.M.

1989-01-01

The authors report Cu NMR studies in the normal state of a single crystal of the T/sub c/ = 90 K superconductor YBa 2 Cu 3 O/sub 7/minus/δ/. The authors have measured the magnetic shift tensor, the electric field gradient tensor, the nuclear spin-lattice relaxation rate tensor, and the time dependence and functional form of the transverse decay. From these data they obtain information about the charge state and magnetic state of the Cu atoms, and the existence and size of the electronic exchange coupling between spins of adjacent Cu atoms. 18 refs., 3 figs., 2 tabs

High-resolution nuclear magnetic resonance studies of proteins.

Science.gov (United States)

Jonas, Jiri

2002-03-25

The combination of advanced high-resolution nuclear magnetic resonance (NMR) techniques with high-pressure capability represents a powerful experimental tool in studies of protein folding. This review is organized as follows: after a general introduction of high-pressure, high-resolution NMR spectroscopy of proteins, the experimental part deals with instrumentation. The main section of the review is devoted to NMR studies of reversible pressure unfolding of proteins with special emphasis on pressure-assisted cold denaturation and the detection of folding intermediates. Recent studies investigating local perturbations in proteins and the experiments following the effects of point mutations on pressure stability of proteins are also discussed. Ribonuclease A, lysozyme, ubiquitin, apomyoglobin, alpha-lactalbumin and troponin C were the model proteins investigated.

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

Science.gov (United States)

Schreckenbach, Georg

2002-12-16

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

Polysaccharides of algae. Pt. 37. Characterization of hybrid structure of substituted agarose from Polysiphonia morrowii (Rhodophyta, Rhodomelaceae) using. beta. -agarase and /sup 13/C-NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Usov, A.I.; Ivanova, E.G.

1987-09-01

Structure of gel-forming galactan from Polysiphonia morrowii was analysed using bacterial ..beta..-agarase and /sup 13/C-nuclear magnetic resonance (/sup 13/C-NMR) spectroscopy. The polysaccharide was shown to contain: a) blocks composed of agarobiose residues, partly 6-O-methylated and 6-sulfated, which are sensitive to enzymolysis; b) extended blocks composed of agarobiose 6-sulfate residues, which are resistant to ..beta..-agarase action. The latter blocks contain also ..beta..-D-galactopyranosyl-(1->4)-..cap alpha..-L-galactopyranose 6.6'-disulfate residues (biogenetic precursors of agarobiose 6-sulfate), which are hardly detectable by /sup 13/C-NMR spectrum of the starting polysaccharide. Action of alkali on the enzyme-resistant fraction afforded a polysaccharide preparation having /sup 13/C-NMR spectrum of agarose 6-sulfate.

Structural study of pyrones by NMR

International Nuclear Information System (INIS)

Mandarino, D.G.

1985-01-01

Extracts of two species of Aniba, designed Aniba-SA (light petroleum extract) and Aniba-SB (benzene extract), afforded by chromatographic fraccionation some compounds. The isolated compounds were identified using spectrometric data and C 13 -NMR coupled and decompled spectra of pyrones were registered. Measurement of the heteronuclear residual coupling by irradiation proton frequency off-resonance was used for distinguish C-5, C-7 and C-8 carbons of the pyrones SB-1, SB-3, SB-4 and SB-5. (M.J.C.) [pt

Alpha low-level stored waste systems design study

Energy Technology Data Exchange (ETDEWEB)

Feizollahi, F.; Teheranian, B. (Morrison Knudson Corp., San Francisco, CA (United States). Environmental Services Div.); Quapp, W.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States))

1992-08-01

The Stored Waste System Design Study (SWSDS), commissioned by the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examines relative life-cycle costs associated with three system concepts for processing the alpha low-level waste (alpha-LLW) stored at the Radioactive Waste Management Complex's Transuranic Storage Area at the INEL. The three system concepts are incineration/melting; thermal treatment/solidification; and sort, treat, and repackage. The SWSDS identifies system functional and operational requirements and assesses implementability; effectiveness; cost; and demonstration, testing, and evaluation (DT E) requirements for each of the three concepts.

Alpha low-level stored waste systems design study

Energy Technology Data Exchange (ETDEWEB)

Feizollahi, F.; Teheranian, B. [Morrison Knudson Corp., San Francisco, CA (United States). Environmental Services Div.; Quapp, W.J. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

1992-08-01

The Stored Waste System Design Study (SWSDS), commissioned by the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examines relative life-cycle costs associated with three system concepts for processing the alpha low-level waste (alpha-LLW) stored at the Radioactive Waste Management Complex`s Transuranic Storage Area at the INEL. The three system concepts are incineration/melting; thermal treatment/solidification; and sort, treat, and repackage. The SWSDS identifies system functional and operational requirements and assesses implementability; effectiveness; cost; and demonstration, testing, and evaluation (DT&E) requirements for each of the three concepts.

Alpha low-level stored waste systems design study

International Nuclear Information System (INIS)

Feizollahi, F.; Teheranian, B.

1992-08-01

The Stored Waste System Design Study (SWSDS), commissioned by the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examines relative life-cycle costs associated with three system concepts for processing the alpha low-level waste (alpha-LLW) stored at the Radioactive Waste Management Complex's Transuranic Storage Area at the INEL. The three system concepts are incineration/melting; thermal treatment/solidification; and sort, treat, and repackage. The SWSDS identifies system functional and operational requirements and assesses implementability; effectiveness; cost; and demonstration, testing, and evaluation (DT ampersand E) requirements for each of the three concepts

sup 1 sup 1 B nutation NMR study of powdered borosilicates

CERN Document Server

Woo, A J; Han, D Y

1998-01-01

In this work, we applied the 1D sup 1 sup 1 B nutation NMR method for the analysis of the local structural environments in powdered borosilicates (SiO sub 2 -B sub 2 O sub 3). Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density matrix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D sup 1 sup 1 B nutation NMR experiment. The sup 1 sup 1 B NMR parameters, quadrupole coupling constants (e sup 2 qQ/h) and asymmetry parameters (eta), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed.

A primer to nutritional metabolomics by NMR spectroscopy and chemometrics

DEFF Research Database (Denmark)

Savorani, Francesco; Rasmussen, Morten Arendt; Mikkelsen, Mette Skau

2013-01-01

This paper outlines the advantages and disadvantages of using high throughput NMR metabolomics for nutritional studies with emphasis on the workflow and data analytical methods for generation of new knowledge. The paper describes one-by-one the major research activities in the interdisciplinary...... metabolomics platform and highlights the opportunities that NMR spectra can provide in future nutrition studies. Three areas are emphasized: (1) NMR as an unbiased and non-destructive platform for providing an overview of the metabolome under investigation, (2) NMR for providing versatile information and data...... structures for multivariate pattern recognition methods and (3) NMR for providing a unique fingerprint of the lipoprotein status of the subject. For the first time in history, by combining NMR spectroscopy and chemometrics we are able to perform inductive nutritional research as a complement to the deductive...

Far-Infrared and Millimeter Continuum Studies of K-Giants: Alpha Boo and Alpha Tau

Science.gov (United States)

Cohen, Martin; Carbon, Duane F.; Welch, William J.; Lim, Tanya; Forster, James R.; Goorvitch, David; Thigpen, William (Technical Monitor)

2002-01-01

We have imaged two normal, non-coronal, infrared-bright K-giants, alpha Boo and alpha Tau, in the 1.4-millimeter and 2.8-millimeter continuum using BIMA. These stars have been used as important absolute calibrators for several infrared satellites. Our goals are: (1) to probe the structure of their upper photospheres; (2) to establish whether these stars radiate as simple photospheres or possess long-wavelength chromospheres; and (3) to make a connection between millimeter-wave and far-infrared absolute flux calibrations. To accomplish these goals we also present ISO Long Wavelength Spectrometer (LWS) measurements of both these K-giants. The far-infrared and millimeter continuum radiation is produced in the vicinity of the temperature minimum in a Boo and a Tau, offering a direct test of the model photospheres and chromospheres for these two cool giants. We find that current photospheric models predict fluxes in reasonable agreement with those observed for those wavelengths which sample the upper photosphere, namely less than or equal to 170 micrometers in alpha Tau and less than or equal to 125 micrometers in alpha Boo. It is possible that alpha Tau is still radiative as far as 0.9 - 1.4 millimeters. We detect chromospheric radiation from both stars by 2.8 millimeters (by 1.4 millimeters in alpha Boo), and are able to establish useful bounds on the location of the temperature minimum. An attempt to interpret the chromospheric fluxes using the two-component "bifurcation model" proposed by Wiedemann et al. (1994) appears to lead to a significant contradiction.

Plutonium-238 alpha-decay damage study of the ceramic waste form

International Nuclear Information System (INIS)

Frank, S. M.; Barber, T. L.; Cummings, D.G.; DiSanto, T.; Esh, D.W.; Giglio, J. J.; Goff, K. M.; Johnson, S.G.; Kennedy, J.R.; Jue, J-F; Noy, M.; O'Holleran, T.P.; Sinkler, W.

2006-01-01

An accelerated alpha-decay damage study of a glass-bonded sodalite ceramic waste form has recently been completed. The purpose of this study was to investigate the physical and chemical durability of the waste form after significant exposure to alpha decay. This accelerated alpha-decay study was performed by doping the ceramic waste form with 238 Pu which has a much greater specific activity than 239 Pu that is normally present in the waste form. The alpha-decay dose at the end of the four year study was approximately 1 x 10 18 alpha-decays/gram of material. An equivalent time period for a similar dose of 239 Pu would require approximately 1100 years. After four years of exposure to 238 Pu alpha decay, the investigation observed little change to the physical or chemical durability of the ceramic waste form (CWF). Specifically, the 238 Pu-loaded CWF maintained it's physical integrity, namely that the density remained constant and no cracking or phase de-bonding was observed. The materials chemical durability and phase stability also did not change significantly over the duration of the study. The only significant measured change was an increase of the unit-cell lattice parameters of the plutonium oxide and sodalite phases of the material and an increase in the release of salt components and plutonium of the waste form during leaching tests, but, as mentioned, these did not lead to any overall loss of waste form durability. The principal findings from this study are: (1) 238 Pu-loaded CWF is similar in microstructure and phase composition to referenced waste form. (2) Pu was observed primarily as oxide comprised of aggregates of nano crystals with aggregates ranging in size from submicron to twenty microns in diameter. (3) Pu phases were primarily found in the intergranular glassy regions. (4) PuO phase shows expected unit cell volume expansion due to alpha decay damage of approximately 0.7%, and the sodalite phase unit cell volume has expanded slightly by 0.3% again

Flow units from integrated WFT and NMR data

Energy Technology Data Exchange (ETDEWEB)

Kasap, E.; Altunbay, M.; Georgi, D.

1997-08-01

Reliable and continuous permeability profiles are vital as both hard and soft data required for delineating reservoir architecture. They can improve the vertical resolution of seismic data, well-to-well stratigraphic correlations, and kriging between the well locations. In conditional simulations, permeability profiles are imposed as the conditioning data. Variograms, covariance functions and other geostatistical indicators are more reliable when based on good quality permeability data. Nuclear Magnetic Resonance (NMR) logging and Wireline Formation Tests (WFT) separately generate a wealth of information, and their synthesis extends the value of this information further by providing continuous and accurate permeability profiles without increasing the cost. NMR and WFT data present a unique combination because WFTs provide discrete, in situ permeability based on fluid-flow, whilst NMR responds to the fluids in the pore space and yields effective porosity, pore-size distribution, bound and moveable fluid saturations, and permeability. The NMR permeability is derived from the T{sub 2}-distribution data. Several equations have been proposed to transform T{sub 2} data to permeability. Regardless of the transform model used, the NMR-derived permeabilities depend on interpretation parameters that may be rock specific. The objective of this study is to integrate WFT permeabilities with NMR-derived, T{sub 2} distribution-based permeabilities and thereby arrive at core quality, continuously measured permeability profiles. We outlined the procedures to integrate NMR and WFT data and applied the procedure to a field case. Finally, this study advocates the use of hydraulic unit concepts to extend the WFT-NMR derived, core quality permeabilities to uncored intervals or uncored wells.

NMR structural studies of oligosaccharides and other natural products

DEFF Research Database (Denmark)

Kjærulff, Louise

produce secondary metabolites for signaling and competing against other organisms, and these molecules are important in drug discovery due to their inherent biological activities. From a marine Photobacterium (P. halotolerans) we isolated the solonamides and the ngercheumicins, two families of cyclic...... through the nJCH correlation, this experiment has exciting applications for configurational assignment of e.g. carbohydrates and for residual dipolar couplings. Identification of known molecules and discovery of novel molecules are other important applications of NMR spectroscopy. Bacteria and fungi....... fijiensis, was also investigated for production of novel secondary metabolites, and a new pyranonigrin (E) was isolated and structure elucidated by NMR spectroscopy along with JBIR-74 and decumbenone A, two known metabolites previously isolated from Aspergillus and Penicillium species. Oligosaccharides...

Resting alpha activity predicts learning ability in alpha neurofeedback

Directory of Open Access Journals (Sweden)

Wenya eNan

2014-07-01

Full Text Available Individuals differ in their ability to learn how to regulate the alpha activity by neurofeedback. This study aimed to investigate whether the resting alpha activity is related to the learning ability of alpha enhancement in neurofeedback and could be used as a predictor. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback in order to learn how to enhance activity in the alpha frequency band. The learning ability was assessed by three indices respectively: the training parameter changes between two periods, within a short period and across the whole training time. It was found that the resting alpha amplitude measured before training had significant positive correlations with all learning indices and could be used as a predictor for the learning ability prediction. This finding would help the researchers in not only predicting the training efficacy in individuals but also gaining further insight into the mechanisms of alpha neurofeedback.

HPLC-NMR revisited: Using time-slice HPLC-SPE-NMR with database assisted dereplication

DEFF Research Database (Denmark)

Johansen, Kenneth; Wubshet, Sileshi Gizachew; Nyberg, Nils

2013-01-01

Time based trapping of chromatographically separated compounds on to solid-phase extraction cartridges (SPE) and subsequent elution to NMR-tubes was done to emulate the function of HPLC–NMR for dereplication purposes. Sufficient mass sensitivity was obtained by the use of a state-of-the-art HPLC......–SPE–NMR-system with a cryogenically cooled probe head, designed for 1.7 mm NMR-tubes. The resulting 1H NMR spectra (600 MHz) were evaluated against a database of previously acquired and prepared spectra. The in-house developed matching algorithm, based on partitioning of the spectra and allowing for changes in the chemical shifts......, is described and the code included as Supplementary Information. Two mixtures of natural products was used to test the approach; one extract of Carthamus oxyacantha (wild safflower) containing an array of spiro compounds and one extract of the endophytic fungus Penicillum namyslowski containing griseofulvin...

NMR for chemists and biologists

CERN Document Server

Carbajo, Rodrigo J

2013-01-01

This book offers a concise introduction to the field of nuclear magnetic resonance or NMR. It presents the basic foundations of NMR in a non-mathematical way and provides an overview of both recent and important biological applications of NMR.

2D NMR studies on muscle and cerebral metabolism in vivo

Energy Technology Data Exchange (ETDEWEB)

Gillet, B.; Doan, B.T.; Verre-Sebrie, C.; Fedeli, O.; Beloeil, J.C. (Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France). Inst. de Chimie des Substances Naturelles); Peres, M. (CERMA-CEV, 91 - Bretigny-sur-Orge (France)); Barrere, B.; Seylaz, J. (Paris-7 Univ., 75 (France)); Morin, S.; Koenig, J. (Bordeaux-1 Univ., 33 - Talence (France)); Sebille, A. (Faculte de Medecine Saint-Antoine, 75 - Paris (France))

1994-06-01

New developments in in vivo 2D[sup 1]H NMR spectroscopy now allow several metabolites, which are not resolved by 1D NMR to be assigned. This report describes the use of this technique to follow the time courses of changes in the concentration of metabolites in the rat brain during physiological and pathophysiological processes (hyperglycemia and hypoxia) and to compare the fatty acid components of normal and dystrophic mouse gastrocnemius muscle. (authors). 15 refs., 5 figs.

31P-NMR studies on perfused mouse liver

International Nuclear Information System (INIS)

McLaughlin, A.C.; Takeda, H.; Chance, B.

1978-01-01

From a metabolic viewpoint, the most important organ in the body is the liver. In contrast to more specialized organs such as heart and kidney which perform only one major function, the liver performs a number of major metabolic functions. Two of the most important functions are the catabolism and storage of foodstuffs (in the form of glycogen) and the control of most of the constituents of the blood (in particular, the blood glucose level). Most of these functions are localized within a single type of cell. One way that the liver is able to regulate these diverse reactions is by the control of the ATP level in the cell. Encouraged by the recent success of many groups in using 31 P-NMR to provide a continuous and non-destructive monitor of ATP levels in isolated cells, skeletal muscle, and perfused organs such as heart and kidney, 31 P-NMR was used to investigate ATP levels in perfused liver of mice

Compact NMR

Energy Technology Data Exchange (ETDEWEB)

Bluemich, Bernhard; Haber-Pohlmeier, Sabina; Zia, Wasif [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMC)

2014-06-01

Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

Application of 31P-NMR spectroscopy to the study of striated muscle metabolism

International Nuclear Information System (INIS)

Meyer, R.A.; Kushmerick, M.J.; Brown, T.R.

1982-01-01

This review presents the principles and limitations of phosphorus nuclear magnetic resonance ( 31 P-NMR) spectroscopy as applied to the study of striated muscle metabolism. Application of the techniques discussed include noninvasive measurement of high-energy phosphate, intracellular pH, intracellular free Mg 2+ , and metabolite compartmentation. In perfused cat biceps (fast-twitch) muscles, but not in soleus (slow-twitch), NMR spectra indicate a substantially lower (1 mM) free inorganic phosphate level than when measured chemically (6 mM). In addition, saturation and inversion spin-transfer methods that enable direct measurement of the unidirectional fluxes through creatine kinase are described. In perfused cat biceps muscle, results suggest that this enzyme and its substrates are in simple chemical equilibrium

Xenon NMR of liquid crystals confined to cylindrical nanocavities: a simulation study.

Science.gov (United States)

Karjalainen, Jouni; Vaara, Juha; Straka, Michal; Lantto, Perttu

2015-03-21

independent of temperature. Our results show that the combination of CG simulations and a QC pre-parameterised (129)Xe NMR shielding allows efficient studies of the phase behaviour and structure of complex systems containing thousands of molecules, and brings us closer to the simulation of NMR experiments.

1H and 13C NMR assignments for two new cordiaquinones from roots of Cordia leucocephala.

Science.gov (United States)

Diniz, Jaécio Carlos; Viana, Francisco Arnaldo; Oliveira, Odaci Fernandes; Maciel, Maria Aparecida M; Torres, Maria da Conceição de Menezes; Braz-Filho, Raimundo; Silveira, Edilberto R; Pessoa, Otília Deusdênia L

2009-02-01

From the roots of Cordia leucocephala (Boraginaceae), two new meroterpenoid naphthoquinones, 6-[10-(12,12-dimethyl-13alpha-hydroxy-16-methenyl-cyclohexyl)ethyl]-1,4-naphthalenedione (cordiaquinone L) and 5-methyl-6-[10-(12,12-dimethyl-13beta-hydroxy-16-methenyl-cyclohexyl)methyl-1,4-naphthalenedione (cordiaquinone M) were isolated. Their structures were elucidated after detailed 1D and 2D NMR (COSY, HSQC, HMBC and NOESY) data analyses and comparison with literature data for analogous compounds. 2008 John Wiley & Sons, Ltd.

