PSYCHE Pure Shift NMR Spectroscopy.

Science.gov (United States)

Foroozandeh, Mohammadali; Morris, Gareth; Nilsson, Mathias

2018-03-13

Broadband homodecoupling techniques in NMR, also known as "pure shift" methods, aim to enhance spectral resolution by suppressing the effects of homonuclear coupling interactions to turn multiplet signals into singlets. Such techniques typically work by selecting a subset of "active" nuclear spins to observe, and selectively inverting the remaining, "passive", spins to reverse the effects of coupling. Pure Shift Yielded by Chirp Excitation (PSYCHE) is one such method; it is relatively recent, but has already been successfully implemented in a range of different NMR experiments. Paradoxically, PSYCHE is one of the trickiest of pure shift NMR techniques to understand but one of the easiest to use. Here we offer some insights into theoretical and practical aspects of the method, and into the effects and importance of the experimental parameters. Some recent improvements that enhance the spectral purity of PSYCHE spectra will be presented, and some experimental frameworks including examples in 1D and 2D NMR spectroscopy, for the implementation of PSYCHE will be introduced. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

31-P NMR spectroscopy in radiotherapy

International Nuclear Information System (INIS)

Kiricuta, I.C.; Schmitt, W.G.H.; Beyer, H.K.

1987-01-01

Results suggest 31-P NMR spectroscopy to allow a discrimination between good and bad blood supply to the tumour owing to different metabolic behaviour and to furnish important information on tumour response to radiotherapy just a few hours after the application of a relatively low dose. Spectroscopy showed the radiation-sensitive tumour cells to behave relatively uniformly after radiotherapy suggesting this behaviour to be interpreted as therapeutical effectiveness. (orig./SHA) [de

High resolution NMR spectroscopy of physiological fluids: from metabolism to physiology

International Nuclear Information System (INIS)

Vion-Dury, J.; Nicoli, F.; Torri, G.; Torri, J.; Kriat, M.; Sciaky, M.; Davin, A.; Viout, P.; Confort-Gouny, S.; Cozzone, P.J.

1992-01-01

High resolution NMR spectroscopy of physiological fluids provides quantitative, qualitative and dynamic information on the metabolic status of the interstitial and plasma compartments under a variety of pathophysiological conditions. The simultaneous detection and quantitation by NMR spectroscopy of numerous compounds of the intermediary metabolism offers a new insight in the understanding of the 'milieu interieur'.NMR spectroscopy of physiological fluids offers a unique way to define and monitor the global metabolic homeostasis in humans. The development of this analytical approach is still limited by the scarcity of pluridisciplinary teams able to fully exploit the wealth of information present on the NMR spectrum of a fluid. While application in pharmacology and toxicology is already established, the main areas of current development are cancer, hereditary metabolic disorders, organ transplantation and neurological diseases

Tritiation methods and tritium NMR spectroscopy

International Nuclear Information System (INIS)

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

1991-09-01

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

Cell signaling, post-translational protein modifications and NMR spectroscopy

International Nuclear Information System (INIS)

Theillet, Francois-Xavier; Smet-Nocca, Caroline; Liokatis, Stamatios; Thongwichian, Rossukon; Kosten, Jonas; Yoon, Mi-Kyung; Kriwacki, Richard W.; Landrieu, Isabelle; Lippens, Guy; Selenko, Philipp

2012-01-01

Post-translationally modified proteins make up the majority of the proteome and establish, to a large part, the impressive level of functional diversity in higher, multi-cellular organisms. Most eukaryotic post-translational protein modifications (PTMs) denote reversible, covalent additions of small chemical entities such as phosphate-, acyl-, alkyl- and glycosyl-groups onto selected subsets of modifiable amino acids. In turn, these modifications induce highly specific changes in the chemical environments of individual protein residues, which are readily detected by high-resolution NMR spectroscopy. In the following, we provide a concise compendium of NMR characteristics of the main types of eukaryotic PTMs: serine, threonine, tyrosine and histidine phosphorylation, lysine acetylation, lysine and arginine methylation, and serine, threonine O-glycosylation. We further delineate the previously uncharacterized NMR properties of lysine propionylation, butyrylation, succinylation, malonylation and crotonylation, which, altogether, define an initial reference frame for comprehensive PTM studies by high-resolution NMR spectroscopy.

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)

Temperature-induced transitions in disordered proteins probed by NMR spectroscopy

DEFF Research Database (Denmark)

Kjærgaard, Magnus; Poulsen, Flemming Martin; Kragelund, Birthe Brandt

2012-01-01

Intrinsically disordered proteins are abundant in nature and perform many important physiological functions. Multidimensional NMR spectroscopy has been crucial for the understanding of the conformational properties of disordered proteins and is increasingly used to probe their conformational...... ensembles. Compared to folded proteins, disordered proteins are more malleable and more easily perturbed by environmental factors. Accordingly, the experimental conditions and especially the temperature modify the structural and functional properties of disordered proteins. NMR spectroscopy allows analysis...... of temperature-induced structural changes at residue resolution using secondary chemical shift analysis, paramagnetic relaxation enhancement, and residual dipolar couplings. This chapter discusses practical aspects of NMR studies of temperature-induced structural changes in disordered proteins....

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

New methods for the correction of 31P NMR spectra in in vivo NMR spectroscopy

International Nuclear Information System (INIS)

Starcuk, Z.; Bartusek, K.; Starcuk, Z. jr.

1994-01-01

The new methods for the correction of 31 P NMR spectra in vivo NMR spectroscopy have been performed. A method for the baseline correction of the spectra which represents a combination of time-domain and frequency-domain has been discussed.The method is very fast and efficient for minimization of base line artifacts of biological tissues impact

NMR comparison of prokaryotic and eukaryotic cytochromes c

International Nuclear Information System (INIS)

Chau, Meihing; Cai, Meng Li; Timkovich, R.

1990-01-01

1 H NMR spectroscopy has been used to examine ferrocytochrome c-551 from Pseudomonas aeruginosa (ATCC 19429) over the pH range 3.5-10.6 and the temperature range 4-60 degree C. Resonance assignments are proposed for main-chain and side-chain protons. Comparison of results for cytochrome c-551 to recently assigned spectra for horse cytochrome c and mutants of yeast iso-1 cytochrome reveals some unique resonances with unusual chemical shifts in all cytochromes that may serve as markers for the heme region. Results for cytochrome c-551 indicate that in the smaller prokaryotic cytochrome, all benzoid side chains are rapidly flipping on the NMR time scale. In contrast, in eukaryotic cytochromes there are some rings flipping slowly on the NMR time scale. The ferrocytochrome c-551 undergoes a transition linked to pH with a pK around 7. The pH behavior of assigned resonances provides evidence that the site of protonation is the inner or buried 17-propionic acid heme substituent (IUPAC-IUB porphyrin nomenclature). Conformational heterogeneity has been observed for segments near the inner heme propionate substituent

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

Application of NMR Spectroscopy in the Analysis of Petroleum Derivatives and Products

Directory of Open Access Journals (Sweden)

Parlov Vuković, J.

2012-11-01

Full Text Available Complex chemical composition and physical properties of oil and fuel make their complete cha racterization very difficult. Components present in oil and oil products differ in structure, size, po larity and functionality. The presence and structure of specific hydrocarbons in final products depend on the processing procedure and type of the fuel. In order to predict or improve fuel pro perties it is necessary to determine its composition. Thus, new and more sophisticated analytical methods and procedures are constantly being developed. NMR spectroscopy plays a significant role in analysis and identification of complex hydrocarbon mixtures of petroleum and petroleum products. In this review, we describe the application of NMR spectroscopy for analyzing gasoline and diesel fuels. Hence, by using NMR spectroscopy it is possible to determine gasoline composition and presence of benzene and oxygenates, as well as some important physical characteristics of gasoli ne such as the research octane number. An application of different NMR techniques made it pos sible to characterize diesel fuels and middle oil distillates from various refineries. Data so obtained can be used in combination with statistical methods to predict fuel properties and to monitor pro- duction processes in the petroleum industry. NMR spectroscopy has proven useful in analysis of FAME which has recently been used as an ecologically acceptable alternative fuel. Furthermore, techniques such as CP/MAS for characterization of solid state oil-geochemical samples are inclu- ded. Also, possibilities of using NMR spectroscopy in the analysis of polymeric additives are di- scussed.

Solid-State NMR Spectroscopy for the Physical Chemistry Laboratory

Science.gov (United States)

Kinnun, Jacob J.; Leftin, Avigdor; Brown, Michael F.

2013-01-01

Solid-state nuclear magnetic resonance (NMR) spectroscopy finds growing application to inorganic and organic materials, biological samples, polymers, proteins, and cellular membranes. However, this technique is often neither included in laboratory curricula nor typically covered in undergraduate courses. On the other hand, spectroscopy and…

[Non-invasive analysis of proteins in living cells using NMR spectroscopy].

Science.gov (United States)

Tochio, Hidehito; Murayama, Shuhei; Inomata, Kohsuke; Morimoto, Daichi; Ohno, Ayako; Shirakawa, Masahiro

2015-01-01

NMR spectroscopy enables structural analyses of proteins and has been widely used in the structural biology field in recent decades. NMR spectroscopy can be applied to proteins inside living cells, allowing characterization of their structures and dynamics in intracellular environments. The simplest "in-cell NMR" approach employs bacterial cells; in this approach, live Escherichia coli cells overexpressing a specific protein are subjected to NMR. The cells are grown in an NMR active isotope-enriched medium to ensure that the overexpressed proteins are labeled with the stable isotopes. Thus the obtained NMR spectra, which are derived from labeled proteins, contain atomic-level information about the structure and dynamics of the proteins. Recent progress enables us to work with higher eukaryotic cells such as HeLa and HEK293 cells, for which a number of techniques have been developed to achieve isotope labeling of the specific target protein. In this review, we describe successful use of electroporation for in-cell NMR. In addition, (19)F-NMR to characterize protein-ligand interactions in cells is presented. Because (19)F nuclei rarely exist in natural cells, when (19)F-labeled proteins are delivered into cells and (19)F-NMR signals are observed, one can safely ascertain that these signals originate from the delivered proteins and not other molecules.

Two-dimensional NMR spectroscopy. Applications for chemists and biochemists

International Nuclear Information System (INIS)

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

1987-01-01

Two-dimensional nuclear magnetic resonance spectroscopy (2-D NMR) has become a very powerful class of experiments (in the hands of an adept scientist) with broad adaptability to new situations. It is the product of a happy marriage between modern pulse FT-NMR technology, with its large memory and high-speed computers, and the physicists and chemists who love to manipulate spin systems. Basic 2-D experiments are now a standard capability of modern NMR spectrometers, and this timely book intends to make 2-D NMR users of those who are familiar with normal 1-D NMR. The 2-D NMR goal is correlation of the lines of the observed NMR spectrum with other properties of the system. This book deals with applications to high-resolution spectrum analysis, utilizing either coupling between the NMR-active nuclei or chemical exchange to perform the correlation. The coupling can be scalar (through bonds) or direct through space (within 5 A). The coupling may be homonuclear (between like nuclei) or heteronuclear

DNP-enhanced solid-state NMR spectroscopy of active pharmaceutical ingredients.

Science.gov (United States)

Zhao, Li; Pinon, Arthur C; Emsley, Lyndon; Rossini, Aaron J

2017-11-28

Solid-state NMR spectroscopy has become a valuable tool for the characterization of both pure and formulated active pharmaceutical ingredients (APIs). However, NMR generally suffers from poor sensitivity that often restricts NMR experiments to nuclei with favorable properties, concentrated samples, and acquisition of one-dimensional (1D) NMR spectra. Here, we review how dynamic nuclear polarization (DNP) can be applied to routinely enhance the sensitivity of solid-state NMR experiments by one to two orders of magnitude for both pure and formulated APIs. Sample preparation protocols for relayed DNP experiments and experiments on directly doped APIs are detailed. Numerical spin diffusion models illustrate the dependence of relayed DNP enhancements on the relaxation properties and particle size of the solids and can be used for particle size determination when the other factors are known. We then describe the advanced solid-state NMR experiments that have been enabled by DNP and how they provide unique insight into the molecular and macroscopic structure of APIs. For example, with large sensitivity gains provided by DNP, natural isotopic abundance, 13 C- 13 C double-quantum single-quantum homonuclear correlation NMR spectra of pure APIs can be routinely acquired. DNP also enables solid-state NMR experiments with unreceptive quadrupolar nuclei such as 2 H, 14 N, and 35 Cl that are commonly found in APIs. Applications of DNP-enhanced solid-state NMR spectroscopy for the molecular level characterization of low API load formulations such as commercial tablets and amorphous solid dispersions are described. Future perspectives for DNP-enhanced solid-state NMR experiments on APIs are briefly discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Determination of gluconeogenesis in man by the use of deuterium-NMR-spectroscopy

International Nuclear Information System (INIS)

Rosian, E.

2000-03-01

The aim of this dissertation is the quantification of the deuterium--distribution in human glucose by the use of the deuterium NMR spectroscopy of deuteriated water. The glucose production in human organism is composed of gluconeogenesis and glycolysis. The quantification of the part of gluconeogenesis on the total glucose production was determined by the use of deuterium NMR spectroscopy. (boteke)

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.

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

Photochromism of indolino-benzopyrans studied by NMR and UV-visible spectroscopy

Directory of Open Access Journals (Sweden)

S. Delbaere

2006-01-01

is described. The structures of photomerocyanines elucidated by NMR spectroscopy and spectrokinetic data (λmax⁡ of colored form, colorability, and rate constant of bleaching obtained by UV-visible spectroscopy are reported.

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...

An Oil Spill in a Tube: An Accessible Approach for Teaching Environmental NMR Spectroscopy

Science.gov (United States)

Simpson, Andre´ J.; Mitchell, Perry J.; Masoom, Hussain; Mobarhan, Yalda Liaghati; Adamo, Antonio; Dicks, Andrew P.

2015-01-01

NMR spectroscopy has great potential as an instrumental method for environmental chemistry research and monitoring but may be underused in teaching laboratories because of its complexity and the level of expertise required in operating the instrument and interpreting data. This laboratory experiment introduces environmental NMR spectroscopy to…

MULTIVARIATE CURVE RESOLUTION OF NMR SPECTROSCOPY METABONOMIC DATA

Science.gov (United States)

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

In vivo NMR spectroscopy of ripening avocado

International Nuclear Information System (INIS)

Bennett, A.B.; Smith, G.M.; Nichols, B.

1987-01-01

Ripening of avocado fruit is associated with a dramatic increase in respiration. Previous studies have indicated that the increase in respiration is brought about by activation of the glycolytic reaction catalyzing the conversion of fructose-6-phosphate to fructose 1,6-bisphosphate. The authors reinvestigated the proposed role of glycolytic regulation in the respiratory increase using in vivo 31 P nuclear magnetic resonance (NMR) spectroscopy using an external surface coil and analysis of phosphofructokinase (PFK), phosphofructophosphotransferase (PFP), and fructose 2,6-bisphosphate (fru 2,6-P 2 ) levels in ripening avocado fruit. In vivo 31 P NMR spectroscopy revealed large increases in ATP levels accompanying the increase in respiration. Both glycolytic enzymes, PFK and PFP, were present in avocado fruit, with the latter activity being highly stimulated by fru 2,6-P 2 . Fructose 2,6-bisphosphate levels increased approximately 90% at the onset of ripening, indicating that the respiratory increase in ripening avocado may be regulated by the activation of PFP brought about by an increase in fru 2,6-P 2

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Science.gov (United States)

Lu, Yi; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

2016-01-01

NMR measurements do not require separation and chemical modification of samples and therefore rapidly and directly provide non-targeted information on chemical components in complex mixtures. In this study, one-dimensional (1H, 13C, and 31P) and two-dimensional (1H-13C and 1H-31P) NMR spectroscopy were conducted to analyze yogurt without any pretreatment. 1H, 13C, and 31P NMR signals were assigned to 10 types of compounds. The signals of α/β-lactose and α/β-galactose were separately observed in the 1H NMR spectra. In addition, the signals from the acyl chains of milk fats were also successfully identified but overlapped with many other signals. Quantitative difference spectra were obtained by subtracting the diffusion ordered spectroscopy (DOSY) spectra from the quantitative 1H NMR spectra. This method allowed us to eliminate interference on the overlaps; therefore, the correct intensities of signals overlapped with those from the acyl chains of milk fat could be determined directly without separation. Moreover, the 1H-31P HMBC spectra revealed for the first time that N-acetyl-d-glucosamine-1-phosphate is contained in yogurt. PMID:27322339

Remeasuring HEWL pKa values by NMR spectroscopy 

DEFF Research Database (Denmark)

Webb, Helen; Tynan-Connolly, Barbara Mary; Lee, Gregory M

2011-01-01

Site-specific pK(a) values measured by NMR spectroscopy provide essential information on protein electrostatics, the pH-dependence of protein structure, dynamics and function, and constitute an important benchmark for protein pK(a) calculation algorithms. Titration curves can be measured by track......Site-specific pK(a) values measured by NMR spectroscopy provide essential information on protein electrostatics, the pH-dependence of protein structure, dynamics and function, and constitute an important benchmark for protein pK(a) calculation algorithms. Titration curves can be measured...... by tracking the NMR chemical shifts of several reporter nuclei versus sample pH. However, careful analysis of these curves is needed to extract residue-specific pK(a) values since pH-dependent chemical shift changes can arise from many sources, including through-bond inductive effects, through-space electric...... protonated carbons and protons in this protein. We extracted pK(a) values from the resulting titration curves using standard fitting methods, and compared these values to each other, and with those measured previously by ¹H NMR (Bartik et al., Biophys J 1994;66:1180–1184). This analysis gives insights...

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.

19F labelled dextrans and antibodies as NMR imaging and spectroscopy agents

International Nuclear Information System (INIS)

Antich, P.P.; Kulkarni, P.V.

1993-01-01

A method is described of NMR imaging or spectroscopy, comprising the steps of administering to a living subject a 19 F labelled NMR agent, the NMR agent comprising (a) a transport polymer selected from the group consisting of dextran polymers and amino dextrans, having a molecular weight between approximately 100 d and 500 kd, and antibodies and fragments thereof, and (b) a 19F-containing sensor moiety selected from the group consisting of fluorinated alkyls, fluorinated acetates, fluoroaniline, and fluoroalkyl phosphonates, in an amount effective to provide a detectable NMR signal; and then detecting the 19 F NMR signal produced

Pectins from apple pomace - characterization by 13C and 1H NMR spectroscopy

International Nuclear Information System (INIS)

Marcon, M.V.; Carneiro, P.I.B.; Wosiacki, G.; Beleski-Carneiro, E.; Petkowicz, C.L.O.

2005-01-01

Pectins were extracted from apple pomace flour with 5% (w/v) aqueous citric acid solutions under different time and temperature according to an experimental design (factorial 2 2 with triplicate of central point). Monosaccharide composition of fractions was determined by colorimetric analysis and gas chromatography. The structure of pectins was studied by NMR spectroscopy. The degree of esterification (DE=30.5-55.9), determined by FT-IR spectroscopy, was indirectly correlated with increasing temperature and time of extraction, showing that drastic conditions for extraction promote hydrolysis of esterified units. High content of galacturonic acid is consistent with the smooth region of the polysaccharide. 13 C and 1 H NMR spectroscopy confirmed the presence of uronic acids in the free and methyl ester forms. NMR data also showed the presence of arabinan and galactan as side chains. (author)

High resolution NMR spectroscopy of nanocrystalline proteins at ultra-high magnetic field

International Nuclear Information System (INIS)

Sperling, Lindsay J.; Nieuwkoop, Andrew J.; Lipton, Andrew S.; Berthold, Deborah A.; Rienstra, Chad M.

2010-01-01

Magic-angle spinning (MAS) solid-state NMR (SSNMR) spectroscopy of uniformly- 13 C, 15 N labeled protein samples provides insight into atomic-resolution chemistry and structure. Data collection efficiency has advanced remarkably in the last decade; however, the study of larger proteins is still challenged by relatively low resolution in comparison to solution NMR. In this study, we present a systematic analysis of SSNMR protein spectra acquired at 11.7, 17.6 and 21.1 Tesla ( 1 H frequencies of 500, 750, and 900 MHz). For two protein systems-GB1, a 6 kDa nanocrystalline protein and DsbA, a 21 kDa nanocrystalline protein-line narrowing is demonstrated in all spectral regions with increasing field. Resolution enhancement is greatest in the aliphatic region, including methine, methylene and methyl sites. The resolution for GB1 increases markedly as a function of field, and for DsbA, resolution in the C-C region increases by 42%, according to the number of peaks that can be uniquely picked and integrated in the 900 MHz spectra when compared to the 500 MHz spectra. Additionally, chemical exchange is uniquely observed in the highest field spectra for at least two isoleucine Cδ1 sites in DsbA. These results further illustrate the benefits of high-field MAS SSNMR spectroscopy for protein structural studies.

Development of a micro flow-through cell for high field NMR spectroscopy.

Energy Technology Data Exchange (ETDEWEB)

Alam, Todd Michael; McIntyre, Sarah K.

2011-05-01

A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.

High-resolution proton NMR spectroscopy of cerebrospinal fluid: methodological issues and potential clinical applications

International Nuclear Information System (INIS)

Kriat, M.; Nicoli, F.; Vion-Dury, J.; Confort-Gouny, S.; Cozzone, P.J.; Nicoli, F.; Gastaut, J.L.; Dano, P.; Grisoli, F.

1991-01-01

High resolution proton nuclear magnetic resonance (NMR) spectroscopy is a new analytical technique which allows to readily identify and quantitate a variety of key metabolites in cerebrospinal fluid (CSF) in relation to normal and pathological brain activity. Proton NMR spectroscopy can be performed on native CSF, with or without addition of exchange reagent (NH 4 Cl). The analysis of native CSF provides qualitative information (identification) of metabolites or xenobiotics present in the fluid. Alternately, CSF can be lyophilized and dissolved in deuterated water. This concentration offers 2 advantages: additional compounds are detected and a precise quantification of all CSF metabolites can be obtained. Both protocols require a very small volume of CFS (1-2 ml). The high informational content available on the NMR spectra of CSF, the ease-of-use of NMR spectroscopy and its cost effectiveness concur to predict that this analytical approach will keep developing to completement the array of existing tests which are already routinely performed on CSF. 6 figs [fr

Photochromism of indolino-benzopyrans studied by NMR and UV-visible spectroscopy

OpenAIRE

S. Delbaere; J. Berthet; M. A. Salvador; G. Vermeersch; M. M. Oliveira

2006-01-01

The synthesis of photochromic 3,3-di(4′-fluorophenyl)-3H-benzopyrans fused to an indole moiety is described. The structures of photomerocyanines elucidated by NMR spectroscopy and spectrokinetic data (λmax⁡ of colored form, colorability, and rate constant of bleaching) obtained by UV-visible spectroscopy are reported.

Determination of the three-dimensional structure for weakly aligned biomolecules by NMR spectroscopy

International Nuclear Information System (INIS)

Shahkhatuni, Astghik A; Shahkhatuni, Aleksan G

2002-01-01

The key achievements and the potential of NMR spectroscopy for weakly aligned biomolecules are considered. Due to weak alignment, it becomes possible to determine a number of NMR parameters dependent on the orientation of biomolecules, which are averaged to zero in usual isotropic media. The addition of new orientational constraints to standard procedures of 3D structure determination markedly increases the achievable accuracy. The possibility of structure determination for biomolecules using only orientation-dependent parameters without invoking other NMR data is discussed. The methods of orientation, experimental techniques, and calculation methods are systematised. The main results obtained and the prospects of using NMR spectroscopy of weakly aligned systems to study different classes of biomolecules and to solve various problems of molecular biology are analysed. Examples of biomolecules whose structures have been determined using orientation-dependent parameters are given. The bibliography includes 508 references.

[Detection of peranesthetic malignant hyperthermia by muscle contracture tests and NMR spectroscopy].

Science.gov (United States)

Kozak-Reiss, G; Gascard, J P; Redouane-Bénichou, K

1986-01-01

To diagnose malignant hyperthermia susceptibility (MHS), caffeine and halothane contracture tests were performed on six patients. One of them, who presented a peroperative crisis, was recognized as MHS; the five others were negative (MHN). By means of 31P-NMR spectroscopy, the muscular energetic metabolism of these patients was studied during and after moderate exercise in normal and moderate ischaemic conditions. Metabolic abnormalities appeared in the MHS patient. It must be concluded therefore that malignant hyperthermia is a latent myopathy. 31P-NMR spectroscopy appeared to be a useful non-invasive tool for screening for this affliction.

31P NMR spectroscopy of tumors in the evaluation of response to therapy

International Nuclear Information System (INIS)

Sijens, P.E.

1988-01-01

In this thesis the effects of different kinds of therapy on tumour metabolism were investigated by in vivo 31P NMR spectroscopy. From the first five chapters (laboratory-animal studies) it turns out that after radiotherapy as well as after hyperthermy or chemoterapy changes can be observed in the 31P NMR spectra of tumours. In a number of cases a durable decline occurred in the ratio of the high-energetic adenosinephosphate (ATP) and the low-energeic anorganic phosphate, cuased by the mortification of tumourcells. On the other hand, tumour regression after effective chemotherapy resulted in a growth of the ATP/Pi ratio. In one case a temporary drop occurred which could be related to a temporary decrease in tumour perfusion. In anoter case a temporary drop of the ATP/Pi ratio correlated with resistence against treatment with cis-diaminodichoroplatina. In contrast with the changes in ATP/Pi ratio, the changes, after (chemo)therapy, in tumour pH do not seem to be related with the respons of the tumour. The results of the laboratory-animal experiments indicate that in vivo 31P NMR spectroscopy could be applied in the clinic in order to establish betime the response of tumours on therapy. In ch. 6 initial experiences with clinical NMR spectroscopy of human breast cancer are described. The results indicate that by 31P NMR spectroscopy malignant breast tissues can be discerned from normal breast tissues, following radiotherapy and subsequent tumour regression, in the spectrum of the tumorous region an intense PCr signal developed which appeared to reflect a metabolic change in the tumous itself. 177 refs.; 27 figs.; 6 tabs

Dynamics in photosynthetic transient complexes studied by paramagnetic NMR spectroscopy

NARCIS (Netherlands)

Scanu, Sandra

2013-01-01

This PhD thesis focuses on fundamental aspects of protein-protein interactions. A multidisciplinary methodology for the detection and visualization of transient, lowly-populated encounter protein complexes is described. The new methodology combined paramagnetic NMR spectroscopy with computational

(Cicer arietinum L.) seeds during germination by NMR spectroscopy

African Journals Online (AJOL)

Experiments were conducted to characterize the changes in water status during imbibition by nuclear magnetic resonance (NMR) spectroscopy in chickpea seeds exposed to static magnetic fields of 100 mT for 1 h. Water uptake during seed germination showed three phases with rapid initial hydration phase I, followed by ...

Combined In Situ Illumination-NMR-UV/Vis Spectroscopy: A New Mechanistic Tool in Photochemistry.

Science.gov (United States)

Seegerer, Andreas; Nitschke, Philipp; Gschwind, Ruth M

2018-06-18

Synthetic applications in photochemistry are booming. Despite great progress in the development of new reactions, mechanistic investigations are still challenging. Therefore, we present a fully automated in situ combination of NMR spectroscopy, UV/Vis spectroscopy, and illumination to allow simultaneous and time-resolved detection of paramagnetic and diamagnetic species. This optical fiber-based setup enables the first acquisition of combined UV/Vis and NMR spectra in photocatalysis, as demonstrated on a conPET process. Furthermore, the broad applicability of combined UVNMR spectroscopy for light-induced processes is demonstrated on a structural and quantitative analysis of a photoswitch, including rate modulation and stabilization of transient species by temperature variation. Owing to the flexibility regarding the NMR hardware, temperature, and light sources, we expect wide-ranging applications of this setup in various research fields. © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

[Rapid analysis of suppositories by quantitative 1H NMR spectroscopy].

Science.gov (United States)

Abramovich, R A; Kovaleva, S A; Goriainov, S V; Vorob'ev, A N; Kalabin, G A

2012-01-01

Rapid analysis of suppositories with ibuprofen and arbidol by quantitative 1H NMR spectroscopy was performed. Optimal conditions for the analysis were developed. The results are useful for design of rapid methods for quality control of suppositories with different components

Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy.

Science.gov (United States)

Jakes, W; Gerdova, A; Defernez, M; Watson, A D; McCallum, C; Limer, E; Colquhoun, I J; Williamson, D C; Kemsley, E K

2015-05-15

This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz (1)H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional "authentic" beef region (p=0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze-thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz (1)H NMR represents a feasible high-throughput approach for screening raw meat. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

NMR-based approach to the analysis of radiopharmaceuticals: radiochemical purity, specific activity, and radioactive concentration values by proton and tritium NMR spectroscopy.