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

International Nuclear Information System (INIS)

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

1990-01-01

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

Understanding of the mechanical and structural changes induced by alpha particles and heavy ions in the French simulated nuclear waste glass

International Nuclear Information System (INIS)

Karakurt, G.; Abdelouas, A.; Guin, J.-P.; Nivard, M.; Sauvage, T.; Paris, M.; Bardeau, J.-F.

2016-01-01

Borosilicate glasses are considered for the long-term confinement of high-level nuclear wastes. External irradiations with 1 MeV He + ions and 7 MeV Au 5+ ions were performed to simulate effects produced by alpha particles and by recoil nuclei in the simulated SON68 nuclear waste glass. To better understand the structural modifications, irradiations were also carried out on a 6-oxides borosilicate glass, a simplified version of the SON68 glass (ISG glass). The mechanical and macroscopic properties of the glasses were studied as function of the deposited electronic and nuclear energies. Alpha particles and gold ions induced a volume change up to −0.7% and −2.7%, respectively, depending on the glass composition. Nano-indentations tests were used to determine the mechanical properties of the irradiated glasses. A decrease of about −22% to −38% of the hardness and a decrease of the reduced Young's modulus by −8% were measured after irradiations. The evolution of the glass structure was studied by Raman spectroscopy, and also 11 B and 27 Al Nuclear Magnetic Resonance (MAS-NMR) on a 20 MeV Kr irradiated ISG glass powder. A decrease of the silica network connectivity after irradiation with alpha particles and gold ions is deduced from the structural changes observations. NMR spectra revealed a partial conversion of BO 4 to BO 3 units but also a formation of AlO 5 and AlO 6 species after irradiation with Kr ions. The relationships between the mechanical and structural changes are also discussed. - Highlights: • Mechanical and structural properties of two borosilicate glass compositions irradiated with alpha particles and heavy ions were investigated. • Both kinds of particles induced a decrease of the hardness, reduced Young's modulus and density. • Electronic and nuclear interactions are responsible for the changes observed. • The evolution of the mechanical properties under irradiation is linked to the changes occured in the

Deuterium NMR, induced and intrinsic cholesteric lyomesophases

International Nuclear Information System (INIS)

Alcantara, M.R.

1982-01-01

Induced and intrinsic cholesteric lyotropic mesophases were studied. Induced cholesteric lyomesophases based on potassium laurate (KL) system, with small amounts of cholesterol added, were studied by deuterium NMR and by polarizing microscopy. Order profiles obtained from deuterium NMR of KL perdenderated chains in both induced cholesteric and normal mesophases were compared. The intrinsic cholesteric lyotropic mesophases were based on the amphiphile potassium N-lauroyl serinate (KLNS) in the resolved levo form. The study of the type I intrinsic cholesteric mesophase was made by optical microscopy under polarized light and the type II intrinsic cholesteric lyomesophase was characterized by deuterium NMR. The new texture was explained by the use of the theory of disclinations developed for thermotropic liquid crystals, specially for cholesteric type. (M.J.C.) [pt

Effect of alpha amylase on early childhood caries: a matched case-control study

OpenAIRE

Mojarad, Farzad; Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan; Fazlollahifar, Samira; Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan; Poorolajal, Jalal; Research Center for Health Sciences, Department of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan; Hajilooi, Mehrdad; Department of Pathology, School of Dentistry, Hamadan University of Medical Sciences, Hamadan

2013-01-01

Objectives: There are a few studies addressing the relationship between salivary alpha-amylase and dental caries. This study was implemented in order to investigate the effect of salivary alpha-amylase level on early childhood caries (ECC).Materials and Methods: In this matched case-control study, which was carried out from November 2011 to March 2012 in Hamadan City, the west of Iran, mean levels of salivary alpha-amylase of 84 ECC-active cases were compared to that of 84 ECC-free controls u...

Synthesis of Fischer carbene complexes of iridium by C-H bond activation of methyl and cyclic ethers: Evidence for reversible {alpha}-hydrogen migration

Energy Technology Data Exchange (ETDEWEB)

Luecke, H.F.; Arndtsen, B.A.; Burger, P.; Bergman, R.G. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

1996-03-13

We report here a mild and versatile route to Fischer carbene complexes of iridium via the activation of C-H bonds of methyl and cyclic ethers, along with our preliminary studies of this rare family of carbene complexes. Theoretical studies suggest that {alpha}-hydrogen migrations can be kinetically favorable if a coordinatively unsaturated species can be accessed. Thus, the lability of the triflate ligand presumably facilitates this process. Further evidence for the rapidity, as well as reversibility, of this rearrangement was obtained by NMR analysis. 20 refs.

A thermogravimetric analysis (TGA) method developed for estimating the stoichiometric ratio of solid-state {alpha}-cyclodextrin-based inclusion complexes

Energy Technology Data Exchange (ETDEWEB)

Bai, Yuxiang; Wang, Jinpeng; Bashari, Mohanad; Hu, Xiuting [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Feng, Tao [School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418 (China); Xu, Xueming [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Jin, Zhengyu, E-mail: jinlab2008@yahoo.com [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Tian, Yaoqi, E-mail: yqtian@jiangnan.edu.cn [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China)

2012-08-10

Highlights: Black-Right-Pointing-Pointer We develop a TGA method for the measurement of the stoichiometric ratio. Black-Right-Pointing-Pointer A series of formulas are deduced to calculate the stoichiometric ratio. Black-Right-Pointing-Pointer Four {alpha}-CD-based inclusion complexes were successfully prepared. Black-Right-Pointing-Pointer The developed method is applicable. - Abstract: An approach mainly based on thermogravimetric analysis (TGA) was developed to evaluate the stoichiometric ratio (SR, guest to host) of the guest-{alpha}-cyclodextrin (Guest-{alpha}-CD) inclusion complexes (4-cresol-{alpha}-CD, benzyl alcohol-{alpha}-CD, ferrocene-{alpha}-CD and decanoic acid-{alpha}-CD). The present data obtained from Fourier transform-infrared (FT-IR) spectroscopy showed that all the {alpha}-CD-based inclusion complexes were successfully prepared in a solid-state form. The stoichiometric ratios of {alpha}-CD to the relative guests (4-cresol, benzyl alcohol, ferrocene and decanoic acid) determined by the developed method were 1:1, 1:2, 2:1 and 1:2, respectively. These SR data were well demonstrated by the previously reported X-ray diffraction (XRD) method and the NMR confirmatory experiments, except the SR of decanoic acid with a larger size and longer chain was not consistent. It is, therefore, suggested that the TGA-based method is applicable to follow the stoichiometric ratio of the polycrystalline {alpha}-CD-based inclusion complexes with smaller and shorter chain guests.

Study on 1H-NMR fingerprinting of Rhodiolae Crenulatae Radix et Rhizoma.

Science.gov (United States)

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.

NMR study of hydride systems

International Nuclear Information System (INIS)

Peretz, M.

1980-02-01

The hydrides of thorium (ThH 2 , Th 4 H 15 and Th 4 D 15 ) and the intermetallic compound system (Zr(Vsub(1-x)Cosub(x)) 2 and its hydrides were investigated using the nuclear magnetic resonance (NMR) technique. From the results for the thorium hydride samples it was concluded that the density of states at the Fermi level n(Esub(f)) is higher in Th 4 H 15 than in ThH 2 ; there is an indirect reaction between the protons and the d electrons belonging to the Th atoms in Th 4 H 15 ; n(E) has a sharp structure near Esub(f). It was also found that the hydrogen diffusion mechanism changes with temperature. From the results for the intermetallic compound system conclusions were drawn concerning variations in the electronic structure, which explain the behavior of the system. In hydrogen diffusion studies in several samples it was found that Co atoms slow the diffusion rate. Quadrupole spectra obtained at low temperatures show that the H atoms preferably occupy tetrahedral sites formed by three V atoms and one Z atom. (H.K.)

Clinical studies on the radioimmunodetection of tumors containing alpha-fetoprotein

International Nuclear Information System (INIS)

Goldenberg, D.M.; Kim, E.E.; Deland, F.; Spremulli, E.; Nelson, M.O.; Gockerman, J.P.; Primus, F.J.; Corgan, R.L.; Alpert, E.

1980-01-01

This study reports the use of radiolabeled antibodies to alpha-fetoprotein for the detection and localization of hepatocellular and germ cell carcinomas. Twelve patients with histories of histologically-confirmed neoplasia received a total dose between 1.0 and 4.4 mCi of 131 I-labeled goat IgG prepared against human alpha-fetoprotein. Total-body photoscans were taken with a gamma scintillation camera at various intervals after injection of the radioactive antibody. Computer subtraction of radioactive technetium background images from the antibody 131 I scans permitted the visualization of all tumor sites known to be present in 4 patients with either primary hepatocellular cancer or metastatic germ cell carcinoma of the testis. Among 8 patients with diverse neoplasms not believed to contain alpha-fetoprotein, 5 of 19 tumor sites showed radioactive antibody accretion, although significantly less than in the patients with liver or testicular cancer. This investigation indicates that alpha-fetoprotein-containing tumors can be detected and localized in vivo by the method of radioimmunodetection

New catalytic roles for serine esterases: a 19F-NMR study of the interaction of 3,3,3-trifluoro-2,2-dihydroxy-1-phenyl-1-propanone with chicken liver carboxylesterase.

Science.gov (United States)

Bowles, M R; King, G J; Berndt, M C; Zerner, B

1996-12-05

The reactions of 3,3,3-trifluoro-2,2-dihydroxy-1-phenyl-1-propanone (TDPP) with chicken liver carboxylesterase have shown that this ketone hydrate is not only a potent inhibitor of the enzyme, but also a substrate for a number of enzyme-catalyzed reactions. The kinetics of inhibition are consistent with a mechanism in which the bound hydrate is initially dehydrated in a rate-limiting step catalyzed by the enzyme. Nucleophilic attack by the active-site serine on the parent ketone then produces a hemiketal adduct. However, the slow reactivation (by dialysis) of TDPP-inhibited enzyme indicates that the interaction with this inhibitor is more complex. At equilibrium, a dissociation constant of 2.4 pM was obtained for this interaction. 19F-NMR studies of the enzyme-TDPP complex show that after pre-equilibration, the major adduct is not the hemiketal adduct. It is proposed that this final adduct is a cross-linked adduct formed between TDPP, the active-site serine and the active-site histidine. 19F-NMR studies reveal that chicken liver carboxylesterase catalyses the cleavage of TDPP to yield either fluoride ion or trifluoroacetate, and also the benzilic acid rearrangement of TDPP to alpha-trifluoromethylmandelate. These products have also been identified in model studies of the reaction between TDPP and imidazole.

Dimerization of A-[alpha]-[SiNb3W9O40]7- by pH-controlled formation of individual Nb−µ-O−Nb linkages

Science.gov (United States)

Gyu-Shik Kim; Huadong Zeng; Wade A. Neiwert; Jennifer J. Cowan; Donald VanDerveer; Craig L. Hill; Ira A. Weinstock

2003-01-01

The reversible, stepwise formation of individual Nb−µ-O−Nb linkages during acid condensation of 2 equiv of A-[alpha]-[SiNb3W9O40]7- (1) to the tri-µ-oxo-bridged structure A-[alpha]-[Si2Nb6W18O77]8- (4) is demonstrated by a combination of X-ray crystallography and variable-pD solution 183W and 29Si NMR spectroscopy. Addition of DCl to a pD 8.4...

Hyperpolarized NMR Probes for Biological Assays

Directory of Open Access Journals (Sweden)

Sebastian Meier

2014-01-01

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

Bayesian Peak Picking for NMR Spectra

KAUST Repository

Cheng, Yichen

2014-02-01

Protein structure determination is a very important topic in structural genomics, which helps people to understand varieties of biological functions such as protein-protein interactions, protein–DNA interactions and so on. Nowadays, nuclear magnetic resonance (NMR) has often been used to determine the three-dimensional structures of protein in vivo. This study aims to automate the peak picking step, the most important and tricky step in NMR structure determination. We propose to model the NMR spectrum by a mixture of bivariate Gaussian densities and use the stochastic approximation Monte Carlo algorithm as the computational tool to solve the problem. Under the Bayesian framework, the peak picking problem is casted as a variable selection problem. The proposed method can automatically distinguish true peaks from false ones without preprocessing the data. To the best of our knowledge, this is the first effort in the literature that tackles the peak picking problem for NMR spectrum data using Bayesian method.

O-17 NMR measurement of water

International Nuclear Information System (INIS)

Fukazawa, Nobuyuki

1990-01-01

Recently, attention has been paid to the various treatment of water and the utilization of water by magnetic treatment, electric field treatment and so on. It has been said that by these treatments, the change in the properties of water arises. The state of this treated water cannot be explained by the properties of water from conventional physical and chemical standpoints. In addition, the method of measurement of whether the change arose or not is not yet determined. It is necessary to establish the method of measurement for the basic state of water. In this study, O-17 NMR which observes the state of water directly at molecular or atomic level was investigated as the method of measuring water. The measurement of O-17 NMR was carried out with a JNR 90Q FT NMR of Fourier transformation type of JEOL Ltd. The experimental method and the results are reported. The result of measurement of the O-17 NMR spectrum for distilled ion exchange water is shown. It is know that it has very wide line width as compared with the NMR spectra of protons and C-13. The relative sensitivity of O-17 observation is about 1/100,000 of that of protons. As to the information on the state of water obtained by O-17 NMR, there are chemical shift and line width. As temperature rose, the line width showed decrease, which seemed to be related to the decrease of hydrogen combination. (K.I.)

Quantification of aluminium-27 NMR spectra of high-surface-area oxides

International Nuclear Information System (INIS)

Pearson, R.M.; Schramm, C.M.

1990-01-01

This paper discusses the quantitation of 27 Al NMR spectra. It is showns that the so called 'invisible' aluminium atoms seen by recent workers are completely consistent with known continuous wave NMR studies of the 27 Al NMR spectra of high surface area aluminium oxides. The use of pulsed NMR techniques further complicate the quantitative measurement of 27 Al NMR spectra, especially when high resolution NMR spectrometers are used for this purpose. Methods are described which allow both the estimation of aluminium not seen by continuous wave techniques and the amounts of the NMR spectra lost in pulsed work. (author). 24 refs.; 6 figs.; 1 tab

Chemical constituents from leaves of the Qualea grandiflora: attribution of the NMR data of two diastereoisomeric acylated flavonoid glycosides; Constituintes quimicos das folhas de Qualea grandiflora: atribuicao dos dados de RMN de dois flavoides glicosilados acilados diastereoisomericos

Energy Technology Data Exchange (ETDEWEB)

Ayres, Mariane Cruz Costa; Escorcio, Samuel Portela; Costa, Danielly Albuquerque da; Chaves, Mariana H. [Universidade Federal do Piaui, Teresina, PI (Brazil). Dept. de Quimica]. E-mail: mariana@ufpi.br; Gerardo, Magela Vieira Junior; Cavalheiro, Alberto J. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica

2008-07-01

Phytochemical investigation from leaves of the Qualea grandiflora (Vochysiaceae) resulted in the isolation and identification of kaempferol-3-O-alpha-L-(4{sup -}E-p-coumaroyl)-rhamnoside, kaempferol-3-O-alpha-L-(4{sup -}Z-p-coumaroyl)-rhamnoside, squalene, phytol, lupeol, alpha-amyrin, beta-amyrin, sitosterol, sitostenone, sitosterol-3-O-beta-D-glucopyranoside, ursolic and oleanolic acids. The structures of the compounds were identified by 1D- and 2D-NMR experiments, mass and UV spectrometry and comparison with literature data. (author)

NMR analysis of male fathead minnow urinary metabolites: A potential approach for studying impacts of chemical exposures

Energy Technology Data Exchange (ETDEWEB)

Ekman, D.R. [Ecosystems Research Division, U.S. EPA, 960 College Station Road, Athens, GA 30605 (United States)], E-mail: ekman.drew@epa.gov; Teng, Q. [Ecosystems Research Division, U.S. EPA, 960 College Station Road, Athens, GA 30605 (United States); Jensen, K.M.; Martinovic, D.; Villeneuve, D.L.; Ankley, G.T. [Mid-Continent Ecology Division, U.S. EPA, 6201 Congdon Boulevard, Duluth, MN 55804 (United States); Collette, T.W. [Ecosystems Research Division, U.S. EPA, 960 College Station Road, Athens, GA 30605 (United States)

2007-11-30

The potential for profiling metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures was explored using nuclear magnetic resonance (NMR) spectroscopy. Both one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy was used for the assignment of metabolites in urine from unexposed fish. Because fathead minnow urine is dilute, we lyophilized these samples prior to analysis. Furthermore, 1D {sup 1}H NMR spectra of unlyophilized urine from unexposed male fathead minnow and Sprague-Dawley rat were acquired to qualitatively compare rat and fish metabolite profiles and to provide an estimate of the total urinary metabolite pool concentration difference. As a small proof-of-concept study, lyophilized urine samples from male fathead minnows exposed to three different concentrations of the antiandrogen vinclozolin were analyzed by 1D {sup 1}H NMR to assess exposure-induced changes. Through a combination of principal components analysis (PCA) and measurements of {sup 1}H NMR peak intensities, several metabolites were identified as changing with statistical significance in response to exposure. Among those changes occurring in response to exposure to the highest concentration (450 {mu}g/L) of vinclozolin were large increases in taurine, lactate, acetate, and formate. These increases coincided with a marked decrease in hippurate, a combination potentially indicative of hepatotoxicity. The results of these investigations clearly demonstrate the potential utility of an NMR-based approach for assessing chemical exposures in male fathead minnow, using urine collected from individual fish.

NMR analysis of male fathead minnow urinary metabolites: A potential approach for studying impacts of chemical exposures

International Nuclear Information System (INIS)

Ekman, D.R.; Teng, Q.; Jensen, K.M.; Martinovic, D.; Villeneuve, D.L.; Ankley, G.T.; Collette, T.W.

2007-01-01

The potential for profiling metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures was explored using nuclear magnetic resonance (NMR) spectroscopy. Both one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy was used for the assignment of metabolites in urine from unexposed fish. Because fathead minnow urine is dilute, we lyophilized these samples prior to analysis. Furthermore, 1D 1 H NMR spectra of unlyophilized urine from unexposed male fathead minnow and Sprague-Dawley rat were acquired to qualitatively compare rat and fish metabolite profiles and to provide an estimate of the total urinary metabolite pool concentration difference. As a small proof-of-concept study, lyophilized urine samples from male fathead minnows exposed to three different concentrations of the antiandrogen vinclozolin were analyzed by 1D 1 H NMR to assess exposure-induced changes. Through a combination of principal components analysis (PCA) and measurements of 1 H NMR peak intensities, several metabolites were identified as changing with statistical significance in response to exposure. Among those changes occurring in response to exposure to the highest concentration (450 μg/L) of vinclozolin were large increases in taurine, lactate, acetate, and formate. These increases coincided with a marked decrease in hippurate, a combination potentially indicative of hepatotoxicity. The results of these investigations clearly demonstrate the potential utility of an NMR-based approach for assessing chemical exposures in male fathead minnow, using urine collected from individual fish

Analysis of Alpha-2 Macroglobulin from the Long-Lived and Cancer-Resistant Naked Mole-Rat and Human Plasma.

Science.gov (United States)

Thieme, René; Kurz, Susanne; Kolb, Marlen; Debebe, Tewodros; Holtze, Susanne; Morhart, Michaela; Huse, Klaus; Szafranski, Karol; Platzer, Matthias; Hildebrandt, Thomas B; Birkenmeier, Gerd

2015-01-01

The naked mole-rat (NMR) is a long-lived and cancer resistant species. Identification of potential anti-cancer and age related mechanisms is of great interest and makes this species eminent to investigate anti-cancer strategies and understand aging mechanisms. Since it is known that the NMR expresses higher liver mRNA-levels of alpha 2-macroglobulin than mice, nothing is known about its structure, functionality or expression level in the NMR compared to the human A2M. Here we show a comprehensive analysis of NMR- and human plasma-A2M, showing a different prediction in glycosylation of NMR-A2M, which results in a higher molecular weight compared to human A2M. Additionally, we found a higher concentration of A2M (8.3±0.44 mg/mL vs. and 4.4±0.20 mg/mL) and a lower total plasma protein content (38.7±1.79 mg/mL vs. 61.7±3.20 mg/mL) in NMR compared to human. NMR-A2M can be transformed by methylamine and trypsin resulting in a conformational change similar to human A2M. NMR-A2M is detectable by a polyclonal antibody against human A2M. Determination of tryptic and anti-tryptic activity of NMR and human plasma revealed a higher anti-tryptic activity of the NMR plasma. On the other hand, less proteolytic activity was found in NMR plasma compared to human plasma. We found transformed NMR-A2M binding to its specific receptor LRP1. We could demonstrate lower protein expression of LRP1 in the NMR liver tissue compared to human but higher expression of A2M. This was accompanied by a higher EpCAM protein expression as central adhesion molecule in cancer progression. NMR-plasma was capable to increase the adhesion in human fibroblast in vitro most probably by increasing CD29 protein expression. This is the first report, demonstrating similarities as well as distinct differences between A2M in NMR and human plasma. This might be directly linked to the intriguing phenotype of the NMR and suggests that A2M might probably play an important role in anti-cancer and the anti

Analysis of Alpha-2 Macroglobulin from the Long-Lived and Cancer-Resistant Naked Mole-Rat and Human Plasma.

Directory of Open Access Journals (Sweden)

René Thieme

Full Text Available The naked mole-rat (NMR is a long-lived and cancer resistant species. Identification of potential anti-cancer and age related mechanisms is of great interest and makes this species eminent to investigate anti-cancer strategies and understand aging mechanisms. Since it is known that the NMR expresses higher liver mRNA-levels of alpha 2-macroglobulin than mice, nothing is known about its structure, functionality or expression level in the NMR compared to the human A2M.Here we show a comprehensive analysis of NMR- and human plasma-A2M, showing a different prediction in glycosylation of NMR-A2M, which results in a higher molecular weight compared to human A2M. Additionally, we found a higher concentration of A2M (8.3±0.44 mg/mL vs. and 4.4±0.20 mg/mL and a lower total plasma protein content (38.7±1.79 mg/mL vs. 61.7±3.20 mg/mL in NMR compared to human. NMR-A2M can be transformed by methylamine and trypsin resulting in a conformational change similar to human A2M. NMR-A2M is detectable by a polyclonal antibody against human A2M. Determination of tryptic and anti-tryptic activity of NMR and human plasma revealed a higher anti-tryptic activity of the NMR plasma. On the other hand, less proteolytic activity was found in NMR plasma compared to human plasma.We found transformed NMR-A2M binding to its specific receptor LRP1. We could demonstrate lower protein expression of LRP1 in the NMR liver tissue compared to human but higher expression of A2M. This was accompanied by a higher EpCAM protein expression as central adhesion molecule in cancer progression. NMR-plasma was capable to increase the adhesion in human fibroblast in vitro most probably by increasing CD29 protein expression. This is the first report, demonstrating similarities as well as distinct differences between A2M in NMR and human plasma. This might be directly linked to the intriguing phenotype of the NMR and suggests that A2M might probably play an important role in anti-cancer and the

1H NMR studies of substrate hydrogen exchange reactions catalyzed by L-methionine gamma-lyase

International Nuclear Information System (INIS)

Esaki, N.; Nakayama, T.; Sawada, S.; Tanaka, H.; Soda, K.

1985-01-01

Hydrogen exchange reactions of various L-amino acids catalyzed by L-methionine gamma-lyase (EC 4.4.1.11) have been studied. The enzyme catalyzes the rapid exchange of the alpha- and beta-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium from the solvent. The rate of alpha-hydrogen exchange was about 40 times faster than that of the enzymatic elimination reaction of the sulfur-containing amino acids. The enzyme also catalyzes the exchange reaction of alpha- and beta-hydrogens of the straight-chain L-amino acids which are not susceptible to elimination. The exchange rates of the alpha-hydrogen and the total beta-hydrogens of L-alanine and L-alpha-aminobutyrate with deuterium followed first-order kinetics. For L-norvaline, L-norleucine, S-methyl-L-cysteine, and L-methionine, the rate of alpha-hydrogen exchange followed first-order kinetics, but the rate of total beta-hydrogen exchange decreased due to a primary isotope effect at the alpha-position. L-Phenylalanine and L-tryptophan slowly underwent alpha-hydrogen exchange. The pro-R hydrogen of glycine was deuterated stereospecifically

Structural Biology: Practical NMR Applications

CERN Document Server

Teng, Quincy

2005-01-01

This textbook begins with an overview of NMR development and applications in biological systems. It describes recent developments in instrument hardware and methodology. Chapters highlight the scope and limitation of NMR methods. While detailed math and quantum mechanics dealing with NMR theory have been addressed in several well-known NMR volumes, chapter two of this volume illustrates the fundamental principles and concepts of NMR spectroscopy in a more descriptive manner. Topics such as instrument setup, data acquisition, and data processing using a variety of offline software are discussed. Chapters further discuss several routine stategies for preparing samples, especially for macromolecules and complexes. The target market for such a volume includes researchers in the field of biochemistry, chemistry, structural biology and biophysics.

NMR and domain wall mobility in intermetallic compounds

International Nuclear Information System (INIS)

Guimaraes, A.P.; Sampaio, L.C.; Cunha, S.F.; Alves, K.M.B.

1991-01-01

The technique of pulsed NMR can be used to study the distribution of hyperfine fields in a magnetic matrix. The dynamics of the domain walls are relevant to the generation of NMR signals. In the present study on the (R x Y 1-x ) Fe 2 intermetallic compounds, the reduction in the signals is associated to increased propagation fields. This indicates that a smaller domain wall mobility is at the origin of these effects. NMR spectra in this system show the importance of direct and indirect (i.e., mediated by Fe atoms) terms in the transferred hyperfine field. (author)

Study of transfer reactions ({alpha},t), ({alpha},{sup 3}He) in the f-p shell: mechanism and spectroscopic use; Etude des reactions de transfert ({alpha},t), ({alpha},{sup 3}He) dans la couche f-p mecanisme et utilisation spectroscopique

Energy Technology Data Exchange (ETDEWEB)

Roussel, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-05-01

We describe an experimental study of ({alpha},t), ({alpha},{sup 3}He) reactions at 44 MeV using a solid-state identifier, on the target-nuclei {sup 54}Fe and {sup 58,60,62,64}Ni. A critical study of optical model and of disturbed wave analysis has been performed. We show the complementarity of different transfer-reactions, the ambiguity of spectroscopic factors, the importance of the problem of the reaction mechanism. (author) [French] On decrit une etude experimentale des reactions ({alpha},t), ({alpha},{sup 3}He) a 44 MeV utilisant un systeme identificateur de particules sur les noyaux-cibles {sup 54}Fe et {sup 58,60,62,64}Ni. Une etude critique de modele optique et d'analyse en ondes deformees (D.W.B.A.) a ete entreprise. On montre la complementarite des differentes reactions de transfert, l'ambiguite des facteurs spectroscopiques, l'importance du probleme du mecanisme. (auteur)

TG/DTG, FT-ICR Mass Spectrometry, and NMR Spectroscopy Study of Heavy Fuel Oil

KAUST Repository

Elbaz, Ayman M.; Abdul Jameel, Abdul Gani; Hourani, Nadim; Emwas, Abdul-Hamid M.; Sarathy, Mani; Roberts, William L.

2015-01-01

infusion atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry (APCI-FTICR MS), high resolution 1H nuclear magnetic resonance (NMR), 13C NMR, and two-dimensional heteronuclear multiple bond correlation (HMBC

In vivo 7Li and 19F NMR studies of drugs in the brain

International Nuclear Information System (INIS)

Komoroski, Richard A.

1999-01-01

For various reasons, it is advantageous to measure the concentration of a psychoactive drug in the brain in vivo. Many drugs contain the element fluorine. Using 19 F NMR spectroscopy, we have studied the psychoactive drugs trifluoperazine and fluoxetine in the brain in vivo. Using 7 Li NMR, it is possible to detect lithium ion, used to treat manic depressive illness. We have measured the concentration and distribution of lithium in both human and rat brain in vivo. Measurement of drug levels in the human brain may provide a measure of therapeutic or toxic effects, as well as insight into drug metabolism and mechanism of action. (author)

NMR study of damage on isolated perfused rat heart exposed to ischemia and hypoxia

International Nuclear Information System (INIS)

Luo Xuechun; Yan Yongbin; Zhang Riqing; Fan Lili

2001-01-01

Myocardial ischemia is the most common and primary cause of myocardium damage. Numerous conventional techniques and methods have been developed for ischemia and reperfusion studies. However, because of damage to the heart sample, most of these techniques can not be used to continuously monitor the full dynamic course of the myocardial metabolic pathway. The nuclear magnetic resonance (NMR) surface coil technique, which overcomes the limitations of conventional instrumentation, can be used to quantitatively study every stage of the perfused heart (especially after perfusion stoppage) continuously, dynamically, and without damage under normal or designed physiological conditions at the molecular level. In this paper, 31 P-NMR was used to study the effects of ischemia and hypoxia on isolated perfused hearts. The results show that complete hypoxia caused more severe functional damage to the myocardial cells than complete ischemia

Protein folding kinetics by combined use of rapid mixing techniques and NMR observation of individual amide protons

International Nuclear Information System (INIS)

Roder, H.; Wuethrich, K.

1986-01-01

A method to be used for experimental studies of protein folding introduced by Schmid and Baldwin, which is based on the competition between amide hydrogen exchange and protein refolding, was extended by using rapid mixing techniques and 1 H NMR to provide site-resolved kinetic information on the early phases of protein structure acquisition. In this method, a protonated solution of the unfolded protein is rapidly mixed with a deuterated buffer solution at conditions assuring protein refolding in the mixture. This simultaneously initiates the exchange of unprotected amide protons with solvent deuterium and the refolding of protein segments which can protect amide groups from further exchange. After variable reaction times the amide proton exchange is quenched while folding to the native form continues to completion. By using 1 H NMR, the extent of exchange at individual amide sites is then measured in the refolded protein. Competition experiments at variable reaction times or variable pH indicate the time at which each amide group is protected in the refolding process. This technique was applied to the basic pancreatic trypsin inhibitor, for which sequence-specific assignments of the amide proton NMR lines had previously been obtained. For eight individual amide protons located in the beta-sheet and the C-terminal alpha-helix of this protein, apparent refolding rates in the range from 15 s-1 to 60 s-1 were observed. These rates are on the time scale of the fast folding phase observed with optical probes

Metabolic studies with NMR spectroscopy of the alga Dunaliella salina trapped within agarose beads.

Science.gov (United States)

Bental, M; Pick, U; Avron, M; Degani, H

1990-02-22

A technique for the entrapment of the unicellular algae Dunaliella salina in agarose beads and their perfusion during NMR measurements is presented. The trapped cells maintained their ability to proliferate under normal growth conditions, and remained viable and stable under steady-state conditions for long periods during NMR measurements. Following osmotic shock in the dark, prominent changes were observed in the intracellular level of ATP and polyphosphates, but little to no changes in the intracellular pH or orthoposphate content. When cells were subjected to hyperosmotic shock, the ATP level decreased. The content of NMR-visible polyphosphates decreased as well, presumably due to the production of longer, NMR-invisible structures. Following hypoosmotic shock, the ATP content increased and longer polyphosphates were broken down to shorter, more mobile polymers.

A 55Mn NMR study of the La0.75Sr0.25MnO3 nanoparticles

International Nuclear Information System (INIS)

Rybicki, D.; Sikora, M.; Kapusta, Cz.; Riedi, P.C.; Jirak, Z.; Knizek, K.; Marysko, M.; Pollert, E.; Veverka, P.

2006-01-01

We report on a 55 Mn NMR study of the La 0.75 Sr 0.25 MnO 3 nanoparticles of the average grain size 33 nm and 114 nm at 4.2 K and 77 K and at applied field of 0, 0.2 and 0.5T. A dominant signal from the double exchange (DE) controlled metallic ferromagnetic interior of the grains as well as a small signal from insulating ferromagnetic regions is observed. From a comparison with bulk magnetization measurement the thickness of the nonferromagnetic outer layer of the grains and the amount of the ferromagnetic insulating phase was determined. The relative amount of these phases with respect to the ferromagnetic metallic phase increases with decreasing grain size. The DE line in the NMR spectrum shows a frequency shift with applied field according to a full 55 Mn gyromagnetic ratio. A value of the demagnetizing field close to zero is obtained, which indicates a single domain state of the nanoparticles. For the sample with larger grains a higher NMR enhancement is observed, which indicates a higher magnetic susceptibility of the sample at the NMR frequencies. A comparison with the NMR data obtained on a microcrystalline material is made. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

NMR study of the 1-13C glucose colon bacterial metabolism

International Nuclear Information System (INIS)

Briet, F.; Flourie, B.; Pochart, P.; Rambaud, J.C.; Desjeux, J.F.; Dallery, L.; Grivet, J.P.

1994-01-01

The aim of the study is to examine in-vitro and by nuclear magnetic resonance the biological pathways for the fermentation of the 1- 13 C labelled glucose (99 atoms percent) by human colon bacteria. The preparation of the bacterial suspension and the glucose degradation kinetics are presented; the NMR analysis sensitivity and quantification features are discussed and results are presented. 2 figs., 1 ref

Intracellular pH and inorganic phosphate content of heart in vivo: A 31P-NMR study

International Nuclear Information System (INIS)

Katz, L.A.; Swain, J.A.; Portman, M.A.; Balaban, R.S.

1988-01-01

Studies were performed to determine the contribution of red blood cells to the 31 P-nuclear magnetic resonance (NMR) spectrum of the canine heart in vivo and the feasibility of measuring myocardial intracellular phosphate and pH. This was accomplished by replacing whole blood with a perfluorochemical perfusion emulsion blood substitute, Oxypherol, and noting the difference in the 31 P-NMR spectrum of the heart. NMR data were collected with a NMR transmitter-receiver coil on the surface of the distal portion of the left ventricle. These studies demonstrated that a small contribution from 2,3-diphosphoglycerate (2,3-DPG) and phosphodiesters in the blood could be detected. The magnitude and shift of these blood-borne signals permitted the relative quantification of intracellular inorganic phosphate (P i ) content as well as intracellular pH. Under resting conditions, the intracellular ATP/P i was 7.0 ± 0.08. This corresponds to a free intracellular P 1 content of ∼ 0.8 μmol./g wet wt. The intracellular pH was 7.10 ± 0.01. Acute respiratory alkalosis and acidosis, with the arterial pH ranging from ∼7.0 to 7.7, resulted in only small changes in the intracellular pH. These latter results demonstrate an effective myocardial intracellular proton-buffering mechanism in vivo

An in-cell NMR study of monitoring stress-induced increase of cytosolic Ca{sup 2+} concentration in HeLa cells

Energy Technology Data Exchange (ETDEWEB)

Hembram, Dambarudhar Shiba Sankar; Haremaki, Takahiro; Hamatsu, Jumpei; Inoue, Jin; Kamoshida, Hajime; Ikeya, Teppei; Mishima, Masaki [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0373 (Japan); Mikawa, Tsutomu [Cellular and Molecular Biology Unit, RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198 (Japan); Hayashi, Nobuhiro [Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B-1, Nagatsuda-chou, Midori-ku, Yokohama, Kanagawa 226-8501 (Japan); Shirakawa, Masahiro [Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Ito, Yutaka, E-mail: ito-yutaka@tmu.ac.jp [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0373 (Japan)

2013-09-06

Highlights: •We performed time-resolved NMR observations of calbindin D{sub 9k} in HeLa cells. •Stress-induced increase of cytosolic Ca{sup 2+} concentration was observed by in-cell NMR. •Calbindin D{sub 9k} showed the state-transition from Mg{sup 2+}- to Ca{sup 2+}-bound state in cells. •We provide a useful tool for in situ monitoring of the healthiness of the cells. -- Abstract: Recent developments in in-cell NMR techniques have allowed us to study proteins in detail inside living eukaryotic cells. The lifetime of in-cell NMR samples is however much shorter than that in culture media, presumably because of various stresses as well as the nutrient depletion in the anaerobic environment within the NMR tube. It is well known that Ca{sup 2+}-bursts occur in HeLa cells under various stresses, hence the cytosolic Ca{sup 2+} concentration can be regarded as a good indicator of the healthiness of cells in NMR tubes. In this study, aiming at monitoring the states of proteins resulting from the change of cytosolic Ca{sup 2+} concentration during experiments, human calbindin D{sub 9k} (P47M + C80) was used as the model protein and cultured HeLa cells as host cells. Time-resolved measurements of 2D {sup 1}H–{sup 15}N SOFAST–HMQC experiments of calbindin D{sub 9k} (P47M + C80) in HeLa cells showed time-dependent changes in the cross-peak patterns in the spectra. Comparison with in vitro assignments revealed that calbindin D{sub 9k} (P47M + C80) is initially in the Mg{sup 2+}-bound state, and then gradually converted to the Ca{sup 2+}-bound state. This conversion process initiates after NMR sample preparation. These results showed, for the first time, that cells inside the NMR tube were stressed, presumably because of cell precipitation, the lack of oxygen and nutrients, etc., thereby releasing Ca{sup 2+} into cytosol during the measurements. The results demonstrated that in-cell NMR can monitor the state transitions of stimulated cells through the observation of

Investigation of zeolites by solid state quadrapole NMR

International Nuclear Information System (INIS)

Janssen, R.

1990-01-01

The subject of this thesis is the NMR investigation of zeolites. The nature and properties of zeolites are discussed. Some of the basic priniples of NMR techniques on quadrupole nuclei are presented. A special technique, namely a two-dimensional nutation experiment is discussed in detail. The theory of the nutation experiment for quadrupole spin species with spin quantum number 3/2 as well as 5/2 is presented. For both spin spcies the theoretical spectra are compared with experimental results. It is also shown that the nutation expeirment can be performed with several pulse schemes. It is shown how phase-sensitive pure-absorption nutation spectra can be obtained and an NMR-probe is presented that is capable of performing NMR experiments at high (up to 500 degree C) temperatures. The two-dimensional nutation NMR technique has been applied to sodium cations in zeolite NaA. For this purpose a numbre of zeolite samples were prepared that contained different amounts of water. With the aid of nutation NMR the hydration of the zeolite can be studied and conclusions can be drawn about the symmetry of the surrounding of the sodium cations. With the aid of an extension of the nutation NMR experiment: Rotary Echo Nutation NMR, it is shown that in zeolite NaA, in various stages of hydration, the sodium cations or water molecules are mobile. Proof is given by means of high-temperature 23 Na-NMR that dehydrates zeolite NaA undergoes a phase transition at ca. 120 degree C. In a high-temperature NMR investigation of zeolite ZSM-5 it is shown that the sodium ions start to execute motions when the temperature is increased. (author). 198 refs.; 72 figs.; 6 tabs

Frontal Alpha Oscillations and Attentional Control: A Virtual Reality Neurofeedback Study.