Science.gov (United States)

Schenk, David J; Dormer, Peter G; Hesk, David; Pollack, Scott R; Lavey, Carolee Flader

2015-06-15

Compounds containing tritium are widely used across the drug discovery and development landscape. These materials are widely utilized because they can be efficiently synthesized and produced at high specific activity. Results from internally calibrated (3)H and (1)H nuclear magnetic resonance (NMR) spectroscopy suggests that at least in some cases, this calibrated approach could supplement or potentially replace radio-high-performance liquid chromatography for radiochemical purity, dilution and scintillation counting for the measurement of radioactivity per volume, and liquid chromatography/mass spectrometry analysis for the determination of specific activity. In summary, the NMR-derived values agreed with those from the standard approaches to within 1% to 9% for solution count and specific activity. Additionally, the NMR-derived values for radiochemical purity deviated by less than 5%. A benefit of this method is that these values may be calculated at the same time that (3)H NMR analysis provides the location and distribution of tritium atoms within the molecule. Presented and discussed here is the application of this method, advantages and disadvantages of the approach, and a rationale for utilizing internally calibrated (1)H and (3)H NMR spectroscopy for specific activity, radioactive concentration, and radiochemical purity whenever acquiring (3)H NMR for tritium location. Copyright © 2015 John Wiley & Sons, Ltd.

Delineating pMDI model reactions with loblolly pine via solution-state NMR spectroscopy. Part 1, Catalyzed reactions with wood models and wood polymers

Science.gov (United States)

Daniel J. Yelle; John Ralph; Charles R. Frihart

2011-01-01

To better understand adhesive interactions with wood, reactions between model compounds of wood and a model compound of polymeric methylene diphenyl diisocyanate (pMDI) were characterized by solution-state NMR spectroscopy. For comparison, finely ground loblolly pine sapwood, milled-wood lignin and holocellulose from the same wood were isolated and derivatized with...

Exploring high-resolution magic angle spinning (HR-MAS) NMR spectroscopy for metabonomic analysis of apples.

Science.gov (United States)

Vermathen, Martina; Marzorati, Mattia; Vermathen, Peter

2012-01-01

Classical liquid-state high-resolution (HR) NMR spectroscopy has proved a powerful tool in the metabonomic analysis of liquid food samples like fruit juices. In this paper the application of (1)H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to apple tissue is presented probing its potential for metabonomic studies. The (1)H HR-MAS NMR spectra are discussed in terms of the chemical composition of apple tissue and compared to liquid-state NMR spectra of apple juice. Differences indicate that specific metabolic changes are induced by juice preparation. The feasibility of HR-MAS NMR-based multivariate analysis is demonstrated by a study distinguishing three different apple cultivars by principal component analysis (PCA). Preliminary results are shown from subsequent studies comparing three different cultivation methods by means of PCA and partial least squares discriminant analysis (PLS-DA) of the HR-MAS NMR data. The compounds responsible for discriminating organically grown apples are discussed. Finally, an outlook of our ongoing work is given including a longitudinal study on apples.

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

International Nuclear Information System (INIS)

Richards, T.

1984-09-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Richards, T.

1984-09-01

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

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

Directory of Open Access Journals (Sweden)

Márcio S. Silva

2017-02-01

Full Text Available Nuclear magnetic resonance (NMR is a powerful tool for the elucidation of chemical structure and chiral recognition. In the last decade, the number of probes, media, and experiments to analyze chiral environments has rapidly increased. The evaluation of chiral molecules and systems has become a routine task in almost all NMR laboratories, allowing for the determination of molecular connectivities and the construction of spatial relationships. Among the features that improve the chiral recognition abilities by NMR is the application of different nuclei. The simplicity of the multinuclear NMR spectra relative to 1H, the minimal influence of the experimental conditions, and the larger shift dispersion make these nuclei especially suitable for NMR analysis. Herein, the recent advances in multinuclear (19F, 31P, 13C, and 77Se NMR spectroscopy for chiral recognition of organic compounds are presented. The review describes new chiral derivatizing agents and chiral solvating agents used for stereodiscrimination and the assignment of the absolute configuration of small organic compounds.

Probing Spin Crossover in a Solution by Paramagnetic NMR Spectroscopy.

Science.gov (United States)

Pavlov, Alexander A; Denisov, Gleb L; Kiskin, Mikhail A; Nelyubina, Yulia V; Novikov, Valentin V

2017-12-18

Spin transitions in spin-crossover compounds are now routinely studied in the solid state by magnetometry; however, only a few methods exist for studies in solution. The currently used Evans method, which relies on NMR spectroscopy to measure the magnetic susceptibility, requires the availability of a very pure sample of the paramagnetic compound and its exact concentration. To overcome these limitations, we propose an alternative NMR-based technique for evaluating spin-state populations by only using the chemical shifts of a spin-crossover compound; those can be routinely obtained for a solution that contains unknown impurities and paramagnetic admixtures or is contaminated otherwise.

Insights into reaction mechanisms in heterogeneous catalysis revealed by in situ NMR spectroscopy.

Science.gov (United States)

Blasco, Teresa

2010-12-01

This tutorial review intends to show the possibilities of in situ solid state NMR spectroscopy in the elucidation of reaction mechanisms and the nature of the active sites in heterogeneous catalysis. After a brief overview of the more usual experimental devices used for in situ solid state NMR spectroscopy measurements, some examples of applications taken from the recent literature will be presented. It will be shown that in situ NMR spectroscopy allows: (i) the identification of stable intermediates and transient species using indirect methods, (ii) to prove shape selectivity in zeolites, (iii) the study of reaction kinetics, and (iv) the determination of the nature and the role played by the active sites in a catalytic reaction. The approaches and methodology used to get this information will be illustrated here summarizing the most relevant contributions on the investigation of the mechanisms of a series of reactions of industrial interest: aromatization of alkanes on bifunctional catalysts, carbonylation reaction of methanol with carbon monoxide, ethylbenzene disproportionation, and the Beckmann rearrangement reaction. Special attention is paid to the research carried out on the role played by carbenium ions and alkoxy as intermediate species in the transformation of hydrocarbon molecules on solid acid catalysts.

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.

NMR spectroscopy in the optimization and evaluation of RAFT agents

NARCIS (Netherlands)

Klumperman, B.; McLeary, J.B.; van den Dungen, E.; Pound, G.

2007-01-01

The selection of a suitable mediating agent in Reversible Addition-Fragmentation Chain Transfer (RAFT) mediated polymerization is crucial to the degree of control that can be achieved. An overview of work from the Stellenbosch group is presented in which the use of NMR spectroscopy as a tool for

Structure determination of helical filaments by solid-state NMR spectroscopy

Science.gov (United States)

Ahmed, Mumdooh; Spehr, Johannes; König, Renate; Lünsdorf, Heinrich; Rand, Ulfert; Lührs, Thorsten; Ritter, Christiane

2016-01-01

The controlled formation of filamentous protein complexes plays a crucial role in many biological systems and represents an emerging paradigm in signal transduction. The mitochondrial antiviral signaling protein (MAVS) is a central signal transduction hub in innate immunity that is activated by a receptor-induced conversion into helical superstructures (filaments) assembled from its globular caspase activation and recruitment domain. Solid-state NMR (ssNMR) spectroscopy has become one of the most powerful techniques for atomic resolution structures of protein fibrils. However, for helical filaments, the determination of the correct symmetry parameters has remained a significant hurdle for any structural technique and could thus far not be precisely derived from ssNMR data. Here, we solved the atomic resolution structure of helical MAVSCARD filaments exclusively from ssNMR data. We present a generally applicable approach that systematically explores the helical symmetry space by efficient modeling of the helical structure restrained by interprotomer ssNMR distance restraints. Together with classical automated NMR structure calculation, this allowed us to faithfully determine the symmetry that defines the entire assembly. To validate our structure, we probed the protomer arrangement by solvent paramagnetic resonance enhancement, analysis of chemical shift differences relative to the solution NMR structure of the monomer, and mutagenesis. We provide detailed information on the atomic contacts that determine filament stability and describe mechanistic details on the formation of signaling-competent MAVS filaments from inactive monomers. PMID:26733681

High-resolution 1H NMR spectroscopy of fish muscle, eggs and small whole fish via Hadamard-encoded intermolecular multiple-quantum coherence.

Directory of Open Access Journals (Sweden)

Honghao Cai

Full Text Available BACKGROUND AND PURPOSE: Nuclear magnetic resonance (NMR spectroscopy has become an important technique for tissue studies. Since tissues are in semisolid-state, their high-resolution (HR spectra cannot be obtained by conventional NMR spectroscopy. Because of this restriction, extraction and high-resolution magic angle spinning (HR MAS are widely applied for HR NMR spectra of tissues. However, both of the methods are subject to limitations. In this study, the feasibility of HR (1H NMR spectroscopy based on intermolecular multiple-quantum coherence (iMQC technique is explored using fish muscle, fish eggs, and a whole fish as examples. MATERIALS AND METHODS: Intact salmon muscle tissues, intact eggs from shishamo smelt and a whole fish (Siamese algae eater are studied by using conventional 1D one-pulse sequence, Hadamard-encoded iMQC sequence, and HR MAS. RESULTS: When we use the conventional 1D one-pulse sequence, hardly any useful spectral information can be obtained due to the severe field inhomogeneity. By contrast, HR NMR spectra can be obtained in a short period of time by using the Hadamard-encoded iMQC method without shimming. Most signals from fatty acids and small metabolites can be observed. Compared to HR MAS, the iMQC method is non-invasive, but the resolution and the sensitivity of resulting spectra are not as high as those of HR MAS spectra. CONCLUSION: Due to the immunity to field inhomogeneity, the iMQC technique can be a proper supplement to HR MAS, and it provides an alternative for the investigation in cases with field distortions and with samples unsuitable for spinning. The acquisition time of the proposed method is greatly reduced by introduction of the Hadamard-encoded technique, in comparison with that of conventional iMQC method.

Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy

Science.gov (United States)

Jakes, W.; Gerdova, A.; Defernez, M.; Watson, A.D.; McCallum, C.; Limer, E.; Colquhoun, I.J.; Williamson, D.C.; Kemsley, E.K.

2015-01-01

This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz 1H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional “authentic” beef region (p = 0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze–thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz 1H NMR represents a feasible high-throughput approach for screening raw meat. PMID:25577043

The contribution of solid-state NMR spectroscopy to understanding biomineralization: Atomic and molecular structure of bone

Science.gov (United States)

Duer, Melinda J.

2015-04-01

Solid-state NMR spectroscopy has had a major impact on our understanding of the structure of mineralized tissues, in particular bone. Bone exemplifies the organic-inorganic composite structure inherent in mineralized tissues. The organic component of the extracellular matrix in bone is primarily composed of ordered fibrils of collagen triple-helical molecules, in which the inorganic component, calcium phosphate particles, composed of stacks of mineral platelets, are arranged around the fibrils. This perspective argues that key factors in our current structural model of bone mineral have come about through NMR spectroscopy and have yielded the primary information on how the mineral particles interface and bind with the underlying organic matrix. The structure of collagen within the organic matrix of bone or any other structural tissue has yet to be determined, but here too, this perspective shows there has been real progress made through application of solid-state NMR spectroscopy in conjunction with other techniques. In particular, NMR spectroscopy has highlighted the fact that even within these structural proteins, there is considerable dynamics, which suggests that one should be cautious when using inherently static structural models, such as those arising from X-ray diffraction analyses, to gain insight into molecular roles. It is clear that the NMR approach is still in its infancy in this area, and that we can expect many more developments in the future, particularly in understanding the molecular mechanisms of bone diseases and ageing.

Recombinant Kinase Production and Fragment Screening by NMR Spectroscopy.

Science.gov (United States)

Han, Byeonggu; Ahn, Hee-Chul

2016-01-01

During the past decade fragment-based drug discovery (FBDD) has rapidly evolved and several drugs or drug candidates developed by FBDD approach are clinically in use or in clinical trials. For example, vemurafenib, a V600E mutated BRAF inhibitor, was developed by utilizing FBDD approach and approved by FDA in 2011. In FBDD, screening of fragments is the starting step for identification of hits and lead generation. Fragment screening usually relies on biophysical techniques by which the protein-bound small molecules can be detected. NMR spectroscopy has been extensively used to study the molecular interaction between the protein and the ligand, and has many advantages in fragment screening over other biophysical techniques. This chapter describes the practical aspects of fragment screening by saturation transfer difference NMR.

Ion counting in supercapacitor electrodes using NMR spectroscopy.

Science.gov (United States)

Griffin, John M; Forse, Alexander C; Wang, Hao; Trease, Nicole M; Taberna, Pierre-Louis; Simon, Patrice; Grey, Clare P

2014-01-01

(19)F NMR spectroscopy has been used to study the local environments of anions in supercapacitor electrodes and to quantify changes in the populations of adsorbed species during charging. In the absence of an applied potential, anionic species adsorbed within carbon micropores (in-pore) are distinguished from those in large mesopores and spaces between particles (ex-pore) by a characteristic nucleus-independent chemical shift (NICS). Adsorption experiments and two-dimensional exchange experiments confirm that anions are in dynamic equilibrium between the in- and ex-pore environments with an exchange rate in the order of tens of Hz. (19)F in situ NMR spectra recorded at different charge states reveal changes in the intensity and NICS of the in-pore resonances, which are interpreted in term of changes in the population and local environments of the adsorbed anions that arise due to the charge-storage process. A comparison of the results obtained for a range of electrolytes reveals that several factors influence the charging mechanism. For a tetraethylammonium tetrafluoroborate electrolyte, positive polarisation of the electrode is found to proceed by anion adsorption at a low concentration, whereas increased ion exchange plays a more important role for a high concentration electrolyte. In contrast, negative polarization of the electrode proceeds by cation adsorption for both concentrations. For a tetrabutylammonium tetrafluoroborate electrolyte, anion expulsion is observed in the negative charging regime; this is attributed to the reduced mobility and/or access of the larger cations inside the pores, which forces the expulsion of anions in order to build up ionic charge. Significant anion expulsion is also observed in the negative charging regime for alkali metal bis(trifluoromethane)sulfonimide electrolytes, suggesting that more subtle factors also affect the charging mechanism.

Applications of /sup 43/Ca, /sup 25/Mg, and /sup 67/Zn NMR spectroscopies to biological systems

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Tohru; Hatano, Masahiro [Tohoku Univ., Sendai (Japan). Chemical Research Inst. of Non-Aqueous Solutions

1983-12-01

/sup 43/Ca, /sup 25/Mg and /sup 67/Zn NMR spectroscopies applied to biologically important systems are summarized mainly on the basis of our findings. It was found from our studies that (1) /sup 25/Mg NMR can be utilized for studying the dynamic and/or static behavior of Mg/sup 2 +/ in the Mg/sup 2 +/ -ATP (ADP)-kinase ternary complexes and (2) /sup 67/Zn NMR bands of diluted Zn/sup 2 +/ are much narrower than predicted and thus can be applicable for studying the dynamic and/or static behavior of Zn/sup 2 +/ in Zn/sup 2 +/ -enzyme solutions. In addition, /sup 43/Ca NMR spectra were successfully applied to some Ca/sup 2 +/ -binding proteins. In concluding remarks, we discussed possibilities of applications of those metal NMR spectroscopies to medical purposes.

NMR spectroscopy up to 35.2T using a series-connected hybrid magnet.

Science.gov (United States)

Gan, Zhehong; Hung, Ivan; Wang, Xiaoling; Paulino, Joana; Wu, Gang; Litvak, Ilya M; Gor'kov, Peter L; Brey, William W; Lendi, Pietro; Schiano, Jeffrey L; Bird, Mark D; Dixon, Iain R; Toth, Jack; Boebinger, Gregory S; Cross, Timothy A

2017-11-01

The National High Magnetic Field Laboratory has brought to field a Series-Connected Hybrid magnet for NMR spectroscopy. As a DC powered magnet it can be operated at fields up to 36.1T. The series connection between a superconducting outsert and a resistive insert dramatically minimizes the high frequency fluctuations of the magnetic field typically observed in purely resistive magnets. Current-density-grading among various resistive coils was used for improved field homogeneity. The 48mm magnet bore and 42mm outer diameter of the probes leaves limited space for conventional shims and consequently a combination of resistive and ferromagnetic shims are used. Field maps corrected for field instabilities were obtained and shimming achieved better than 1ppm homogeneity over a cylindrical volume of 1cm diameter and height. The magnetic field is regulated within 0.2ppm using an external 7 Li lock sample doped with paramagnetic MnCl 2 . The improved field homogeneity and field regulation using a modified AVANCE NEO console enables NMR spectroscopy at 1 H frequencies of 1.0, 1.2 and 1.5GHz. NMR at 1.5GHz reflects a 50% increase in field strength above the highest superconducting magnets currently available. Three NMR probes have been constructed each equipped with an external lock rf coil for field regulation. Initial NMR results obtained from the SCH magnet using these probes illustrate the very exciting potential of ultra-high magnetic fields. Copyright © 2017 Elsevier Inc. All rights reserved.

Stereochemistry of 16a-Hydroxyfriedelin and 3-Oxo-16-methylfriedel-16-ene Established by 2D NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Vagner Fernandes Knupp

2009-02-01

Full Text Available Friedelin (1, 3b-friedelinol (2, 28-hydroxyfriedelin (3, 16a-hydroxyfriedelin (4, 30-hydroxyfriedelin (5 and 16a,28-dihydroxyfriedelin (6 were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16a-hydroxyfriedelin (4 reacted turning into 3-oxo-16-methylfriedel-16-ene (7. This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY spectroscopy and mass spectrometry (GC-MS. It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.

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

Heteronuclear three-dimensional NMR spectroscopy of the inflammatory protein C5a

International Nuclear Information System (INIS)

Zuiderweg, E.R.P.; Fesik, S.W.

1989-01-01

The utility of three-dimensional heteronuclear NMR spectroscopy for the assignment of 1 H and 15 N resonances of the inflammatory protein C5a (MW 8500), uniformly labeled with 15 N, is demonstrated at a protein concentration of 0.7 mM. It is shown that dramatic simplification of the 2D nuclear Overhauser effect spectrum (NOESY) is obtained by editing with respect to the frequency of the 15 N heteronucleus in a third dimension. The improved resolution in the 3D experiment largely facilitates the assignment of protein NMR spectra and allows for the determination of distance constraints from otherwise overlapping NOE cross peaks for purposes of 3D structure determination. The results show that 15 N heteronuclear 3D NMR can facilitate the structure determination of small proteins and promises to be a useful tool for the study of larger systems that cannot be studied by conventional 2D NMR techniques

Heteronuclear three-dimensional NMR spectroscopy of the inflammatory protein C5a

Energy Technology Data Exchange (ETDEWEB)

Zuiderweg, E.R.P.; Fesik, S.W. (Abbott Laboratories, Abbott Park, IL (USA))

1989-03-21

The utility of three-dimensional heteronuclear NMR spectroscopy for the assignment of {sup 1}H and {sup 15}N resonances of the inflammatory protein C5a (MW 8500), uniformly labeled with {sup 15}N, is demonstrated at a protein concentration of 0.7 mM. It is shown that dramatic simplification of the 2D nuclear Overhauser effect spectrum (NOESY) is obtained by editing with respect to the frequency of the {sup 15}N heteronucleus in a third dimension. The improved resolution in the 3D experiment largely facilitates the assignment of protein NMR spectra and allows for the determination of distance constraints from otherwise overlapping NOE cross peaks for purposes of 3D structure determination. The results show that {sup 15}N heteronuclear 3D NMR can facilitate the structure determination of small proteins and promises to be a useful tool for the study of larger systems that cannot be studied by conventional 2D NMR techniques.

Heteronuclear three-dimensional NMR spectroscopy. Natural abundance 13C chemical shift editing of 1H-1H COSY spectra

International Nuclear Information System (INIS)

Fesik, S.W.; Gampe, R.T. Jr.; Zuiderweg, E.R.P.

1989-01-01

It has been demonstrated that heteronuclear 3D NMR spectroscopy can be effectively applied to small molecules with 13 C at natural abundance. A 78mM solution of the aminoglycoside, kanamycin A was used for this experiment. The heteronuclear 3D NMR spectroscopy is shown to be a useful method for resolving spectral overlap in all frequency domains. 10 refs., 2 figs

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.

Organic matter characterization during the anaerobic digestion of different biomasses by means of CPMAS 13C NMR spectroscopy

International Nuclear Information System (INIS)

Tambone, Fulvia; Adani, Fabrizio; Gigliotti, Giovanni; Volpe, Daniela; Fabbri, Claudio; Provenzano, Maria Rosaria

2013-01-01

The aim of this work was to characterize ingestates and their corresponding digestates obtained in two full-scale biogas production plants processing a) mixtures of organic wastes in co-digestion, and b) pig slurry in order to assess the organic matter transformation during anaerobic digestion by means of chemical analysis and 13 CPMAS-NMR spectroscopy. Results proved that digestates obtained by different organic substrates exhibited significant chemical differences related to the different initial composition of substrates. We proposed the use of the aliphaticity index in order to highlight the different chemical nature of ingestates and their corresponding digestates. In order to verify whether the AD process leads to stabilized final products regardless the initial composition of biomass in view of a possible agronomical use of digestate, a comparison of CPMAS 13 C NMR data of a number of ingestates and digestates available in literature was carried out. Results indicated that most of the aromatic structures present in the substrate tend to degrade during the process and that anaerobic digestion proceeds through preferential degradation of carbohydrates such as cellulose and hemicellulose and, as a consequence, concentration of more chemically recalcitrant aliphatic molecules occurs. -- Highlights: ► We studied anaerobic digestion by means of chemical analysis and 13 CPMAS-NMR spectroscopy. ► Significant chemical differences in digestates were highlighted. ► We proposed the use of the aliphaticity index in order to differentiate digestates. ► Most of the aromatic structures tend to degrade. ► Carbohydrates are degraded and recalcitrant aliphatic molecules concentrate

Predicting Fuel Ignition Quality Using 1H NMR Spectroscopy and Multiple Linear Regression

KAUST Repository

Abdul Jameel, Abdul Gani; Naser, Nimal; Emwas, Abdul-Hamid M.; Dooley, Stephen; Sarathy, Mani

2016-01-01

An improved model for the prediction of ignition quality of hydrocarbon fuels has been developed using 1H nuclear magnetic resonance (NMR) spectroscopy and multiple linear regression (MLR) modeling. Cetane number (CN) and derived cetane number (DCN

Toward high-resolution NMR spectroscopy of microscopic liquid samples

Energy Technology Data Exchange (ETDEWEB)

Butler, Mark C.; Mehta, Hardeep S.; Chen, Ying; Reardon, Patrick N.; Renslow, Ryan S.; Khbeis, Michael; Irish, Duane; Mueller, Karl T.

2017-01-01

A longstanding limitation of high-resolution NMR spectroscopy is the requirement for samples to have macroscopic dimensions. Commercial probes, for example, are designed for volumes of at least 5 mL, in spite of decades of work directed toward the goal of miniaturization. Progress in miniaturizing inductive detectors has been limited by a perceived need to meet two technical requirements: (1) minimal separation between the sample and the detector, which is essential for sensitivity, and (2) near-perfect magnetic-field homogeneity at the sample, which is typically needed for spectral resolution. The first of these requirements is real, but the second can be relaxed, as we demonstrate here. By using pulse sequences that yield high-resolution spectra in an inhomogeneous field, we eliminate the need for near-perfect field homogeneity and the accompanying requirement for susceptibility matching of microfabricated detector components. With this requirement removed, typical imperfections in microfabricated components can be tolerated, and detector dimensions can be matched to those of the sample, even for samples of volume << 5 uL. Pulse sequences that are robust to field inhomogeneity thus enable small-volume detection with optimal sensitivity. We illustrate the potential of this approach to miniaturization by presenting spectra acquired with a flat-wire detector that can easily be scaled to subnanoliter volumes. In particular, we report high-resolution NMR spectroscopy of an alanine sample of volume 500 pL.

Analysis of Polycyclic Aromatic Hydrocarbon (PAH Mixtures Using Diffusion-Ordered NMR Spectroscopy and Adsorption by Powdered Activated Carbon and Biochar

Directory of Open Access Journals (Sweden)

Dong An

2018-03-01

Full Text Available Analysis of polycyclic aromatic hydrocarbons (PAHs in air and water sources is a key part of environmental chemistry research, since most PAHs are well known to be associated with negative health impacts on humans. This study explores an approach for analyzing PAH mixtures with advanced nuclear magnetic resonance (NMR spectroscopic techniques including high-resolution one-dimensional (1D NMR spectroscopy and diffusion-ordered NMR spectroscopy (DOSY NMR. With this method, different kinds of PAHs can be detected and differentiated from a mixture with high resolution. The adsorption process of PAH mixtures by PAC and biochar was studied to understand the mechanism and assess the method.

Analysis of Hydroperoxides in solid Polyethylene by NMR and EPR Spectroscopy

International Nuclear Information System (INIS)

Assink, Roger A.; Celina, Mathias C.; Dunbar, Timothy D.; Alam, Todd M.; Clough, Roger Lee; Gillen, Kenneth T.

2000-01-01

The authors have shown that the hydroperoxide species in γ-irradiated 13 C-polyethylene can be directly observed by 13 C MAS NMR spectroscopy. The experiment was performed without the need for special sample preparation such as chemical derivatization or dissolution. Annealing experiments were employed to study the thermal decomposition of the hydroperoxide species and to measure an activation energy of 98 kJ/mol. EPR spectroscopy suggests that residual polyenyl and alkylperoxy radicals are predominantly trapped in interracial or crystalline regions, while the peroxy radicals observed after UV-photolysis of hydroperoxides are in amorphous regions

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)

Structures of larger proteins in solution: Three- and four-dimensional heteronuclear NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Gronenborn, A.M.; Clore, G.M. [National Institutes of Health, Bethesda, MD (United States)

1994-12-01

Complete understanding of a protein`s function and mechanism of action can only be achieved with a knowledge of its three-dimensional structure at atomic resolution. At present, there are two methods available for determining such structures. The first method, which has been established for many years, is x-ray diffraction of protein single crystals. The second method has blossomed only in the last 5 years and is based on the application of nuclear magnetic resonance (NMR) spectroscopy to proteins in solution. This review paper describes three- and four-dimensional NMR methods applied to protein structure determination and was adapted from Clore and Gronenborn. The review focuses on the underlying principals and practice of multidimensional NMR and the structural information obtained.

Two-site jumps in dimethyl sulfone studied by one- and two-dimensional 17O NMR spectroscopy

Science.gov (United States)

Beerwerth, J.; Storek, M.; Greim, D.; Lueg, J.; Siegel, R.; Cetinkaya, B.; Hiller, W.; Zimmermann, H.; Senker, J.; Böhmer, R.

2018-03-01

Polycrystalline dimethyl sulfone is studied using central-transition oxygen-17 exchange NMR. The quadrupolar and chemical shift tensors are determined by combining quantum chemical calculations with line shape analyses of rigid-lattice spectra measured for stationary and rotating samples at several external magnetic fields. Quantum chemical computations predict that the largest principal axes of the chemical shift anisotropy and electrical field gradient tensors enclose an angle of about 73°. This prediction is successfully tested by comparison with absorption spectra recorded at three different external magnetic fields. The experimental one-dimensional motionally narrowed spectra and the two-dimensional exchange spectrum are compatible with model calculations involving jumps of the molecules about their two-fold symmetry axis. This motion is additionally investigated by means of two-time stimulated-echo spectroscopy which allows for a determination of motional correlation functions over a wider temperature range than previously reported using carbon and deuteron NMR. On the basis of suitable second-order quadrupolar frequency distributions, sin-sin stimulated-echo amplitudes are calculated for a two-site model in the limit of vanishing evolution time and compared with experimental findings. The present study thus establishes oxygen-17 NMR as a powerful method that will be particularly useful for the study of solids and liquids devoid of nuclei governed by first-order anisotropies.

Using an Interactive Web-Based Learning NMR Spectroscopy as a Means to Improve Problem Solving Skills for Undergraduates

International Nuclear Information System (INIS)

Supasorn, Saksri; Vibuljun, Sunantha; Panijpan, Bhinyo; Rajviroongit, Shuleewan

2005-10-01

An Interactive Web-Based Learning NMR Spectroscopy course is developed to improve and facilitate student ' s learning as well as achievement of learning objectives in the concepts of multiplicity, chemical shift, and problem solving. This web-based learning course is emphasized on NMR problem solving, therefore, the concepts of multiplicity and chemical shift, basic concepts for practice problem solving, are also emphasized. Most of animations and pictures in this web-based learning are new created and simplified to explain processes and principles in NMR spectroscopy. With meaningful animations and pictures, simplified English language used, step-by-step problem solving, and interactive test, it can be self-learning web site and best on the student ' s convenience

Illumination of Nanoliter-NMR Spectroscopy Chips for Real-Time Photochemical Reaction Monitoring

NARCIS (Netherlands)

Gomez, M.V.; Juan, Alberto; Jiménez-Márquez, Francisco; La Hoz, De Antonio; Velders, Aldrik H.

2018-01-01

We report the use of a small-volume nuclear-magnetic-resonance (NMR)-spectroscopy device with integrated fiber-optics for the real-time detection of UV-vis-light-assisted chemical reactions. An optical fiber is used to guide the light from LEDs or a laser diode positioned safely outside the magnet

Uptake of BSH in M2R melanoma cells monitored by NMR spectroscopy

International Nuclear Information System (INIS)

Koudinova, N.; Elhanati, G.; Salomon, Y.; Bendel, P.

2000-01-01

The accumulation ratio of BSH, relative to that of boric acid, in M2R mouse melanoma cells, was measured using 11 B NMR of the cell extracts. The cells were incubated in growth medium for up to 24 h, in the presence of 0.8 mM boric acid and 0.25-1.5 mM BSH. The aqueous phase of the cellular extracts was re-suspended for NMR spectroscopy. The relative accumulation ratio of BSH/boric acid determined from 9 separate experiments was 0.45±0.09. (author)

Dynamic membrane interactions of antibacterial and antifungal biomolecules, and amyloid peptides, revealed by solid-state NMR spectroscopy.

Science.gov (United States)

Naito, Akira; Matsumori, Nobuaki; Ramamoorthy, Ayyalusamy

2018-02-01

A variety of biomolecules acting on the cell membrane folds into a biologically active structure in the membrane environment. It is, therefore, important to determine the structures and dynamics of such biomolecules in a membrane environment. While several biophysical techniques are used to obtain low-resolution information, solid-state NMR spectroscopy is one of the most powerful means for determining the structure and dynamics of membrane bound biomolecules such as antibacterial biomolecules and amyloidogenic proteins; unlike X-ray crystallography and solution NMR spectroscopy, applications of solid-state NMR spectroscopy are not limited by non-crystalline, non-soluble nature or molecular size of membrane-associated biomolecules. This review article focuses on the applications of solid-state NMR techniques to study a few selected antibacterial and amyloid peptides. Solid-state NMR studies revealing the membrane inserted bent α-helical structure associated with the hemolytic activity of bee venom melittin and the chemical shift oscillation analysis used to determine the transmembrane structure (with α-helix and 3 10 -helix in the N- and C-termini, respectively) of antibiotic peptide alamethicin are discussed in detail. Oligomerization of an amyloidogenic islet amyloid polypeptide (IAPP, or also known as amylin) resulting from its aggregation in a membrane environment, molecular interactions of the antifungal natural product amphotericin B with ergosterol in lipid bilayers, and the mechanism of lipid raft formation by sphingomyelin studied using solid state NMR methods are also discussed in this review article. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017 Elsevier B.V. All rights reserved.

In situ solid-state NMR spectroscopy of electrochemical cells: batteries, supercapacitors, and fuel cells.

Science.gov (United States)

Blanc, Frédéric; Leskes, Michal; Grey, Clare P

2013-09-17

Electrochemical cells, in the form of batteries (or supercapacitors) and fuel cells, are efficient devices for energy storage and conversion. These devices show considerable promise for use in portable and static devices to power electronics and various modes of transport and to produce and store electricity both locally and on the grid. For example, high power and energy density lithium-ion batteries are being developed for use in hybrid electric vehicles where they improve the efficiency of fuel use and help to reduce greenhouse gas emissions. To gain insight into the chemical reactions involving the multiple components (electrodes, electrolytes, interfaces) in the electrochemical cells and to determine how cells operate and how they fail, researchers ideally should employ techniques that allow real-time characterization of the behavior of the cells under operating conditions. This Account reviews the recent use of in situ solid-state NMR spectroscopy, a technique that probes local structure and dynamics, to study these devices. In situ NMR studies of lithium-ion batteries are performed on the entire battery, by using a coin cell design, a flat sealed plastic bag, or a cylindrical cell. The battery is placed inside the NMR coil, leads are connected to a potentiostat, and the NMR spectra are recorded as a function of state of charge. (7)Li is used for many of these experiments because of its high sensitivity, straightforward spectral interpretation, and relevance to these devices. For example, (7)Li spectroscopy was used to detect intermediates formed during electrochemical cycling such as LixC and LiySiz species in batteries with carbon and silicon anodes, respectively. It was also used to observe and quantify the formation and growth of metallic lithium microstructures, which can cause short circuits and battery failure. This approach can be utilized to identify conditions that promote dendrite formation and whether different electrolytes and additives can help

Nanodisc-Targeted STD NMR Spectroscopy Reveals Atomic Details of Ligand Binding to Lipid Environments.

Science.gov (United States)

Muñoz-García, Juan C; Inacio Dos Reis, Rosana; Taylor, Richard J; Henry, Alistair J; Watts, Anthony

2018-05-18

Saturation transfer difference (STD) NMR spectroscopy is one of the most popular ligand-based NMR techniques for the study of protein-ligand interactions. This is due to its robustness and the fact that it is focused on the signals of the ligand, without any need for NMR information on the macromolecular target. This technique is most commonly applied to systems involving different types of ligands (e.g., small organic molecules, carbohydrates or lipids) and a protein as the target, in which the latter is selectively saturated. However, only a few examples have been reported where membrane mimetics are the macromolecular binding partners. Here, we have employed STD NMR spectroscopy to investigate the interactions of the neurotransmitter dopamine with mimetics of lipid bilayers, such as nanodiscs, by saturation of the latter. In particular, the interactions between dopamine and model lipid nanodiscs formed either from charged or zwitterionic lipids have been resolved at the atomic level. The results, in agreement with previous isothermal titration calorimetry studies, show that dopamine preferentially binds to negatively charged model membranes, but also provide detailed atomic insights into the mode of interaction of dopamine with membrane mimetics. Our findings provide relevant structural information for the design of lipid-based drug carriers of dopamine and its structural analogues and are of general applicability to other systems. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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...

Simple methods via Mid-IR or {sup 1}H NMR spectroscopy for the determination of the iodine value of vegetable oils

Energy Technology Data Exchange (ETDEWEB)

Shimamoto, Gustavo G.; Favaro, Martha M.A.; Tubino, Matthieu, E-mail: tubino@iqm.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Química

2015-07-01

Two methods for determining the iodine value in vegetable oils are described. One employs mid-infrared (mid-IR) spectroscopy and the other uses hydrogen nuclear magnetic resonance ({sup 1}H NMR). The determination of the iodine value is based on either the transmittance intensity of mid-IR signals or on the {sup 1}H NMR signal integration and multivariate calibration. Both of the methods showed adequate coefficients of determination (r{sup 2} = 0.9974 and 0.9978, respectively) when compared to Wijs method, which is recommended by the norm EN 14111. A statistical comparison between the results from the proposed methods and from Wijs method shows that both instrumental methods offer equivalent results and greater precision compared to Wijs method. The regressions obtained from the constructed models were considered statistically significant and useful for making predictions. The proposed methods present several advantages compared to Wijs method because they significantly reduce analysis time, reagent consumption and waste generation. Furthermore, an analyst can choose between the mid-IR or {sup 1}H NMR to determine the iodine value. (author)

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

Protolytic properties of polyamine wasp toxin analogues studied by 13C NMR spectroscopy

DEFF Research Database (Denmark)

Strømgaard, Kristian; Piazzi, Lorna; Olsen, Christian A

2006-01-01

Acid-base properties of the natural polyamine wasp toxin PhTX-433 (1) and seven synthetic analogues [PhTX-343 (2), PhTX-334 (3), PhTX-443 (4), PhTX-434 (5), PhTX-344 (6), PhTX-444 (7), and PhTX-333 (8)], each having four protolytic sites, were characterized by 13C NMR spectroscopy. Nonlinear......, multiparameter, simultaneous fit of all chemical shift data obtained from the NMR titration curves yielded macroscopic pKa values as well as intrinsic chemical shift data of all differently protonated macrospecies. Analyses of the chemical shift data demonstrated strong interactions between all four sites...

Isobutylene Dimerization: A Discovery-Based Exploration of Mechanism and Regioselectivity by NMR Spectroscopy and Molecular Modeling

Science.gov (United States)

Schuster, Mariah L.; Peterson, Karl P.; Stoffregen, Stacey A.

2018-01-01

This two-period undergraduate laboratory experiment involves the synthesis of a mixture of isomeric unknowns, isolation of the mixture by means of distillation, and characterization of the two products primarily by NMR spectroscopy (1D and 2D) supported with IR spectroscopy and GC-MS techniques. Subsequent calculation and examination of the…

Quantitative 1H-NMR Spectroscopy for Profiling Primary Metabolites in Mulberry Leaves

Directory of Open Access Journals (Sweden)

Qianqian Liang

2018-03-01

Full Text Available The primary metabolites in aqueous extract of mulberry (Morus alba L. leaves were characterized by using proton nuclear magnetic resonance (1H-NMR spectroscopy. With the convenience of resonance assignment, GABA together with the other 10 primary metabolites was simultaneously identified and quantified in one 1H-NMR spectrum. In this study, external calibration curves for metabolites were employed to calculate the concentrations of interests. The proposed quantitative approach was demonstrated with good linearity (r2 ranged in the interval of 0.9965–0.9999, precision, repeatability, stability (RSD values in the ranges of 0.35–4.89%, 0.77–7.13% and 0.28–2.33%, respectively and accuracy (recovery rates from 89.2% to 118.5%. The established 1H-NMR method was then successfully applied to quantify 11 primary metabolites in mulberry leaves from different geographical regions within a rapid analysis time and a simple sample preparation procedure.

Symmetry Breaking in NMR Spectroscopy: The Elucidation of Hidden Molecular Rearrangement Processes

Directory of Open Access Journals (Sweden)

Michael J. McGlinchey

2014-08-01

Full Text Available Variable-temperature NMR spectroscopy is probably the most convenient and sensitive technique to monitor changes in molecular structure in solution. Rearrangements that are rapid on the NMR time-scale exhibit simplified spectra, whereby non-equivalent nuclear environments yield time-averaged resonances. At lower temperatures, when the rate of exchange is sufficiently reduced, these degeneracies are split and the underlying “static” molecular symmetry, as seen by X-ray crystallography, becomes apparent. Frequently, however, such rearrangement processes are hidden, even when they become slow on the NMR time-scale, because the molecular point group remains unchanged. Judicious symmetry breaking, such as by substitution of a molecular fragment by a similar, but not identical moiety, or by the incorporation of potentially diastereotopic (chemically non-equivalent nuclei, allows the elucidation of the kinetics and energetics of such processes. Examples are chosen that include a wide range of rotations, migrations and other rearrangements in organic, inorganic and organometallic chemistry.

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.

NMR clinical imaging and spectroscopy: Its impact on nuclear medicine

International Nuclear Information System (INIS)

1990-01-01

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

Theory and Applications of Solid-State NMR Spectroscopy to Biomembrane Structure and Dynamics

Science.gov (United States)

Xu, Xiaolin

Solid-state Nuclear Magnetic Resonance (NMR) is one of the premiere biophysical methods that can be applied for addressing the structure and dynamics of biomolecules, including proteins, lipids, and nucleic acids. It illustrates the general problem of determining the average biomolecular structure, including the motional mean-square amplitudes and rates of the fluctuations. Lineshape and relaxtion studies give us a view into the molecular properties under different environments. To help the understanding of NMR theory, both lineshape and relaxation experiments are conducted with hexamethylbezene (HMB). This chemical compound with a simple structure serves as a perfect test molecule. Because of its highly symmetric structure, its motions are not very difficult to understand. The results for HMB set benchmarks for other more complicated systems like membrane proteins. After accumulating a large data set on HMB, we also proceed to develop a completely new method of data analysis, which yields the spectral densities in a body-fixed frame revealing internal motions of the system. Among the possible applications of solid-state NMR spectroscopy, we study the light activation mechanism of visual rhodopsin in lipid membranes. As a prototype of G-protein-coupled receptors, which are a large class of membrane proteins, the cofactor isomerization is triggered by photon absorption, and the local structural change is then propagated to a large-scale conformational change of the protein. Facilitation of the binding of transducin then passes along the visual signal to downstream effector proteins like transducin. To study this process, we introduce 2H labels into the rhodopsin chromophore retinal and the C-terminal peptide of transducin to probe the local structure and dynamics of these two hotspots of the rhodopsin activation process. In addition to the examination of local sites with solid-state 2H NMR spectroscopy, wide angle X-ray scattering (WAXS) provides us the chance of

Metabolomic Characterization of Ovarian Epithelial Carcinomas by HRMAS-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

D. Ben Sellem

2011-01-01

Full Text Available Objectives. The objectives of the present study are to determine if a metabolomic study by HRMAS-NMR can (i discriminate between different histological types of epithelial ovarian carcinomas and healthy ovarian tissue, (ii generate statistical models capable of classifying borderline tumors and (iii establish a potential relationship with patient's survival or response to chemotherapy. Methods. 36 human epithelial ovarian tumor biopsies and 3 healthy ovarian tissues were studied using 1H HRMAS NMR spectroscopy and multivariate statistical analysis. Results. The results presented in this study demonstrate that the three histological types of epithelial ovarian carcinomas present an effective metabolic pattern difference. Furthermore, a metabolic signature specific of serous (N-acetyl-aspartate and mucinous (N-acetyl-lysine carcinomas was found. The statistical models generated in this study are able to predict borderline tumors characterized by an intermediate metabolic pattern similar to the normal ovarian tissue. Finally and importantly, the statistical model of serous carcinomas provided good predictions of both patient's survival rates and the patient's response to chemotherapy. Conclusions. Despite the small number of samples used in this study, the results indicate that metabolomic analysis of intact tissues by HRMAS-NMR is a promising technique which might be applicable to the therapeutic management of patients.

Microfabricated inserts for magic angle coil spinning (MACS wireless NMR spectroscopy.

Directory of Open Access Journals (Sweden)

Vlad Badilita

Full Text Available This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the "magic angle" of 54.74° with respect to the direction of the magnetic field (magic angle spinning - MAS, accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii given the high spinning rates (tens of kHz involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds.

High-Resolution Solid-State NMR Spectroscopy: Characterization of Polymorphism in Cimetidine, a Pharmaceutical Compound

Science.gov (United States)

Pacilio, Julia E.; Tokarski, John T.; Quiñones, Rosalynn; Iuliucci, Robbie J.

2014-01-01

High-resolution solid-state NMR (SSNMR) spectroscopy has many advantages as a tool to characterize solid-phase material that finds applications in polymer chemistry, nanotechnology, materials science, biomolecular structure determination, and others, including the pharmaceutical industry. The technology associated with achieving high resolution…

Some new insights into biology and medicine through NMR spectroscopy

International Nuclear Information System (INIS)

Radda, G.K.

1990-01-01

The contributions to biology and medicine by NMR spectroscopy in vivo require careful definition of the problems that are studied. Temporal and spatial resolution of the biochemical information obtained are the key to success, although the latter is limited owing to low sensitivity and small concentrations of the metabolites studied. Using 31 P NMR investigations in four areas are described. Control of energetics by ADP in normal and diseased muscle is shown to be important. Enzyme catalysed fluxes are obtained for creatine kinase and ATP synthase in muscle and in the human brain enzyme activity maps are derived. The measurements on the ionic environment and fluxes for H + , Na + and K + (Rb + ) give us new information about the role of ions in cell proliferation (e.g. in cancer) and hypertension. Molecular architecture of phospholipids in vivo is readily observed and is perturbed in the brain in chronic head injury and demyelination. (author)

Atomic substitutions in synthetic apatite; Insights from solid-state NMR spectroscopy

Science.gov (United States)

Vaughn, John S.

Apatite, Ca5(PO4)3X (where X = F, Cl, or OH), is a unique mineral group capable of atomic substitutions for cations and anions of varied size and charge. Accommodation of differing substituents requires some kind of structural adaptation, e.g. new atomic positions, vacancies, or coupled substitutions. These structural adaptations often give rise to important physicochemical properties relevant to a range of scientific disciplines. Examples include volatile trapping during apatite crystallization, substitution for large radionuclides for long-term storage of nuclear fission waste, substitution for fluoride to improve acid resistivity in dental enamel composed dominantly of hydroxylapatite, and the development of novel biomaterials with enhanced biocompatibility. Despite the importance and ubiquity of atomic substitutions in apatite materials, many of the mechanisms by which these reactions occur are poorly understood. Presence of substituents at dilute concentration and occupancy of disordered atomic positions hinder detection by bulk characterization methods such as X-ray diffraction (XRD) and infrared (IR) spectroscopy. Solid-state nuclear magnetic resonance (NMR) spectroscopy is an isotope-specific structural characterization technique that does not require ordered atomic arrangements, and is therefore well suited to investigate atomic substitutions and structural adaptations in apatite. In the present work, solid-state NMR is utilized to investigate structural adaptations in three different types of apatite materials; a series of near-binary F, Cl apatite, carbonate-hydroxylapatite compositions prepared under various synthesis conditions, and a heat-treated hydroxylapatite enriched in 17O. The results indicate that hydroxyl groups in low-H, near binary F,Cl apatite facilitate solid-solution between F and Cl via column reversals, which result in average hexagonal symmetry despite very dilute OH concentration ( 2 mol percent). In addition, 19F NMR spectra indicate

Influence of water on stability of geopolymers investigated by NMR solid state spectroscopy

Czech Academy of Sciences Publication Activity Database

Kobera, Libor; Brus, Jiří; Urbanová, Martina; Slavík, R.

2008-01-01

Roč. 33, - (2008), s. 86 ISSN 1896-2203. [Mid-European Clay Conference MECC 08 /4./. 22.09.2008-27.09.2008, Zakopane] R&D Projects: GA AV ČR IAA400500602 Institutional research plan: CEZ:AV0Z40500505 Keywords : stability * NMR * solid state spectroscopy * geopolymer Subject RIV: CD - Macromolecular Chemistry

Structural Elucidation of Metabolites of Synthetic Cannabinoid UR-144 by Cunninghamella elegans Using Nuclear Magnetic Resonance (NMR) Spectroscopy.

Science.gov (United States)

Watanabe, Shimpei; Kuzhiumparambil, Unnikrishnan; Fu, Shanlin

2018-03-08

The number of new psychoactive substances keeps on rising despite the controlling efforts by law enforcement. Although metabolism of the newly emerging drugs is continuously studied to keep up with the new additions, the exact structures of the metabolites are often not identified due to the insufficient sample quantities for techniques such as nuclear magnetic resonance (NMR) spectroscopy. The aim of the study was to characterise several metabolites of the synthetic cannabinoid (1-pentyl-1H-indol-3-yl) (2,2,3,3-tetramethylcyclopropyl) methanone (UR-144) by NMR spectroscopy after the incubation with the fungus Cunninghamella elegans. UR-144 was incubated with C. elegans for 72 h, and the resulting metabolites were chromatographically separated. Six fractions were collected and analysed by NMR spectroscopy. UR-144 was also incubated with human liver microsomes (HLM), and the liquid chromatography-high resolution mass spectrometry analysis was performed on the HLM metabolites with the characterised fungal metabolites as reference standards. Ten metabolites were characterised by NMR analysis including dihydroxy metabolites, carboxy and hydroxy metabolites, a hydroxy and ketone metabolite, and a carboxy and ketone metabolite. Of these metabolites, dihydroxy metabolite, carboxy and hydroxy metabolites, and a hydroxy and ketone metabolite were identified in HLM incubation. The results indicate that the fungus is capable of producing human-relevant metabolites including the exact isomers. The capacity of the fungus C. elegans to allow for NMR structural characterisation by enabling production of large amounts of metabolites makes it an ideal model to complement metabolism studies.

Systematic Evaluation of Non-Uniform Sampling Parameters in the Targeted Analysis of Urine Metabolites by 1H,1H 2D NMR Spectroscopy.

Science.gov (United States)

Schlippenbach, Trixi von; Oefner, Peter J; Gronwald, Wolfram

2018-03-09

Non-uniform sampling (NUS) allows the accelerated acquisition of multidimensional NMR spectra. The aim of this contribution was the systematic evaluation of the impact of various quantitative NUS parameters on the accuracy and precision of 2D NMR measurements of urinary metabolites. Urine aliquots spiked with varying concentrations (15.6-500.0 µM) of tryptophan, tyrosine, glutamine, glutamic acid, lactic acid, and threonine, which can only be resolved fully by 2D NMR, were used to assess the influence of the sampling scheme, reconstruction algorithm, amount of omitted data points, and seed value on the quantitative performance of NUS in 1 H, 1 H-TOCSY and 1 H, 1 H-COSY45 NMR spectroscopy. Sinusoidal Poisson-gap sampling and a compressed sensing approach employing the iterative re-weighted least squares method for spectral reconstruction allowed a 50% reduction in measurement time while maintaining sufficient quantitative accuracy and precision for both types of homonuclear 2D NMR spectroscopy. Together with other advances in instrument design, such as state-of-the-art cryogenic probes, use of 2D NMR spectroscopy in large biomedical cohort studies seems feasible.

Metabolic Profiling of Food Protective Cultures by in vitro NMR Spectroscopy

DEFF Research Database (Denmark)

Ebrahimi, Parvaneh

Food spoilage is of major concern to the food industry, because it leads to considerable economic losses, a deteriorated environmental food-print, and to possible public health hazards. In order to limit food spoilage, research on the preservation of food products has always received particular......-called protective cultures) has unexploited potential to inhibit the growth of pathogenic microorganisms and enhance the shelf life of the final food product. In order to apply biopreservation in food products effectively, detailed knowledge on the metabolism of protective cultures is required. The present Ph......D project is mainly focused on the application of in vitro NMR spectroscopy for studying the metabolism of protective cultures. As an important part of this work, an analytical protocol was developed for realtime in vitro NMR measurements of bacterial fermentation, which includes guidelines from the sample...

Determination of the biogenic secondary organic aerosol fraction in the boreal forest by NMR spectroscopy

Directory of Open Access Journals (Sweden)

E. Finessi

2012-01-01

Full Text Available The study investigates the sources of fine organic aerosol (OA in the boreal forest, based on measurements including both filter sampling (PM₁ and online methods and carried out during a one-month campaign held in Hyytiälä, Finland, in spring 2007. Two aerosol mass spectrometers (Q-AMS, ToF-AMS were employed to measure on-line concentrations of major non-refractory aerosol species, while the water extracts of the filter samples were analyzed by nuclear magnetic resonance (NMR spectroscopy for organic functional group characterization of the polar organic fraction of the aerosol. AMS and NMR spectra were processed separately by non-negative factorization algorithms, in order to apportion the main components underlying the submicrometer organic aerosol composition and depict them in terms of both mass fragmentation patterns and functional group compositions.

The NMR results supported the AMS speciation of oxidized organic aerosol (OOA into two main fractions, which could be generally labelled as more and less oxidized organics. The more oxidized component was characterized by a mass spectrum dominated by the m/z 44 peak, and in parallel by a NMR spectrum showing aromatic and aliphatic backbones highly substituted with oxygenated functional groups (carbonyls/carboxyls and hydroxyls. Such component, contributing on average 50% of the OA mass throughout the observing period, was associated with pollution outbreaks from the Central Europe. The less oxidized component was enhanced in concomitance with air masses originating from the North-to-West sector, in agreement with previous investigations conducted at this site. NMR factor analysis was able to separate two distinct components under the less oxidized fraction of OA. One of these NMR-factors was associated with the formation of terrestrial biogenic secondary organic aerosol (BSOA, based on the comparison with spectral profiles obtained from laboratory experiments of

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

International Nuclear Information System (INIS)

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

1988-01-01

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

Structural investigation of bistrifluron using x-ray crystallography, NMR spectroscopy, and molecular modeling

CERN Document Server

Moon, J K; Rhee, S K; Kim, G B; Yun, H S; Chung, B J; Lee, S S; Lim, Y H

2002-01-01

A new insecticide, bistrifluron acts as an inhibitor of insect development and interferes with the cuticle formation of insects. Since it shows low acute oral and dermal toxicities, it can be one of potent insecticides. Based on X-ray crystallography, NMR spectroscopy and molecular modeling, the structural studies of bistrifluron have been carried out.

Visualising substrate-fingermark interactions: Solid-state NMR spectroscopy of amino acid reagent development on cellulose substrates.

Science.gov (United States)

Spindler, Xanthe; Shimmon, Ronald; Roux, Claude; Lennard, Chris

2015-05-01

Most spectroscopic studies of the reaction products formed by ninhydrin, 1,2-indanedione-zinc (Ind-Zn) and 1,8-diazafluoren-9-one (DFO) when reacted with amino acids or latent fingermarks on paper substrates are focused on visible absorption or luminescence spectroscopy. In addition, structural elucidation studies are typically limited to solution-based mass spectrometry or liquid nuclear magnetic resonance (NMR) spectroscopy, which does not provide an accurate representation of the fingermark development process on common paper substrates. The research presented in this article demonstrates that solid-state carbon-13 magic angle spinning NMR ((13)C-MAS-NMR) is a technique that can not only be utilised for structural studies of fingermark enhancement reagents, but is a promising technique for characterising the effect of paper chemistry on fingermark deposition and enhancement. The latter opens up a research area that has been under-explored to date but has the potential to improve our understanding of how fingermark secretions and enhancement reagents interact with paper substrates. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

1H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet

Directory of Open Access Journals (Sweden)

Carmelo Corsaro

2015-01-01

Full Text Available NMR spectroscopy has become an experimental technique widely used in food science. The experimental procedures that allow precise and quantitative analysis on different foods are relatively simple. For a better sensitivity and resolution, NMR spectroscopy is usually applied to liquid sample by means of extraction procedures that can be addressed to the observation of particular compounds. For the study of semisolid systems such as intact tissues, High-Resolution Magic Angle Spinning (HR-MAS has received great attention within the biomedical area and beyond. Metabolic profiling and metabolism changes can be investigated both in animal organs and in foods. In this work we present a proton HR-MAS NMR study on the typical vegetable foods of Mediterranean diet such as the Protected Geographical Indication (PGI cherry tomato of Pachino, the PGI Interdonato lemon of Messina, several Protected Designation of Origin (PDO extra virgin olive oils from Sicily, and the Traditional Italian Food Product (PAT red garlic of Nubia. We were able to identify and quantify the main metabolites within the studied systems that can be used for their characterization and authentication.

Phase-alternated composite π/2 pulses for solid state quadrupole echo NMR spectroscopy

International Nuclear Information System (INIS)

Ramamoorthy, A.; Narasimhan, P.T.

1991-01-01

Phase-alternated composite π/2 pulses have been constructed for spin I=1 to overcome quadrupole interaction effects in solid state nuclear magnetic resonance(NMR) spectroscopy. Magnus expansion approach is used to design these sequences in a manner similar to the NMR coherent averaging theory. It is inferred that the symmetric phase-alternated composite π/2 pulses reported here are quite successful in producing quadrupole echo free phase distortions. This effectiveness of the present composite pulses is due to the fact that most of them are of shorter durations as compared to the ones reported in literature. In this theoretical procedure, irreducible spherical tensor operator formalism is employed to simplify the complexity involved in the evaluation of Magnus expansion terms. It has been argued in this paper that composite π/2 pulse sequences for this purpose can also be derived from the broadband inversion π pulses which are designed to compensate electric field gradient(efg) inhomogeniety in spin I=1 nuclear quadrupole resonance(NQR) spectroscopy. (author). 28 refs

Characterization of the serum metabolic profile of dairy cows with milk fever using 1H-NMR spectroscopy.

Science.gov (United States)

Sun, Yuhang; Xu, Chuchu; Li, Changsheng; Xia, Cheng; Xu, Chuang; Wu, Ling; Zhang, Hongyou

2014-01-01

Milk fever (MF) is a common calcium metabolism disorder in perinatal cows. Currently, information regarding the detailed metabolism in cows suffering from MF is scant. The purpose was to study the metabolic profiling of serum samples from cows with MF in comparison to control cows, and thereby exploring other underlying pathological mechanisms of this disease. In the current study, we compared the serum metabolomic profile of dairy cows with MF (n = 8) to that of healthy dairy cows (n = 24) using a 500-MHz digital (1)H-nuclear magnetic resonance ((1)H-NMR) spectrometer. Based on their clinical presentation and serum calcium concentration, cows were assigned either to the control group (no MF symptoms and serum calcium concentration >2.5 mmol/L) or to the MF group (MF symptoms and serum calcium concentration cows with MF. Most of these were carbohydrates and amino acids involved in various energy metabolism pathways. The different metabolites in cows with MF reflected the pathological features of negative energy balance and fat mobilization, suggesting that MF is associated with altered energy metabolism. The (1)H-NMR spectroscopy can be used to understand the pathogenesis of MF and identify biomarkers of the disease.

The structure of phosphate and borosilicate glasses and their structural evolution at high temperatures as studied with solid state NMR spectroscopy: Phase separation, crystallisation and dynamic species exchange

International Nuclear Information System (INIS)

Wegner, S.; Van Wullen, L.; Tricot, G.; Tricot, G.