Science.gov (United States)

Berger, Anna M; Davelaar, Eddy J

2018-05-15

Two competing views about alpha oscillations suggest that cortical alpha reflect either cortical inactivity or cortical processing efficiency. We investigated the role of alpha oscillations in attentional control, as measured with a Stroop task. We used neurofeedback to train 22 participants to increase their level of alpha amplitude. Based on the conflict/control loop theory, we selected to train prefrontal alpha and focus on the Gratton effect as an index of deployment of attentional control. We expected an increase or a decrease in the Gratton effect with increase in neural learning depending on whether frontal alpha oscillations reflect cortical idling or enhanced processing efficiency, respectively. In order to induce variability in neural learning beyond natural occurring individual differences, we provided half of the participants with feedback on alpha amplitude in a 3-dimensional (3D) virtual reality environment and the other half received feedback in a 2D environment. Our results showed variable neural learning rates, with larger rates in the 3D compared to the 2D group, corroborating prior evidence of individual differences in EEG-based learning and the influence of a virtual environment. Regression analyses revealed a significant association between the learning rate and changes on deployment of attentional control, with larger learning rates being associated with larger decreases in the Gratton effect. This association was not modulated by feedback medium. The study supports the view of frontal alpha oscillations being associated with efficient neurocognitive processing and demonstrates the utility of neurofeedback training in addressing theoretical questions in the non-neurofeedback literature. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Study of acute biochemical effects of thallium toxicity in mouse urine by NMR spectroscopy.

Science.gov (United States)

Tyagi, Ritu; Rana, Poonam; Khan, Ahmad Raza; Bhatnagar, Deepak; Devi, M Memita; Chaturvedi, Shubhra; Tripathi, Rajendra P; Khushu, Subash

2011-10-01

Thallium (Tl) is a toxic heavy metal and its exposure to the human body causes physiological and biochemical changes due to its interference with potassium-dependent biological reactions. A high-resolution (1)H NMR spectroscopy based metabonomic approach has been applied for investigating acute biochemical effects caused by thallium sulfate (Tl(2)SO(4)). Male strain A mice were divided in three groups and received three doses of Tl(2)SO(4) (5, 10 and 20 mg kg(-1) b.w., i.p.). Urine samples collected at 3, 24, 72 and 96 h post-dose time points were analyzed by (1)H NMR spectroscopy. NMR spectral data were processed and analyzed using principal components analysis to represent biochemical variations induced by Tl(2)SO(4). Results showed Tl-exposed mice urine to have distinct metabonomic phenotypes and revealed dose- and time-dependent clustering of treated groups. The metabolic signature of urine analysis from Tl(2)SO(4)-treated animals exhibited an increase in the levels of creatinine, taurine, hippurate and β-hydroxybutyrate along with a decrease in energy metabolites trimethylamine and choline. These findings revealed Tl-induced disturbed gut flora, membrane metabolite, energy and protein metabolism, representing physiological dysfunction of vital organs. The present study indicates the great potential of NMR-based metabonomics in mapping metabolic response for toxicology, which could ultimately lead to identification of potential markers for Tl toxicity. Copyright © 2011 John Wiley & Sons, Ltd.

Natural abundant solid state NMR studies in designed tripeptides for differentiation of multiple conformers.

Science.gov (United States)

Jayanthi, S; Chatterjee, Bhaswati; Raghothama, S

2009-10-01

Solid state NMR (SSNMR) experiments on heteronuclei in natural abundance are described for three synthetically designed tripeptides Piv-(L)Pro-(L)Pro-(L)Phe-OMe (1), Piv-(D)Pro-(L)Pro-(L)Phe-OMe (2), and Piv-(D)Pro-(L)Pro-(L)Phe-NHMe (3). These peptides exist in different conformation as shown by solution state NMR and single crystal X-ray analysis (Chatterjee et al., Chem Eur J 2008, 14, 6192). In this study, SSNMR has been used to probe the conformations of these peptides in their powder form. The (13)C spectrum of peptide (1) showed doubling of resonances corresponding to cis/cis form, unlike in solution where the similar doubling is attributed to cis/trans form. This has been confirmed by the chemical shift differences of C(beta) and C(gamma) carbon of Proline in peptide (1) both in solution and SSNMR. Peptide (2) and (3) provided single set of resonances which represented all trans form across the di-Proline segment. The results are in agreement with the X-ray analysis. Solid state (15)N resonances, especially from Proline residues provided additional information, which is normally not observable in solution state NMR. (1)H chemical shifts are also obtained from a two-dimensional heteronuclear correlation experiment between (1)H--(13)C. The results confirm the utility of NMR as a useful tool for identifying different conformers in peptides in the solid state. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 851-860, 2009.

MAS NMR of HIV-1 protein assemblies

Science.gov (United States)

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

2015-04-01

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

NMR study of CeTe at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Hinderer, J. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland)]. E-mail: hinderer@phys.ethz.ch; Weyeneth, S.M. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Weller, M. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Gavilano, J.L. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Felder, E. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Hulliger, F. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland); Ott, H.R. [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zurich (Switzerland)

2006-05-01

We present {sup 125}Te NMR measurements on CeTe powder at temperatures between 1 and 150K and in magnetic fields between 5 and 8T. CeTe is a rocksalt-type intermetallic compound. It orders antiferromagnetically at T{sub N}{approx}2.2K with a much reduced ordered moment [H.R. Ott, J.K. Kjems, F. Hulliger, Phys. Rev. Lett. 42 20 (1979) 1378]. From our low-temperature NMR spectra we infer the presence of at least three inequivalent Te sites at low temperatures. Considering the crystal structure this result is completely unexpected. The linewidths and the Knight shifts of the individual lines are significantly different and increase substantially with decreasing temperature. They follow the temperature dependence of the magnetic susceptibility above 20K. Above T{sub N}, hyperfine fields of 1.6, 0.8 and 0.0T at the three Te sites per Bohr magneton of Ce moment are deduced from Knight shift vs. magnetic susceptibility data. These values are typical for transferred hyperfine fields via conduction electrons.

An improved ultrafast 2D NMR experiment: Towards atom-resolved real-time studies of protein kinetics at multi-Hz rates

International Nuclear Information System (INIS)

Gal, Maayan; Kern, Thomas; Schanda, Paul; Frydman, Lucio; Brutscher, Bernhard

2009-01-01

Multidimensional NMR spectroscopy is a well-established technique for the characterization of structure and fast-time-scale dynamics of highly populated ground states of biological macromolecules. The investigation of short-lived excited states that are important for molecular folding, misfolding and function, however, remains a challenge for modern biomolecular NMR techniques. Off-equilibrium real-time kinetic NMR methods allow direct observation of conformational or chemical changes by following peak positions and intensities in a series of spectra recorded during a kinetic event. Because standard multidimensional NMR methods required to yield sufficient atom-resolution are intrinsically time-consuming, many interesting phenomena are excluded from real-time NMR analysis. Recently, spatially encoded ultrafast 2D NMR techniques have been proposed that allow one to acquire a 2D NMR experiment within a single transient. In addition, when combined with the SOFAST technique, such ultrafast experiments can be repeated at high rates. One of the problems detected for such ultrafast protein NMR experiments is related to the heteronuclear decoupling during detection with interferences between the pulses and the oscillatory magnetic field gradients arising in this scheme. Here we present a method for improved ultrafast data acquisition yielding higher signal to noise and sharper lines in single-scan 2D NMR spectra. In combination with a fast-mixing device, the recording of 1 H- 15 N correlation spectra with repetition rates of up to a few Hertz becomes feasible, enabling real-time studies of protein kinetics occurring on time scales down to a few seconds

Nuclear Magnetic Resonance (NMR Study for the Detection and Quantitation of Cholesterol in HSV529 Therapeutic Vaccine Candidate

Directory of Open Access Journals (Sweden)

Rahima Khatun

Full Text Available This study describes the NMR-based method to determine the limit of quantitation (LOQ and limit of detection (LOD of cholesterol, a process-related impurity in the replication-deficient Herpes Simplex Virus (HSV type 2 candidate vaccine HSV529. Three signature peaks from the 1D 1H NMR of a cholesterol reference spectrum were selected for the identification of cholesterol. The LOQ for a cholesterol working standard was found to be 1 μg/mL, and the LOD was found to be 0.1 μg/mL. The identity of cholesterol, separated from the formulation of growth supplement by thin layer chromatography (TLC, was confirmed by 1D 1H NMR and 2D 1H-13C HSQC NMR. The three signature peaks of cholesterol were detected only in a six-times concentrated sample of HSV529 candidate vaccine sample and not in the single dose HSV529 vaccine sample under similar experimental conditions. Taken together, the results demonstrated that NMR is a direct method that can successfully identify and quantify cholesterol in viral vaccine samples, such as HSV529, and as well as in the growth supplement used during the upstream stages of HSV529 manufacturing. Keywords: Herpes simplex virus type 2 (HSV-2, Viral vaccine, NMR, Residuals, LOD and LOQ, TLC, Growth supplement

Muscular pathology: echographic and NMR imaging aspects

International Nuclear Information System (INIS)

Pascal-Suisse, P.; Beaurain, P.; Mougniot, C.

1995-01-01

A comparison of echographic techniques and NMR imaging has been done for the diagnosis of muscular trauma and tumor pathologies. In traumatic pathology, the echographic analysis allows to determine the complete assessment of recent muscular injuries. NMR imaging can be used in granuloma or fibrous callosity appreciation and for the analysis of deep injury (muscles and muscles-tendon junctions) and of muscular aponeurosis. Echography must be used together with color coding Doppler technique in the diagnosis of tumor pathology and for the study of slow fluxes. The recently available energy Doppler technique seems to be powerful in the study of vascularization of small expansive formations, but their extension to adjacent bone or tissue can only be appreciated using NMR imaging. (J.S.)

1H NMR studies of human lysozyme: Spectral assignment and comparison with hen lysozyme

International Nuclear Information System (INIS)

Redfield, C.; Dobson, C.M.

1990-01-01

Complete main-chain (NH and αCH) 1 H NMR assignments are reported for the 130 residues of human lysozyme, along with extensive assignments for side-chain protons. Analysis of 2-D NOESY experiments shows that the regions of secondary structure for human lysozyme in solution are essentially identical with those found previously in a similar study of hen lysozyme and are in close accord with the structure of the protein reported previously from x-ray diffraction studies in the crystalline state. Comparison of the chemical shifts, spin-spin coupling constants, and hydrogen exchange behavior are also consistent with closely similar structures for the two proteins in solution. In a number of cases specific differences in the NMR parameters between hen and human lysozymes can be correlated with specific differences observed in the crystal structures

Structure determination of a peptide model of the repeated helical domain in Samia cynthia ricini silk fibroin before spinning by a combination of advanced solid-state NMR methods.

Science.gov (United States)

Nakazawa, Yasumoto; Asakura, Tetsuo

2003-06-18

Fibrous proteins unlike globular proteins, contain repetitive amino acid sequences, giving rise to very regular secondary protein structures. Silk fibroin from a wild silkworm, Samia cynthia ricini, consists of about 100 repeats of alternating polyalanine (poly-Ala) regions of 12-13 residues in length and Gly-rich regions. In this paper, the precise structure of the model peptide, GGAGGGYGGDGG(A)(12)GGAGDGYGAG, which is a typical repeated sequence of the silk fibroin, was determined using a combination of three kinds of solid-state NMR studies; a quantitative use of (13)C CP/MAS NMR chemical shift with conformation-dependent (13)C chemical shift contour plots, 2D spin diffusion (13)C solid-state NMR under off magic angle spinning and rotational echo double resonance. The structure of the model peptide corresponding to the silk fibroin structure before spinning was determined. The torsion angles of the central Ala residue, Ala(19), in the poly-Ala region were determined to be (phi, psi) = (-59 degrees, -48 degrees ) which are values typically associated with alpha-helical structures. However, the torsion angles of the Gly(25) residue adjacent to the C-terminal side of the poly-Ala chain were determined to be (phi, psi) = (-66 degrees, -22 degrees ) and those of Gly(12) and Ala(13) residues at the N-terminal of the poly-Ala chain to be (phi, psi) = (-70 degrees, -30 degrees ). In addition, REDOR experiments indicate that the torsion angles of the two C-terminal Ala residues, Ala(23) and Ala(24), are (phi, psi) = (-66 degrees, -22 degrees ) and those of N-terminal two Ala residues, Ala(13) and Ala(14) are (phi, psi) = (-70 degrees, -30 degrees ). Thus, the local structure of N-terminal and C-terminal residues, and also the neighboring residues of alpha-helical poly-Ala chain in the model peptide is a more strongly wound structure than found in typical alpha-helix structures.

Structure and Dynamics Studies of Cytolytic Peptides in Lipid Bilayers using NMR Spectroscopy

DEFF Research Database (Denmark)

Hansen, Sara Krogh

2015-01-01

different and cytolytic peptides were investigated in this work. The peptides were SPF-5506-A4 from Trichoderma sp, Conolysin-Mt1 from Conus mustelinus, and Alamethicin from Trichoderma viride. The studies employed solution and solid-state NMR spectroscopy in combination with different biophysical methods...

NMR Studies of Protein Hydration and Protein-Ligand Interactions

Science.gov (United States)

Chong, Yuan

Water on the surface of a protein is called hydration water. Hydration water is known to play a crucial role in a variety of biological processes including protein folding, enzymatic activation, and drug binding. Although the significance of hydration water has been recognized, the underlying mechanism remains far from being understood. This dissertation employs a unique in-situ nuclear magnetic resonance (NMR) technique to study the mechanism of protein hydration and the role of hydration in alcohol-protein interactions. Water isotherms in proteins are measured at different temperatures via the in-situ NMR technique. Water is found to interact differently with hydrophilic and hydrophobic groups on the protein. Water adsorption on hydrophilic groups is hardly affected by the temperature, while water adsorption on hydrophobic groups strongly depends on the temperature around 10 C, below which the adsorption is substantially reduced. This effect is induced by the dramatic decrease in the protein flexibility below 10 C. Furthermore, nanosecond to microsecond protein dynamics and the free energy, enthalpy, and entropy of protein hydration are studied as a function of hydration level and temperature. A crossover at 10 C in protein dynamics and thermodynamics is revealed. The effect of water at hydrophilic groups on protein dynamics and thermodynamics shows little temperature dependence, whereas water at hydrophobic groups has stronger effect above 10 C. In addition, I investigate the role of water in alcohol binding to the protein using the in-situ NMR detection. The isotherms of alcohols are first measured on dry proteins, then on proteins with a series of controlled hydration levels. The free energy, enthalpy, and entropy of alcohol binding are also determined. Two distinct types of alcohol binding are identified. On the one hand, alcohols can directly bind to a few specific sites on the protein. This type of binding is independent of temperature and can be

Development of 19F-NMR chemical shift detection of DNA B-Z equilibrium using 19F-NMR.

Science.gov (United States)

Nakamura, S; Yang, H; Hirata, C; Kersaudy, F; Fujimoto, K

2017-06-28

Various DNA conformational changes are in correlation with biological events. In particular, DNA B-Z equilibrium showed a high correlation with translation and transcription. In this study, we developed a DNA probe containing 5-trifluoromethylcytidine or 5-trifluoromethylthymidine to detect DNA B-Z equilibrium using 19 F-NMR. Its probe enabled the quantitative detection of B-, Z-, and ss-DNA based on 19 F-NMR chemical shift change.

Chemical behavior of methylpyranomalvidin-3-O-glucoside in aqueous solution studied by NMR and UV-visible spectroscopy.

Science.gov (United States)

Oliveira, Joana; Petrov, Vesselin; Parola, A Jorge; Pina, Fernando; Azevedo, Joana; Teixeira, Natércia; Brás, Natércia F; Fernandes, Pedro A; Mateus, Nuno; Ramos, Maria João; de Freitas, Victor

2011-02-17

In the present work, the proton-transfer reactions of the methylpyranomalvidin-3-O-glucoside pigment in water with different pH values was studied by NMR and UV-visible spectroscopies. The results showed four equilibrium forms: the methylpyranomalvidin-3-O-glucoside cation, the neutral quinoidal base, the respective anionic quinoidal base, and a dianionic base unprotonated at the methyl group. According to the NMR data, it seems that for methylpyranomalvidin-3-O-glucoside besides the acid-base equilibrium between the pyranoflavylium cation and the neutral quinoidal base, a new species is formed at pD 4.88-6.10. This is corroborated by the appearance of a new set of signals in the NMR spectrum that may be assigned to the formation of hemiketal/cis-chalcone species to a small extent. The two ionization constants (pK(a1) and pK(a2)) obtained by both methods (NMR and UV-visible) for methylpyranomalvidin-3-O-glucoside are in agreement (pK(a1) = 5.17 ± 0.03; pK(a2) = 8.85 ± 0.08; and pK(a1) = 4.57 ± 0.07; pK(a2) = 8.23 ± 0.04 obtained by NMR and UV-visible spectroscopies, respectively). Moreover, the fully dianionic unprotonated form (at the methyl group) of the methylpyranomalvidin-3-O-glucoside is converted slowly into a new structure that displays a yellow color at basic pH. On the basis of the results obtained through LC-MS and NMR, the proposed structure was found to correspond to the flavonol syringetin-3-glucoside.

Magic Angle Spinning NMR Metabolomics

Energy Technology Data Exchange (ETDEWEB)

Zhi Hu, Jian

2016-01-01

Nuclear Magnetic Resonance (NMR) spectroscopy is a non-destructive, quantitative, reproducible, untargeted and unbiased method that requires no or minimal sample preparation, and is one of the leading analytical tools for metabonomics research [1-3]. The easy quantification and the no need of prior knowledge about compounds present in a sample associated with NMR are advantageous over other techniques [1,4]. 1H NMR is especially attractive because protons are present in virtually all metabolites and its NMR sensitivity is high, enabling the simultaneous identification and monitoring of a wide range of low molecular weight metabolites.

NMR Phase Noise in Bitter Magnets

Science.gov (United States)

Sigmund, E. E.; Calder, E. S.; Thomas, G. W.; Mitrović, V. F.; Bachman, H. N.; Halperin, W. P.; Kuhns, P. L.; Reyes, A. P.

2001-02-01

We have studied the temporal instability of a high field resistive Bitter magnet through nuclear magnetic resonance (NMR). This instability leads to transverse spin decoherence in repeated and accumulated NMR experiments as is normally performed during signal averaging. We demonstrate this effect via Hahn echo and Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation experiments in a 23-T resistive magnet. Quantitative analysis was found to be consistent with separate measurements of the magnetic field frequency fluctuation spectrum, as well as with independent NMR experiments performed in a magnetic field with a controlled instability. Finally, the CPMG sequence with short pulse delays is shown to be successful in recovering the intrinsic spin-spin relaxation even in the presence of magnetic field temporal instability.

A study of excess H-alpha emission in chromospherically active M dwarf

International Nuclear Information System (INIS)

Young, A.; Skumanich, A.; Stauffer, J.R.; Harlan, E.; Bopp, B.W.

1989-01-01

Spectroscopic observations from three observatories are combined to study the properties of the excess H-alpha emission which characterizes the most chromospherically active subset of the M dwarf stars, known as the dMe stars. It is demonstrated that the excess H-alpha luminosity from these stars is a monotonically decreasing function of their (R-I) color, and evidence is presented which suggests that the product of the mean surface brightness and the mean filling factor of the emissive regions is essentially constant with color. Another significant result of the study is a linear correlation between the excess luminosity in H-alpha and the coronal X-ray luminosity. 39 refs

Comparing pharmacophore models derived from crystallography and NMR ensembles

Science.gov (United States)

Ghanakota, Phani; Carlson, Heather A.

2017-11-01

NMR and X-ray crystallography are the two most widely used methods for determining protein structures. Our previous study examining NMR versus X-Ray sources of protein conformations showed improved performance with NMR structures when used in our Multiple Protein Structures (MPS) method for receptor-based pharmacophores (Damm, Carlson, J Am Chem Soc 129:8225-8235, 2007). However, that work was based on a single test case, HIV-1 protease, because of the rich data available for that system. New data for more systems are available now, which calls for further examination of the effect of different sources of protein conformations. The MPS technique was applied to Growth factor receptor bound protein 2 (Grb2), Src SH2 homology domain (Src-SH2), FK506-binding protein 1A (FKBP12), and Peroxisome proliferator-activated receptor-γ (PPAR-γ). Pharmacophore models from both crystal and NMR ensembles were able to discriminate between high-affinity, low-affinity, and decoy molecules. As we found in our original study, NMR models showed optimal performance when all elements were used. The crystal models had more pharmacophore elements compared to their NMR counterparts. The crystal-based models exhibited optimum performance only when pharmacophore elements were dropped. This supports our assertion that the higher flexibility in NMR ensembles helps focus the models on the most essential interactions with the protein. Our studies suggest that the "extra" pharmacophore elements seen at the periphery in X-ray models arise as a result of decreased protein flexibility and make very little contribution to model performance.

Solid state NMR of materials

Energy Technology Data Exchange (ETDEWEB)

Taylor, Sharon A; Ferguson, David B; Haw, James F [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry

1994-12-31

In situ NMR experiments are studied, including probe of several structures such as the structures of the organic adsorbates, Broensted acid sites, other nuclei associated with active sites, and other framework sites. The authors report that in the absence of high concentrations of paramagnetic sites or metal particles, high resolution MAS spectra are relatively easy to obtain and interpret. It is also concluded that NMR can measure spatial distributions and rates of diffusion; and are able to characterize equilibrium structures and the frequencies and amplitudes of molecular motion

A 55Mn NMR Study of the La0.75Sr0.25MnO3 Nanoparticles

International Nuclear Information System (INIS)

Kapusta, Cz.; Rybicki, D.; Sikora, M.

2005-01-01

We report on a 55 Mn NMR study of the La 0.75 Sr 0.25 MnO 3 nanoparticles with the average grain size of 33 nm and 114 nm at 4.2 K and at the applied field 0, 0.2 and 0.5 T. A dominant signal from the double exchange (DE) controlled metallic ferromagnetic interior of the grains as well as a small signal from insulating ferromagnetic surface regions of the grains are observed. The DE resonant line shows a frequency shift in the applied field according to a full gyromagnetic ratio and a value of the demagnetizing field much smaller than 0.2 T is obtained. In both samples studied a two-exponential nuclear spin-spin (T 2 ) relaxation is observed at zero field, whereas a single-exponential relaxation is observed at the applied field of 0.5 T. For the sample with larger grains a higher NMR enhancement is observed, which indicates a higher magnetic susceptibility of the sample at the NMR frequencies. A comparison to the NMR data obtained on a bulk material is made. The results are discussed in terms of the influence of the grain size and on the presence of domain walls or other magnetic inhomogeneities and on the magnetic anisotropy

Composition of the volatile fraction of Ocotea bofo Kunth (Lauraceae) calyces by GC-MS and NMR fingerprinting and its antimicrobial and antioxidant activity.

Science.gov (United States)

Guerrini, Alessandra; Sacchetti, Gianni; Muzzoli, Mariavittoria; Moreno Rueda, Gabriela; Medici, Alessandro; Besco, Elena; Bruni, Renato

2006-10-04

The chemical composition of the essential oil obtained by steam distillation of the floral calyces of Ocotea bofo Kunth (Lauraceae) was studied by means of GC, GC-MS, and 1H, 13C, and bidimensional NMR (COSY, HSQC, HMBC). Twenty-five constituents were identified, and estragole (48.7%), alpha-phellandrene (19.6%) and sabinene (10.4%) were found to be the major components. Antimicrobial activity against six aerobic bacteria and five yeasts and antioxidant activity performed by photochemiluminescence (PCL), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and beta-carotene bleaching assays are reported. The oil showed fair inhibiting properties against bacteria and a good inhibition against most yeasts. Its radical scavenging and chain-breaking antioxidant properties were comparable to or better than those provided by synthetic controls. Particular emphasis has been given to the use of NMR as a fast and reliable tool to discriminate O. bofo essential oil from other commercial anethole- and estragole-rich oils, namely, Illicium verum, Foeniculum vulgare, and Artemisia dracunculus.

Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal 2-aminobenzoates

Science.gov (United States)

Samsonowicz, M.; Świsłocka, R.; Regulska, E.; Lewandowski, W.

2008-09-01

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons ( 1H NMR) and carbons ( 13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G ∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds.

MRI and unilateral NMR study of reindeer skin tanning processes.

Science.gov (United States)

Zhu, Lizheng; Del Federico, Eleonora; Ilott, Andrew J; Klokkernes, Torunn; Kehlet, Cindie; Jerschow, Alexej

2015-04-07

The study of arctic or subarctic indigenous skin clothing material, known for its design and ability to keep the body warm, provides information about the tanning materials and techniques. The study also provides clues about the culture that created it, since tanning processes are often specific to certain indigenous groups. Untreated skin samples and samples treated with willow (Salix sp) bark extract and cod liver oil are compared in this study using both MRI and unilateral NMR techniques. The two types of samples show different proton spatial distributions and different relaxation times, which may also provide information about the tanning technique and aging behavior.

Murine alpha1-adrenoceptor subtypes. I. Radioligand binding studies

NARCIS (Netherlands)

Yang, M.; Reese, J.; Cotecchia, S.; Michel, M. C.

1998-01-01

Alpha1-adrenoceptors were identified in murine tissues by [3H]prazosin saturation binding studies, with a rank order of cerebral cortex > cerebellum > liver > lung > kidney > heart > spleen, with the spleen not exhibiting detectable expression. Competition binding studies were performed with

[Studies on the flavonoids from Dendranthema lavandulifolium].

Science.gov (United States)

Shen, Y X; Quan, L H; Guan, L; Chen, J M

1997-06-01

From the whole plant of Dendranthema lavandulifolium, two flavonoides (I, II) and two flavone glycosides (III, IV) were isolated. They were identified as luteolin (I), apigenin (II), 5-hydroxy-4'-methoxy-flavone-7-O-alpha-L-rhamnopyranosyl(1-->6)-beta- D-glucopyranosyl (acaciin III) and 5-hydroxy-4'-methoxy-flavone-7-O-alpha-L-rhamnopyranosyl (1-->6) [2-O-acetyl-beta-D-glucopyranosyl(1-->2)]-beta-D-glucopyranoside (IV) by means of IR, UV, 1H-NMR, 13C-NMR, EI-MS, HRFAB, etc. Among these four compounds, I, II were isolated for the first time from this plant, IV is a new compound.

NMR investigations of molecular dynamics

Science.gov (United States)

Palmer, Arthur

2011-03-01

NMR spectroscopy is a powerful experimental approach for characterizing protein conformational dynamics on multiple time scales. The insights obtained from NMR studies are complemented and by molecular dynamics (MD) simulations, which provide full atomistic details of protein dynamics. Homologous mesophilic (E. coli) and thermophilic (T. thermophilus) ribonuclease H (RNase H) enzymes serve to illustrate how changes in protein sequence and structure that affect conformational dynamic processes can be monitored and characterized by joint analysis of NMR spectroscopy and MD simulations. A Gly residue inserted within a putative hinge between helices B and C is conserved among thermophilic RNases H, but absent in mesophilic RNases H. Experimental spin relaxation measurements show that the dynamic properties of T. thermophilus RNase H are recapitulated in E. coli RNase H by insertion of a Gly residue between helices B and C. Additional specific intramolecular interactions that modulate backbone and sidechain dynamical properties of the Gly-rich loop and of the conserved Trp residue flanking the Gly insertion site have been identified using MD simulations and subsequently confirmed by NMR spin relaxation measurements. These results emphasize the importance of hydrogen bonds and local steric interactions in restricting conformational fluctuations, and the absence of such interactions in allowing conformational adaptation to substrate binding.

NMR study of thermoresponsive block copolymer in aqueous solution

Czech Academy of Sciences Publication Activity Database

Spěváček, Jiří; Konefal, Rafal; Čadová, Eva

2016-01-01

Roč. 217, č. 12 (2016), s. 1370-1375 ISSN 1022-1352 R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:61389013 Keywords : aqueous solutions * NMR * NOESY Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.500, year: 2016

C-13 NMR spectroscopy of plasma reduces interference of hypertriglyceridemia in the H-1 NMR detection of malignancy

International Nuclear Information System (INIS)

Fossell, E.T.; Hall, F.M.; McDonagh, J.

1991-01-01

The authors have previously described the application of water-suppressed proton nuclear magnetic resonance (H-1 NMR) spectroscopy of plasma for detection of malignancy. Subsequently, hypertriglyceridemia has been identified as a source of false positive results. Here is described a confirmatory, adjunctive technique -analysis of the carbon-13 (C-13) NMR spectrum of plasma- which also identifies the presence of malignancy but is not sensitive to the plasma triglyceride level. Blinded plasma samples from 480 normal donors and 208 patients scheduled for breast biopsy were analyzed by water-suppressed H-1 and C-13 NMR spectroscopy. Triglyceride levels were also measured. Among the normal donors, there were 38 individuals with hypertriglyceridemia of whom 18 had results consistent with malignancy by H-1 NMR spectroscopy. However, the C-13 technique reduced the apparent H-1 false positive rate from 7.0 to 0.6 percent. Similarly, in the breast biopsy cohort, C-13 reduced the false positive rate from 2.8 to 0.9 percent. Furthermore, the accuracy of the combined H-1/C-13 test in this blinded study was greater than 96 percent in 208 patients studied. (author). 27 refs.; 5 figs.; 4 tabs

EEG-fMRI Study of Alpha-Stimulation Neurobiofeedback Training Course.

Science.gov (United States)

Kozlova, L I; Shtark, M B; Mel'nikov, M E; Verevkin, E G; Savelov, A A; Petrovskii, E D

2016-09-01

fMRI-EEG dynamics of brain activity in volunteers was studied during the course of EEG alpha-stimulation training (20 sessions). Twenty-three healthy men (20-35 years) were subjected to 3-fold mapping in a feedback loop (EEG alpha-rhythm biofeedback with acoustic reinforcement). This procedure was performed at the beginning, middle, and end of the course. During the first neurofeedback training session, deactivation (pBrodmann area 39, and cerebellum. Activation (pareas of both hemispheres, and Brodmann area 32. During final (third) neurofeedback training session, we observed strong deactivation (pBrodmann areas 6, 9, 7, 31, 8, 13, and 22). Changes in the alpha wave power were most pronounced in the primary and secondary somatosensory cortex of the left hemisphere (Brodmann areas 2L and 5L).

Selected topics in solution-phase biomolecular NMR spectroscopy

Science.gov (United States)

Kay, Lewis E.; Frydman, Lucio

2017-05-01

Solution bio-NMR spectroscopy continues to enjoy a preeminent role as an important tool in elucidating the structure and dynamics of a range of important biomolecules and in relating these to function. Equally impressive is how NMR continues to 'reinvent' itself through the efforts of many brilliant practitioners who ask increasingly demanding and increasingly biologically relevant questions. The ability to manipulate spin Hamiltonians - almost at will - to dissect the information of interest contributes to the success of the endeavor and ensures that the NMR technology will be well poised to contribute to as yet unknown frontiers in the future. As a tribute to the versatility of solution NMR in biomolecular studies and to the continued rapid advances in the field we present a Virtual Special Issue (VSI) that includes over 40 articles on various aspects of solution-state biomolecular NMR that have been published in the Journal of Magnetic Resonance in the past 7 years. These, in total, help celebrate the achievements of this vibrant field.

Structural biology by NMR: structure, dynamics, and interactions.

Directory of Open Access Journals (Sweden)

Phineus R L Markwick

2008-09-01

Full Text Available The function of bio-macromolecules is determined by both their 3D structure and conformational dynamics. These molecules are inherently flexible systems displaying a broad range of dynamics on time-scales from picoseconds to seconds. Nuclear Magnetic Resonance (NMR spectroscopy has emerged as the method of choice for studying both protein structure and dynamics in solution. Typically, NMR experiments are sensitive both to structural features and to dynamics, and hence the measured data contain information on both. Despite major progress in both experimental approaches and computational methods, obtaining a consistent view of structure and dynamics from experimental NMR data remains a challenge. Molecular dynamics simulations have emerged as an indispensable tool in the analysis of NMR data.

Extracting protein dynamics information from overlapped NMR signals using relaxation dispersion difference NMR spectroscopy.

Science.gov (United States)

Konuma, Tsuyoshi; Harada, Erisa; Sugase, Kenji

2015-12-01

Protein dynamics plays important roles in many biological events, such as ligand binding and enzyme reactions. NMR is mostly used for investigating such protein dynamics in a site-specific manner. Recently, NMR has been actively applied to large proteins and intrinsically disordered proteins, which are attractive research targets. However, signal overlap, which is often observed for such proteins, hampers accurate analysis of NMR data. In this study, we have developed a new methodology called relaxation dispersion difference that can extract conformational exchange parameters from overlapped NMR signals measured using relaxation dispersion spectroscopy. In relaxation dispersion measurements, the signal intensities of fluctuating residues vary according to the Carr-Purcell-Meiboon-Gill pulsing interval, whereas those of non-fluctuating residues are constant. Therefore, subtraction of each relaxation dispersion spectrum from that with the highest signal intensities, measured at the shortest pulsing interval, leaves only the signals of the fluctuating residues. This is the principle of the relaxation dispersion difference method. This new method enabled us to extract exchange parameters from overlapped signals of heme oxygenase-1, which is a relatively large protein. The results indicate that the structural flexibility of a kink in the heme-binding site is important for efficient heme binding. Relaxation dispersion difference requires neither selectively labeled samples nor modification of pulse programs; thus it will have wide applications in protein dynamics analysis.

Extracting protein dynamics information from overlapped NMR signals using relaxation dispersion difference NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Konuma, Tsuyoshi [Icahn School of Medicine at Mount Sinai, Department of Structural and Chemical Biology (United States); Harada, Erisa [Suntory Foundation for Life Sciences, Bioorganic Research Institute (Japan); Sugase, Kenji, E-mail: sugase@sunbor.or.jp, E-mail: sugase@moleng.kyoto-u.ac.jp [Kyoto University, Department of Molecular Engineering, Graduate School of Engineering (Japan)

2015-12-15

Protein dynamics plays important roles in many biological events, such as ligand binding and enzyme reactions. NMR is mostly used for investigating such protein dynamics in a site-specific manner. Recently, NMR has been actively applied to large proteins and intrinsically disordered proteins, which are attractive research targets. However, signal overlap, which is often observed for such proteins, hampers accurate analysis of NMR data. In this study, we have developed a new methodology called relaxation dispersion difference that can extract conformational exchange parameters from overlapped NMR signals measured using relaxation dispersion spectroscopy. In relaxation dispersion measurements, the signal intensities of fluctuating residues vary according to the Carr-Purcell-Meiboon-Gill pulsing interval, whereas those of non-fluctuating residues are constant. Therefore, subtraction of each relaxation dispersion spectrum from that with the highest signal intensities, measured at the shortest pulsing interval, leaves only the signals of the fluctuating residues. This is the principle of the relaxation dispersion difference method. This new method enabled us to extract exchange parameters from overlapped signals of heme oxygenase-1, which is a relatively large protein. The results indicate that the structural flexibility of a kink in the heme-binding site is important for efficient heme binding. Relaxation dispersion difference requires neither selectively labeled samples nor modification of pulse programs; thus it will have wide applications in protein dynamics analysis.

Alpha-eleostearic acid (9Z11E13E-18:3) is quickly converted to conjugated linoleic acid (9Z11E-18:2) in rats.

Science.gov (United States)

Tsuzuki, Tsuyoshi; Tokuyama, Yoshiko; Igarashi, Miki; Nakagawa, Kiyotaka; Ohsaki, Yusuke; Komai, Michio; Miyazawa, Teruo

2004-10-01

We previously showed that alpha-eleostearic acid (alpha-ESA; 9Z11E13E-18:3) is converted to conjugated linoleic acid (CLA; 9,11-18:2) in the liver and plasma of rats that were given diets including 1% alpha-ESA for 4 wk. In this study, we investigated this phenomenon in detail. First, the chemical structure of CLA produced by alpha-ESA administration was determined. After alpha-ESA was orally administered to rats, CLA in rat liver was isolated by HPLC. The positional and geometric isomerism was determined using GC-EI/MS and (13)C-NMR, respectively, and the CLA generated in rats after alpha-ESA feeding was confirmed to be 9Z11E-CLA. Next, the concentrations of alpha-ESA and CLA were determined 0, 3, 6, and 24 h after oral administration of alpha-ESA to rats. Moreover, we also investigated whether enteric bacteria are involved in the conversion of alpha-ESA to CLA using germ-free rats. alpha-ESA was orally administered to germ-free and normal rats and alpha-ESA and CLA were detected in the organs of both groups. In addition, to confirm that this reaction was enzyme-mediated, alpha-ESA was reacted with tissue homogenates (liver, kidney, and small intestine mucous) and coenzymes (NADH, NAD(+), NADPH, and NADP(+)), and the enzyme activities were estimated from the amount of CLA produced. CLA was detected when alpha-ESA was reacted with liver, kidney, and small intestine mucous homogenates and a coenzyme (NADPH). These results indicated that alpha-ESA is converted to 9Z11E-CLA in rats by a Delta13-saturation reaction carried out by an NADPH-dependent enzyme.

Experimental setup for studying the effects of alpha particles on zebrafish embryos

International Nuclear Information System (INIS)

Yum, E.H.W.; Ng, C.K.M.; Lin, A.C.C.; Cheng, S.H.; Yu, K.N.

2007-01-01

In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 μm were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human

Experimental setup for studying the effects of alpha particles on zebrafish embryos

Energy Technology Data Exchange (ETDEWEB)

Yum, E.H.W.; Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Lin, A.C.C.; Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China)], E-mail: peter.yu@cityu.edu.hk

2007-11-15

In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 {mu}m were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human.