2010-01-01

In this contribution we present an in-depth study of the network structure of different phosphate based and borosilicate glasses and its evolution at high temperatures. Employing a range of advanced solid state NMR methodologies, complemented by the results of XPS, the structural motifs on short and intermediate length scales are identified. For the phosphate based glasses, at temperatures above the glass transition temperature Tg, structural relaxation processes and the devitrification of the glasses were monitored in situ employing MAS NMR spectroscopy and X-ray diffraction. Dynamic species exchange involving rapid P-O-P and P-O-Al bond breaking and reforming was observed employing in situ 27 Al and 31 P MAS NMR spectroscopy and could be linked to viscous flow. For the borosilicate glasses, an atomic scale investigation of the phase separation processes was possible in a combined effort of ex situ NMR studies on glass samples with different thermal histories and in situ NMR studies using high temperature MAS NMR spectroscopy including 11 B MAS, 29 Si MAS and in situ 29 Si{ 11 B} REAPDOR NMR spectroscopy. (authors)

Pulse NMR-spectroscopy of structural changes of chemically modified polypropylene

International Nuclear Information System (INIS)

Gafarov, A.M.; Galibeev, S.S.; Kochnev, A.M.; Sukhanov, P.P.; Arkhireev, V.P.

2004-01-01

The structure of polypropylene compositions is studied by the method of pulse NMR-spectroscopy. The polypropylene compositions are derived by means of the modification by multicomponent systems. The analysis of relaxation times in a wide temperature range is carried out. Character of changes going on at a level of supermolecular structures is described. It is shown that the amplifications that manifest themselves under the polypropylene modification by the mixtures based on 2,4-tolyilendiisocyanate and e-caprolactam, are related to the change in the intermolecular interaction and formation of a more ordered polymer structure. (authors)

Anatomising proton NMR spectra with pure shift 2D J-spectroscopy: A cautionary tale

Science.gov (United States)

Kiraly, Peter; Foroozandeh, Mohammadali; Nilsson, Mathias; Morris, Gareth A.

2017-09-01

Analysis of proton NMR spectra has been a key tool in structure determination for over 60 years. A classic tool is 2D J-spectroscopy, but common problems are the difficulty of obtaining the absorption mode lineshapes needed for accurate results, and the need for a 45° shear of the final 2D spectrum. A novel 2D NMR method is reported here that allows straightforward determination of homonuclear couplings, using a modified version of the PSYCHE method to suppress couplings in the direct dimension. The method illustrates the need for care when combining pure shift data acquisition with multiple pulse methods.

Structure determination of the single glycan of rabbit serotransferrin by methylation analysis and 360 MHz 1H NMR spectroscopy

International Nuclear Information System (INIS)

Leger, D.; Tordera, V.; Spik, G.; Dorland, L.; Haverkamp, J.; Vliegenthart, J.F.G.

1978-01-01

The glycopeptide fraction of rabbit serotransferrin (STF) has been investigated applying an original method for the determination of glycan primary structure combining monosaccharide determination, permethylation and 360 MHz 1 H NMR. It is concluded that the highly purified rabbit transferrin contains only 1 glycan chain/molecule. A heterogeneity of the glycan moiety in the sialic acid residues was observed on isolation by paper electrophoresis of a disialylglycopeptide G-1 and a monosialylglycopeptide 2. The primary structure of glycopeptide G-1 deduced on the basis of the data of carbohydrate composition, permethylation analysis and 360 MHz 1 H NMR spectroscopy is identical to the primary structure of human serotransferrin glycan and the glycopeptide G-2 was shown by 1 H NMR spectroscopy, to be a mixture of two isomeric monosialylglycopeptides. (Auth.)

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

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Yulia B. Monakhova

2011-01-01

Full Text Available 1H NMR spectroscopy is utilized to quantify total thujone (sum of α- and β-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 observed from 1 to 100 mg/L. Applicability was proven by analysis of 69 authentic absinthes. The correlation between NMR and our previous method consisting of liquid-liquid extraction followed by GC/MS was significant (P<0.0001,R=0.93. The simple and cheap NMR method can be used for rapid screening of absinthes for total thujone content while chromatographic techniques are recommended for more specific (α- and β-thujone isomers analysis if required.

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.

Sub-minute kinetics of human red cell fumarase: 1 H spin-echo NMR spectroscopy and 13 C rapid-dissolution dynamic nuclear polarization.

Science.gov (United States)

Shishmarev, Dmitry; Wright, Alan J; Rodrigues, Tiago B; Pileio, Giuseppe; Stevanato, Gabriele; Brindle, Kevin M; Kuchel, Philip W

2018-03-01

Fumarate is an important probe of metabolism in hyperpolarized magnetic resonance imaging and spectroscopy. It is used to detect the release of fumarase in cancer tissues, which is associated with necrosis and drug treatment. Nevertheless, there are limited reports describing the detailed kinetic studies of this enzyme in various cells and tissues. Thus, we aimed to evaluate the sub-minute kinetics of human red blood cell fumarase using nuclear magnetic resonance (NMR) spectroscopy, and to provide a quantitative description of the enzyme that is relevant to the use of fumarate as a probe of cell rupture. The fumarase reaction was studied using time courses of 1 H spin-echo and 13 C-NMR spectra. 1 H-NMR experiments showed that the fumarase reaction in hemolysates is sufficiently rapid to make its kinetics amenable to study in a period of approximately 3 min, a timescale characteristic of hyperpolarized 13 C-NMR spectroscopy. The rapid-dissolution dynamic nuclear polarization (RD-DNP) technique was used to hyperpolarize [1,4- 13 C]fumarate, which was injected into concentrated hemolysates. The kinetic data were analyzed using recently developed FmR α analysis and modeling of the enzymatic reaction using Michaelis-Menten equations. In RD-DNP experiments, the decline in the 13 C-NMR signal from fumarate, and the concurrent rise and fall of that from malate, were captured with high spectral resolution and signal-to-noise ratio, which allowed the robust quantification of fumarase kinetics. The kinetic parameters obtained indicate the potential contribution of hemolysis to the overall rate of the fumarase reaction when 13 C-NMR RD-DNP is used to detect necrosis in animal models of implanted tumors. The analytical procedures developed will be applicable to studies of other rapid enzymatic reactions using conventional and hyperpolarized substrate NMR spectroscopy. Copyright © 2018 John Wiley & Sons, Ltd.

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

Energy Technology Data Exchange (ETDEWEB)

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

1985-08-01

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

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

International Nuclear Information System (INIS)

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

1985-08-01

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

From traditional resource to global commodities: - A comparison of Rhodiola species using NMR spectroscopy - metabolomics and HPTLC

Directory of Open Access Journals (Sweden)

Anthony Booker

2016-08-01

Full Text Available The fast developing international trade of products based on traditional knowledge and their value chains has become an important aspect of the ethnopharmacological debate. The structure and diversity of value chains and their impact on the phytochemical composition of herbal medicinal products has been overlooked in the debate about quality problems in transnational trade. Different government policies and regulations governing trade in herbal medicinal products impact on such value chains. Medicinal Rhodiola species, including Rhodiola rosea L. and Rhodiola crenulata (Hook.f. & Thomson H.Ohba, have been used widely in Europe and Asia as traditional herbal medicines with numerous claims for their therapeutic effects. Faced with resource depletion and environment destruction, R. rosea and R. crenulata are becoming endangered, making them more economically valuable to collectors and middlemen, and also increasing the risk of adulteration and low quality. We compare the phytochemical differences among Rhodiola raw materials available on the market to provide a practical method for Rhodiola authentication and the detection of potential adulterant compounds. Samples were collected from Europe and Asia and nuclear magnetic resonance spectroscopy coupled with multivariate analysis software and high performance thin layer chromatography techniques were used to analyse the samples. A method was developed to quantify the amount of adulterant species contained within mixtures. We compared the phytochemical composition of collected Rhodiola samples to authenticated samples. Rosavin and rosarin were mainly present in R. rosea whereas crenulatin was only present in R. crenulata. 30% of the Rhodiola samples purchased from the Chinese market were adulterated by other Rhodiola spp. Moreover, 7 % of the raw-material samples were not labelled satifactorily. The utilisation of both 1H-NMR and HPTLC methods provided an integrated analysis of the phytochemical

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

Chemically Methylated and Reduced Pectins: Preparation and Characterisation by 1H-NMR Spectroscopy, Enzymatic Degradation and Gelling Properties

DEFF Research Database (Denmark)

Rosenbohm, Christoph; Lundt, Inge; Christensen, T.M.I.E.

2003-01-01

with lower DM. A simple method for determination of DM by 1H-NMR spectroscopy is presented. New modified pectins have been prepared by treatment of pectins having different DM’s with NaBH4 to reduce selectively the methyl esters to primary alcohols in the presence of free acids. The degree of reduction (DR......) and the DM of the remaining carboxylic acids could likewise be determined by 1H-NMR spectroscopy. The new reduced pectins can be tolerated by the pectin degrading enzymes polygalacturonase PGI and PGII as well as by pectin lyase, all from Aspergillus niger, but the enzymes exhibit lower specific activities...

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...

NMR spectroscopy: a tool for conformational analysis

International Nuclear Information System (INIS)

Tormena, Claudio F.; Cormanich, Rodrigo A.; Rittner, Roberto; Freitas, Matheus P.

2011-01-01

The present review deals with the application of NMR data to the conformational analysis of simple organic compounds, together with other experimental methods like infrared spectroscopy and with theoretical calculations. Each sub-section describes the results for a group of compounds which belong to a given organic function like ketones, esters, etc. Studies of a single compound, even of special relevance, were excluded since the main goal of this review is to compare the results for a given function, where different substituents were used or small structural changes were introduced in the substrate, in an attempt to disclose their effects in the conformational equilibrium. Moreover, the huge amount of data available in the literature, on this research field, imposed some limitations which will be detailed in the Introduction, but it can be reminded in advance that these limitations include mostly the period when these results were published. (author)

Laser spectroscopy and beta-NMR measurements of short-lived Mg isotopes

CERN Document Server

Kowalska, M

2005-01-01

The feasibility of studying the neutron-rich 29Mg, 31Mg and 33Mg isotopes has been demonstrated with the laser and beta-NMR spectroscopy setup at ISOLDE/CERN. The values of the magnetic moment and the nuclear spin of 31Mg are reported and reveal an intruder ground state. This proves the weakening of N=20 shell gap and places this nucleus inside the so called "island of inversion". The experimental setup and technique, as well as the results, are presented.

Investigation of Oxidative Degradation in Polymers Using (17)O NMR Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Alam, Todd M.; Celina, Mathew; Assink, Roger A.; Clough, Roger L.; Gillen, Kenneth T.; Wheeler David R.

1999-07-20

The thermal oxidation of pentacontane (C{sub 50}H{sub 102}), and of the homopolymer polyisoprene, has been investigated using {sup 17}O NMR spectroscopy. By performing the oxidation using {sup 17}O labeled O{sub 2} gas, it is possible to easily identify degradation products, even at relatively low concentrations. It is demonstrated that details of the degradation mechanism can be obtained from analysis of the {sup 17}O NMR spectra as a function of total oxidation. Pentacontane reveals the widest variety of reaction products, and exhibits changes in the relative product distributions with increasing O{sub 2} consumption. At low levels of oxygen incorporation, peroxides are the major oxidation product, while at later stages of degradation these species are replaced by increasing concentrations of ketones, alcohols, carboxylic acids and esters. Analyzing the product distribution can help in identification of the different free-radical decomposition pathways of hydroperoxides, including recombination, proton abstraction and chain scission, as well as secondary reactions. The {sup 17}O NMR spectra of thermally oxidized polyisoprene reveal fewer degradation functionalities, but exhibit an increased complexity in the type of observed degradation species due to structural features such as unsaturation and methyl branching. Alcohols and ethers formed from hydrogen abstraction and free radical termination.

Determination of the Nucleic Acid Adducts Structure at the Nucleoside/Nucleotide Level by NMR Spectroscopy

Czech Academy of Sciences Publication Activity Database

Dračínský, Martin; Pohl, Radek

2015-01-01

Roč. 28, č. 2 (2015), s. 155-165 ISSN 0893-228X R&D Projects: GA ČR GA13-24880S Institutional support: RVO:61388963 Keywords : NMR spectroscopy * nucleic acids * nucleotides Subject RIV: CC - Organic Chemistry Impact factor: 3.025, year: 2015

Role of hydration in the phase transition of polypeptides investigated by NMR and Raman spectroscopy

Czech Academy of Sciences Publication Activity Database

Dybal, Jiří; Schmidt, Pavel; Kříž, Jaroslav; Kurková, Dana; Rodriguez-Cabello, J. C.; Alonso, M.

2004-01-01

Roč. 205, - (2004), s. 143-150 ISSN 1022-1360 R&D Projects: GA AV ČR IAA4050208 Institutional research plan: CEZ:AV0Z4050913 Keywords : NMR * quantum chemistry * Raman spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.691, year: 2004

Observation of methanol behavior in fuel cells in situ by NMR spectroscopy.

Science.gov (United States)

Han, Oc Hee; Han, Kee Sung; Shin, Chang Woo; Lee, Juhee; Kim, Seong-Soo; Um, Myung Sup; Joh, Han-Ik; Kim, Soo-Kil; Ha, Heung Yong

2012-04-16

The chemical conversion of methanol in direct methanol fuel cells was followed in situ by NMR spectroscopy. Comparing data of the methanol oxidation on Pt and PtRu anode catalysts allowed the role of Ru in both Faradaic and non-Faradaic reactions to be investigated. The spatial distributions of chemicals could also be determined. (Picture: T1-T4=inlet and outlet tubes.). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure determination of the single glycan of rabbit serotransferrin by methylation analysis and 360 MHz /sup 1/H NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Leger, D; Tordera, V; Spik, G [Lille-1 Univ., 59 - Villeneuve-d' Ascq (France); Dorland, L; Haverkamp, J; Vliegenthart, J F.G. [Rijksuniversiteit Utrecht (Netherlands)

1978-09-15

The glycopeptide fraction of rabbit serotransferrin (STF) has been investigated applying an original method for the determination of glycan primary structure combining monosaccharide determination, permethylation and 360 MHz /sup 1/H NMR. It is concluded that the highly purified rabbit transferrin contains only 1 glycan chain/molecule. A heterogeneity of the glycan moiety in the sialic acid residues was observed on isolation by paper electrophoresis of a disialylglycopeptide G-1 and a monosialylglycopeptide 2. The primary structure of glycopeptide G-1 deduced on the basis of the data of carbohydrate composition, permethylation analysis and 360 MHz /sup 1/H NMR spectroscopy is identical to the primary structure of human serotransferrin glycan and the glycopeptide G-2 was shown by /sup 1/H NMR spectroscopy, to be a mixture of two isomeric monosialylglycopeptides.

Photoswitchable Intramolecular Hydrogen Bonds in 5-Phenylazopyrimidines Revealed By In Situ Irradiation NMR Spectroscopy

Czech Academy of Sciences Publication Activity Database

Procházková, Eliška; Čechová, Lucie; Kind, J.; Janeba, Zlatko; Thiele, C. M.; Dračínský, Martin

2018-01-01

Roč. 24, č. 2 (2018), s. 492-498 ISSN 0947-6539 R&D Projects: GA ČR GA15-11223S Institutional support: RVO:61388963 Keywords : azopyrimidines * heterocycles * hydrogen bonds * NMR spectroscopy * UV/Vis in situ irradiation Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 5.317, year: 2016

Redox-dependent conformational changes in eukaryotic cytochromes revealed by paramagnetic NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

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

2012-03-15

Cytochrome c (Cc) is a soluble electron carrier protein, transferring reducing equivalents between Cc reductase and Cc oxidase in eukaryotes. In this work, we assessed the structural differences between reduced and oxidized Cc in solution by paramagnetic NMR spectroscopy. First, we have obtained nearly-complete backbone NMR resonance assignments for iso-1-yeast Cc and horse Cc in both oxidation states. These were further used to derive pseudocontact shifts (PCSs) arising from the paramagnetic haem group. Then, an extensive dataset comprising over 450 measured PCSs and high-resolution X-ray and solution NMR structures of both proteins were used to define the anisotropic magnetic susceptibility tensor, {Delta}{chi}. For most nuclei, the PCSs back-calculated from the {Delta}{chi} tensor are in excellent agreement with the experimental PCS values. However, several contiguous stretches-clustered around G41, N52, and A81-exhibit large deviations both in yeast and horse Cc. This behaviour is indicative of redox-dependent structural changes, the extent of which is likely conserved in the protein family. We propose that the observed discrepancies arise from the changes in protein dynamics and discuss possible functional implications.

Redox-dependent conformational changes in eukaryotic cytochromes revealed by paramagnetic NMR spectroscopy

International Nuclear Information System (INIS)

Volkov, Alexander N.; Vanwetswinkel, Sophie; Van de Water, Karen; Nuland, Nico A. J. van

2012-01-01

Cytochrome c (Cc) is a soluble electron carrier protein, transferring reducing equivalents between Cc reductase and Cc oxidase in eukaryotes. In this work, we assessed the structural differences between reduced and oxidized Cc in solution by paramagnetic NMR spectroscopy. First, we have obtained nearly-complete backbone NMR resonance assignments for iso-1-yeast Cc and horse Cc in both oxidation states. These were further used to derive pseudocontact shifts (PCSs) arising from the paramagnetic haem group. Then, an extensive dataset comprising over 450 measured PCSs and high-resolution X-ray and solution NMR structures of both proteins were used to define the anisotropic magnetic susceptibility tensor, Δχ. For most nuclei, the PCSs back-calculated from the Δχ tensor are in excellent agreement with the experimental PCS values. However, several contiguous stretches—clustered around G41, N52, and A81—exhibit large deviations both in yeast and horse Cc. This behaviour is indicative of redox-dependent structural changes, the extent of which is likely conserved in the protein family. We propose that the observed discrepancies arise from the changes in protein dynamics and discuss possible functional implications.

An experimental validation of a Bayesian model for quantification in NMR spectroscopy

Science.gov (United States)

Matviychuk, Yevgen; von Harbou, Erik; Holland, Daniel J.

2017-12-01

The traditional peak integration method for quantitative analysis in nuclear magnetic resonance (NMR) spectroscopy is inherently limited by its ability to resolve overlapping peaks and is susceptible to noise. The alternative model-based approaches not only extend quantification capabilities to these challenging examples but also provide a means for automation of the entire process of NMR data analysis. In this paper, we present a general model for an NMR signal that, in a principled way, takes into account the effects of chemical shifts, relaxation, lineshape imperfections, phasing, and baseline distortions. We test the model using both simulations and experiments, concentrating on simple spectra with well-resolved peaks where we expect conventional analysis to be effective. Our results of quantifying mixture compositions compare favorably with the established methods. At high SNR (> 40dB), all approaches usually achieve for these test systems an absolute accuracy of at least 0.01mol /mol for the concentrations of all species. Our model-based approach is successful even for SNR < 20dB ; it achieves 0.05 - 0.1mol /mol accuracy in cases where precise phasing is practically impossible due to high levels of noise in the data.

Sensitivity enhancement of 13C nuclei in 2D J-resolved NMR spectroscopy using a recycled-flow system

International Nuclear Information System (INIS)

Ha, S.T.K.; Lee, R.W.K.; Wilkins, C.L.

1987-01-01

Recycled-flow nuclear magnetic resonance for sensitivity enhancement in 1/2 spin nuclei has been reported previously, achieving several-fold signal enhancement. The success of the method depends upon premagnetization of nuclei prior to flowing into the detector region, obviating the need for delays following data acquisition to allow spin-lattice relaxation and reduce experiment time. The actual gains of sensitivity enhancement for 13 C- 1 H 2D J-resolved NMR using a recycled-flow method are evaluated. Possible enhancements for two types of J-resolved measurements, namely, one-bond 13 C- 1 H and long range J-resolved spectroscopy, are estimated using a simple Carr-Purcell spin-echo approach to quantify the 13 C signals. The pulse sequence is simply 90 0 -t /sub 1/2/-180 0 -t/sub 1/2/-AT-t/sub d/, where t/sub 1/2/ is half the evolution time, AT is the acquisition time, and t/sub d/ the experiment repetition time. In a static 2D NMR experiment, t/sub d/ usually must be the same order of the longest spin-lattice relaxation time (T 1 ) of nuclei. Quantitative measurements using a recycled-flow system indicate t/dub d/ can be reduced to a fraction of T 1 ; hence significant time savings can be achieved. Time-savings of between 2 and 25 can be anticipated for 2D spectroscopy under flow measurement conditions used in the present study. Other types of 2D NMR spectroscopy (autocorrelation and double quantum NMR) are discussed

Enhanced detection of aldehydes in Extra-Virgin Olive Oil by means of band selective NMR spectroscopy

Science.gov (United States)

Dugo, Giacomo; Rotondo, Archimede; Mallamace, Domenico; Cicero, Nicola; Salvo, Andrea; Rotondo, Enrico; Corsaro, Carmelo

2015-02-01

High resolution Nuclear Magnetic Resonance (NMR) spectroscopy is a very powerful tool for comprehensive food analyses and especially for Extra-Virgin Olive Oils (EVOOs). We use the NMR technique to study the spectral region of aldehydes (8-10 ppm) for EVOOs coming from the south part of Italy. We perform novel experiments by using mono and bidimensional band selective spin-echo pulse sequences and identify four structural classes of aldehydes in EVOOs. For the first time such species are identified in EVOOs without any chemical treatment; only dilution with CDCl3 is employed. This would allow the discrimination of different EVOOs for the aldehydes content increasing the potentiality of the NMR technique in the screening of metabolites for geographical characterization of EVOOs.

Structure Determination of Unknown Organic Liquids Using NMR and IR Spectroscopy: A General Chemistry Laboratory

Science.gov (United States)

Pavel, John T.; Hyde, Erin C.; Bruch, Martha D.

2012-01-01

This experiment introduced general chemistry students to the basic concepts of organic structures and to the power of spectroscopic methods for structure determination. Students employed a combination of IR and NMR spectroscopy to perform de novo structure determination of unknown alcohols, without being provided with a list of possible…

Ground-state properties of K-isotopes from laser and $\\beta$-NMR spectroscopy

CERN Multimedia

Lievens, P; Rajabali, M M; Krieger, A R

By combining high-resolution laser spectroscopy with $\\beta$-NMR spectroscopy on polarized K-beams we aim to establish the ground-state spins and magnetic moments of the neutron-rich $^{48,49,50,51}$K isotopes from N=29 to N=32. Spins and magnetic moments of the odd-K isotopes up to N=28 reveal an inversion of the ground-state, from the normal $\\,{I}$=3/2 ($\\pi{d}_{3/2}^{-1}$) in $^{41-45}$K$\\to\\,{I}$=1/2 ($\\pi{s}_{1/2}^{-1}$) in $^{47}$K. This inversion of the proton single particle levels is related to the strong proton $d_{3/2}$ - neutron $f_{7/2}$ interaction which lowers the energy of the $\\pi{d}_{3/2}$ single particle state when filling the $\

Styrylpyrylium Salts: 1H and 13C NMR High-Resolution Spectroscopy (1D and 2D

Directory of Open Access Journals (Sweden)

Jean Claude W. Ouédraogo

2010-01-01

Full Text Available 1H and 13C NMR high-resolution spectroscopy (1D and 2D (1H, 1H-COSY, HSQC, HMBC for four styrylpyrylium perchlorates were carried out and signal attributions are reported. Chemical shifts observed on 13C NMR spectra for the styrylpyrylium salts were compared with net atomic charge for carbon obtained by AM1 semiempirical calculations. The position of the styryl group present low effect on chemical shifts for carbon atoms, while the presence of methyl group led to the unshielding of the substituted carbon.

Methyl labeling and TROSY NMR spectroscopy of proteins expressed in the eukaryote Pichia pastoris

International Nuclear Information System (INIS)

Clark, Lindsay; Zahm, Jacob A.; Ali, Rustam; Kukula, Maciej; Bian, Liangqiao; Patrie, Steven M.; Gardner, Kevin H.; Rosen, Michael K.; Rosenbaum, Daniel M.

2015-01-01

13 C Methyl TROSY NMR spectroscopy has emerged as a powerful method for studying the dynamics of large systems such as macromolecular assemblies and membrane proteins. Specific 13 C labeling of aliphatic methyl groups and perdeuteration has been limited primarily to proteins expressed in E. coli, preventing studies of many eukaryotic proteins of physiological and biomedical significance. We demonstrate the feasibility of efficient 13 C isoleucine δ1-methyl labeling in a deuterated background in an established eukaryotic expression host, Pichia pastoris, and show that this method can be used to label the eukaryotic protein actin, which cannot be expressed in bacteria. This approach will enable NMR studies of previously intractable targets

Thermal heterogeneity within aqueous materials quantified by 1H NMR spectroscopy: Multiparametric validation in silico and in vitro

Science.gov (United States)

Lutz, Norbert W.; Bernard, Monique

2018-02-01

We recently suggested a new paradigm for statistical analysis of thermal heterogeneity in (semi-)aqueous materials by 1H NMR spectroscopy, using water as a temperature probe. Here, we present a comprehensive in silico and in vitro validation that demonstrates the ability of this new technique to provide accurate quantitative parameters characterizing the statistical distribution of temperature values in a volume of (semi-)aqueous matter. First, line shape parameters of numerically simulated water 1H NMR spectra are systematically varied to study a range of mathematically well-defined temperature distributions. Then, corresponding models based on measured 1H NMR spectra of agarose gel are analyzed. In addition, dedicated samples based on hydrogels or biological tissue are designed to produce temperature gradients changing over time, and dynamic NMR spectroscopy is employed to analyze the resulting temperature profiles at sub-second temporal resolution. Accuracy and consistency of the previously introduced statistical descriptors of temperature heterogeneity are determined: weighted median and mean temperature, standard deviation, temperature range, temperature mode(s), kurtosis, skewness, entropy, and relative areas under temperature curves. Potential and limitations of this method for quantitative analysis of thermal heterogeneity in (semi-)aqueous materials are discussed in view of prospective applications in materials science as well as biology and medicine.

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

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

Detection of counterfeit brand spirits using 1H NMR fingerprints in comparison to sensory analysis.

Science.gov (United States)

Kuballa, Thomas; Hausler, Thomas; Okaru, Alex O; Neufeld, Maria; Abuga, Kennedy O; Kibwage, Isaac O; Rehm, Jürgen; Luy, Burkhard; Walch, Stephan G; Lachenmeier, Dirk W

2018-04-15

Beverage fraud involving counterfeiting of brand spirits is an increasing problem not only due to deception of the consumer but also because it poses health risks e.g. from possible methanol admixture. Suspicious spirit samples from Russia and Kenya were analysed using 1 H nuclear magnetic resonance (NMR) spectroscopy in comparison to authentic products. Using linear regression analysis of spectral integral values, 4 counterfeited samples from Russia and 2 from Kenya were easily identifiable with R 2  counterfeited and authentic samples but the assessors were unable to correctly identify the counterfeited product in the majority of cases. An important conclusion is that consumers cannot assumed to be self-responsible when consuming counterfeit alcohol because there is no general ability to organoleptically detect counterfeit alcohol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental Determination of pK[subscript a] Values and Metal Binding for Biomolecular Compounds Using [superscript 31]P NMR Spectroscopy

Science.gov (United States)

Swartz, Mason A.; Tubergen, Philip J.; Tatko, Chad D.; Baker, Rachael A.

2018-01-01

This lab experiment uses [superscript 31]P NMR spectroscopy of biomolecules to determine pK[subscript a] values and the binding energies of metal/biomolecule complexes. Solutions of adenosine nucleotides are prepared, and a series of [superscript 31]P NMR spectra are collected as a function of pH and in the absence and presence of magnesium or…

Solid-state 13C magic angle spinning NMR spectroscopy characterization of particle size structural variations in synthetic nanodiamonds

International Nuclear Information System (INIS)

Alam, Todd M.

2004-01-01

Solid-state 13 C magic angle spinning (MAS) NMR spectroscopy has been used to quantify the different carbon species observed in synthetically produced nanodiamonds. Two different diamond-like carbon species were observed using 13 C MAS NMR, which have been attributed to a highly ordered crystalline diamond phase and a disordered crystalline diamond phase. The relative ratio of these different diamond phases was found to vary with the particle size of the nanodiamond materials

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...

Identification and quantitation of anhydrosugars in biomass pyrolytic oils using carbon-13 NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Castola, V.; Bighelli, A. [Universite de Corse, Equipe Chimie et Biomasse, Ajaccio (France); Conti, L.; Scano, G.; Mascia, S. [Universita di Sassari, Dipartimento di Chimica, Sassari (Italy); Casanova, J. [Universite de Corse, Equipe Chimie et Biomasse, Ajaccio (France)

2000-07-01

We described a method which allowed identification and quantitation of anhydrosugars in biomass pyrolysis liquids using carbon-13 NMR spectroscopy. The quantitative procedure was checked and validated (accuracy, precision and response linearity) with pure compounds and artificial mixtures. This method was then applied to the analysis of the glucidic fraction obtained after a simple and rapid fractionation of the bio oil. (author)

Grape juice quality control by means of {sup 1}H NMR spectroscopy and chemometric analyses

Energy Technology Data Exchange (ETDEWEB)

Grandizoli, Caroline Werner Pereira da Silva; Campos, Francinete Ramos; Simonelli, Fabio; Barison, Andersson [Universidade Federal do Paraná (UFPR), Curitiba (Brazil). Departamento de Química

2014-07-01

This work shows the application of {sup 1}H NMR spectroscopy and chemometrics for quality control of grape juice. A wide range of quality assurance parameters were assessed by single {sup 1}H NMR experiments acquired directly from juice. The investigation revealed that conditions and time of storage should be revised and indicated on all labels. The sterilization process of homemade grape juices was efficient, making it possible to store them for long periods without additives. Furthermore, chemometric analysis classified the best commercial grape juices to be similar to homemade grape juices, indicating that this approach can be used to determine the authenticity after adulteration. (author)

Comparison of 13C Nuclear Magnetic Resonance and Fourier Transform Infrared spectroscopy for estimating humification and aromatization of soil organic matter

Science.gov (United States)

Rogers, K.; Cooper, W. T.; Hodgkins, S. B.; Verbeke, B. A.; Chanton, J.