NMR imaging of the brain: initial impressions

International Nuclear Information System (INIS)

Spencer, D.H.; Bydder, G.M.

1983-01-01

An NMR imaging system designed and built by Thorn-EMI Ltd was installed at Hammersmith Hospital in March 1981. In the first year of operation 180 patients and 40 volunteers have had cranial examinations and initial impressions bases on this experience are presented. Patients with a wide variety of neurological diseases have been studied to provide a basis for diagnostic interpretation, to define distinctive features, and to evaluate different types of scanning sequences. NMR imaging appears to be of considerable value in neurological diagnosis and has a number of advantages over CT. The detailed evaluation of NMR imaging will require much more work but the initial results are very promising

Graphical programming for pulse automated NMR experiments

International Nuclear Information System (INIS)

Belmonte, S.B.; Oliveira, I.S.; Guimaraes, A.P.

1999-01-01

We describe a software program designed to control a broadband pulse Nuclear Magnetic Resonance (NMR) spectrometer used in zero-field NMR studies of magnetic metals. The software is written in the graphical language LabVIEW. This type of programming allows modifications and the inclusion of new routines to be easily made by the non-specialist, without changing the basic structure of the program. The program corrects for differences in the gain of the two acquisition channels [U (phase) and V (quadrature)], and automatic baseline subtraction. We present examples of measurements of NMR spectra, spin-echo decay (T 2 ), and quadrupolar oscillations, performed in magnetic intermetallic compounds. (author)

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

International Nuclear Information System (INIS)

Shanks, J.V.

1989-01-01

With intent to quantify NMR measurements as much as possible, analysis techniques of the in vivo 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 31 P NMR spectrum. In addition, in vivo correlation of inorganic phosphate chemical shift with the chemical shifts of 3-phosphoglycerate, β-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 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 1 ) is established. Transient measurements provided by 31 P NMR are applied to reg1 mutant and standard strains. 31 P and 13 C NMR measurements are used to analyze the performance of recombinant strains in which the glucose phosphorylation step had been altered

Structural studies of bacterial transcriptional regulatory proteins by multidimensional heteronuclear NMR

Energy Technology Data Exchange (ETDEWEB)

Volkman, Brian Finley [Univ. of California, Berkeley, CA (United States)

1995-02-01

Nuclear magnetic resonance spectroscopy was used to elucidate detailed structural information for peptide and protein molecules. A small peptide was designed and synthesized, and its three-dimensional structure was calculated using distance information derived from two-dimensional NMR measurements. The peptide was used to induce antibodies in mice, and the cross-reactivity of the antibodies with a related protein was analyzed with enzyme-linked immunosorbent assays. Two proteins which are involved in regulation of transcription in bacteria were also studied. The ferric uptake regulation (Fur) protein is a metal-dependent repressor which controls iron uptake in bacteria. Two- and three-dimensional NMR techniques, coupled with uniform and selective isotope labeling allowed the nearly complete assignment of the resonances of the metal-binding domain of the Fur protein. NTRC is a transcriptional enhancer binding protein whose N-terminal domain is a "receiver domain" in the family of "two-component" regulatory systems. Phosphorylation of the N-terminal domain of NTRC activates the initiation of transcription of aeries encoding proteins involved in nitrogen regulation. Three- and four-dimensional NMR spectroscopy methods have been used to complete the resonance assignments and determine the solution structure of the N-terminal receiver domain of the NTRC protein. Comparison of the solution structure of the NTRC receiver domain with the crystal structures of the homologous protein CheY reveals a very similar fold, with the only significant difference being the position of helix 4 relative to the rest of the protein. The determination of the structure of the NTRC receiver domain is the first step toward understanding a mechanism of signal transduction which is common to many bacterial regulatory systems.

Ab initio/GIAO-CCSD(T) study of structures, energies, and 13C NMR chemical shifts of C4H7(+) and C5H9(+) ions: relative stability and dynamic aspects of the cyclopropylcarbinyl vs bicyclobutonium ions.

Science.gov (United States)

Olah, George A; Surya Prakash, G K; Rasul, Golam

2008-07-16

The structures and energies of the carbocations C 4H 7 (+) and C 5H 9 (+) were calculated using the ab initio method. The (13)C NMR chemical shifts of the carbocations were calculated using the GIAO-CCSD(T) method. The pisigma-delocalized bisected cyclopropylcarbinyl cation, 1 and nonclassical bicyclobutonium ion, 2 were found to be the minima for C 4H 7 (+) at the MP2/cc-pVTZ level. At the MP4(SDTQ)/cc-pVTZ//MP2/cc-pVTZ + ZPE level the structure 2 is 0.4 kcal/mol more stable than the structure 1. The (13)C NMR chemical shifts of 1 and 2 were calculated by the GIAO-CCSD(T) method. Based on relative energies and (13)C NMR chemical shift calculations, an equilibrium involving the 1 and 2 in superacid solutions is most likely responsible for the experimentally observed (13)C NMR chemical shifts, with the latter as the predominant equilibrating species. The alpha-methylcyclopropylcarbinyl cation, 4, and nonclassical bicyclobutonium ion, 5, were found to be the minima for C 5H 9 (+) at the MP2/cc-pVTZ level. At the MP4(SDTQ)/cc-pVTZ//MP2/cc-pVTZ + ZPE level ion 5 is 5.9 kcal/mol more stable than the structure 4. The calculated (13)C NMR chemical shifts of 5 agree rather well with the experimental values of C 5H 9 (+).

Detergent/nanodisc screening for high-resolution NMR studies of an integral membrane protein containing a cytoplasmic domain.

Directory of Open Access Journals (Sweden)

Christos Tzitzilonis

Full Text Available Because membrane proteins need to be extracted from their natural environment and reconstituted in artificial milieus for the 3D structure determination by X-ray crystallography or NMR, the search for membrane mimetic that conserve the native structure and functional activities remains challenging. We demonstrate here a detergent/nanodisc screening study by NMR of the bacterial α-helical membrane protein YgaP containing a cytoplasmic rhodanese domain. The analysis of 2D [(15N,(1H]-TROSY spectra shows that only a careful usage of low amounts of mixed detergents did not perturb the cytoplasmic domain while solubilizing in parallel the transmembrane segments with good spectral quality. In contrast, the incorporation of YgaP into nanodiscs appeared to be straightforward and yielded a surprisingly high quality [(15N,(1H]-TROSY spectrum opening an avenue for the structural studies of a helical membrane protein in a bilayer system by solution state NMR.

observed by high pressure NMR and NQR

Indian Academy of Sciences (India)

Akogun, Hyogo 678-1297, Japan. ∗. Email: kohara@sci.himeji tech.ac.jp. Abstract. NMR and NQR studies on two interesting systems (URu2Si2, CeTIn5) were performed under high pressure. (1) URu2Si2: In the pressure range 3.0 to 8.3 kbar, we have observed new 29Si. NMR signals arising from the antiferromagnetic ...

NMR imaging of human atherosclerosis

International Nuclear Information System (INIS)

Toussaint, J.F.

1995-01-01

Diagnosis and prognosis of atherosclerosis can no longer be evaluated with morphological parameters only. A description of atherosclerotic plaque composition is necessary to study the mechanisms of plaque rupture, which depends on collagenous cap and lipid core thicknesses. NMR, as a biochemical imaging technique, allows visualization of these components using T1 contrast (mobile lipids), T2 contrast (cap vs. core), spin density (calcifications), diffusion imaging, 1H and 13C spectroscopy. Today, these imaging sequences allow to study in vitro the effects of interventional techniques such as angioplasty or atherectomy. Clinical investigations begin, which will attempt to develop in vivo microscopy and test the ability of NMR to predict plaque rupture. (author). 13 refs., 7 figs

Intracellular PHB conversion in a type II methanotroph studied by 13 C NMR

NARCIS (Netherlands)

Vecherskaya, M.; Dijkema, C.; Stams, A.J.M.

2001-01-01

Poly-g-hydroxybutyrate (PHB) formation under aerobic conditions via incorporation of [13C-2]acetate as a cosubstrate and its intracellular degradation under anaerobic conditions in a Type II methanotroph was studied by 13C NMR. During PHB synthesis in the presence of labelled acetate, low levels of

Multinuclear NMR studies of single lipid bilayers supported in cylindrical aluminum oxide nanopores.

Science.gov (United States)

Gaede, Holly C; Luckett, Keith M; Polozov, Ivan V; Gawrisch, Klaus

2004-08-31

Lipid bilayers were deposited inside the 0.2 microm pores of anodic aluminum oxide (AAO) filters by extrusion of multilamellar liposomes and their properties studied by 2H, 31P, and 1H solid-state NMR. Only the first bilayer adhered strongly to the inner surface of the pores. Additional layers were washed out easily by a flow of water as demonstrated by 1H magic angle spinning NMR experiments with addition of Pr3+ ions to shift accessible lipid headgroup resonances. A 13 mm diameter Anopore filter of 60 microm thickness oriented approximately 2.5 x 10(-7) mol of lipid as a single bilayer, corresponding to a total membrane area of about 500 cm2. The 2H NMR spectra of chain deuterated POPC are consistent with adsorption of wavy, tubular bilayers to the inner pore surface. By NMR diffusion experiments, we determined the average length of those lipid tubules to be approximately 0.4 microm. There is evidence for a thick water layer between lipid tubules and the pore surface. The ends of tubules are well sealed against the pore such that Pr3+ ions cannot penetrate into the water underneath the bilayers. We successfully trapped poly(ethylene glycol) (PEG) with a molecular weight of 8000 in this water layer. From the quantity of trapped PEG, we calculated an average water layer thickness of 3 nm. Lipid order parameters and motional properties are unperturbed by the solid support, in agreement with existence of a water layer. Such unperturbed, solid supported membranes are ideal for incorporation of membrane-spanning proteins with large intra- and extracellular domains. The experiments suggest the promise of such porous filters as membrane support in biosensors.

Preliminary studies for the determination of alpha emitters using the gross alpha coprecipitation methods

International Nuclear Information System (INIS)

Suarez-Navarro, J. A.; Pujol, L.; Suarez, J. A.; Pablo, M. A. de

2003-01-01

The radiological quality of drinking water in Spain is regulated by Nuclear Security Guideline No, 7.7 (Rev.1) of the Nuclear Security Council (NSC). this guideline establishes the protocol to follow when the radiological level exceeds 0,1 Bq.l''1. When this level is passed, the responsible alpha emitter must be identified; ''210 Po, ''226Ra, ''230Th, ''239Pu, ''224Ra, ''234 U and ''138 U. Activity due to these isotopes is usually determined using alpha spectrometry with semiconductor detectors. This method allows the activity of the alpha emitters to be determined with a good sensitivity. however, it requires long radiochemical isolations and long counting times, so the method is not suitable for rough estimate radiological analysis. In this preliminary work, we present the conditioning of the sample-precipitate that is essential for further radiochemical isolations. (Author) 9 refs

Microprocessorized NMR measurement

International Nuclear Information System (INIS)

Rijllart, A.

1984-01-01

An MC68000 CAMAC microprocessor system for fast and accurate NMR signal measurement will be presented. A stand-alone CAMAC microprocessor system (MC68000 STAC) with a special purpose interface sweeps a digital frequency synthesizer and digitizes the NMR signal with a 16-bit ADC of 17 μs conversion time. It averages the NMR signal data over many sweeps and then transfers it through CAMAC to a computer for calculation of the signal parameters. The computer has full software control over the timing and sweep settings of this signal averager, and thus allows optimization of noise suppression. Several of these processor systems can be installed in the same crate for parallel processing, and the flexibility of the STAC also allows easy adaptation to other applications such as transient recording or phase-sensitive detection. (orig.)

Kaempferol-3,4'-di-O-beta-glucopyranoside-7-O-alpha-rhamnopyranoside as a new flavonoid from Iberis amara L.

Science.gov (United States)

Kroll, U; Reif, K; Lederer, I; Förster, G; Zapp, J

2009-02-01

A new flavonol glycoside, kaempferol-3,4'-di-O-beta-glucopyranoside-7-O-alpha-rhamno-pyranoside, was isolated from the ethanolic extract of the whole fresh plant of Iberis amara L., an European plant used in gastrointestinal medicine. The structure was established by a combination of 1D and 2D NMR techniques (COSY, HSQC, HMBC, NOESY) as well as UV, IR and mass spectral data.

NMR Techniques in Metabolomic Studies: A Quick Overview on Examples of Utilization.

Science.gov (United States)

Kruk, Joanna; Doskocz, Marek; Jodłowska, Elżbieta; Zacharzewska, Anna; Łakomiec, Joanna; Czaja, Kornelia; Kujawski, Jacek

2017-01-01

Metabolomics is a rapidly developing branch of science that concentrates on identifying biologically active molecules with potential biomarker properties. To define the best biomarkers for diseases, metabolomics uses both models (in vitro, animals) and human, as well as, various techniques such as mass spectroscopy, gas chromatography, liquid chromatography, infrared and UV-VIS spectroscopy and nuclear magnetic resonance. The last one takes advantage of the magnetic properties of certain nuclei, such as 1 H, 13 C, 31 P, 19 F, especially their ability to absorb and emit energy, what is crucial for analyzing samples. Among many spectroscopic NMR techniques not only one-dimensional (1D) techniques are known, but for many years two-dimensional (2D, for example, COSY, DOSY, JRES, HETCORE, HMQS), three-dimensional (3D, DART-MS, HRMAS, HSQC, HMBC) and solid-state NMR have been used. In this paper, authors taking apart fundamental division of nuclear magnetic resonance techniques intend to shown their wide application in metabolomic studies, especially in identifying biomarkers.

Fourier transform n.m.r. spectroscopy

International Nuclear Information System (INIS)

Shaw, D.

1976-01-01

This book is orientated to techniques rather than applications. The basic theory of n.m.r. is dealt with in a unified approach to the Fourier theory. The middle section of the book concentrates on the practical aspects of Fourier n.m.r., both instrumental and experimental. The final chapters briefly cover general application of n.m.r., but concentrate strongly on those areas where Fourier n.m.r. can give information which is not available by conventional techniques

Genetics of Iranian Alpha-Thalassemia Patients: A Comprehensive Original Study.

Science.gov (United States)

Keikhaei, Bijan; Slehi-Fard, Pejman; Shariati, Gholamreza; Khosravi, Abbas

2018-04-07

Alpha thalassemia is the most prevalent monogenic gene disorder in the world, especially in Mediterranean countries. In the current hematological phenotype of patients with different genotypes, the effects of missense mutations on the protein function and also stability were evaluated in a large cohort study. A total of 1,560 subjects were enrolled in the study and divided into two groups: 259 normal subjects; and 1301 alpha-thalassemia carriers. Genomic DNA was extracted and analyzed using ARMS PCR, Multiplex Gap, and direct sequencing. The effects of single nucleotide change on the protein function and stability were predicted by freely available databases of human polymorphisms. Sixty-three different genotypes were seen in the patients. The more prevalent was heterozygote form of -α3.7 (41.4%) followed by -α3.7 homozygote (11.6%) and -MED (3.8%). The significant differences were seen in mean hemoglobin level [F = 20.5, p < 0.001] between the Alpha-globin genotypes, when adjusted for gender. Moreover, 28 different mutations were found in our study. A significant relationship was seen between ethnicity and the alpha-globin mutation frequency χ 2 (df;8) = 38.36, p < 0.0001). Different genotypes could display as different phenotypes. The mutation frequency distributions in our region are different from those of other parts of Iran. Significant differences are seen in the spectrum of mutation frequency among various ethnicities. Finally, some missense mutations might not have considerable effect on the proteins, and they could be neutral mutations.

Metabonomic study of human serum in gallbladder cancer by 1H NMR spectroscopy

International Nuclear Information System (INIS)

Sonkar, Kanchan; Sinha, Neeraj; Behari, Anu; Kapoor, V.K.

2012-01-01

Gallbladder carcinoma (GBC) is one of the most lethal malignancies of upper gastrointestinal tract and it has the highest mortality rate in Chile and India. It has a very high incidence rates in northern India therefore it is also called as an Indian disease. There are several factors which play important role in development of gallbladder cancer including long-standing stones in gallbladder and alterations in composition of bile. Studies on gallstones and gallbladder tissues revealed that benign group can easily be discriminated from malignant group. Many proteomic studies have been performed for different cancers and several responsible serum protein markers have been identified but there is no such metabonomics study that shows the presence of any biomarker associated with gallbladder carcinoma. Identification of such biomarker would help immensely in the diagnostic of GBC. For this study we have collected blood samples (70; including patients from Chronic Cholecystitis (CC), XanthoGranulomatous Cholecystitis (XGC) and Gallbladder Cancer (GBC)) post-operatively (immediately after surgery) from patient undergoing cholecystectomy in Department of Surgical Gastroenterology, SGPGIMS. Control samples were also collected from 20 volunteers after 12 hrs of fasting. 4 ml of blood sample was collected and was allowed to clot in plastic tube for 30 min at room temperature in incubator. The serum was collected by centrifugation and samples were stored at -80 deg C till NMR experiments. 400 μL of serum was used for recording NMR spectra. NMR spectra were recorded at Bruker Avance 800 MHz spectrometer using CPMG pulse sequence with water presaturation. Control serum shows presence of various amino acids and low molecular weight metabolites. Detailed multivariate analysis along with markers found in serum associated with GBC will be presented. (author)

NMR studies of actinide carbide and nitride electronic properties

International Nuclear Information System (INIS)

Boutard, Jean-Louis

1976-12-01

N.M.R. studies applied to 13 C and 15 N in the solid solutions ThCsub(1-x)Nsub(x), UCsub(1-x)Nsub(x) and in the compounds ThCsub(1-x) and U 2 C 3 , were undertaken to study carbon and nitrogen contribution to chemical bonds and magnetism. For THORIUM MONOCARBIDE AND CARBONITRIDE: ThCsub(1-x) and ThCsub(1-x)Nsub(x), the very strong orbital contribution to the frequency shift reveals an important covalent character of the valence band 6d metal and 2p metalloid states. The ThCsub(1-x) band structure stoichiometry variation is due to 6dγ metal states appearing at the Fermi level and is in-opposition to a rigid band model. A non-saturated bond mechanism is suggested. For URANIUM CARBONITRIDE: UCsub(1-x)Nsub(x), in the concentration range in which no magnetic order appears at low temperature (x<0.90), the results are in opposition to a localized 5f 2 configuration model, and show that the uranium fundamental state is non-magnetic. Nevertheless two qualitatively different behaviors exist: nitrogen concentration lower than 40%: and nitrogen concentration higher than 40%. A model is proposed to account for those domains: it relies on the 5f-2p hybridization parameter which is maximum on 2p band edge (UC) and almost nul for UN. For URANIUM SESQUICARBIDE: U 2 C 3 : the N.M.R. line observation at 4.2 K indicates a non-magnetic fundamental state although the magnetic susceptibility presents a maximum at 60 K. Spin fluctuations in 5f bands are proposed to describe the electronic properties of this compound. [fr

Compositional differences among Chinese soy sauce types studied by (13)C NMR spectroscopy coupled with multivariate statistical analysis.

Science.gov (United States)

Kamal, Ghulam Mustafa; Wang, Xiaohua; Bin Yuan; Wang, Jie; Sun, Peng; Zhang, Xu; Liu, Maili

2016-09-01

Soy sauce a well known seasoning all over the world, especially in Asia, is available in global market in a wide range of types based on its purpose and the processing methods. Its composition varies with respect to the fermentation processes and addition of additives, preservatives and flavor enhancers. A comprehensive (1)H NMR based study regarding the metabonomic variations of soy sauce to differentiate among different types of soy sauce available on the global market has been limited due to the complexity of the mixture. In present study, (13)C NMR spectroscopy coupled with multivariate statistical data analysis like principle component analysis (PCA), and orthogonal partial least square-discriminant analysis (OPLS-DA) was applied to investigate metabonomic variations among different types of soy sauce, namely super light, super dark, red cooking and mushroom soy sauce. The main additives in soy sauce like glutamate, sucrose and glucose were easily distinguished and quantified using (13)C NMR spectroscopy which were otherwise difficult to be assigned and quantified due to serious signal overlaps in (1)H NMR spectra. The significantly higher concentration of sucrose in dark, red cooking and mushroom flavored soy sauce can directly be linked to the addition of caramel in soy sauce. Similarly, significantly higher level of glutamate in super light as compared to super dark and mushroom flavored soy sauce may come from the addition of monosodium glutamate. The study highlights the potentiality of (13)C NMR based metabonomics coupled with multivariate statistical data analysis in differentiating between the types of soy sauce on the basis of level of additives, raw materials and fermentation procedures. Copyright © 2016 Elsevier B.V. All rights reserved.

Positional isotope exchange studies on enzyme using NMR spectroscopy

International Nuclear Information System (INIS)

Matsunaga, T.O.

1987-01-01

The isotopically enriched compounds, 18 O-β,γ-ATP and 18 O bridge-labeled pyrophosphate, synthesized previously in this laboratory, were used to investigate and measure the exchange vs. turnover of substrates and products from their central complexes in four selected enzyme systems. Using hi-field 31 P NMR, we were able to differentiate between 18 O labeled in the bridge vs. the non-bridge positions by virtue of the isotope shift upon the phosphorus nuclei. The bridge to non-bridge scrambling of the label was quantitated and the exchange vs. turnover ratios under a variety of conditions was determined. Using the substrate inhibitor carboxycreatinine, PIX experiments with 18 O-β,γ-ATP and creatine kinase were conducted. It was shown that carboxycreatinine and creatine kinase promoted exchange of the 18 O label as determined by NMR. We have concluded that carboxycreatinine is either a substrate that catalyzes very slow turnover or it catalyzes exchange by a dissociative (SN 1 /sub P/) type of mechanism

23Na+- and 39K+-NMR studies of cation-polyanion interactions in vascular connective tissue

International Nuclear Information System (INIS)

Siegel, G.; Walter, A.; Bostanjoglo, M.

1987-01-01

The ion binding properties of vascular connective tissue as well as of substances derived therefrom were studied in dependence on cation concentration by NMR and atomic absorption techniques. 16 refs.; 8 figs

High resolution NMR theory and chemical applications

CERN Document Server

Becker, Edwin D

2012-01-01

High Resolution NMR: Theory and Chemical Applications discusses the principles and theory of nuclear magnetic resonance and how this concept is used in the chemical sciences. This book is written at an intermediate level, with mathematics used to augment verbal descriptions of the phenomena. This text pays attention to developing and interrelating four approaches - the steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The style of this book is based on the assumption that the reader has an acquaintance with the general principles of quantum mechanics, but no extensive background in quantum theory or proficiency in mathematics is required. This book begins with a description of the basic physics, together with a brief account of the historical development of the field. It looks at the study of NMR in liquids, including high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. This book is intended to assis...

13C and 17O NMR binding constant studies of uranyl carbonate complexes in near-neutral aqueous solution. Yucca Mountain Project Milestone Report 3351

International Nuclear Information System (INIS)

Clark, D.L.; Newton, T.W.; Palmer, P.D.; Zwick, B.D.

1995-01-01

Valuable structural information, much of it unavailable by other methods, can be obtained about complexes in solution through NMR spectroscopy. From chemical shift and intensity measurements of complexed species, NMR can serve as a species-specific structural probe for molecules in solution and can be used to validate thermodynamic constants used in geochemical modeling. Fourier-transform nuclear magnetic resonance (FT-NMR) spectroscopy has been employed to study the speciation of uranium(VI) ions in aqueous carbonate solutions as a function of pH, ionic strength, carbonate concentration, uranium concentration, and temperature. Carbon-13 and oxygen-17 NMR spectroscopy were used to monitor the fractions, and hence thermodynamic binding constants of two different uranyl species U0 2 (CO 3 ) 3 4- and (UO 2 ) 3 (CO 3 ) 6 6- in aqueous solution. Synthetic buffer solutions were prepared under the ionic strength conditions used in the NMR studies in order to obtain an accurate measure of the hydrogen ion concentration, and a discussion of pH = -log(a H + ) versus p[H] = -log[H+] is provided. It is shown that for quantitative studies, the quantity p[H] needs to be used. Fourteen uranium(VI) binding constants recommended by the OECD NEA literature review were corrected to the ionic strengths employed in the NMR study using specific ion interaction theory (SIT), and the predicted species distributions were compared with the actual species observed by multinuclear NMR. Agreement between observed and predicted stability fields is excellent. This establishes the utility of multinuclear NMR as a species-specific tool for the study of the actinide carbonate complexation constants, and serves as a means for validating the recommendations provided by the OECD NEA

Raman and NMR study in MgO-doped LiNbO3 crystal

International Nuclear Information System (INIS)

Hu, L.J.; Chang, Y.H.; Chang, C.S.; Yang, S.J.; Hu, M.L.; Tse, W.S.

1991-01-01

This paper reports on the MgO-doped LiNbO 3 crystal grown and studied by NMR and Raman techniques. The solubility of MgO in the LiNbO 3 crystal is as much as 30 mole %. It is shown in NMR spectra that the number of Nb 5+ cations at A-site (Li-site) decrease as Mg concentration increased when the Mg content is lower than 5 mole %. The vibration of (NbO 6 ) octahedron and translations involving Li + and Mg 2+ cations motion can be identified by replacing Nb 5+ and Li + cations with Ta 5+ and Mg 2+ cations through Raman spectra. The 115 cm -1 and 151 cm -1 peaks are due to the translational modes of Mg 2+ and Li + cations. The doping mechanisms of MgO are proposed

Study of the structure of hadronic events and determination of $\\alpha_{s}$ at $\\sqrt{s}$ = 130 GeV and 136 GeV

CERN Document Server

Acciarri, M; Adriani, O; Aguilar-Benítez, M; Ahlen, S P; Alpat, B; Alcaraz, J; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Antreasyan, D; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Ball, R C; Banerjee, S; Banicz, K; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bencze, G L; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Borgia, B; Boucham, A; Bourilkov, D; Bourquin, Maurice; Boutigny, D; Brambilla, Elena; Branson, J G; Brigljevic, V; Brock, I C; Buijs, A; Bujak, A T; Burger, J D; Burger, W J; Burgos, C; Busenitz, J K; Buytenhuijs, A O; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Caria, M; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Castello, R; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chan, A; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, C; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chéreau, X J; Chiefari, G; Chien, C Y; Choi, M T; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Coan, T E; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Dai, T S; D'Alessandro, R; De Asmundis, R; De Boeck, H; Degré, A; Deiters, K; Dénes, E; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dorne, I; Dova, M T; Drago, E; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabbretti, R; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Felcini, Marta; Ferguson, T; Fernández, D; Fernández, G; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Forconi, G; Fredj, L; Freudenreich, Klaus; Gailloud, M; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gerald, J; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; González, E; Gougas, Andreas; Goujon, D; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gustafson, H R; Gutay, L J; Hangarter, K; Hartmann, B; Hasan, A; He, J T; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hoorani, H; Hou, S R; Hu, G; Ilyas, M M; Innocente, Vincenzo; Janssen, H; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamyshkov, Yu A; Kapinos, P; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kittel, E W; Klimentov, A; Koffeman, E; Köngeter, A; Koutsenko, V F; Koulbardis, A; Krämer, R W; Kramer, T; Krenz, W; Kuijten, H; Kunin, A; Ladrón de Guevara, P; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee Jae Sik; Lee, K Y; Leggett, C; Le Goff, J M; Leiste, R; Lenti, M; Leonardi, E; Levchenko, P M; Li Chuan; Lieb, E H; Lin, W T; Linde, Frank L; Lindemann, B; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Ludovici, L; Luminari, L; Lustermann, W; Ma Wen Gan; Macchiolo, A; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangla, S; Maolinbay, M; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; Mazumdar, K; McNally, D; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Möller, M; Monteleoni, B; Moore, R; Morganti, S; Mount, R; Müller, S; Muheim, F; Nagy, E; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nippe, A; Nowak, H; Organtini, G; Ostonen, R; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Raghavan, R; Rahal-Callot, G; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Redaelli, M; Ren, D; Rescigno, M; Reucroft, S; Ricker, A; Riemann, S; Riemers, B C; Riles, K; Rind, O; Ro, S; Robohm, A; Rodin, J; Rodríguez-Calonge, F J; Roe, B P; Röhner, S; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Rykaczewski, H; Salicio, J; Salicio, J M; Sánchez, E; Santocchia, A; Sarakinos, M E; Sarkar, S; Sassowsky, M; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Schneegans, M; Schöneich, B; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schulte, R; Schultze, K; Schwenke, J; Schwering, G; Sciacca, C; Seiler, P G; Sens, Johannes C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Siedenburg, T; Son, D; Sopczak, André; Soulimov, V; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Sticozzi, F; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Toker, O; Tonisch, F; Tonutti, M; Tonwar, S C; Tóth, J; Tsaregorodtsev, A Yu; Tully, C; Tuchscherer, H; Tung, K L; Ulbricht, J; Urbàn, L; Uwer, U; Valente, E; Van de Walle, R T; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vuilleumier, L; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Y F; Wang, Z M; Weber, A; Weill, R; Willmott, C; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zaccardelli, C; Zalite, A; Zemp, P; Zeng, J Y; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhou, G J; Zhou, Y; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Van der Zwaan, B C C

1996-01-01

We present a study of the structure of hadronic events recorded by the L3 detector at center-of-mass energies of 130 and 136 GeV. The data sample corresponds to an integrated luminosity of 5 pb-1 collected during the high energy run of 1995. The shapes of the event shape distributions and the energy dependence of their mean values are well reproduced by QCD models. From a comparison of the data with resummed O(alpha_s^2) QCD calculations, we determine the strong coupling constant to be alpha_s(133 GeV) = 0.107 +/- 0.005(exp) +/- 0.006(theor).

Targeted Alpha Therapy: From Alpha to Omega

International Nuclear Information System (INIS)

Allen, Barry J; Clarke, Raymond; Huang Chenyu

2013-01-01

This review covers the broad spectrum of Targeted Alpha Therapy (TAT) research in Australia; from in vitro and in vivo studies to clinical trials. The principle of tumour anti-vascular alpha therapy (TAVAT) is discussed in terms of its validation by Monte Carlo calculations of vascular models and the potential role of biological dosimetry is examined. Summmary of this review is as follows: 1. The essence of TAT 2. Therapeutic objectives 3. TAVAT and Monte Carlo microdosimetry 4. Biological dosimetry 5. Preclinical studies 6. Clinical trials 7. What next? 8. Obstacles. (author)

Optimized bacterial expression and purification of the c-Src catalytic domain for solution NMR studies

International Nuclear Information System (INIS)

Piserchio, Andrea; Ghose, Ranajeet; Cowburn, David

2009-01-01

Progression of a host of human cancers is associated with elevated levels of expression and catalytic activity of the Src family of tyrosine kinases (SFKs), making them key therapeutic targets. Even with the availability of multiple crystal structures of active and inactive forms of the SFK catalytic domain (CD), a complete understanding of its catalytic regulation is unavailable. Also unavailable are atomic or near-atomic resolution information about their interactions, often weak or transient, with regulating phosphatases and downstream targets. Solution NMR, the biophysical method best suited to tackle this problem, was previously hindered by difficulties in bacterial expression and purification of sufficient quantities of soluble, properly folded protein for economically viable labeling with NMR-active isotopes. Through a choice of optimal constructs, co-expression with chaperones and optimization of the purification protocol, we have achieved the ability to bacterially produce large quantities of the isotopically-labeled CD of c-Src, the prototypical SFK, and of its activating Tyr-phosphorylated form. All constructs produce excellent spectra allowing solution NMR studies of this family in an efficient manner

A novel tridentate Schiff base dioxo-molybdenum(VI) complex: synthesis, experimental and theoretical studies on its crystal structure, FTIR, UV-visible, ¹H NMR and ¹³C NMR spectra.

Science.gov (United States)

Saheb, Vahid; Sheikhshoaie, Iran; Stoeckli-Evans, Helen

2012-09-01

A new dioxo-molybdenum(VI) complex [MoO(2)(L)(H(2)O)] has been synthesized, using 5-methoxy 2-[(2-hydroxypropylimino)methyl]phenol as tridentate ONO donor Schiff base ligand (H(2)L) and MoO(2)(acac)(2). The yellow crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FTIR), UV-visible, (1)H NMR and (13)C NMR spectra. Electronic structure calculations at the B3LYP and PW91PW91 levels of theory are performed to optimize the molecular geometry and to calculate the UV-visible, FTIR, (1)H NMR and (13)C NMR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TDDFT) method is used to calculate the electronic transitions of the complex. All theoretical methods can well reproduce the structure of the compound. The (1)H NMR shielding tensors computed at the B3LYP/DGDZVP level of theory is in agreement with experimental (1)H NMR spectra. However, the (13)C NMR shielding tensors computed at the B3LYP level, employing a combined basis set of DGDZVP for Mo and 6-31+G(2df,p) for other atoms, are in better agreement with experimental (13)C NMR spectra. The electronic transitions calculated at the B3LYP/DGDZVP level by using TD-DFT method is in accordance with the observed UV-visible spectrum of the compound. Copyright © 2012 Elsevier B.V. All rights reserved.

NMR study of thermal decomposition of lithium tetrahydroaluminate

International Nuclear Information System (INIS)

Tarasov, V.P.; Bakum, S.I.; Kuznetsova, S.F.

1997-01-01

Pyrolysis of lithium aluminotetrahydrides and deuterides, LiAlH 4 and LiAlD 4 , was studied by 1 H, 7 Li, 27 Al NMR in 20-700 deg C range. 20-30 time constriction of resonance lines of studied nuclei at 170 deg C testifies to melting of the compounds. It is shown that at LiAlD 4 melting point the first stage of pyrolysis is described by two parallel reactions: LiAlD 4 -> LiD + Al + D 2 , LiAlD 4 + LiD -> Li 3 AlD 6 , which proceed with different rates. It was revealed that reactions of lithium hydride (deuteride) with metallic aluminium at temperatures above 400 deg C resulted to formation of intermetallic compounds of LiAl and LiAl 3 composition. LiAl is characterized by higher thermal stability, than LiAl 3 . 20 refs., 6 figs., 2 tabs

Applications of NMR spectroscopy to xenobiotic metabolism

International Nuclear Information System (INIS)

Harris, T.M.

1989-01-01

Recent years have seen high field NMR spectrometers become commonplace in research laboratories. At the same time, major advances in methodology for structural analysis have occurred, particularly notable among these being the development of two-dimensional spectroscopic techniques. Many applications have been made of NMR spectroscopy in the study of xenobiotic metabolic processes. This deals with two specific applications which have been made in the author's laboratory and involve mechanistic studies of the reactions of the carcinogens ethylene dibromide and aflatoxin with DNA

Deuteron NMR and modelling in solid polymers

International Nuclear Information System (INIS)

Hirschinger, J.

1992-01-01

Deuteron NMR techniques are described and some recent applications to the study of rotational motions in solid polymers are reviewed. The information content and the domain of applicability of each technique are presented. Ultra-slow motions are studied in real time without any motional model consideration. For very fast motions, computer molecular dynamics simulations are shown to complement the NMR results. Experimental examples deal with the chain motion in the crystalline α-phase of poly(vinylidenefluoride) and nylon 6,6

Brain atrophy during aging. Quantitative studies with X-CT and NMR-CT

Energy Technology Data Exchange (ETDEWEB)

Matsuzawa, Taiju; Yamada, Kenji; Yamada, Susumu; Ono, Shuichi; Takeda, Shunpei; Hatazawa, Jun; Ito, Masatoshi; Kubota, Kazuo

1985-12-01

Age-related brain atrophy was investigated in thousands of persons with no neurologic disturbances using X-CT and NMR-CT. Brain atrophy was minimal in 34-35 years old in both sexes, increased exponentially to the increasing age after 34-35 years, and probably resulted in dementia, such as vascular or multi-infarct dementia. Brain atrophy was significantly greater in men than in women at all ages. Brain volumes were maximal in 34-35 years old in both sexes with minimal individual differences which increased proportionally to the increasing age. Remarkable individual differences in the extent of brain atrophy (20 - 30 %) existed among aged subjects. Progression of brain atrophy was closely related to loss of mental activities independently of their ages. Our longitudinal study has revealed that the most important factors promoting brain atrophy during aging was the decrease in the cerebral blood flow. We have classified brain atrophy into sulcal and cisternal enlargement type (type I), ventricular enlargement type (type II) and mixed type (type III) according to the clinical study using NMR-CT. Brain atrophy of type I progresses significantly in almost all of the geriatric disorders. This type of brain atrophy progresses significantly in heavy smokers and drinkers. Therefore this type of brain atrophy might be caused by the decline in the blood flow in anterior and middle cerebral arteries. Brain atrophy of type II was caused by the disturbance of cerebrospinal fluid circulation after cerebral bleeding and subarachnoid bleeding. Brain atrophy of type III was seen in vascular dementia or multi-infarct dementia which was caused by loss of brain matter after multiple infarction, and was seen also in dementia of Alzheimer type in which degeneration of nerve cells results in brain atrophy. NMR-CT can easily detect small infarction (lacunae) and edematous lesions resulting from ischemia and hypertensive encephalopathy. (J.P.N.).

NMR as a probe metabolic disorders in disease and treatment

Energy Technology Data Exchange (ETDEWEB)

Yushmanov, Victor E [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Chemical Physics

1994-12-31

The effects of malignant tumors, chemical and physical factors (toxic agents, ionizing radiation) as well as of their treatment on tissue metabolism were studied by NMR imaging. The importance of NMR is highlighted since it enables to a better understanding of molecular mechanisms of diseases and therapeutic interventions, in addition to the analysis of metabolic disorders in human beings. Combined with the studies of experimental animal pathologies, may constitute a base for new types of NMR-diagnosis in vivo 10 refs.

Structural comparison of 1{beta}-Methylcarbapenem, Carbapenem and Penem: NMR studies and theoretical calculations

Energy Technology Data Exchange (ETDEWEB)

Sunagawa, M.; Sasaki, A.; Igarashi, J.-E.; Nishimura, T. [Research Center, Sumitomo Pharmaceuticals Co., Ltd., 3-1-98 Kasugadenaka, Konohanaku, Osaka (Japan)

1998-04-01

Structural comparisons of meropenem (1), desmethyl meropenem (2) and the penem analogue (3) which contain the same side chains at both C-2 and C-6 were performed using {sup 1}H NMR measurements together with 3-21G* level of ab initio MO and molecular mechanics calculations. The ab initio MO calculations reproduced the skeletons of these strained {beta}-lactam rings in good agreement with the crystallographic data. {sup 1}H NMR measurements in aqueous solution together with molecular modeling studies indicated that there were conformational differences of the C-2 and C-6 side chains in this series of compounds. These observations suggested that the conformational differences could affect their biological activities. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Structural comparison of 1β-Methylcarbapenem, Carbapenem and Penem: NMR studies and theoretical calculations

International Nuclear Information System (INIS)

Sunagawa, M.; Sasaki, A.; Igarashi, J.-E.; Nishimura, T.