2017-12-01

Solid state direct polarization 13C NMR spectroscopy (DP-NMR) is generally considered the most quantitatively reliable method for soil organic matter (SOM) characterization, including determination of the relative abundances of carbon functional groups. These functional abundances can then be used to calculate important soil parameters such as degree of humification and extent of aromaticity that reveal differences in reactivity or compositional changes along gradients (e.g. thaw chronosequence in permafrost). Unfortunately, the 13C NMR DP-NMR experiment is time-consuming, with a single sample often requiring over 24 hours of instrument time. Alternatively, solid state cross polarization 13C NMR (CP-NMR) can circumvent this problem, reducing analyses times to 4-6 hours but with some loss of quantitative reliability. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) is a quick and relatively inexpensive method for characterizing solid materials, and has been suggested as an alternative to NMR for analysis of soil organic matter and determination of humification (HI) and aromatization (AI) indices. However, the quantitative reliability of ATR-FTIR for SOM analyses has never been verified, nor have any ATR-FTIR data been compared to similar measurements by NMR. In this work we focused on FTIR vibrational bands that correspond to the three functional groups used to calculate HI and AI values: carbohydrates (1030 cm-1), aromatics (1510, 1630 cm-1), and aliphatics (2850, 2920 cm-1). Data from ATR-FTIR measurements were compared to analogous quantitation by DP- and CP-NMR using peat samples from Sweden, Minnesota, and North Carolina. DP- and CP-NMR correlate very strongly, although the correlations are not always 1:1. Direct comparison of relative abundances of the three functional groups determined by NMR and ATR-FTIR yielded satisfactory results for carbohydrates (r2= 0.78) and aliphatics (r2=0.58), but less so for aromatics (r2= 0

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

UV-vis, IR and 1H NMR spectroscopic studies and characterization of ionic-pair crystal violet-oxytetracycline

Science.gov (United States)

Orellana, Sandra; Soto, César; Toral, M. Inés

2010-01-01

The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0 ± 0.2 extracted into chloroform. The characterization was demonstrated using UV-vis spectrophotometry, 1H NMR, measurement of relaxation times T1 and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV-OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic.

Reactive surface organometallic complexes observed using dynamic nuclear polarization surface enhanced NMR spectroscopy

KAUST Repository

Pump, Eva; Viger-Gravel, Jasmine; Abou-Hamad, Edy; Samantaray, Manoja; Hamzaoui, Bilel; Gurinov, Andrei; Anjum, Dalaver H.; Gajan, David; Lesage, Anne; Bendjeriou-Sedjerari, Anissa; Emsley, Lyndon; Basset, Jean-Marie

2016-01-01

Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an emerging technique that allows access to high-sensitivity NMR spectra from surfaces. However, DNP SENS usually requires the use of radicals as an exogenous source of polarization, which has so far limited applications for organometallic surface species to those that do not react with the radicals. Here we show that reactive surface species can be studied if they are immobilized inside porous materials with suitably small windows, and if bulky nitroxide bi-radicals (here TEKPol) are used as the polarization source and which cannot enter the pores. The method is demonstrated by obtaining significant DNP enhancements from highly reactive complelxes [(equivalent to Si-O-)W(Me)(5)] supported on MCM-41, and effects of pore size (6.0, 3.0 and 2.5 nm) on the performance are discussed.

Reactive surface organometallic complexes observed using dynamic nuclear polarization surface enhanced NMR spectroscopy

KAUST Repository

Pump, Eva

2016-08-15

Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an emerging technique that allows access to high-sensitivity NMR spectra from surfaces. However, DNP SENS usually requires the use of radicals as an exogenous source of polarization, which has so far limited applications for organometallic surface species to those that do not react with the radicals. Here we show that reactive surface species can be studied if they are immobilized inside porous materials with suitably small windows, and if bulky nitroxide bi-radicals (here TEKPol) are used as the polarization source and which cannot enter the pores. The method is demonstrated by obtaining significant DNP enhancements from highly reactive complelxes [(equivalent to Si-O-)W(Me)(5)] supported on MCM-41, and effects of pore size (6.0, 3.0 and 2.5 nm) on the performance are discussed.

UV-visible-DAD and 1H-NMR spectroscopy data fusion for studying the photodegradation process of azo-dyes using MCR-ALS.

Science.gov (United States)

Fernández, Cristina; Pilar Callao, M; Larrechi, M Soledad

2013-12-15

The photodegradation process of three azo-dyes - Acid Orange 61, Acid Red 97 and Acid Brown 425 - was monitored simultaneously by ultraviolet-visible spectroscopy with diode array detector (UV-vis-DAD) and (1)H-nuclear magnetic resonance ((1)H-NMR). Multivariate curve resolution-alternating least squares (MCR-ALS) was applied to obtain the concentration and spectral profile of the chemical compounds involved in the process. The analysis of the H-NMR data suggests there are more intermediate compounds than those obtained with the UV-vis-DAD data. The fusion of UV-vis-DAD and the (1)H-NMR signal before the multivariate analysis provides better results than when only one of the two detector signals was used. It was concluded that three degradation products were present in the medium when the three azo-dyes had practically degraded. This study is the first application of UV-vis-DAD and (1)H-NMR spectroscopy data fusion in this field and illustrates its potential as a quick method for evaluating the evolution of the azo-dye photodegradation process. © 2013 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

Schneider, E.

1985-11-01

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

Systematic comparison of crystal and NMR protein structures deposited in the protein data bank.

Science.gov (United States)

Sikic, Kresimir; Tomic, Sanja; Carugo, Oliviero

2010-09-03

Nearly all the macromolecular three-dimensional structures deposited in Protein Data Bank were determined by either crystallographic (X-ray) or Nuclear Magnetic Resonance (NMR) spectroscopic methods. This paper reports a systematic comparison of the crystallographic and NMR results deposited in the files of the Protein Data Bank, in order to find out to which extent these information can be aggregated in bioinformatics. A non-redundant data set containing 109 NMR - X-ray structure pairs of nearly identical proteins was derived from the Protein Data Bank. A series of comparisons were performed by focusing the attention towards both global features and local details. It was observed that: (1) the RMDS values between NMR and crystal structures range from about 1.5 Å to about 2.5 Å; (2) the correlation between conformational deviations and residue type reveals that hydrophobic amino acids are more similar in crystal and NMR structures than hydrophilic amino acids; (3) the correlation between solvent accessibility of the residues and their conformational variability in solid state and in solution is relatively modest (correlation coefficient = 0.462); (4) beta strands on average match better between NMR and crystal structures than helices and loops; (5) conformational differences between loops are independent of crystal packing interactions in the solid state; (6) very seldom, side chains buried in the protein interior are observed to adopt different orientations in the solid state and in solution.

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...

Characterization of the ground state dynamics of proteorhodopsin by NMR and optical spectroscopies

International Nuclear Information System (INIS)

Stehle, Jochen; Scholz, Frank; Löhr, Frank; Reckel, Sina; Roos, Christian; Blum, Michaela; Braun, Markus; Glaubitz, Clemens; Dötsch, Volker; Wachtveitl, Josef; Schwalbe, Harald

2012-01-01

We characterized the dynamics of proteorhodopsin (PR), solubilized in diC7PC, a detergent micelle, by liquid-state NMR spectroscopy at T = 323 K. Insights into the dynamics of PR at different time scales could be obtained and dynamic hot spots could be identified at distinct, functionally relevant regions of the protein, including the BC loop, the EF loop, the N-terminal part of helix F and the C-terminal part of helix G. We further characterize the dependence of the photocycle on different detergents (n-Dodecyl β-D-maltoside DDM; 1,2-diheptanoyl-sn-glycero-3-phosphocholine diC7PC) by ultrafast time-resolved UV/VIS spectroscopy. While the photocycle intermediates of PR in diC7PC and DDM exhibit highly similar spectral characteristics, significant changes in the population of these intermediates are observed. In-situ NMR experiments have been applied to characterize structural changes during the photocycle. Light-induced chemical shift changes detected during the photocycle in diC7PC are very small, in line with the changes in the population of intermediates in the photocycle of proteorhodopsin in diC7PC, where the late O-intermediate populated in DDM is missing and the population is shifted towards an equilibrium of intermediates states (M, N, O) without accumulation of a single populated intermediate.

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.

Structural analysis of the carbohydrate chains of glycoproteins by 500-MHz 1H-NMR spectroscopy

International Nuclear Information System (INIS)

Mutsaers, J.H.G.M.

1986-01-01

This thesis deals with the structural analysis by 500-MHz 1 H-NMR spectroscopy of carbohydrate chains obtained from glycoproteins. In the chapters 1 to 6 the structural analysis of N-glycosidically linked carbohydrate chains is described. The chapters 7 to 10 describe the structural analysis of O-glycosidically linked carbohydrate chains. 381 refs.; 44 figs.; 24 tabs.; 7 schemes

Determination of structural topology of a membrane protein in lipid bilayers using polarization optimized experiments (POE) for static and MAS solid state NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Mote, Kaustubh R. [University of Minnesota, Department of Chemistry (United States); Gopinath, T. [University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics (United States); Veglia, Gianluigi, E-mail: vegli001@umn.edu [University of Minnesota, Department of Chemistry (United States)

2013-10-15

The low sensitivity inherent to both the static and magic angle spinning techniques of solid-state NMR (ssNMR) spectroscopy has thus far limited the routine application of multidimensional experiments to determine the structure of membrane proteins in lipid bilayers. Here, we demonstrate the advantage of using a recently developed class of experiments, polarization optimized experiments, for both static and MAS spectroscopy to achieve higher sensitivity and substantial time-savings for 2D and 3D experiments. We used sarcolipin, a single pass membrane protein, reconstituted in oriented bicelles (for oriented ssNMR) and multilamellar vesicles (for MAS ssNMR) as a benchmark. The restraints derived by these experiments are then combined into a hybrid energy function to allow simultaneous determination of structure and topology. The resulting structural ensemble converged to a helical conformation with a backbone RMSD {approx}0.44 A, a tilt angle of 24 Degree-Sign {+-} 1 Degree-Sign , and an azimuthal angle of 55 Degree-Sign {+-} 6 Degree-Sign . This work represents a crucial first step toward obtaining high-resolution structures of large membrane proteins using combined multidimensional oriented solid-state NMR and magic angle spinning solid-state NMR.

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.

Quantitative analysis of sesquiterpene lactone cnicin in seven Centaurea species wild-growing in Serbia and Montenegro using 1H-NMR spectroscopy

Directory of Open Access Journals (Sweden)

IRIS DJORDJEVIC

2007-12-01

Full Text Available 1H-NMR spectroscopy was applied for the quantitative analysis of cnicin, a bioactive germacranolide type sesquiterpene lactone, in the aerial parts of seven wild-growing Centaurea species collected in Serbia and Montenegro. The analysis was performed by comparison of the integral of the one-proton signal of cnicin (H-13, δ 5.75 with that of the two-proton singlet (δ 6.98 of 2,6-bis(1,1-dimethylethyl-4-methylphenol (BHT, used as the internal standard. Cnicin, within concentration the range 1.06–6.12 mg/g, calculated per weight of the fresh plant material was detected in six species, the exception being C. salonitana. This method allows the rapid and simple quantification of cnicin without any pre-purification step.

β-Lactam antibiotics epitope mapping with STD NMR spectroscopy: a study of drug-human serum albumin interaction

International Nuclear Information System (INIS)

Milagre, Cintia D. F.; Cabeca, Luis F.; Almeida, Wanda P.; Marsaioli, Anita J.

2012-01-01

Molecular recognition events are key issues in many biological processes. STD NMR (saturation transfer difference nuclear magnetic resonance spectroscopy) is one of the techniques used to understand such biological interactions. Herein, we have investigated the interactions of four β-lactam antibiotics belonging to two classes (cephalosporins and penicillins) with human serum albumin (HSA) by 1 H STD NMR revealing that the interaction between the aromatic moiety and HSA is responsible for the binding efficiency. Thus, the structural differences from the five to six-membered thio ring in penicillins and cephalosporins do not seem to influence antibiotic albumin interactions. (author)

Chiral discrimination in NMR spectroscopy: computation of the relevant molecular pseudoscalars

Science.gov (United States)

Buckingham, A. David; Lazzeretti, Paolo; Pelloni, Stefano

2015-07-01

Nuclear magnetic resonance (NMR) is normally blind to chirality but it has been predicted that precessing nuclear spins in a strong magnetic field induce a rotating electric polarisation that is of opposite sign for enantiomers. The polarisation is determined by two pseudoscalars, ? and ?. The former arises from the distortion of the electronic structure by the nuclear magnetic moment in the presence of the strong magnetic field and is equivalent to the linear effect of an electric field on the nuclear shielding tensor. ? determines the temperature-dependent partial orientation of the permanent electric dipole moment of the molecule by the antisymmetric part of the nuclear shielding tensor. Computations of these two contributions are reported for the nuclei in the chiral molecules N-methyloxaziridine, 2-methyloxirane, 1,3-dimethylallene, 1-fluoroethanol, 2-fluoroazirine, 1,2-M-dioxin, 1,2-M-dithiin, 1,2-M-diselenin and 1,2-M-ditellurin. For strongly dipolar molecules, ? is typically two to three orders of magnitude greater than ?, raising hopes for the detection of chirality in NMR spectroscopy. This paper is dedicated to the memory of Prof. Nicholas Handy, F.R.S.

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

Energy Technology Data Exchange (ETDEWEB)

Schneider, E.

1985-11-01

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

Purification and Characterization of Recombinant N-Terminally Pyroglutamate-Modified Amyloid-β Variants and Structural Analysis by Solution NMR Spectroscopy.

Directory of Open Access Journals (Sweden)

Christina Dammers

Full Text Available Alzheimer's disease (AD is the leading cause of dementia in the elderly and is characterized by memory loss and cognitive decline. Pathological hallmark of AD brains are intracellular neurofibrillary tangles and extracellular amyloid plaques. The major component of these plaques is the highly heterogeneous amyloid-β (Aβ peptide, varying in length and modification. In recent years pyroglutamate-modified amyloid-β (pEAβ peptides have increasingly moved into the focus since they have been described to be the predominant species of all N-terminally truncated Aβ. Compared to unmodified Aβ, pEAβ is known to show increased hydrophobicity, higher toxicity, faster aggregation and β-sheet stabilization and is more resistant to degradation. Nuclear magnetic resonance (NMR spectroscopy is a particularly powerful method to investigate the conformations of pEAβ isoforms in solution and to study peptide/ligand interactions for drug development. However, biophysical characterization of pEAβ and comparison to its non-modified variant has so far been seriously hampered by the lack of highly pure recombinant and isotope-enriched protein. Here we present, to our knowledge, for the first time a reproducible protocol for the production of pEAβ from a recombinant precursor expressed in E. coli in natural isotope abundance as well as in uniformly [U-15N]- or [U-13C, 15N]-labeled form, with yields of up to 15 mg/l E. coli culture broth. The chemical state of the purified protein was evaluated by RP-HPLC and formation of pyroglutamate was verified by mass spectroscopy. The recombinant pyroglutamate-modified Aβ peptides showed characteristic sigmoidal aggregation kinetics as monitored by thioflavin-T assays. The quality and quantity of produced pEAβ40 and pEAβ42 allowed us to perform heteronuclear multidimensional NMR spectroscopy in solution and to sequence-specifically assign the backbone resonances under near-physiological conditions. Our results suggest

Determination of the structural changes by Raman and {sup 13}C CP/MAS NMR spectroscopy on native corn starch with plasticizers

Energy Technology Data Exchange (ETDEWEB)

Cozar, O. [Academy of Romanian Scientists, Splaiul Independentei 54, 050094, Bucharest, Romania and National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch (Romania); Filip, C.; Tripon, C. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Cioica, N.; Coţa, C.; Nagy, E. M. [National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch, RO-400458 Cluj-Napoca (Romania)

2013-11-13

The plasticizing - antiplasticizing effect of water and glycerol contents on native corn starch samples is investigated by FT-Raman and {sup 13}C CP/MAS NMR spectroscopy. The presence of both amorphous and crystalline structural phases was evidenced in pure native corn starch and also in the samples containing plasticizers. Among the crystalline starch structures, the A- and V- types were suggested by CP/MAS NMR spectra.

Interaction of primaquine and chloroquine with ionic micelles: 1 H NMR and electronic absorption spectroscopy

International Nuclear Information System (INIS)

Perussi, Janice R.; Monte, Shirley C.; Imasato, Hidetake; Tabak, Marcel; Yushmanov, Victor E.

1995-01-01

The characteristic of binding of primaquine (PQ) and chloroquine (CQ) to micelles of surfactants with different charge of headgroups were studied by 1 H-NMR and optical absorption spectroscopy. Cetyltrimethylammonium (CTAC) was used as a cationic surfactant, sodium dodecylsulfate (SDS) as an anionic surfactant and N-hexadecyl-N, N-dimethyl-3-ammonio-1-propanesulfonate (HPS) as zwitterionic. The pK values and binding constants were estimated. (author)

Rapid approach to identify the presence of Arabica and Robusta species in coffee using 1H NMR spectroscopy.

Science.gov (United States)

Monakhova, Yulia B; Ruge, Winfried; Kuballa, Thomas; Ilse, Maren; Winkelmann, Ole; Diehl, Bernd; Thomas, Freddy; Lachenmeier, Dirk W

2015-09-01

NMR spectroscopy was used to verify the presence of Arabica and Robusta species in coffee. Lipophilic extracts of authentic roasted and green coffees showed the presence of established markers for Robusta (16-O-methylcafestol (16-OMC)) and for Arabica (kahweol). The integration of the 16-OMC signal (δ 3.165 ppm) was used to estimate the amount of Robusta in coffee blends with an approximate limit of detection of 1-3%. The method was successfully applied for the analysis of 77 commercial coffee samples (coffee pods, coffee capsules, and coffee beans). Furthermore, principal component analysis (PCA) was applied to the spectra of lipophilic and aqueous extracts of 20 monovarietal authentic samples. Clusters of the two species were observed. NMR spectroscopy can be used as a rapid prescreening tool to discriminate Arabica and Robusta coffee species before the confirmation applying the official method. Copyright © 2015 Elsevier Ltd. All rights reserved.

Direct detection of ligand binding to Sepharose-immobilised protein using saturation transfer double difference (STDD) NMR spectroscopy

International Nuclear Information System (INIS)

Haselhorst, Thomas; Muenster-Kuehnel, Anja K.; Oschlies, Melanie; Tiralongo, Joe; Gerardy-Schahn, Rita; Itzstein, Mark von

2007-01-01

We report an easy and direct application of 'Saturation Transfer Double Difference' (STDD) NMR spectroscopy to identify ligands that bind to a Sepharose-immobilised target protein. The model protein, cytidine 5'-monophosphate sialic acid (CMP-Sia) synthetase, was expressed as a Strep-Tag II fusion protein and immobilised on Strep-Tactin Sepharose. STD NMR experiments of the protein-enriched Sepharose matrix in the presence of a binding ligand (cytidine 5'-triphosphate, CTP) and a non-binding ligand (α/β-glucose) clearly show that CTP binds to the immobilised enzyme, whereas glucose has no affinity. This approach has three major advantages: (a) only low quantities of protein are required, (b) no specialised NMR technology or the application of additional data analysis by non-routine methods is required, and (c) easy multiple use of the immobilised protein is available

Application of 13C NMR spectroscopy to characterize organic chemical components of decomposing coarse woody debris from different climatic regions

Directory of Open Access Journals (Sweden)

Takuya Hishinuma

2015-04-01

Full Text Available Solid-state 13C nuclear magnetic resonance (NMR spectroscopy was applied to coarse woody debris (CWD in different stages of decomposition and collected from forest floor of a subtropical, a cool temperate, and a subalpine forest in Japan. The purpose was to test its applicability to characterize organic chemical composition of CWD of broad-leaved and coniferous trees from different climatic conditions. O-alkyl-C, mainly representing carbohydrates, was the predominant component of CWD at the three sites, accounting for 43.5-58.1% of the NMR spectra. Generally, the relative area under the signals for aromatic-C and phenolic-C, mainly representing lignin, increased, whereas the relative area for O-alkyl-C decreased, as the decay class advanced. The relative area under NMR chemical shift regions was significantly correlated with the chemical properties examined with proximate analyses. That is, O-alkyl-C and di-O-alkyl-C NMR signal areas were positively correlated with the volumetric density of CWD and the content of total carbohydrates. Methoxyl-C, aromatic-C, phenolic-C, carboxyl-C, and carbonyl-C were positively correlated with the contents of acid-unhydrolyzable residues (lignin, tannins, and cutin and nitrogen. Lignin-C calculated from NMR signals increased, and polysaccharide-C decreased, with the decay class of CWD at the three study sites. A review of previous studies on 13C NMR spectroscopy for decomposing CWD suggested further needs of its application to broad-leaved trees from tropical and subtropical regions.

Structural Investigations of Portland Cement Components, Hydration, and Effects of Admixtures by Solid-State NMR Spectroscopy

DEFF Research Database (Denmark)

Skibsted, Jørgen Bengaard; Andersen, Morten D.; Jakobsen, Hans Jørgen

2006-01-01

for the C-S-H phase formed during hydration. It will be demonstrated that Al3+ and flouride guest-ions in the anhydrous and hydrated calcium silicates can be studied in detail by 27Al and 19F MAS NMR, thereby providing information on the local structure and the mechanisms for incorporation of these ions......Solid-state, magic-angle spinning (MAS) NMR spectroscopy represents a valuable tool for structural investigations on the nanoscale of the most important phases in anhydrous and hydrated Portland cements and of various admixtures. This is primarily due to the fact that the method reflects the first......- and second-coordination spheres of the spin nucleus under investigation while it is less sensitive to long-range order. Thus, crystalline as well as amorphous phases can be detected in a quantitative manner by solid-state NMR. In particular the structure of the calcium-silicate-hydrate (C-S-H) phase have...

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

Early history of NMR at Los Alamos

International Nuclear Information System (INIS)

Jackson, J.A.

1985-11-01

Nuclear magnetic resonance (NMR) spectroscopy has developed into an important research tool in chemistry. More recently, NMR imaging and in vivo spectroscopy promise to produce a revolution in medicine and biochemistry. Early experiments at Los Alamos led to DOE programs involving stable isotopes of importance to biology and to medicine. These events are briefly recounted. 2 refs

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.

NMR and IR Spectroscopy for the Structural Characterization of Edible Fats and Oils: An Instrumental Analysis Laboratory

Science.gov (United States)

Crowther, Molly W.

2008-01-01

This article describes an upper-level instrumental laboratory for undergraduates that explores the complementary nature of IR and NMR spectroscopy for analysis of several edible fats and oils that are structurally similar but differ in physical properties and health implications. Five different fats and oils are analyzed for average chain length,…

Dynamic domains of amyloid fibrils can be site-specifically assigned with proton detected 3D NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Falk, Alexander S.; Siemer, Ansgar B., E-mail: asiemer@usc.edu [Keck School of Medicine of USC, Department of Biochemistry and Molecular Medicine, Zilkha Neurogenetic Institute (United States)

2016-11-15

Several amyloid fibrils have cores framed by highly dynamic, intrinsically disordered, domains that can play important roles for function and toxicity. To study these domains in detail using solid-state NMR spectroscopy, site-specific resonance assignments are required. Although the rapid dynamics of these domains lead to considerable averaging of orientation-dependent NMR interactions and thereby line-narrowing, the proton linewidths observed in these samples is far larger than what is regularly observed in solution. Here, we show that it is nevertheless possible to record 3D HNCO, HNCA, and HNcoCA spectra on these intrinsically disordered domains and to obtain site-specific assignments.

Dynamic domains of amyloid fibrils can be site-specifically assigned with proton detected 3D NMR spectroscopy

International Nuclear Information System (INIS)

Falk, Alexander S.; Siemer, Ansgar B.

2016-01-01

Several amyloid fibrils have cores framed by highly dynamic, intrinsically disordered, domains that can play important roles for function and toxicity. To study these domains in detail using solid-state NMR spectroscopy, site-specific resonance assignments are required. Although the rapid dynamics of these domains lead to considerable averaging of orientation-dependent NMR interactions and thereby line-narrowing, the proton linewidths observed in these samples is far larger than what is regularly observed in solution. Here, we show that it is nevertheless possible to record 3D HNCO, HNCA, and HNcoCA spectra on these intrinsically disordered domains and to obtain site-specific assignments.

High pressure {sup 31}P NMR spectroscopy on guanine nucleotides

Energy Technology Data Exchange (ETDEWEB)

Spoerner, Michael; Karl, Matthias; Lopes, Pedro; Hoering, Marcus; Loeffel, Karoline; Nuehs, Andrea; Adelsberger, Joseph; Kremer, Werner; Kalbitzer, Hans Robert, E-mail: hans-robert.kalbitzer@ur.de [University of Regensburg, Centre of Magnetic Resonance in Chemistry and Biomedicine, Institute of Biophysics and Physical Biochemistry (Germany)

2017-01-15

The {sup 31}P NMR pressure response of guanine nucleotides bound to proteins has been studied in the past for characterizing the pressure perturbation of conformational equilibria. The pressure response of the {sup 31}P NMR chemical shifts of the phosphate groups of GMP, GDP, and GTP as well as the commonly used GTP analogs GppNHp, GppCH{sub 2}p and GTPγS was measured in the absence and presence of Mg{sup 2+}-ions within a pressure range up to 200 MPa. The pressure dependence of chemical shifts is clearly non-linear. For all nucleotides a negative first order pressure coefficient B{sub 1} was determined indicating an upfield shift of the resonances with pressure. With exception of the α-phosphate group of Mg{sup 2+}·GMP and Mg{sup 2+}·GppNHp the second order pressure coefficients are positive. To describe the data of Mg{sup 2+}·GppCH{sub 2}p and GTPγS a Taylor expansion of 3rd order is required. For distinguishing pH effects from pressure effects a complete pH titration set is presented for GMP, as well as GDP and GTP in absence and presence of Mg{sup 2+} ions using indirect referencing to DSS under identical experimental conditions. By a comparison between high pressure {sup 31}P NMR data on free Mg{sup 2+}-GDP and Mg{sup 2+}-GDP in complex with the proto-oncogene Ras we demonstrate that pressure induced changes in chemical shift are clearly different between both forms.

Lectures on pulsed NMR

International Nuclear Information System (INIS)

Pines, A.

1988-08-01

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

Fragment-Linking Approach Using (19)F NMR Spectroscopy To Obtain Highly Potent and Selective Inhibitors of β-Secretase.

Science.gov (United States)

Jordan, John B; Whittington, Douglas A; Bartberger, Michael D; Sickmier, E Allen; Chen, Kui; Cheng, Yuan; Judd, Ted

2016-04-28

Fragment-based drug discovery (FBDD) has become a widely used tool in small-molecule drug discovery efforts. One of the most commonly used biophysical methods in detecting weak binding of fragments is nuclear magnetic resonance (NMR) spectroscopy. In particular, FBDD performed with (19)F NMR-based methods has been shown to provide several advantages over (1)H NMR using traditional magnetization-transfer and/or two-dimensional methods. Here, we demonstrate the utility and power of (19)F-based fragment screening by detailing the identification of a second-site fragment through (19)F NMR screening that binds to a specific pocket of the aspartic acid protease, β-secretase (BACE-1). The identification of this second-site fragment allowed the undertaking of a fragment-linking approach, which ultimately yielded a molecule exhibiting a more than 360-fold increase in potency while maintaining reasonable ligand efficiency and gaining much improved selectivity over cathepsin-D (CatD). X-ray crystallographic studies of the molecules demonstrated that the linked fragments exhibited binding modes consistent with those predicted from the targeted screening approach, through-space NMR data, and molecular modeling.

Microcomputer utilization for comparison of 1H-NMR spectra with data base standards

International Nuclear Information System (INIS)

Vale Rodrigues, G. do; Nagem, T.J.

1989-01-01

A new computacional technique for the storage of spectrometric data of natural products listed in the literature and its comparison with data of new compounds isolated as natural products is described here. The programs allow a correlation of two spectra by inverting one relative to the other. The programs again permit the comparison of two NMR spectra in different frequencies. (author) [pt

31P-NMR spectroscopy in measurements of physiological parameters and response to therapy of human melanoma xenografts

International Nuclear Information System (INIS)

Olsen, Dag Rune

1999-01-01

The aim of the study was to investigate whether ''31P-NMR spectroscopy can be utilized in prediction and monitoring of response to therapy or tumours. The specific aims were: 1) To investigate possible correlations between on the one hand bio energetics status, phospholipids resonance ratios, intracellular pH and phosphorus T 1 s and on the other hand tumour blood supply and oxygenation, tumour proliferation and necrotic fraction across tumour lines. 2) Reveal possible correlations between changes in tumour bio energetics status and phosphorus T 1 s and the changes in tumour blood flow, tumour oxygenation and necrotic fraction. 3) To investigate whether irradiation and hyperthermia treatment of tumours affect bio energetics status and phosphorus T 1 s. 4) To identify the tumour physiological factors that is effected by the treatment and influence the bio energetics status and phosphorus T 1 s. The results are presented in 8 papers with titles: 1)''31P-nuclear magnetic resonance spectroscopy in vivo of six human melanoma zeno graft lines: Tumour bio energetic status and blood supply. 2) ''31P NMR spectroscopy studies of phospholipid metabolism in human melanoma xenograft lines differing in rate of tumour cell proliferation. 3) ''31P-nuclear magnetic resonance spectroscopy in vivo of four human melanoma xenograft lines: Spin-lattice relaxation times. 4) Effect of melanin on phosphorus T 1 s in human melanoma xenografts studied by ''31P MRS 5) Spin-lattice relaxation time of inorganic phosphate in human tumour xenografts measured in vivo by ''31P-magnetic resonance spectroscopy influence of oxygen tension. 6) Effects of hyperthermia on bio energetic status and phosphorus T 1 s in human melanoma xenografts monitored by ''31P-MRS. 7) Monitoring of tumour reoxygenation following irradiation by ''31P magnetic resonance spectroscopy an experimental study of human melanoma xenografts. 8) Radiation-induced changes in phosphorus T 1 values in human melanoma xenografts studied

Integrative NMR for biomolecular research

International Nuclear Information System (INIS)

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

2016-01-01

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

Integrative NMR for biomolecular research

Energy Technology Data Exchange (ETDEWEB)

Lee, Woonghee, E-mail: whlee@nmrfam.wisc.edu; Cornilescu, Gabriel; Dashti, Hesam; Eghbalnia, Hamid R.; Tonelli, Marco; Westler, William M.; Butcher, Samuel E.; Henzler-Wildman, Katherine A.; Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, National Magnetic Resonance Facility at Madison and Biochemistry Department (United States)

2016-04-15

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

Comparison of NMR and crystal structures for the proteins TM1112 and TM1367

International Nuclear Information System (INIS)

Mohanty, Biswaranjan; Serrano, Pedro; Pedrini, Bill; Jaudzems, Kristaps; Geralt, Michael; Horst, Reto; Herrmann, Torsten; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

2010-01-01

NMR structures of the proteins TM1112 and TM1367 solved by the JCSG in solution at 298 K could be superimposed with the corresponding crystal structures at 100 K with r.m.s.d. values of <1.0 Å for the backbone heavy atoms. For both proteins the structural differences between multiple molecules in the asymmetric unit of the crystals correlated with structural variations within the bundles of conformers used to represent the NMR solution structures. A recently introduced JCSG NMR structure-determination protocol, which makes use of the software package UNIO for extensive automation, was further evaluated by comparison of the TM1112 structure obtained using these automated methods with another NMR structure that was independently solved in another PSI center, where a largely interactive approach was applied. The NMR structures of the TM1112 and TM1367 proteins from Thermotoga maritima in solution at 298 K were determined following a new protocol which uses the software package UNIO for extensive automation. The results obtained with this novel procedure were evaluated by comparison with the crystal structures solved by the JCSG at 100 K to 1.83 and 1.90 Å resolution, respectively. In addition, the TM1112 solution structure was compared with an NMR structure solved by the NESG using a conventional largely interactive methodology. For both proteins, the newly determined NMR structure could be superimposed with the crystal structure with r.m.s.d. values of <1.0 Å for the backbone heavy atoms, which provided a starting platform to investigate local structure variations, which may arise from either the methods used or from the different chemical environments in solution and in the crystal. Thereby, these comparative studies were further explored with the use of reference NMR and crystal structures, which were computed using the NMR software with input of upper-limit distance constraints derived from the molecular models that represent the results of structure

NATURAL CYCLOPENTANOID CYANOHYDRIN GLYCOSIDES .13. STRUCTURE DETERMINATION OF NATURAL EPOXYCYCLOPENTANES BY X-RAY CRYSTALLOGRAPHY AND NMR-SPECTROSCOPY

DEFF Research Database (Denmark)

Olafsdottir, E. S.; Sorensen, A. M.; Cornett, Claus

1991-01-01

nonannellated cyclopentane derivatives. The new glucosides were shown, by NMR spectroscopy (including NOE measurements), X-ray crystallography, and enzymatic hydrolysis to the corresponding cyanohydrins, to be (1R,2R,3R,4R)- and (1S,2S,3S,4S)-1-(beta-D-glucopyranosyloxy)-2,3-epoxy-4-hydroxycyclopenta ne-1...

NMR in the SPINE Structural Proteomics project.

Science.gov (United States)

Ab, E; Atkinson, A R; Banci, L; Bertini, I; Ciofi-Baffoni, S; Brunner, K; Diercks, T; Dötsch, V; Engelke, F; Folkers, G E; Griesinger, C; Gronwald, W; Günther, U; Habeck, M; de Jong, R N; Kalbitzer, H R; Kieffer, B; Leeflang, B R; Loss, S; Luchinat, C; Marquardsen, T; Moskau, D; Neidig, K P; Nilges, M; Piccioli, M; Pierattelli, R; Rieping, W; Schippmann, T; Schwalbe, H; Travé, G; Trenner, J; Wöhnert, J; Zweckstetter, M; Kaptein, R

2006-10-01

This paper describes the developments, role and contributions of the NMR spectroscopy groups in the Structural Proteomics In Europe (SPINE) consortium. Focusing on the development of high-throughput (HTP) pipelines for NMR structure determinations of proteins, all aspects from sample preparation, data acquisition, data processing, data analysis to structure determination have been improved with respect to sensitivity, automation, speed, robustness and validation. Specific highlights are protonless (13)C-direct detection methods and inferential structure determinations (ISD). In addition to technological improvements, these methods have been applied to deliver over 60 NMR structures of proteins, among which are five that failed to crystallize. The inclusion of NMR spectroscopy in structural proteomics pipelines improves the success rate for protein structure determinations.

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

Science.gov (United States)

Koskela, Harri; Hakala, Ullastiina; Vanninen, Paula

2010-06-15

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

Nuclear magnetic resonance (NMR) spectroscopy and its application to biomedical research

Energy Technology Data Exchange (ETDEWEB)

Nakazawa, Mikio; Imai, Shoichi

1988-07-01

The principles of nuclear magnetic resonance (NMR) spectroscopy were explained and its application to biomedical research discussed. With /sup 31/P-NMR, it is feasible to conduct a continuous, non-invasive measurement of the contents of myocardial high-energy phosphate compounds and the intracellular pH (determined by monitoring the pH dependent shift of the inorganic phosphate peak relative to that of creatine phosphate), and to correlate them with the mechanical function. The determination of the free magnesium concentration is also possible on a similar principle to that for pH determination (the shift of MgATP peaks relative to ATP is utilized in this case). It is estimated to be 0.3 mM and was found not to be changed during ischemia. Several examples of studies including our own conducted to delineate the ischemic derangements of the myocardial energy metabolism and the effects of various interventions thereupon were illustrated. Finally a brief mention was made of the saturation transfer technique. This is the only method with which one can study the kinetics of the enzyme reactions under in vivo conditions. The application of the method for analysis of the creatine kinase reaction and the ATP synthesis was demonstrated. (author) 49 refs.

Nuclear magnetic resonance (NMR) spectroscopy and its application to biomedical research

International Nuclear Information System (INIS)

Nakazawa, Mikio; Imai, Shoichi

1988-01-01

The principles of nuclear magnetic resonance (NMR) spectroscopy were explained and its application to biomedical research discussed. With 31 P-NMR, it is feasible to conduct a continuous, non-invasive measurement of the contents of myocardial high-energy phosphate compounds and the intracellular pH (determined by monitoring the pH dependent shift of the inorganic phosphate peak relative to that of creatine phosphate), and to correlate them with the mechanical function. The determination of the free magnesium concentration is also possible on a similar principle to that for pH determination (the shift of MgATP peaks relative to ATP is utilized in this case). It is estimated to be 0.3 mM and was found not to be changed during ischemia. Several examples of studies including our own conducted to delineate the ischemic derangements of the myocardial energy metabolism and the effects of various interventions thereupon were illustrated. Finally a brief mention was made of the saturation transfer technique. This is the only method with which one can study the kinetics of the enzyme reactions under in vivo conditions. The application of the method for analysis of the creatine kinase reaction and the ATP synthesis was demonstrated. (author) 49 refs

Structural analysis of the exopolysaccharide produced by Streptococcus thermophilus ST1 solely by NMR spectroscopy

International Nuclear Information System (INIS)

Saewen, Elin; Huttunen, Eine; Zhang Xue; Yang Zhennai; Widmalm, Goeran

2010-01-01

The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT experiments. The EPS is composed of hexasaccharide repeating units with the following structure: → 3)[α-d-Glcp-(1 → 4)]-β-d-Galp-(1 → 4)-β-d-Glcp-(1 → 4)[β-d-Galf-(1 → 6)]-β-d-Glcp-(1 → 6)-β-d-Glcp-(1 → , in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined using translational diffusion experiments which resulted in M w = 62 kDa, corresponding to 64 repeating units in the EPS.

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...

Internal dynamics in helical molecules studied by X-ray diffraction, NMR spectroscopy and DFT calculations

Czech Academy of Sciences Publication Activity Database

Dračínský, Martin; Storch, Jan; Církva, Vladimír; Císařová, I.; Sýkora, Jan

2017-01-01

Roč. 19, č. 4 (2017), s. 2900-2907 ISSN 1463-9076 R&D Projects: GA ČR GA15-11223S; GA ČR GA15-12719S Institutional support: RVO:61388963 ; RVO:67985858 Keywords : helicene * NMR spectroscopy * DFT calculations Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry; Physical chemistry (UCHP-M) Impact factor: 4.123, year: 2016 http://pubs.rsc.org/en/content/articlehtml/2013/cp/c6cp07552e

Powder-XRD and (14) N magic angle-spinning solid-state NMR spectroscopy of some metal nitrides.

Science.gov (United States)

Kempgens, Pierre; Britton, Jonathan

2016-05-01

Some metal nitrides (TiN, ZrN, InN, GaN, Ca3 N2 , Mg3 N2 , and Ge3 N4 ) have been studied by powder X-ray diffraction (XRD) and (14) N magic angle-spinning (MAS) solid-state NMR spectroscopy. For Ca3 N2 , Mg3 N2 , and Ge3 N4 , no (14) N NMR signal was observed. Low speed (νr  = 2 kHz for TiN, ZrN, and GaN; νr  = 1 kHz for InN) and 'high speed' (νr  = 15 kHz for TiN; νr  = 5 kHz for ZrN; νr  = 10 kHz for InN and GaN) MAS NMR experiments were performed. For TiN, ZrN, InN, and GaN, powder-XRD was used to identify the phases present in each sample. The number of peaks observed for each sample in their (14) N MAS solid-state NMR spectrum matches perfectly well with the number of nitrogen-containing phases identified by powder-XRD. The (14) N MAS solid-state NMR spectra are symmetric and dominated by the quadrupolar interaction. The envelopes of the spinning sidebands manifold are Lorentzian, and it is concluded that there is a distribution of the quadrupolar coupling constants Qcc 's arising from structural defects in the compounds studied. Copyright © 2015 John Wiley & Sons, Ltd.

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

Science.gov (United States)

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

2011-02-23

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

Comparison of NMR and crystal structures highlights conformational isomerism in protein active sites

International Nuclear Information System (INIS)

Serrano, Pedro; Pedrini, Bill; Geralt, Michael; Jaudzems, Kristaps; Mohanty, Biswaranjan; Horst, Reto; Herrmann, Torsten; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

2010-01-01

Tools for systematic comparisons of NMR and crystal structures developed by the JCSG were applied to two proteins with known functions: the T. maritima anti-σ factor antagonist TM1081 and the mouse γ-glutamylamine cyclotransferase A2LD1 (gi:13879369). In an attempt to exploit the complementarity of crystal and NMR data, the combined use of the two structure-determination techniques was explored for the initial steps in the challenge of searching proteins of unknown functions for putative active sites. The JCSG has recently developed a protocol for systematic comparisons of high-quality crystal and NMR structures of proteins. In this paper, the extent to which this approach can provide function-related information on the two functionally annotated proteins TM1081, a Thermotoga maritima anti-σ factor antagonist, and A2LD1 (gi:13879369), a mouse γ-glutamylamine cyclotransferase, is explored. The NMR structures of the two proteins have been determined in solution at 313 and 298 K, respectively, using the current JCSG protocol based on the software package UNIO for extensive automation. The corresponding crystal structures were solved by the JCSG at 100 K and 1.6 Å resolution and at 100 K and 1.9 Å resolution, respectively. The NMR and crystal structures of the two proteins share the same overall molecular architectures. However, the precision of the structure determination along the amino-acid sequence varies over a significantly wider range in the NMR structures than in the crystal structures. Thereby, in each of the two NMR structures about 65% of the residues have displacements below the average and in both proteins the less well ordered residues include large parts of the active sites, in addition to some highly solvent-exposed surface areas. Whereas the latter show increased disorder in the crystal and in solution, the active-site regions display increased displacements only in the NMR structures, where they undergo local conformational exchange on the

Metabolic profiling of lymph from pigs fed with ß-glucan by high-resolution 1H NMR spectroscopy

DEFF Research Database (Denmark)

Larsen, Flemming Hofmann; Jørgensen, Henry Johs. Høgh; Engelsen, Søren Balling

2010-01-01

To gain information about the effect of ingesting different β-glucan sources on intestinal lymph metabolic profile, 10 growing pigs (30-36 kg) were fitted with a catheter in the jejunal lymphatic trunk, and lymph samples collected continuously -1 to 8 h postprandial and again at 24 h after feeding...... a diet containing either 0.4% added yeast or barley β-glucan and compared to a Control diet. The lymph samples were analysed by proton nuclear magnetic resonance (1H NMR) spectroscopy and subsequently subjected to chemometric analysis. The dominant resonances in the 1H NMR spectra of lymph arose...... of increased lymph viscosity induced by barley β-glucan compared to yeast β-glucan were observed...

Predicting Fuel Ignition Quality Using 1H NMR Spectroscopy and Multiple Linear Regression

KAUST Repository

Abdul Jameel, Abdul Gani

2016-09-14

An improved model for the prediction of ignition quality of hydrocarbon fuels has been developed using 1H nuclear magnetic resonance (NMR) spectroscopy and multiple linear regression (MLR) modeling. Cetane number (CN) and derived cetane number (DCN) of 71 pure hydrocarbons and 54 hydrocarbon blends were utilized as a data set to study the relationship between ignition quality and molecular structure. CN and DCN are functional equivalents and collectively referred to as D/CN, herein. The effect of molecular weight and weight percent of structural parameters such as paraffinic CH3 groups, paraffinic CH2 groups, paraffinic CH groups, olefinic CH–CH2 groups, naphthenic CH–CH2 groups, and aromatic C–CH groups on D/CN was studied. A particular emphasis on the effect of branching (i.e., methyl substitution) on the D/CN was studied, and a new parameter denoted as the branching index (BI) was introduced to quantify this effect. A new formula was developed to calculate the BI of hydrocarbon fuels using 1H NMR spectroscopy. Multiple linear regression (MLR) modeling was used to develop an empirical relationship between D/CN and the eight structural parameters. This was then used to predict the DCN of many hydrocarbon fuels. The developed model has a high correlation coefficient (R2 = 0.97) and was validated with experimentally measured DCN of twenty-two real fuel mixtures (e.g., gasolines and diesels) and fifty-nine blends of known composition, and the predicted values matched well with the experimental data.

Measurement and Characterization of Hydrogen-Deuterium Exchange Chemistry Using Relaxation Dispersion NMR Spectroscopy.

Science.gov (United States)

Khirich, Gennady; Holliday, Michael J; Lin, Jasper C; Nandy, Aditya

2018-03-01

One-dimensional heteronuclear relaxation dispersion NMR spectroscopy at 13 C natural abundance successfully characterized the dynamics of the hydrogen-deuterium exchange reaction occurring at the N ε position in l-arginine by monitoring C δ in varying amounts of D 2 O. A small equilibrium isotope effect was observed and quantified, corresponding to ΔG = -0.14 kcal mol -1 . A bimolecular rate constant of k D = 5.1 × 10 9 s -1 M -1 was determined from the pH*-dependence of k ex (where pH* is the direct electrode reading of pH in 10% D 2 O and k ex is the nuclear spin exchange rate constant), consistent with diffusion-controlled kinetics. The measurement of ΔG serves to bridge the millisecond time scale lifetimes of the detectable positively charged arginine species with the nanosecond time scale lifetime of the nonobservable low-populated neutral arginine intermediate species, thus allowing for characterization of the equilibrium lifetimes of the various arginine species in solution as a function of fractional solvent deuterium content. Despite the system being in fast exchange on the chemical shift time scale, the magnitude of the secondary isotope shift due to the exchange reaction at N ε was accurately measured to be 0.12 ppm directly from curve-fitting D 2 O-dependent dispersion data collected at a single static field strength. These results indicate that relaxation dispersion NMR spectroscopy is a robust and general method for studying base-catalyzed hydrogen-deuterium exchange chemistry at equilibrium.

Single-Crystalline cooperite (PtS): Crystal-Chemical characterization, ESR spectroscopy, and {sup 195}Pt NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Rozhdestvina, V. I., E-mail: veronika@ascnet.ru; Ivanov, A. V.; Zaremba, M. A. [Far East Division, Russian Academy of Sciences, Institute of Geology and Nature Management (Russian Federation); Antsutkin, O. N.; Forsling, W. [Lulea University of Technology (Sweden)

2008-05-15

Single-crystalline cooperite (PtS) with a nearly stoichiometric composition was characterized in detail by X-ray diffraction, electron-probe X-ray microanalysis, and high-resolution scanning electron microscopy. For the first time it was demonstrated that {sup 195}Pt static and MAS NMR spectroscopy can be used for studying natural platinum minerals. The {sup 195}Pt chemical-shift tensor of cooperite was found to be consistent with the axial symmetry and is characterized by the following principal values: {delta}{sub xx} = -5920 ppm, {delta}{sub yy} = -3734 ppm, {delta}{sub zz} = +4023 ppm, and {delta}{sub iso} = -1850 ppm. According to the ESR data, the samples of cooperite contain copper(II), which is adsorbed on the surface during the layer-by-layer crystal growth and is not involved in the crystal lattice.

Two-dimensional NMR spectroscopy of 13C methanol at less than 5 μT

Science.gov (United States)

Shim, Jeong Hyun; Lee, Seong-Joo; Hwang, Seong-min; Yu, Kwon-Kyu; Kim, Kiwoong

2014-09-01

Two-dimensional (2D) spectroscopy is one of the most significant applications of nuclear magnetic resonance (NMR). Here, we demonstrate that the 2D NMR can be performed even at a low magnetic field of less than 5 μT, which is ten times less than the Earth’s magnetic field. The pulses used in the experiment were composed of circularly polarized fields for coherent as well as wideband excitations. Since the excitation band covers the entire spectral range, the simplest two-pulse sequence delivered the full 2D spectrum. At 5 μT, methanol with 13C enriched up to 99% belongs to a strongly coupled regime, and thus its 2D spectrum exhibits complicated spectral correlations, which can be exploited as a fingerprint in chemical analysis. In addition, we show that, with compressive sensing, the acquisition of the 2D spectrum can be accelerated to take only 45% of the overall duration.

Hydrothermal liquefaction oil and hydrotreated product from pine feedstock characterized by heteronuclear two-dimensional NMR spectroscopy and FT-ICR mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Sudasinghe, Nilusha; Cort, John R.; Hallen, Richard T.; Olarte, Mariefel V.; Schmidt, Andrew J.; Schaub, Tanner

2014-12-01

Hydrothermal liquefaction (HTL) crude oil and hydrotreated product from pine tree farm waste (forest product residual, FPR) have been analyzed by direct infusion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) in both positive- and negative-ionization modes and high-resolution twodimensional heteronuclear 1H-13C NMR spectroscopy. FT-ICR MS resolves thousands of compounds in complex oils and provides unparalleled compositional details for individual molecules for identification of compound class (heteroatom content), type (number of rings plus double bonds to carbon or double bond equivalents (DBE) and carbon number (degree of alkylation). Heteronuclear 1H-13C NMR spectroscopy provides one-bond and multiple-bond correlations between pairs of 1H and 13C chemical shifts that are characteristic of different organic functional groups. Taken together this information provides a picture of the chemical composition of these oils. Pyrolysis crude oil product from pine wood was characterized for comparison. Generally, pyrolysis oil is comprised of a more diverse distribution of heteroatom classes with higher oxygen number relative to HTL oil as shown by both positive- and negative-ion ESI FT-ICR MS. A total of 300 N1, 594 O1 and 267 O2 compounds were observed as products of hydrotreatment. The relative abundance of N1O1, N1O2, N1O3, N2, N2O1, N2O2 and O3 compounds are reduced to different degrees after hydrotreatment and other higher heteroatom containing species (O4-O10, N1O4, N1O5 and N2O3) are completely removed by hydrotreatment.

Advances in solid-state NMR of cellulose.

Science.gov (United States)

Foston, Marcus

2014-06-01

Nuclear magnetic resonance (NMR) spectroscopy is a well-established analytical and enabling technology in biofuel research. Over the past few decades, lignocellulosic biomass and its conversion to supplement or displace non-renewable feedstocks has attracted increasing interest. The application of solid-state NMR spectroscopy has long been seen as an important tool in the study of cellulose and lignocellulose structure, biosynthesis, and deconstruction, especially considering the limited number of effective solvent systems and the significance of plant cell wall three-dimensional microstructure and component interaction to conversion yield and rate profiles. This article reviews common and recent applications of solid-state NMR spectroscopy methods that provide insight into the structural and dynamic processes of cellulose that control bulk properties and biofuel conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cerebral NMR spectroscopy to study intracellular space in vivo: methodological development for diffusion weighted spectroscopy at short time scale and for pH measurement using 31P detection

International Nuclear Information System (INIS)

Marchadour, Charlotte

2013-01-01

NMR spectroscopy is a unique modality to evaluate intracellular environment in vivo. Indeed observed molecules are specifically intracellular and generally have a biochemistry role and a specific cellular compartmentation. That could be a useful tool to understand cell functioning in their environment. My thesis work consisted in development of new sequence in both diffusion and phosphorus NMR spectroscopy.My first study was to develop a diffusion-weighted spectroscopy at ultra-short diffusion time to look at the anomalous diffusion in the rat brain. ADC evolution as a function of time shows that brain metabolites motion is mainly due to random diffusion and that active transport (if exist) are negligible. Data modeling evidences that diffusion at short diffusion time is sensitive to cytoplasm viscosity and short scale crowding. In collaboration with the pharmaceutical company, this technique was chosen to follow up transgenic mice (rTg4510), model of tau pathology. Preliminary results show significant differences of ADC at an early stage of neuro-degenerescence (3 and 6 months).Phosphorus spectroscopy allows observation of metabolites directly implicated in energetic processes. During this thesis, localization sequences were developed to measure intracellular pH in the primate striatum. These sequences are supposed to be used to evaluate the potential of pH as a bio-marker of neuro-degenerescence in a phenotypic model of the Huntington disease in the non-human primate. (author) [fr

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

The Solid Solution Sr(1-x)Ba(x)Ga2: Substitutional Disorder and Chemical Bonding Visited by NMR Spectroscopy and Quantum Mechanical Calculations.

Science.gov (United States)

Pecher, Oliver; Mausolf, Bernhard; Lamberts, Kevin; Oligschläger, Dirk; Niewieszol, Carina; Englert, Ulli; Haarmann, Frank

2015-09-28

Complete miscibility of the intermetallic phases (IPs) SrGa2 and BaGa2 forming the solid solution Sr(1-x)Ba(x)Ga2 is shown by means of X-ray diffraction, thermoanalytical and metallographic studies. Regarding the distances of Sr/Ba sites versus substitution degree, a model of isolated substitution centres (ISC) for up to 10% cation substitution is explored to study the influence on the Ga bonding situation. A combined application of NMR spectroscopy and quantum mechanical (QM) calculations proves the electric field gradient (EFG) to be a sensitive measure of different bonding situations. The experimental resolution is boosted by orientation-dependent NMR on magnetically aligned powder samples, revealing in first approximation two different Ga species in the ISC regimes. EFG calculations using superlattice structures within periodic boundary conditions are in fair agreement with the NMR spectroscopy data and are discussed in detail regarding their application on disordered IPs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lanthanide paramagnetic probes for NMR spectroscopic studies of fast molecular conformational dynamics and temperature control. Effective six-site proton exchange in 18-crown-6 by exchange spectroscopy.

Science.gov (United States)

Babailov, Sergey P

2012-02-06

(1)H and (13)C NMR measurements are reported for the CDCl(3) and CD(2)Cl(2) solutions of [La(18-crown-6)(NO(3))(3)] (I), [Pr(18-crown-6) (NO(3))(3)] (II), [Ce(18-crown-6)(NO(3))(3)] (III), and [Nd(18-crown-6)(NO(3))(3)] (IV) complexes. Temperature dependencies of the (1)H NMR spectra of paramagnetic II-IV have been analyzed using the dynamic NMR (DNMR) methods for six-site exchange. Two types of conformational dynamic processes were identified (the first one is conditioned by interconversion of complex enantiomeric forms and pseudorotation of a macrocycle molecule upon the C(2) symmetry axis; the second one is conditioned by macrocycle molecule inversion). Application of exchange spectroscopy (2D-EXSY) of DNMR for investigation of this dynamic system (II-IV) simplifies the assignment of the NMR signals and represents the first experimental study of multisite exchange. In the present work, the methodology of paramagnetic 4f (Ce, Pr, and Nd) probe applications for the study of free-energy, enthalpy, and entropy changes in chemical exchange processes, as well as the advantages of this method in a comparison with DNMR studies of diamagnetic substances, is discussed. In particular, as a result of paramagnetic chemical shifts in 4f complexes, the range of measurable rate constants expands considerably compared to the analogous range in diamagnetic compounds. Coordination compounds investigated in the paper represent new types of thermometric NMR sensors and lanthanide paramagnetic probes for in situ temperature control in solution.

Simultaneous 31P NMR spectroscopy and EMG in exercising and recovering human skeletal muscle: technical aspects

DEFF Research Database (Denmark)

Vestergaard-Poulsen, P; Thomsen, C; Sinkjaer, T

1994-01-01

The bioenergetics of human skeletal muscle can be studied by 31P NMR spectroscopy (31P-MRS) and by surface electromyography (SEMG). Simultaneous 31P-MRS and SEMG permit accurate and noninvasive studies of the correlation between metabolic and electrical changes in exercising and recovering human....... A nonmagnetic ergometer was used for ankle dorsiflexions that activated only the anterior tibial muscle as verified by post exercise imaging. The coil design and the adiabatic sech/tanh pulse improved sensitivity by 45% and 56% respectively, compared with standard techniques. Simultaneous electromyographic...... recordings did not deteriorate the NMR spectra. The VARPRO time domain fitting routine was very suitable for estimating 31P muscle spectra. With these methods it was possible to accurately estimate parameters describing metabolic and electrical changes during rest, exercise and the entire recovery period...

Can NMR solve some significant challenges in metabolomics?

Science.gov (United States)

Gowda, G.A. Nagana; Raftery, Daniel

2015-01-01

The field of metabolomics continues to witness rapid growth driven by fundamental studies, methods development, and applications in a number of disciplines that include biomedical science, plant and nutrition sciences, drug development, energy and environmental sciences, toxicology, etc. NMR spectroscopy is one of the two most widely used analytical platforms in the metabolomics field, along with mass spectrometry (MS). NMR's excellent reproducibility and quantitative accuracy, its ability to identify structures of unknown metabolites, its capacity to generate metabolite profiles using intact biospecimens with no need for separation, and its capabilities for tracing metabolic pathways using isotope labeled substrates offer unique strengths for metabolomics applications. However, NMR's limited sensitivity and resolution continue to pose a major challenge and have restricted both the number and the quantitative accuracy of metabolites analyzed by NMR. Further, the analysis of highly complex biological samples has increased the demand for new methods with improved detection, better unknown identification, and more accurate quantitation of larger numbers of metabolites. Recent efforts have contributed significant improvements in these areas, and have thereby enhanced the pool of routinely quantifiable metabolites. Additionally, efforts focused on combining NMR and MS promise opportunities to exploit the combined strength of the two analytical platforms for direct comparison of the metabolite data, unknown identification and reliable biomarker discovery that continue to challenge the metabolomics field. This article presents our perspectives on the emerging trends in NMR-based metabolomics and NMR's continuing role in the field with an emphasis on recent and ongoing research from our laboratory. PMID:26476597

Can NMR solve some significant challenges in metabolomics?