1998-01-01

Structural comparisons of meropenem (1), desmethyl meropenem (2) and the penem analogue (3) which contain the same side chains at both C-2 and C-6 were performed using 1 H NMR measurements together with 3-21G* level of ab initio MO and molecular mechanics calculations. The ab initio MO calculations reproduced the skeletons of these strained β-lactam rings in good agreement with the crystallographic data. 1 H NMR measurements in aqueous solution together with molecular modeling studies indicated that there were conformational differences of the C-2 and C-6 side chains in this series of compounds. These observations suggested that the conformational differences could affect their biological activities. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

High Resolution NMR Studies of Encapsulated Proteins In Liquid Ethane

Science.gov (United States)

Peterson, Ronald W.; Lefebvre, Brian G.; Wand, A. Joshua

2005-01-01

Many of the difficulties presented by large, aggregation-prone, and membrane proteins to modern solution NMR spectroscopy can be alleviated by actively seeking to increase the effective rate of molecular reorientation. An emerging approach involves encapsulating the protein of interest within the protective shell of a reverse micelle, and dissolving the resulting particle in a low viscosity fluid, such as the short chain alkanes. Here we present the encapsulation of proteins with high structural fidelity within reverse micelles dissolved in liquid ethane. The addition of appropriate co-surfactants can significantly reduce the pressure required for successful encapsulation. At these reduced pressures, the viscosity of the ethane solution is low enough to provide sufficiently rapid molecular reorientation to significantly lengthen the spin-spin NMR relaxation times of the encapsulated protein. PMID:16028922

Determination of the molecular complexation constant between alprostadil and alpha-cyclodextrin by conductometry: implications for a freeze-dried formulation.

Science.gov (United States)

Sheehy, Philip M; Ramstad, Tore

2005-10-04

The binding constant between alprostadil (PGE1) and alpha-cyclodextrin (alpha-CD) was determined at four temperatures using conductance measurements. Alpha-cyclodextrin is an excipient material in Caverject dual chamber syringe (DCS) that was added to enhance stability. The binding constant was used to calculate the amount of PGE1 free upon reconstitution and injection, since only the free drug is clinically active. The conductivity measurement is based on a decrease in specific conductance as alprostadil is titrated with alpha-CD. The change in conductivity was plotted versus free ligand concentration (alpha-CD) to generate a binding curve. As the value of the binding constant proved to be dependent on substrate concentration, it is really a pseudo binding constant. A value of 742+/-60 M(-1) was obtained for a 0.5 mM solution of alprostadil at 27 degrees C and a value of 550+/-52 M(-1) at 37 degrees C. These results compare favorably to values previously obtained by NMR and capillary electrophoresis. Calculation of the fraction PGE1 free upon reconstitution and injection show it to approach the desired outcome of one. Hence, the amount of drug delivered by Caverject DCS is nominally equivalent to that delivered by Caverject S. Po., a predecessor product that contains no alpha-cyclodextrin.

The NMR Probe of High-T$_{c}$ Materials

CERN Document Server

Walstedt, Russell E

2008-01-01

The NMR probe has yielded a vast array of data for the high-Tc materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. Over the twenty years, since the discovery of superconducting cuprates, ongoing analysis and discussion of cuprate NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are threefold. First, it reviews NMR methodology as it has been applied to the cuprate studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of cuprate NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data. Parts two and three are presented in parallel, as there are many aspects to both topics, each with its own interesting history. There is, even twenty years on, a...

NMR in structure-based drug design.

Science.gov (United States)

Carneiro, Marta G; Ab, Eiso; Theisgen, Stephan; Siegal, Gregg

2017-11-08

NMR spectroscopy is a powerful technique that can provide valuable structural information for drug discovery endeavors. Here, we discuss the strengths (and limitations) of NMR applications to structure-based drug discovery, highlighting the different levels of resolution and throughput obtainable. Additionally, the emerging field of paramagnetic NMR in drug discovery and recent developments in approaches to speed up and automate protein-observed NMR data collection and analysis are discussed. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

UTOPIA NMR: activating unexploited magnetization using interleaved low-gamma detection

Energy Technology Data Exchange (ETDEWEB)

Viegas, Aldino; Viennet, Thibault [Heinrich-Heine-University, Institute of Physical Biology (Germany); Yu, Tsyr-Yan [Academia Sinica, Institute of Atomic and Molecular Sciences (China); Schumann, Frank [Bruker BioSpin GmbH (Switzerland); Bermel, Wolfgang [Bruker BioSpin GmbH (Germany); Wagner, Gerhard [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States); Etzkorn, Manuel, E-mail: manuel.etzkorn@hhu.de [Heinrich-Heine-University, Institute of Physical Biology (Germany)

2016-01-15

A growing number of nuclear magnetic resonance (NMR) spectroscopic studies are impaired by the limited information content provided by the standard set of experiments conventionally recorded. This is particularly true for studies of challenging biological systems including large, unstructured, membrane-embedded and/or paramagnetic proteins. Here we introduce the concept of unified time-optimized interleaved acquisition NMR (UTOPIA-NMR) for the unified acquisition of standard high-γ (e.g. {sup 1}H) and low-γ (e.g. {sup 13}C) detected experiments using a single receiver. Our aim is to activate the high level of polarization and information content distributed on low-γ nuclei without disturbing conventional magnetization transfer pathways. We show that using UTOPIA-NMR we are able to recover nearly all of the normally non-used magnetization without disturbing the standard experiments. In other words, additional spectra, that can significantly increase the NMR insights, are obtained for free. While we anticipate a broad range of possible applications we demonstrate for the soluble protein Bcl-x{sub L} (ca. 21 kDa) and for OmpX in nanodiscs (ca. 160 kDa) that UTOPIA-NMR is particularly useful for challenging protein systems including perdeuterated (membrane) proteins.

UTOPIA NMR: activating unexploited magnetization using interleaved low-gamma detection

International Nuclear Information System (INIS)

Viegas, Aldino; Viennet, Thibault; Yu, Tsyr-Yan; Schumann, Frank; Bermel, Wolfgang; Wagner, Gerhard; Etzkorn, Manuel

2016-01-01

A growing number of nuclear magnetic resonance (NMR) spectroscopic studies are impaired by the limited information content provided by the standard set of experiments conventionally recorded. This is particularly true for studies of challenging biological systems including large, unstructured, membrane-embedded and/or paramagnetic proteins. Here we introduce the concept of unified time-optimized interleaved acquisition NMR (UTOPIA-NMR) for the unified acquisition of standard high-γ (e.g. 1 H) and low-γ (e.g. 13 C) detected experiments using a single receiver. Our aim is to activate the high level of polarization and information content distributed on low-γ nuclei without disturbing conventional magnetization transfer pathways. We show that using UTOPIA-NMR we are able to recover nearly all of the normally non-used magnetization without disturbing the standard experiments. In other words, additional spectra, that can significantly increase the NMR insights, are obtained for free. While we anticipate a broad range of possible applications we demonstrate for the soluble protein Bcl-x L (ca. 21 kDa) and for OmpX in nanodiscs (ca. 160 kDa) that UTOPIA-NMR is particularly useful for challenging protein systems including perdeuterated (membrane) proteins

UTOPIA NMR: activating unexploited magnetization using interleaved low-gamma detection.

Science.gov (United States)

Viegas, Aldino; Viennet, Thibault; Yu, Tsyr-Yan; Schumann, Frank; Bermel, Wolfgang; Wagner, Gerhard; Etzkorn, Manuel

2016-01-01

A growing number of nuclear magnetic resonance (NMR) spectroscopic studies are impaired by the limited information content provided by the standard set of experiments conventionally recorded. This is particularly true for studies of challenging biological systems including large, unstructured, membrane-embedded and/or paramagnetic proteins. Here we introduce the concept of unified time-optimized interleaved acquisition NMR (UTOPIA-NMR) for the unified acquisition of standard high-γ (e.g. (1)H) and low-γ (e.g. (13)C) detected experiments using a single receiver. Our aim is to activate the high level of polarization and information content distributed on low-γ nuclei without disturbing conventional magnetization transfer pathways. We show that using UTOPIA-NMR we are able to recover nearly all of the normally non-used magnetization without disturbing the standard experiments. In other words, additional spectra, that can significantly increase the NMR insights, are obtained for free. While we anticipate a broad range of possible applications we demonstrate for the soluble protein Bcl-xL (ca. 21 kDa) and for OmpX in nanodiscs (ca. 160 kDa) that UTOPIA-NMR is particularly useful for challenging protein systems including perdeuterated (membrane) proteins.

Immunostimulatory effects of natural human interferon-alpha (huIFN-alpha) on carps Cyprinus carpio L.

Science.gov (United States)

Watanuki, Hironobu; Chakraborty, Gunimala; Korenaga, Hiroki; Kono, Tomoya; Shivappa, R B; Sakai, Masahiro

2009-10-15

Human interferon-alpha (huIFN-alpha) is an important immunomodulatory substance used in the treatment and prevention of numerous infectious and immune-related diseases in animals. However, the immunostimulatory effects of huIFN-alpha in fish remain to be investigated. In the current study, the immune responses of the carp species Cyprinus carpio L. to treatment with huIFN-alpha were analyzed via measurement of superoxide anion production, phagocytic activity and the expression of cytokine genes including interleukin-1beta, tumor necrosis factor-alpha and interleukin 10. Low doses of huIFN-alpha were administered orally once a day for 3 days, and sampling was carried out at 1, 3 and 5 days post-treatment. Our results indicate that a low dose of huIFN-alpha significantly increased phagocytic activity and superoxide anion production in the carp kidney. The huIFN-alpha-treated fish also displayed a significant upregulation in cytokine gene expression. The current study demonstrates the stimulatory effects of huIFN-alpha on the carp immune system and highlights the immunomodulatory role of huIFN-alpha in fish.

Applications of solid-state Nuclear Magnetic Resonance (NMR) in studies of Portland cements-based materials

DEFF Research Database (Denmark)

Skibsted, Jørgen; Andersen, Morten Daugaard; Jakobsen, Hans Jørgen

2007-01-01

Solid-state NMR spectroscopy represents an important research tool in the characterization of a range of structural properties for cement-based materials. Different approaches of the technique can be used to obtain information on hydration kinetics, mobile and bound water, porosity, and local...... atomic structures. After a short introduction to these NMR techniques, it is exemplified how magic-angle spinning (MAS) NMR can provide quantitative and structural information about specific phases in anhydrous and hydrated Portland cements with main emphasis on the incorporation of Al3+ ions...

Variant Selection during Alpha Precipitation in Titanium Alloys: A Simulation Study

Science.gov (United States)

Shi, Rongpei

Variant selection of alpha phase during its precipitation from beta matrix plays a key role in determining transformation texture and final mechanical properties of alpha/beta and beta titanium alloys. In this study we develop a three-dimensional quantitative phase field model (PFM) to predict variant selection and microstructure evolution during beta to alpha transformation in polycrystalline Ti-6Al-4V under the influence of different processing variables. The model links its inputs directly to thermodynamic and mobility databases, and incorporates crystallography of BCC to HCP transformation, elastic anisotropy, defects within semi-coherent alpha/beta interfaces and elastic inhomogeneities among different beta grains. In particular, microstructure and transformation texture evolution are treated simultaneously via orientation distribution function (ODF) modeling of alpha/beta two-phase microstructure in beta polycrystalline obtained by PFM. It is found that, for a given undercooling, the development of transformation texture of the alpha phase due to variant selection during precipitation depends on both externally applied stress or strain, initial texture state of parent beta sample and internal stress generated by the precipitation reaction itself. Moreover, the growth of pre-existing widmanstatten alpha precipitates is accompanied by selective nucleation and growth of secondary alpha plates of preferred variants. We further develop a crystallographic model based on the ideal Burgers orientation relationship (BOR) between GBalpha and one of the two adjacent beta grains to investigate how a prior beta grain boundary contributes to variant selection of grain boundary allotriomorph (GBalpha). The model is able to predict all possible special beta grain boundaries where GBalpha is able to maintain BOR with two neighboring grain. In particular, the model has been used to evaluate the validity of all current empirical variant selection rules to obtain more insight of

Chronic myeloid leukemia and interferon-alpha : a study of complete cytogenetic responders

NARCIS (Netherlands)

Bonifazi, F; de Vivo, A; Rosti, G; Guilhot, F; Guilhot, J; Trabacchi, E; Hehlmann, R; Hochhaus, A; Shepherd, PCA; Steegmann, JL; Kluin-Nelemans, HC; Thaler, J; Simonsson, B; Louwagie, A; Reiffers, J; Mahon, FX; Montefusco, E; Alimena, G; Hasford, J; Richards, S; Saglio, G; Testoni, N; Martinelli, G; Tura, S; Baccarani, M

2001-01-01

Achieving a complete cytogenetic response (CCgR) is a major target in the treatment of chronic myeloid leukemia (CIVIL) with interferon-alpha (IFN-alpha), but CCgRs are rare. The mean CCgR rate is 13%, in a range of 5% to 33%. A collaborative study of 9 European Union countries has led to the

Nuclear Magnetic Resonance (NMR) Spectroscopic Characterization of Nanomaterials and Biopolymers

Science.gov (United States)

Guo, Chengchen

Nanomaterials have attracted considerable attention in recent research due to their wide applications in various fields such as material science, physical science, electrical engineering, and biomedical engineering. Researchers have developed many methods for synthesizing different types of nanostructures and have further applied them in various applications. However, in many cases, a molecular level understanding of nanoparticles and their associated surface chemistry is lacking investigation. Understanding the surface chemistry of nanomaterials is of great significance for obtaining a better understanding of the properties and functions of the nanomaterials. Nuclear magnetic resonance (NMR) spectroscopy can provide a familiar means of looking at the molecular structure of molecules bound to surfaces of nanomaterials as well as a method to determine the size of nanoparticles in solution. Here, a combination of NMR spectroscopic techniques including one- and two-dimensional NMR spectroscopies was used to investigate the surface chemistry and physical properties of some common nanomaterials, including for example, thiol-protected gold nanostructures and biomolecule-capped silica nanoparticles. Silk is a natural protein fiber that features unique properties such as excellent mechanical properties, biocompatibility, and non-linear optical properties. These appealing physical properties originate from the silk structure, and therefore, the structural analysis of silk is of great importance for revealing the mystery of these impressive properties and developing novel silk-based biomaterials as well. Here, solid-state NMR spectroscopy was used to elucidate the secondary structure of silk proteins in N. clavipes spider dragline silk and B. mori silkworm silk. It is found that the Gly-Gly-X (X=Leu, Tyr, Gln) motif in spider dragline silk is not in a beta-sheet or alpha-helix structure and is very likely to be present in a disordered structure with evidence for 31-helix

Advances in 27Al MAS NMR studies of geopolymers

Czech Academy of Sciences Publication Activity Database

Brus, Jiří; Abbrent, Sabina; Kobera, Libor; Urbanová, Martina; Cuba, P.

2016-01-01

Roč. 88, č. 2016 (2016), s. 79-147 ISSN 0066-4103 R&D Projects: GA ČR(CZ) GA13-24155S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : geopolymers * aluminosilicates * solid-state NMR Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.600, year: 2016

Lectures on pulsed NMR

International Nuclear Information System (INIS)

Pines, A.

1986-09-01

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

Comparative carbon-13 nuclear magnetic resonance study at 67. 9 MHz on lysozyme (human and egg-white) and. cap alpha. -lactalbumin (human and bovine) in their native and denatured state

Energy Technology Data Exchange (ETDEWEB)

van Binst, G; Biesemans, M [Brussels Univ. (Belgium). Faculte des Sciences

1975-01-01

A first detailed comparison of the /sup 13/C spectra at high field of two lysozymes (human and egg-white) and two ..cap alpha..-lactalbumins (human and bovine milk) is presented. Assignments were made on most of the resonance peaks in the aliphatic and aromatic regions of the denatured proteins. The relative peak intensities clearly demonstrate the differences in the amino acid composition of the related proteins. The broadening and the complexity of the spectra of the native proteins reflect the non equivalence of the chemical groups in the folded conformation. The usefulness of /sup 13/C nmr spectroscopy in the study of the interaction between small molecules and proteins was tested on N-acteyl-glucosamine in the presence of lysozyme.

A fragment separator at LBL for beta-NMR experiment

International Nuclear Information System (INIS)

Matsuta, K.; Ozawa, A.; Nojiri, Y.; Minamisono, T.; Fukuda, M.; Kitagawa, A.; Ohtsubo, T.; Momota, S.; Fukuda, S.; Matsuo, Y.; Takechi, H.; Minami, I.; Sugimoto, K.; Tanihata, I.; Omata, K.; Alonso, J.R.; Krebs, G.F.; Symons, T.J.M.

1992-03-01

The Beam 44 fragment separator was built at the Bevalac of LBL for NMR studies of beta emitting nuclei. 37 K, 39 Ca, and 43 Ti fragments originating from 40 Ca and 46 Ti primary beams were separated by the separator for NMR studies on these nuclei. Nuclear spin polarization was created in 39 Ca and 43 Ti using the tilted foil technique (TFT), and the magnetic moment of 43 Ti was deduced. Fragment polarization was measured for 37 K and 39 Ca emitted to finite deflection angles. The Beam 44 fragment separator in combination with a proper polarization technique, such as TFT or fragment polarization, has been very effective for such NMR studies

Alpha resonant scattering for astrophysical reaction studies

International Nuclear Information System (INIS)

Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

2014-01-01

Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of 7 Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the 7 Be(α,γ) reaction, and proposed a new cluster band in 11 C

NMR studies of chemical structural variation of insoluble organic matter from different carbonaceous chondrite groups

Science.gov (United States)

Cody, George D.; Alexander, Conel M. O.'D.

2005-02-01

Solid-state 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopic experiments have been performed on isolated meteoritic Insoluble Organic Matter (IOM) spanning four different carbonaceous chondrite meteorite groups; a CR2 (EET92042), a CI1 (Orgueil), a CM2 (Murchison), and the unique C2 meteorite, Tagish Lake. These solid state NMR experiments reveal considerable variation in bulk organic composition across the different meteorite group's IOM. The fraction of aromatic carbon increases as CR2 meteorite groups. Single pulse (SP) 13C magic angle spinning (MAS) NMR experiments reveal the presence of nanodiamonds with an apparent concentration ranking in the IOM of CR2 IOM of all four meteoritic IOM fractions are highly substituted. Fast spinning SP 1H MAS NMR spectral data combined with other NMR experimental data reveal that the average hydrogen content of sp 3 bonded carbon functional groups is low, requiring a high degree of aliphatic chain branching in each IOM fraction. The variation in chemistry across the meteorite groups is consistent with alteration by low temperature chemical oxidation. It is concluded that such chemistry principally affected the aliphatic moieties whereas the aromatic moieties and nanodiamonds may have been largely unaffected.

Understanding of the mechanical and structural changes induced by alpha particles and heavy ions in the French simulated nuclear waste glass

Energy Technology Data Exchange (ETDEWEB)