Science.gov (United States)

Nagana Gowda, G A; Raftery, Daniel

2015-11-01

The field of metabolomics continues to witness rapid growth driven by fundamental studies, methods development, and applications in a number of disciplines that include biomedical science, plant and nutrition sciences, drug development, energy and environmental sciences, toxicology, etc. NMR spectroscopy is one of the two most widely used analytical platforms in the metabolomics field, along with mass spectrometry (MS). NMR's excellent reproducibility and quantitative accuracy, its ability to identify structures of unknown metabolites, its capacity to generate metabolite profiles using intact bio-specimens with no need for separation, and its capabilities for tracing metabolic pathways using isotope labeled substrates offer unique strengths for metabolomics applications. However, NMR's limited sensitivity and resolution continue to pose a major challenge and have restricted both the number and the quantitative accuracy of metabolites analyzed by NMR. Further, the analysis of highly complex biological samples has increased the demand for new methods with improved detection, better unknown identification, and more accurate quantitation of larger numbers of metabolites. Recent efforts have contributed significant improvements in these areas, and have thereby enhanced the pool of routinely quantifiable metabolites. Additionally, efforts focused on combining NMR and MS promise opportunities to exploit the combined strength of the two analytical platforms for direct comparison of the metabolite data, unknown identification and reliable biomarker discovery that continue to challenge the metabolomics field. This article presents our perspectives on the emerging trends in NMR-based metabolomics and NMR's continuing role in the field with an emphasis on recent and ongoing research from our laboratory. Copyright © 2015 Elsevier Inc. All rights reserved.

Can NMR solve some significant challenges in metabolomics?

Science.gov (United States)

Nagana Gowda, G. A.; Raftery, Daniel

2015-11-01

The field of metabolomics continues to witness rapid growth driven by fundamental studies, methods development, and applications in a number of disciplines that include biomedical science, plant and nutrition sciences, drug development, energy and environmental sciences, toxicology, etc. NMR spectroscopy is one of the two most widely used analytical platforms in the metabolomics field, along with mass spectrometry (MS). NMR's excellent reproducibility and quantitative accuracy, its ability to identify structures of unknown metabolites, its capacity to generate metabolite profiles using intact bio-specimens with no need for separation, and its capabilities for tracing metabolic pathways using isotope labeled substrates offer unique strengths for metabolomics applications. However, NMR's limited sensitivity and resolution continue to pose a major challenge and have restricted both the number and the quantitative accuracy of metabolites analyzed by NMR. Further, the analysis of highly complex biological samples has increased the demand for new methods with improved detection, better unknown identification, and more accurate quantitation of larger numbers of metabolites. Recent efforts have contributed significant improvements in these areas, and have thereby enhanced the pool of routinely quantifiable metabolites. Additionally, efforts focused on combining NMR and MS promise opportunities to exploit the combined strength of the two analytical platforms for direct comparison of the metabolite data, unknown identification and reliable biomarker discovery that continue to challenge the metabolomics field. This article presents our perspectives on the emerging trends in NMR-based metabolomics and NMR's continuing role in the field with an emphasis on recent and ongoing research from our laboratory.

High-resolution magic angle spinning 1H-NMR spectroscopy studies on the renal biochemistry in the bank vole (Clethrionomys glareolus) and the effects of arsenic (As3+) toxicity.

Science.gov (United States)

Griffin, J L; Walker, L; Shore, R F; Nicholson, J K

2001-06-01

1. High-resolution magic angle spinning (MAS) 1H-NMR spectroscopy was used to study renal metabolism and the toxicity of As3+, a common environmental contaminant, in the bank vole (Clethrionomys glareolus), a wild species of rodent. 2. Following a 14-day exposure to an environmentally relevant dose of As2O3 (28 mg kg(-1) feed), voles displayed tissue damage at autopsy. MAS 1H spectra indicated abnormal lipid profiles in these samples. 3. Tissue necrosis was also evident from measurements of the apparent diffusion coefficient of water in the intact tissue using MAS 1H diffusion-weighted spectroscopy, its first application to toxicology. 4. Comparison of renal tissue from the wood mouse (Apodemus sylvaticus) exposed to identical exposure levels of As3+ suggested that the bank vole is particularly vulnerable to As3+ toxicity.

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

1H and 13C NMR spectral assignments of four dammarane triterpenoids from carnauba wax.

Science.gov (United States)

Cysne, Juliana de Brito; Braz-Filho, Raimundo; Assunção, Marcus Vinícius; Uchoa, Daniel E de Andrade; Silveira, Edilberto R; Pessoa, Otília Deusdênia L

2006-06-01

The phytochemical investigation of carnauba wax led to the isolation of three new dammarane triterpenoids 1, 2 and 4, together with the known triterpene 3. The structures of the new compounds were determined by 1D and 2D NMR spectroscopy and by comparison with published data for closely related compounds. 2006 John Wiley & Sons, Ltd.

Frontiers of NMR in Molecular Biology

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-08-25

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

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...

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

Science.gov (United States)

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

2009-01-01

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

Structural analysis of the exopolysaccharide produced by Streptococcus thermophilus ST1 solely by NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Saewen, Elin [Arrhenius Laboratory, Stockholm University, Department of Organic Chemistry (Sweden); Huttunen, Eine; Zhang Xue [University of Helsinki, Department of Food Technology (Finland); Yang Zhennai [Northeast Agricultural Research Center of China, Center of Agro-food Technology (China); Widmalm, Goeran, E-mail: gw@organ.su.s [Arrhenius Laboratory, Stockholm University, Department of Organic Chemistry (Sweden)

2010-06-15

The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT experiments. The EPS is composed of hexasaccharide repeating units with the following structure: {yields} 3)[{alpha}-d-Glcp-(1 {yields} 4)]-{beta}-d-Galp-(1 {yields} 4)-{beta}-d-Glcp-(1 {yields} 4)[{beta}-d-Galf-(1 {yields} 6)]-{beta}-d-Glcp-(1 {yields} 6)-{beta}-d-Glcp-(1 {sup {yields}}, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined using translational diffusion experiments which resulted in M{sub w} = 62 kDa, corresponding to 64 repeating units in the EPS.

Measurement of lipid accumulation in Chlorella vulgaris via flow cytometry and liquid-state ¹H NMR spectroscopy for development of an NMR-traceable flow cytometry protocol.

Directory of Open Access Journals (Sweden)

Michael S Bono

Full Text Available In this study, we cultured Chlorella vulgaris cells with a range of lipid contents, induced via nitrogen starvation, and characterized them via flow cytometry, with BODIPY 505/515 as a fluorescent lipid label, and liquid-state 1H NMR spectroscopy. In doing so, we demonstrate the utility of calibrating flow cytometric measurements of algal lipid content using triacylglyceride (TAG, also known as triacylglycerol or triglyceride content per cell as measured via quantitative 1H NMR. Ensemble-averaged fluorescence of BODIPY-labeled cells was highly correlated with average TAG content per cell measured by bulk NMR, with a linear regression yielding a linear fit with r2 = 0.9974. This correlation compares favorably to previous calibrations of flow cytometry protocols to lipid content measured via extraction, and calibration by NMR avoids the time and complexity that is generally required for lipid quantitation via extraction. Flow cytometry calibrated to a direct measurement of TAG content can be used to investigate the distribution of lipid contents for cells within a culture. Our flow cytometry measurements showed that Chlorella vulgaris cells subjected to nitrogen limitation exhibited higher mean lipid content but a wider distribution of lipid content that overlapped the relatively narrow distribution of lipid content for replete cells, suggesting that nitrogen limitation induces lipid accumulation in only a subset of cells. Calibration of flow cytometry protocols using direct in situ measurement of TAG content via NMR will facilitate rapid development of more precise flow cytometry protocols, enabling investigation of algal lipid accumulation for development of more productive algal biofuel feedstocks and cultivation protocols.

Measurement of Lipid Accumulation in Chlorella vulgaris via Flow Cytometry and Liquid-State ¹H NMR Spectroscopy for Development of an NMR-Traceable Flow Cytometry Protocol

Science.gov (United States)

Bono Jr., Michael S.; Garcia, Ravi D.; Sri-Jayantha, Dylan V.; Ahner, Beth A.; Kirby, Brian J.

2015-01-01

In this study, we cultured Chlorella vulgaris cells with a range of lipid contents, induced via nitrogen starvation, and characterized them via flow cytometry, with BODIPY 505/515 as a fluorescent lipid label, and liquid-state 1H NMR spectroscopy. In doing so, we demonstrate the utility of calibrating flow cytometric measurements of algal lipid content using triacylglyceride (TAG, also known as triacylglycerol or triglyceride) content per cell as measured via quantitative 1H NMR. Ensemble-averaged fluorescence of BODIPY-labeled cells was highly correlated with average TAG content per cell measured by bulk NMR, with a linear regression yielding a linear fit with r 2 = 0.9974. This correlation compares favorably to previous calibrations of flow cytometry protocols to lipid content measured via extraction, and calibration by NMR avoids the time and complexity that is generally required for lipid quantitation via extraction. Flow cytometry calibrated to a direct measurement of TAG content can be used to investigate the distribution of lipid contents for cells within a culture. Our flow cytometry measurements showed that Chlorella vulgaris cells subjected to nitrogen limitation exhibited higher mean lipid content but a wider distribution of lipid content that overlapped the relatively narrow distribution of lipid content for replete cells, suggesting that nitrogen limitation induces lipid accumulation in only a subset of cells. Calibration of flow cytometry protocols using direct in situ measurement of TAG content via NMR will facilitate rapid development of more precise flow cytometry protocols, enabling investigation of algal lipid accumulation for development of more productive algal biofuel feedstocks and cultivation protocols. PMID:26267664

Measurement of lipid accumulation in Chlorella vulgaris via flow cytometry and liquid-state ¹H NMR spectroscopy for development of an NMR-traceable flow cytometry protocol.

Science.gov (United States)

Bono, Michael S; Garcia, Ravi D; Sri-Jayantha, Dylan V; Ahner, Beth A; Kirby, Brian J

2015-01-01

In this study, we cultured Chlorella vulgaris cells with a range of lipid contents, induced via nitrogen starvation, and characterized them via flow cytometry, with BODIPY 505/515 as a fluorescent lipid label, and liquid-state 1H NMR spectroscopy. In doing so, we demonstrate the utility of calibrating flow cytometric measurements of algal lipid content using triacylglyceride (TAG, also known as triacylglycerol or triglyceride) content per cell as measured via quantitative 1H NMR. Ensemble-averaged fluorescence of BODIPY-labeled cells was highly correlated with average TAG content per cell measured by bulk NMR, with a linear regression yielding a linear fit with r2 = 0.9974. This correlation compares favorably to previous calibrations of flow cytometry protocols to lipid content measured via extraction, and calibration by NMR avoids the time and complexity that is generally required for lipid quantitation via extraction. Flow cytometry calibrated to a direct measurement of TAG content can be used to investigate the distribution of lipid contents for cells within a culture. Our flow cytometry measurements showed that Chlorella vulgaris cells subjected to nitrogen limitation exhibited higher mean lipid content but a wider distribution of lipid content that overlapped the relatively narrow distribution of lipid content for replete cells, suggesting that nitrogen limitation induces lipid accumulation in only a subset of cells. Calibration of flow cytometry protocols using direct in situ measurement of TAG content via NMR will facilitate rapid development of more precise flow cytometry protocols, enabling investigation of algal lipid accumulation for development of more productive algal biofuel feedstocks and cultivation protocols.

(S)Pinning down protein interactions by NMR

DEFF Research Database (Denmark)

Teilum, Kaare; Kunze, Micha Ben Achim; Erlendsson, Simon

2017-01-01

Protein molecules are highly diverse communication platforms and their interaction repertoire stretches from atoms over small molecules such as sugars and lipids to macromolecules. An important route to understanding molecular communication is to quantitatively describe their interactions...... all types of protein reactions, which can span orders of magnitudes in affinities, reaction rates and lifetimes of states. As the more versatile technique, solution NMR spectroscopy offers a remarkable catalogue of methods that can be successfully applied to the quantitative as well as qualitative...... descriptions of protein interactions. In this review we provide an easy-access approach to NMR for the non-NMR specialist and describe how and when solution state NMR spectroscopy is the method of choice for addressing protein ligand interaction. We describe very briefly the theoretical background...

Which kind of aromatic structures are produced during biomass charring? New insights provided by modern solid-state NMR spectroscopy

Science.gov (United States)

Knicker, Heike; Paneque-Carmona, Marina; Velasco-Molina, Marta; de la Rosa, José Maria; León-Ovelar, Laura Regina; Fernandez-Boy, Elena

2017-04-01

Intense research on biochar and charcoal of the last years has revealed that depending on the production conditions, the chemical and physical characteristics of their aromatic network can greatly vary. Since such variations are determining the behavior and stability of charred material in soils, a better understanding of the structural changes occurring during their heating and the impact of those changes on their function is needed. One method to characterize pyrogenic organic matter (PyOM) represents solid-state 13C NMR spectroscopy applying the cross polarization (CP) magic angle spinning technique (MAS). A drawback of this technique is that the quantification of NMR spectra of samples with highly condensed and proton-depleted structures is assumed to be bias. Typical samples with such attributes are charcoals produced at temperatures above 700°C under pyrolytic conditions. Commonly their high condensation degree leads to graphenic structures that are not only reducing the CP efficiency but create also a conductive lattice which acts as a shield and prevents the entering of the excitation pulse into the sample during the NMR experiments. Since the latter can damage the NMR probe and in the most cases the obtained NMR spectra show only one broad signal assignable to aromatic C, this technique is rarely applied for characterizing high temperature chars or soot. As a consequence, a more detailed knowledge of the nature of the aromatic ring systems is still missing. The latter is also true for the aromatic domains of PyOM produced at lower temperatures, since older NMR instruments operating at low magnetic fields deliver solid-state 13C NMR spectra with low resolution which turns a more detailed analysis of the aromatic chemical shift region into a challenging task. In order to overcome this disadvantages, modern NMR spectroscopy offers not only instruments with greatly improved resolution but also special pulse sequences for NMR experiments which allow a more

Measuring 13Cβ chemical shifts of invisible excited states in proteins by relaxation dispersion NMR spectroscopy

International Nuclear Information System (INIS)

Lundstroem, Patrik; Lin Hong; Kay, Lewis E.

2009-01-01

A labeling scheme is introduced that facilitates the measurement of accurate 13 C β chemical shifts of invisible, excited states of proteins by relaxation dispersion NMR spectroscopy. The approach makes use of protein over-expression in a strain of E. coli in which the TCA cycle enzyme succinate dehydrogenase is knocked out, leading to the production of samples with high levels of 13 C enrichment (30-40%) at C β side-chain carbon positions for 15 of the amino acids with little 13 C label at positions one bond removed (∼5%). A pair of samples are produced using [1- 13 C]-glucose/NaH 12 CO 3 or [2- 13 C]-glucose as carbon sources with isolated and enriched (>30%) 13 C β positions for 11 and 4 residues, respectively. The efficacy of the labeling procedure is established by NMR spectroscopy. The utility of such samples for measurement of 13 C β chemical shifts of invisible, excited states in exchange with visible, ground conformations is confirmed by relaxation dispersion studies of a protein-ligand binding exchange reaction in which the extracted chemical shift differences from dispersion profiles compare favorably with those obtained directly from measurements on ligand free and fully bound protein samples

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.

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.

Detection of free radicals by radical trapping and 15N NMR spectroscopy in copolymerization of methyl acrylate and styrene

NARCIS (Netherlands)

Kelemen, P.; Klumperman, B.

2003-01-01

The macroradicals taking part in the copolymn. of Me acrylate and styrene were trapped by reaction with a 15N labeled stable nitroxyl radical at 70 DegC. The nitroxyl radical is formed in situ from a thermally instable alkoxyamine precursor. 15N NMR spectroscopy is applied to detect the trapping

A new carbamidemethyl-linked lanthanoid chelating tag for PCS NMR spectroscopy of proteins in living HeLa cells

Energy Technology Data Exchange (ETDEWEB)

Hikone, Yuya [Tokyo Metropolitan University, Department of Chemistry, Graduate School of Science and Engineering (Japan); Hirai, Go [RIKEN, Synthetic Organic Chemistry Laboratory (Japan); Mishima, Masaki [Tokyo Metropolitan University, Department of Chemistry, Graduate School of Science and Engineering (Japan); Inomata, Kohsuke [RIKEN, Quantitative Biology Center (Japan); Ikeya, Teppei; Arai, Souichiro [Tokyo Metropolitan University, Department of Chemistry, Graduate School of Science and Engineering (Japan); Shirakawa, Masahiro [Japan Agency for Medical Research and Development, AMED-CREST (Japan); Sodeoka, Mikiko [RIKEN, Synthetic Organic Chemistry Laboratory (Japan); Ito, Yutaka, E-mail: ito-yutaka@tmu.ac.jp [Tokyo Metropolitan University, Department of Chemistry, Graduate School of Science and Engineering (Japan)

2016-10-15

Structural analyses of proteins under macromolecular crowding inside human cultured cells by in-cell NMR spectroscopy are crucial not only for explicit understanding of their cellular functions but also for applications in medical and pharmaceutical sciences. In-cell NMR experiments using human cultured cells however suffer from low sensitivity, thus pseudocontact shifts from protein-tagged paramagnetic lanthanoid ions, analysed using sensitive heteronuclear two-dimensional correlation NMR spectra, offer huge potential advantage in obtaining structural information over conventional NOE-based approaches. We synthesised a new lanthanoid-chelating tag (M8-CAM-I), in which the eight-fold, stereospecifically methylated DOTA (M8) scaffold was retained, while a stable carbamidemethyl (CAM) group was introduced as the functional group connecting to proteins. M8-CAM-I successfully fulfilled the requirements for in-cell NMR: high-affinity to lanthanoid, low cytotoxicity and the stability under reducing condition inside cells. Large PCSs for backbone N–H resonances observed for M8-CAM-tagged human ubiquitin mutant proteins, which were introduced into HeLa cells by electroporation, demonstrated that this approach readily provides the useful information enabling the determination of protein structures, relative orientations of domains and protein complexes within human cultured cells.

A new carbamidemethyl-linked lanthanoid chelating tag for PCS NMR spectroscopy of proteins in living HeLa cells.

Science.gov (United States)

Hikone, Yuya; Hirai, Go; Mishima, Masaki; Inomata, Kohsuke; Ikeya, Teppei; Arai, Souichiro; Shirakawa, Masahiro; Sodeoka, Mikiko; Ito, Yutaka

2016-10-01

Structural analyses of proteins under macromolecular crowding inside human cultured cells by in-cell NMR spectroscopy are crucial not only for explicit understanding of their cellular functions but also for applications in medical and pharmaceutical sciences. In-cell NMR experiments using human cultured cells however suffer from low sensitivity, thus pseudocontact shifts from protein-tagged paramagnetic lanthanoid ions, analysed using sensitive heteronuclear two-dimensional correlation NMR spectra, offer huge potential advantage in obtaining structural information over conventional NOE-based approaches. We synthesised a new lanthanoid-chelating tag (M8-CAM-I), in which the eight-fold, stereospecifically methylated DOTA (M8) scaffold was retained, while a stable carbamidemethyl (CAM) group was introduced as the functional group connecting to proteins. M8-CAM-I successfully fulfilled the requirements for in-cell NMR: high-affinity to lanthanoid, low cytotoxicity and the stability under reducing condition inside cells. Large PCSs for backbone N-H resonances observed for M8-CAM-tagged human ubiquitin mutant proteins, which were introduced into HeLa cells by electroporation, demonstrated that this approach readily provides the useful information enabling the determination of protein structures, relative orientations of domains and protein complexes within human cultured cells.

A new carbamidemethyl-linked lanthanoid chelating tag for PCS NMR spectroscopy of proteins in living HeLa cells

International Nuclear Information System (INIS)

Hikone, Yuya; Hirai, Go; Mishima, Masaki; Inomata, Kohsuke; Ikeya, Teppei; Arai, Souichiro; Shirakawa, Masahiro; Sodeoka, Mikiko; Ito, Yutaka

2016-01-01

Structural analyses of proteins under macromolecular crowding inside human cultured cells by in-cell NMR spectroscopy are crucial not only for explicit understanding of their cellular functions but also for applications in medical and pharmaceutical sciences. In-cell NMR experiments using human cultured cells however suffer from low sensitivity, thus pseudocontact shifts from protein-tagged paramagnetic lanthanoid ions, analysed using sensitive heteronuclear two-dimensional correlation NMR spectra, offer huge potential advantage in obtaining structural information over conventional NOE-based approaches. We synthesised a new lanthanoid-chelating tag (M8-CAM-I), in which the eight-fold, stereospecifically methylated DOTA (M8) scaffold was retained, while a stable carbamidemethyl (CAM) group was introduced as the functional group connecting to proteins. M8-CAM-I successfully fulfilled the requirements for in-cell NMR: high-affinity to lanthanoid, low cytotoxicity and the stability under reducing condition inside cells. Large PCSs for backbone N–H resonances observed for M8-CAM-tagged human ubiquitin mutant proteins, which were introduced into HeLa cells by electroporation, demonstrated that this approach readily provides the useful information enabling the determination of protein structures, relative orientations of domains and protein complexes within human cultured cells.

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.

Exploring abiotic stress on asynchronous protein metabolism in single kernels of wheat studied by NMR spectroscopy and chemometrics

DEFF Research Database (Denmark)

Winning, H.; Viereck, N.; Wollenweber, B.

2009-01-01

at the vegetative growth stage had little effect on the parameters investigated. For the first time, H-1 HR-MAS NMR spectra of grains taken during grain-filling were analysed by an advanced multiway model. In addition to the results from the chemical protein analysis and the H-1 HR-MAS NMR spectra of single kernels...... was to examine the implications of different drought treatments on the protein fractions in grains of winter wheat using H-1 nuclear magnetic resonance spectroscopy followed by chemometric analysis. Triticum aestivum L. cv. Vinjett was studied in a semi-field experiment and subjected to drought episodes either...... at terminal spikelet, during grain-filling or at both stages. Principal component trajectories of the total protein content and the protein fractions of flour as well as the H-1 NMR spectra of single wheat kernels, wheat flour, and wheat methanol extracts were analysed to elucidate the metabolic development...

Detection of Apoptosis and Necrosis in Normal Human Lung Cells Using 1H NMR Spectroscopy

Science.gov (United States)

Shih, Chwen-Ming; Ko, Wun-Chang; Yang, Liang-Yo; Lin, Chien-Ju; Wu, Jui-Sheng; Lo, Tsui-Yun; Wang, Shwu-Huey; Chen, Chien-Tsu

2005-05-01

This study aimed to detect apoptosis and necrosis in MRC-5, a normal human lung cell line, by using noninvasive proton nuclear magnetic resonance (1H NMR). Live MRC-5 cells were processed first for 1H NMR spectroscopy; subsequently their types and the percentage of cell death were assessed on a flow cytometer. Cadmium (Cd) and mercury (Hg) induced apoptosis and necrosis in MRC-5 cells, respectively, as revealed by phosphatidylserine externalization on a flow cytometer. The spectral intensity ratio of methylene (CH2) resonance (at 1.3 ppm) to methyl (CH3) resonance (at 0.9 ppm) was directly proportional to the percentage of apoptosis and strongly and positively correlated with PI staining after Cd treatment (r2 = 0.9868, P In contrast, this ratio only increased slightly within 2-h Hg treatment, and longer Hg exposure failed to produce further increase. Following 2-h Hg exposure, the spectral intensity of choline resonance (at 3.2 ppm) was abolished, but this phenomenon was absent in Cd-induced apoptosis. These findings together demonstrate that 1H NMR is a novel tool with a quantitative potential to distinguish apoptosis from necrosis as early as the onset of cell death in normal human lung cells.

Regional tumor oximetry: 19F NMR spectroscopy of hexafluorobenzene

International Nuclear Information System (INIS)

Hunjan, Sandeep; Mason, Ralph P.; Constantinescu, Anca; Peschke, Peter; Hahn, Eric W.; Antich, Peter P.

1998-01-01

Purpose: An accurate method for monitoring oxygen tension (pO 2 ) of individual tumors could be valuable for optimizing treatment plans. We have recently shown that 19 F nuclear magnetic resonance (NMR) spin-lattice relaxometry of hexafluorobenzene (HFB) provides a highly sensitive indicator of tumor oxygenation. We have now refined the methodology to provide enhanced precision, and applied the method to investigate dynamic changes in tumor oxygenation. Methods and Materials: Dunning prostate adenocarcinoma R3327-AT1 was grown in the form of pedicles on the foreback of male Copenhagen rats. When the tumors reached ≅1 cm diameter, HFB (20 μl) was administered, either centrally or peripherally, by direct intratumoral (IT) injection. Local pO 2 was determined using pulse-burst saturation recovery (PBSR) 19 F NMR spectroscopy on the basis of the spin-lattice relaxation rate, R1. Results: Interrogation of the central region of tumors provided typical values in the range pO 2 = 1.4-6.4 mmHg, with a typical stability of ±2 mmHg over a period of 20 min, when rats breathed 33% O 2 . Altering the inhaled gas to oxygen or carbogen (95% O 2 /5% CO 2 ) produced no significant change. In contrast, interrogation of tumor periphery indicated baseline pO 2 in the range 7.9-78.9 mmHg. Altering inspired gas produced significant changes (p 2 or carbogen, although the change was generally greater with carbogen. In each case, pO 2 returned to baseline within 16 min of returning the inhaled gas to baseline. Conclusion: We believe this method provides a valuable new approach with the requisite precision and accuracy to investigate tumor pO 2

5-Chlorouracil and 5-bromouracil acid-base equilibrium study in water and DMSO by NMR spectroscopy

Science.gov (United States)

Abdrakhimova, G. S.; Ovchinnikov, M. Yu; Lobov, A. N.; Spirikhin, L. V.; Khursan, S. L.; Ivanov, S. P.

2018-04-01

Mechanism of 5-chloro- and 5-bromouracil deprotonation in water and dimethyl sulfoxide (DMSO) has been studied by the 13C and 1H NMR spectroscopy. NMR spectra were interpreted using DFT quantum chemical calculations at the CSGT-PCM-TPSSTPSS/6-311+G(d, p) level of theory. It was found that 5-chloro- (5ClU) and 5-bromouracil (5BrU) are present as a mixture of two anionic forms where the deprotonation is realized at the first (N1) and the third (N3) positions of the pyrimidine ring. N1 form is major for water-alkaline [xAN1/xAN3 (5ClU) = 0.65/0.35 and xAN1/xAN3 (5BrU) = 0.72/0.28, x - molar fraction] and the only one for DMSO solution.

In-situ annotation of carbohydrate diversity, abundance, and degradability in highly complex mixtures using NMR spectroscopy

DEFF Research Database (Denmark)

Meier, Sebastian

2014-01-01

Many functions of carbohydrates depend on the detection of short structural motifs, approximately up to hexasaccharide length, by receptors or catalysts. This study investigates the usefulness of state-of-the-art 1H–13C nuclear-magnetic-resonance (NMR) spectroscopy for characterizing the diversity......, abundance, and degradability of such short structural motifs in plant-derived carbohydrates. Assignments of carbohydrate signals for 1H–13C NMR spectra of beer, wine, and fruit juice yield up to >130 assignments in situ, i.e. in individual samples without separation or derivatization. More than 500...... structural motifs can be resolved over a concentration range of ~103 in experiments of a few hours duration. The diversity of carbohydrate units increases according to power laws at lower concentrations for both cereal and fruit-derived samples. Simple graphs resolve the smaller overall contribution of more...

XRD, TEM, IR, Raman and NMR Spectroscopy of In Situ Crystallization of Lithium Disilicate Glass

Science.gov (United States)

Fuss, T.; Mogus-Milankovic, A.; Ray, C. S.; Lesher, C. E.; Youngman, R.; Day, D. E.

2006-01-01

The structure of a Li2O-2SiO2 (LS2) glass was investigated as a function of pressure and temperature up to 6 GPa and 750 C respectively, using XRD, TEM, IR, Raman and NMR spectroscopy. Glass densified at 6 GPa has an average Si-O-Si bond angle approx.7deg lower than that found in glass processed at 4.5 GPa. At 4.5 GPa, lithium disilicate crystallizes from the glass, while at 6 GPa a new high pressure form of lithium metasilicate crystallizes. The new phase, while having lithium metasilicate crystal symmetry, contains at least 4 different Si sites. NMR results for 6 GPa sample indicate the presence of Q4 species with (Q(sup 4))Si-O-Si(Q(sup 4)) bond angles of approx.157deg. This is the first reported occurrence of Q(sup 4) species with such large bond angles in alumina free alkali silicate glass. No five- or six- coordinated Si are found.

Monitoring of the insecticide trichlorfon by phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy

International Nuclear Information System (INIS)

Talebpour, Zahra; Ghassempour, Alireza; Zendehzaban, Mehdi; Bijanzadeh, Hamid Reza; Mirjalili, Mohammad Hossein

2006-01-01

Trichlorfon is an organophosphorus insecticide, which is extensively being used for protection of fruit crops. Trichlorfon is a thermal labile compound, which cannot be easily determined by gas chromatography (GC) and has no suitable group for sensitive detection by high performance liquid chromatography (HPLC). In this study, a 31 P nuclear magnetic resonance ( 31 P NMR) has been described for monitoring of trichlorfon without any separation step. The quantitative works of 31 P NMR spectroscopy has been performed in the presence of an internal standard (hexamethylphosphoramide). Limit of detection (LOD) for this method has been found to be 55 mg L -1 , without any sample preparation, and the linear working range was 150-5500 mg L -1 . Relative standard deviation (R.S.D.%) of the method for three replicates within and between days was obtained ≤9%. The average recovery efficiency was approximately 99-112%. This method was applied for monitoring trichlorfon in a commercial insecticide sample and tomato sample

PGI chicory (Cichorium intybus L.) traceability by means of HRMAS-NMR spectroscopy: a preliminary study.

Science.gov (United States)

Ritota, Mena; Casciani, Lorena; Valentini, Massimiliano

2013-05-01

Analytical traceability of PGI and PDO foods (Protected Geographical Indication and Protected Denomination Origin respectively) is one of the most challenging tasks of current applied research. Here we proposed a metabolomic approach based on the combination of (1)H high-resolution magic angle spinning-nuclear magnetic resonance (HRMAS-NMR) spectroscopy with multivariate analysis, i.e. PLS-DA, as a reliable tool for the traceability of Italian PGI chicories (Cichorium intybus L.), i.e. Radicchio Rosso di Treviso and Radicchio Variegato di Castelfranco, also known as red and red-spotted, respectively. The metabolic profile was gained by means of HRMAS-NMR, and multivariate data analysis allowed us to build statistical models capable of providing clear discrimination among the two varieties and classification according to the geographical origin. Based on Variable Importance in Projection values, the molecular markers for classifying the different types of red chicories analysed were found accounting for both the cultivar and the place of origin. © 2012 Society of Chemical Industry.

Structures of Biomolecules by NMR Spectroscopy

Indian Academy of Sciences (India)

IAS Admin

an edge over the X-ray method as it can be used to study biomolecules ... currently as an Associate. Professor. ... Such a wealth of data is made available to the NMR ... important step towards structural characterization of a biomolecule. Box 1.

EASY: a simple tool for simultaneously removing background, deadtime and acoustic ringing in quantitative NMR spectroscopy--part I: basic principle and applications.

Science.gov (United States)

Jaeger, Christian; Hemmann, Felix

2014-01-01

Elimination of Artifacts in NMR SpectroscopY (EASY) is a simple but very effective tool to remove simultaneously any real NMR probe background signal, any spectral distortions due to deadtime ringdown effects and -specifically- severe acoustic ringing artifacts in NMR spectra of low-gamma nuclei. EASY enables and maintains quantitative NMR (qNMR) as only a single pulse (preferably 90°) is used for data acquisition. After the acquisition of the first scan (it contains the wanted NMR signal and the background/deadtime/ringing artifacts) the same experiment is repeated immediately afterwards before the T1 waiting delay. This second scan contains only the background/deadtime/ringing parts. Hence, the simple difference of both yields clean NMR line shapes free of artefacts. In this Part I various examples for complete (1)H, (11)B, (13)C, (19)F probe background removal due to construction parts of the NMR probes are presented. Furthermore, (25)Mg EASY of Mg(OH)2 is presented and this example shows how extremely strong acoustic ringing can be suppressed (more than a factor of 200) such that phase and baseline correction for spectra acquired with a single pulse is no longer a problem. EASY is also a step towards deadtime-free data acquisition as these effects are also canceled completely. EASY can be combined with any other NMR experiment, including 2D NMR, if baseline distortions are a big problem. © 2013 Published by Elsevier Inc.

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.

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.      ...

Computer Assisted Instruction (Cain) For Nuclear Magnetic Resonance Spectroscopy

International Nuclear Information System (INIS)

Jaturonrusmee, Wasna; Arthonvorakul, Areerat; Assateranuwat, Adisorn

2005-10-01

A computer assisted instruction program for nuclear magnetic resonance spectroscopy was developed by using Author ware 5.0, Adobe Image Styler 1.0, Adobe Photo shop 7.0 and Flash MX. The contents included the basic theory of 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, the instrumentation of NMR spectroscopy, the two dimensional (2D) NMR spectroscopy and the interpretation of NMR spectra. The program was also provided examples, and exercises, with emphasis on NMR spectra interpretation to determine the structure of unknown compounds and solutions for self study. The questionnaire from students showed that they were very satisfied with the software

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

Science.gov (United States)

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

2015-12-01

The increased sales of organically produced food create a strong need for analytical methods, which could authenticate organic and conventional products. Combined chemometric analysis of (1)H NMR-, (13)C NMR-spectroscopy data, stable-isotope data (IRMS) and α-linolenic acid content (gas chromatography) was used to differentiate organic and conventional milk. In total 85 raw, pasteurized and ultra-heat treated (UHT) milk samples (52 organic and 33 conventional) were collected between August 2013 and May 2014. The carbon isotope ratios of milk protein and milk fat as well as the α-linolenic acid content of these samples were determined. Additionally, the milk fat was analyzed by (1)H and (13)C NMR spectroscopy. The chemometric analysis of combined data (IRMS, GC, NMR) resulted in more precise authentication of German raw and retail milk with a considerably increased classification rate of 95% compared to 81% for NMR and 90% for IRMS using linear discriminate analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

1D and 2D NMR Spectroscopy of Bonding Interactions within Stable and Phase-Separating Organic Electrolyte-Cellulose Solutions.

Science.gov (United States)

Clough, Matthew T; Farès, Christophe; Rinaldi, Roberto

2017-09-11

Organic electrolyte solutions (i.e. mixtures containing an ionic liquid and a polar, molecular co-solvent) are highly versatile solvents for cellulose. However, the underlying solvent-solvent and solvent-solute interactions are not yet fully understood. Herein, mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate, the co-solvent 1,3-dimethyl-2-imidazolidinone, and cellulose are investigated using 1D and 2D NMR spectroscopy. The use of a triply- 13 C-labelled ionic liquid enhances the signal-to-noise ratio for 13 C NMR spectroscopy, enabling changes in bonding interactions to be accurately pinpointed. Current observations reveal an additional degree of complexity regarding the distinct roles of cation, anion, and co-solvent toward maintaining cellulose solubility and phase stability. Unexpectedly, the interactions between the dialkylimidazolium ring C 2 -H substituent and cellulose become more pronounced at high temperatures, counteracted by a net weakening of acetate-cellulose interactions. Moreover, for mixtures that exhibit critical solution behavior, phase separation is accompanied by the apparent recombination of cation-anion pairs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stripline-based microfluidic devices for high-resolution NMR spectroscopy

NARCIS (Netherlands)

Bart, J.

2009-01-01

A novel route towards microchip integrated NMR analysis was studied. For NMR analysis of mass-limited samples, research has focussed for decennia on microsolenoidal or planar helical detection coils on microfluidic substrates. Since these approaches suffer from static field distortion resulting in

Complete resonance assignment for the polypeptide backbone of interleukin 1β using three-dimensional heteronuclear NMR spectroscopy

International Nuclear Information System (INIS)

Driscoll, P.C.; Clore, G.M.; Marion, D.; Gronenborn, A.M.; Wingfield, P.T.

1990-01-01

The complete sequence-specific assignment of the 15 N and 1 H backbone resonances of the NMR spectrum of recombinant human interleukin 1β has been obtained by using primarily 15 N- 1 H heteronuclear three-dimensional (3D) NMR techniques in combination with 15 N- 1 H heteronuclear and 1 H homonuclear two-dimensional NMR. The fingerprint region of the spectrum was analyzed by using a combination of 3D heteronuclear 1 H Hartmann-Hahn 15 N- 1 H multiple quantum coherence (3D HOHAHA-HMQC) and 3D heteronuclear 1 H nuclear Overhauser 15 N- 1 H multiple quantum coherence (3D NOESY-HMQC) spectroscopies. The authors show that the problems of amide NH and C α H chemical shift degeneracy that are prevalent for proteins of the size are readily overcome by using the 3D heteronuclear NMR technique. A doubling of some peaks in the spectrum was found to be due to N-terminal heterogeneity of the 15 N-labeled protein, corresponding to a mixture of wild-type and des-Ala-1-interleukin 1β. The complete list of 15 N and 1 H assignments is given for all the amide NH and C α H resonances of all non-proline residues, as well as the 1 H assignments for some of the amino acid side chains. This first example of the sequence-specific assignment of a protein using heteronuclear 3D NMR provides a basis for further conformational and dynamic studies of interleukin 1β

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.

On the structure of amorphous calcium carbonate--a detailed study by solid-state NMR spectroscopy.

Science.gov (United States)

Nebel, Holger; Neumann, Markus; Mayer, Christian; Epple, Matthias

2008-09-01

The calcium carbonate phases calcite, aragonite, vaterite, monohydrocalcite (calcium carbonate monohydrate), and ikaite (calcium carbonate hexahydrate) were studied by solid-state NMR spectroscopy ( (1)H and (13)C). Further model compounds were sodium hydrogencarbonate, potassium hydrogencarbonate, and calcium hydroxide. With the help of these data, the structure of synthetically prepared additive-free amorphous calcium carbonate (ACC) was analyzed. ACC contains molecular water (as H 2O), a small amount of mobile hydroxide, and no hydrogencarbonate. This supports the concept of ACC as a transient precursor in the formation of calcium carbonate biominerals.

Metabolic Characterization of Peripheral Host Responses to Drainage-Resistant Klebsiella pneumoniae Liver Abscesses by Serum 1H-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Zhihui Chang

2018-06-01

Full Text Available Purpose: To explore the metabolic characterization of host responses to drainage-resistant Klebsiella pneumoniae liver abscesses (DRKPLAs with serum 1H-nuclear magnetic resonance (NMR spectroscopy.Materials and Methods: The hospital records of all patients with a diagnosis of a liver abscess between June 2015 and December 2016 were retrieved from an electronic hospital database. Eighty-six patients with Klebsiella pneumoniae (K. pneumoniae liver abscesses who underwent percutaneous drainage were identified. Twenty patients with confirmed DRKPLAs were studied. Moreover, we identified 20 consecutive patients with drainage-sensitive Klebsiella pneumoniae liver abscesses (DSKPLAs as controls. Serum samples from the two groups were analyzed with 1H NMR spectroscopy. Partial least squares discriminant analysis (PLS-DA was used to perform 1H NMR metabolic profiling. Metabolites were identified using the Human Metabolome Database, and pathway analysis was performed with MetaboAnalyst 3.0.Results: The PLS-DA test was able to discriminate between the two groups. Five key metabolites that contributed to their discrimination were identified. Glucose, lactate, and 3-hydroxybutyrate were found to be upregulated in DRKPLAs, whereas glutamine and alanine were downregulated compared with the DSKPLAs. Pathway analysis indicated that amino acid metabolisms were significantly different between the DRKPLAs and the DSKPLAs. The D-glutamine and D-glutamate metabolisms exhibited the greatest influences.Conclusions: The five key metabolites identified in our study may be potential targets for guiding novel therapeutics of DRKPLAs and are worthy of additional investigation.

In-cell NMR spectroscopy of proteins inside Xenopus laevis oocytes

International Nuclear Information System (INIS)

Sakai, Tomomi; Tochio, Hidehito; Tenno, Takeshi; Ito, Yutaka; Kokubo, Tetsuro; Hiroaki, Hidekazu; Shirakawa, Masahiro

2006-01-01

In-cell NMR is an application of solution NMR that enables the investigation of protein conformations inside living cells. We have measured in-cell NMR spectra in oocytes from the African clawed frog Xenopus laevis. 15 N-labeled ubiquitin, its derivatives and calmodulin were injected into Xenopus oocytes and two-dimensional 1 H- 15 N correlation spectra of the proteins were obtained. While the spectrum of wild-type ubiquitin in oocytes had rather fewer cross-peaks compared to its in vitro spectrum, ubiquitin derivatives that are presumably unable to bind to ubiquitin-interacting proteins gave a markedly larger number of cross-peaks. This observation suggests that protein-protein interactions between ubiquitin and ubiquitin-interacting proteins may cause NMR signal broadening, and hence spoil the quality of the in-cell HSQC spectra. In addition, we observed the maturation of ubiquitin precursor derivative in living oocytes using the in-cell NMR technique. This process was partly inhibited by pre-addition of ubiquitin aldehyde, a specific inhibitor for ubiquitin C-terminal hydrolase (UCH). Our work demonstrates the potential usefulness of in-cell NMR with Xenopus oocytes for the investigation of protein conformations and functions under intracellular environmental conditions

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...

Tannin fingerprinting in vegetable tanned leather by solid state NMR spectroscopy and comparison with leathers tanned by other processes.

Science.gov (United States)

Romer, Frederik H; Underwood, Andrew P; Senekal, Nadine D; Bonnet, Susan L; Duer, Melinda J; Reid, David G; van der Westhuizen, Jan H

2011-01-28

Solid state ¹³C-NMR spectra of pure tannin powders from four different sources--mimosa, quebracho, chestnut and tara--are readily distinguishable from each other, both in pure commercial powder form, and in leather which they have been used to tan. Groups of signals indicative of the source, and type (condensed vs. hydrolyzable) of tannin used in the manufacture are well resolved in the spectra of the finished leathers. These fingerprints are compared with those arising from leathers tanned with other common tanning agents. Paramagnetic chromium (III) tanning causes widespread but selective disappearance of signals from the spectrum of leather collagen, including resonances from acidic aspartyl and glutamyl residues, likely bound to Cr (III) structures. Aluminium (III) and glutaraldehyde tanning both cause considerable leather collagen signal sharpening suggesting some increase in molecular structural ordering. The ²⁷Al-NMR signal from the former material is consistent with an octahedral coordination by oxygen ligands. Solid state NMR thus provides easily recognisable reagent specific spectral fingerprints of the products of vegetable and some other common tanning processes. Because spectra are related to molecular properties, NMR is potentially a powerful tool in leather process enhancement and quality or provenance assurance.

In vivo spectroscopy

International Nuclear Information System (INIS)

Williams, S.R.; Cady, E.B.

1987-01-01

The technique which the authors describe in this chapter provides alternative information to imaging, although based upon the same physical principles. The experiments are carried out differently and have instrumental requirements which are not met by a standard imaging system. Furthermore, although the clinical efficacy of NMR imaging has been proven, clinical spectroscopy is very much in its infancy. With the exception of some specific /sup 31/P applications not is not even clear how spectroscopic investigations will be performed. This is particularly true with regard to localization techniques for investigating other than superficial organs and and in the use of /sup 1/H spectroscopy. They attempt to show what information spectroscopy can provide in principle and point out some of the problems associated with such investigations. NMR has come to the notice of the clinical community mainly through its use as an imaging technique, and many may consider spectroscopy as a secondary discipline. NMR spectroscopy, however, has a longer history than imaging and has been a standard technique in chemistry laboratories for more than two decades. It is a technique without peer for structural analysis of molecules and no new chemical compound is discovered or synthesized without an NMR spectrum being taken. The influence of molecular structure on resonant frequency has been termed the chemical shift

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.

Conformation of flexibly linked triterpene dimers by using RDC-enhanced NMR spectroscopy

Science.gov (United States)

Lakshmi, Jerripothula K.; Pattnaik, Banita; Kavitha, Rachineni; Mallavadhani, Uppuluri V.; Jagadeesh, Bharatam

2018-06-01

Dimers of flexibly linked pentacyclic triterpene ursolic acid (UA) and its related frameworks such as asiatic acid (AA) and oleanolic acid (OA) have recently attracted significant attention due to their enhanced anti-cancer and anti-HCV activity compared to their respective monomers. Determination of conformation/inter-monomer orientation of these molecules is very important to understand their structure-activity relationship and to develop new scaffolds, which, however, is difficult through conventional NOE based solution-state NMR spectroscopy, due to lack of long-range NOEs. In the present work, we report a precise determination of conformation of two 1,2,3-triazole-linked triterpene dimer molecules, UA-AA and UA-OA, by employing one-bond Csbnd H residual dipolar couplings (RDCs) as additional long-range orientational restraints, measured in anisotropic PDMS/CDCl3 solvent medium.

Cool-Climate Red Wines—Chemical Composition and Comparison of Two Protocols for 1H–NMR Analysis

Directory of Open Access Journals (Sweden)

Violetta Aru

2018-01-01

Full Text Available This study investigates the metabolome of 26 experimental cool-climate wines made from 22 grape varieties using two different protocols for wine analysis by proton nuclear magnetic resonance (1H–NMR spectroscopy. The wine samples were analyzed as-is (wet and as dried samples. The NMR datasets were preprocessed by alignment and mean centering. No normalization or scaling was performed. The “wet” method preserved the inherent properties of the samples and provided a fast and effective overview of the molecular composition of the wines. The “dried” method yielded a slightly better sensitivity towards a broader range of the compounds present in wines. A total of 27 metabolites including amino acids, organic acids, sugars, and alkaloids were identified in the 1H–NMR spectra of the wine samples. Principal component analysis was performed on both NMR datasets evidencing well-defined molecular fingerprints for ‘Baco Noir’, ‘Bolero’, ‘Cabernet Cantor’, ‘Cabernet Cortis’, ‘Don Muscat’, ‘Eszter’, ‘Golubok’, ‘New York Muscat’, ‘Regent’, ‘Rondo’, ‘Triomphe d’Alsace’, ‘Précose Noir’, and ‘Vinoslivy’ wines. Amongst the identified metabolites, lactic acid, succinic acid, acetic acid, gallic acid, glycerol, and methanol were found to drive sample groupings. The 1H–NMR data was compared to the absolute concentration values obtained from a reference Fourier transform infrared method, evidencing a high correlation.

Tautomerism and the Protonation/Deprotonation of Isocytosine in Liquid- and Solid-States Studied by NMR Spectroscopy and Theoretical Calculations

Czech Academy of Sciences Publication Activity Database

Dračínský, Martin; Jansa, Petr; Ahonen, K.; Buděšínský, Miloš

-, č. 8 (2011), s. 1544-1551 ISSN 1434-193X R&D Projects: GA AV ČR KJB400550903; GA MŠk 1M0508 Grant - others:AV ČR(CZ) M200380901 Institutional research plan: CEZ:AV0Z40550506 Keywords : NMR spectroscopy * tautomerism * nitrogen heterocycles * density functional calculations Subject RIV: CC - Organic Chemistry Impact factor: 3.329, year: 2011

NMR characterization of simulated Hanford low-activity waste glasses and its use in understanding waste form chemical durability

International Nuclear Information System (INIS)

Darab, J.G.; Linehan, J.C.; McGrail, B.P.

1999-01-01

Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) spectroscopy has been used to characterize the structural and chemical environments of B, Al, and Si in model Hanford low-activity waste glasses. The average 29 Si NMR peak position was found to systematically change with changing glass composition and structure. From an understanding of the structural roles of Al and B obtained from MAS-NMR experiments, the authors first developed a model that reliably predicts the distribution of structural units and the average 29 Si chemical shift value, δ, based purely on glass composition. A product consistency test (PCT) was used to determine the normalized elemental release (NL) from the prepared glasses. Comparison of the NMR and PCT data obtained from sodium boro-aluminosilicate glasses indicates that a rudimentary exponential relationship exists between the 29 Si chemical shift value, and the boron NL value

Determination of P.sub.org./sub. species in fungus .i. Xerocomus badius./i. by .sup.31./sup.P NMR spectroscopy

Czech Academy of Sciences Publication Activity Database

Novák, František; Koukol, Ondřej; Hrabal, R.; Bartošová, I.; Kalčík, Jiří

2006-01-01

Roč. 100, č. 8, (2006), s. 596-597 ISSN 0009-2770 R&D Projects: GA ČR(CZ) GA206/05/0269 Institutional research plan: CEZ:AV0Z60660521; CEZ:AV0Z60050516 Keywords : determination * Xerocomus badius * 31 P NMR spectroscopy Subject RIV: EH - Ecology, Behaviour Impact factor: 0.431, year: 2006

Characterization of the major nutritional components of Caryocar brasiliense fruit pulp by NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Miranda-Vilela, Ana Luisa; Grisolia, Cesar Koppe [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Ciencias Biologicas. Dept. de Genetica e Morfologia; Resck, Ines Sabioni; Mendonca, Marcio Antonio [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Quimica

2009-07-01

Pequi (Caryocar brasiliense Camb.), a typical fruit of Brazilian Cerrado, is well known in regional cookery and used in folk medicine to treat various illnesses. Mass spectrometry and chromatographic methods have identified the organic composition of pequi fruit pulp; however, NMR spectroscopy is used for the first time to characterize the nutritional components of organic and aqueous-ethanolic extracts. This spectroscopic technique determined the triacylglycerols in the pequi organic fraction, which is constituted mainly by oleate and palmitate esters, and detected the carbohydrate mixtures as the major components of aqueous and ethanolic fractions, respectively. In this study, presence of phenolic compounds was only evidenced in the ethanolic fraction. (author)

Characterization of the major nutritional components of Caryocar brasiliense fruit pulp by NMR spectroscopy

International Nuclear Information System (INIS)

Miranda-Vilela, Ana Luisa; Grisolia, Cesar Koppe; Resck, Ines Sabioni; Mendonca, Marcio Antonio

2009-01-01

Pequi (Caryocar brasiliense Camb.), a typical fruit of Brazilian Cerrado, is well known in regional cookery and used in folk medicine to treat various illnesses. Mass spectrometry and chromatographic methods have identified the organic composition of pequi fruit pulp; however, NMR spectroscopy is used for the first time to characterize the nutritional components of organic and aqueous-ethanolic extracts. This spectroscopic technique determined the triacylglycerols in the pequi organic fraction, which is constituted mainly by oleate and palmitate esters, and detected the carbohydrate mixtures as the major components of aqueous and ethanolic fractions, respectively. In this study, presence of phenolic compounds was only evidenced in the ethanolic fraction. (author)

Tannin Fingerprinting in Vegetable Tanned Leather by Solid State NMR Spectroscopy and Comparison with Leathers Tanned by Other Processes

Directory of Open Access Journals (Sweden)

Jan H. van der Westhuizen

2011-01-01

Full Text Available Solid state 13C-NMR spectra of pure tannin powders from four different sources – mimosa, quebracho, chestnut and tara – are readily distinguishable from each other, both in pure commercial powder form, and in leather which they have been used to tan.  Groups of signals indicative of the source, and type (condensed vs. hydrolyzable of tannin used in the manufacture are well resolved in the spectra of the finished leathers.  These fingerprints are compared with those arising from leathers tanned with other common tanning agents.  Paramagnetic chromium (III tanning causes widespread but selective disappearance of signals from the spectrum of leather collagen, including resonances from acidic aspartyl and glutamyl residues, likely bound to Cr (III structures. Aluminium (III and glutaraldehyde tanning both cause considerable leather collagen signal sharpening suggesting some increase in molecular structural ordering. The 27Al-NMR signal from the former material is consistent with an octahedral coordination by oxygen ligands. Solid state NMR thus provides easily recognisable reagent specific spectral fingerprints of the products of vegetable and some other common tanning processes. Because spectra are related to molecular properties, NMR is potentially a powerful tool in leather process enhancement and quality or provenance assurance.

Semi-automated separation of the epimeric dehydropyrrolizidine alkaloids lycopsamine and intermedine: preparation of their N-oxides and NMR comparison with diastereoisomeric rinderine and echinatine.

Science.gov (United States)

Colegate, Steven M; Gardner, Dale R; Betz, Joseph M; Panter, Kip E

2014-01-01

The diversity of structure and, particularly, stereochemical variation of the dehydropyrrolizidine alkaloids can present challenges for analysis and the isolation of pure compounds for the preparation of analytical standards and for toxicology studies. To investigate methods for the separation of gram-scale quantities of the epimeric dehydropyrrolizidine alkaloids lycopsamine and intermedine and to compare their NMR spectroscopic data with those of their heliotridine-based analogues echinatine and rinderine. Lycopsamine and intermedine were extracted, predominantly as their N-oxides and along with their acetylated derivatives, from commercial samples of comfrey (Symphytum officinale) root. Alkaloid enrichment involved liquid-liquid partitioning of the crude methanol extract between dilute aqueous acid and n-butanol, reduction of N-oxides and subsequent continuous liquid-liquid extraction of free base alkaloids into CHCl3 . The alkaloid-rich fraction was further subjected to semi-automated flash chromatography using boronated soda glass beads or boronated quartz sand. Boronated soda glass beads (or quartz sand) chromatography adapted to a Biotage Isolera Flash Chromatography System enabled large-scale separation (at least up to 1-2 g quantities) of lycopsamine and intermedine. The structures were confirmed using one- and two-dimensional (1) H- and (13) C-NMR spectroscopy. Examination of the NMR data for lycopsamine, intermedine and their heliotridine-based analogues echinatine and rinderine allowed for some amendments of literature data and provided useful comparisons for determining relative configurations in monoester dehydropyrrolizidine alkaloids. A similar NMR comparison of lycopsamine and intermedine with their N-oxides showed the effects of N-oxidation on some key chemical shifts. A levorotatory shift in specific rotation from +3.29° to -1.5° was observed for lycopsamine when dissolved in ethanol or methanol respectively. A semi-automated flash

NMR characteristics of low-grade glioma. Comparison with CT

Energy Technology Data Exchange (ETDEWEB)

Asato, Reinin; Tokuriki, Yasuhiko; Nakano, Yoshihisa; Itoh, Harumi; Torizuka, Kanji; Ueda, Tohru; Yamashita, Junkoh; Handa, Hajime

1985-08-01

Sixteen low-grade gliomas were evaluated both with nuclear magnetic resonance (NMR) imaging and with computed tomography (CT). In 13 cases (81%), the NMR images were much better in tissue contrast than the contrast-enhanced CT images. The tumors were shown as well-circumscribed oval lesions in the NMR, though they appeared as ill-defined, irregular, low-attenuation areas in the CT. The extent of the lesion, which was supposed to represent the active tumor tissue, was greater in the NMR than in the CT, because NMR tissue parameters (T/sub 1/, T/sub 2/) are more sensitive to pathological changes in brain tissue than is the X-ray attenuation coefficient. Though, in an optic glioma and a brain-stem astrocytoma, the CT with contrast enhancement displayed the contour of the mass as well as did NMR, it was inferior to the NMR in showing the cephalocaudal extension of the tumors. Calcification does not give a proton NMR signal under the present measuring conditions; thus the calcified cystic wall of a hypothalamic astrocytoma was displayed only in the CT images. In conclusion, the NMR imaging was apparently superior to contrast-enhanced CT in demonstrating the lesions due to low-grade glioma.

[superscript 1]H NMR Spectroscopy-Based Configurational Analysis of Mono- and Disaccharides and Detection of ß-Glucosidase Activity: An Undergraduate Biochemistry Laboratory

Science.gov (United States)

Periyannan, Gopal R.; Lawrence, Barbara A.; Egan, Annie E.

2015-01-01

A [superscript 1]H NMR spectroscopy-based laboratory experiment explores mono- and disaccharide structural chemistry, and the enzyme-substrate specificity of glycosidic bond cleavage by ß-glucosidase towards cellobiose (ß-linked gluco-disaccharide) and maltose (a-linked gluco-disaccharide). Structural differences between cellobiose, maltose, and…

Dissolution mechanism of crystalline cellulose in H3PO4 as assessed by high-field NMR spectroscopy and fast field cycling NMR relaxometry.

Science.gov (United States)

Conte, Pellegrino; Maccotta, Antonella; De Pasquale, Claudio; Bubici, Salvatore; Alonzo, Giuseppe

2009-10-14

Many processes have been proposed to produce glucose as a substrate for bacterial fermentation to obtain bioethanol. Among others, cellulose degradation appears as the most convenient way to achieve reliable amounts of glucose units. In fact, cellulose is the most widespread biopolymer, and it is considered also as a renewable resource. Due to extended intra- and interchain hydrogen bonds that provide a very efficient packing structure, however, cellulose is also a very stable polymer, the degradation of which is not easily achievable. In the past decade, researchers enhanced cellulose reactivity by increasing its solubility in many solvents, among which concentrated phosphoric acid (H(3)PO(4)) played the major role because of its low volatility and nontoxicity. In the present study, the solubilization mechanism of crystalline cellulose in H(3)PO(4) has been elucidated by using high- and low-field NMR spectroscopy. In particular, high-field NMR spectra showed formation of direct bonding between phosphoric acid and dissolved cellulose. On the other hand, molecular dynamics studies by low-field NMR with a fast field cycling (FFC) setup revealed two different H(3)PO(4) relaxing components. The first component, described by the fastest longitudinal relaxation rate (R(1)), was assigned to the H(3)PO(4) molecules bound to the biopolymer. Conversely, the second component, characterized by the slowest R(1), was attributed to the bulk solvent. The understanding of cellulose dissolution in H(3)PO(4) represents a very important issue because comprehension of chemical mechanisms is fundamental for process ameliorations to produce bioenergy from biomasses.

Adducts of nitrogenous ligands with rhodium(II) tetracarboxylates and tetraformamidinate: NMR spectroscopy and density functional theory calculations.

Science.gov (United States)

Cmoch, Piotr; Głaszczka, Rafał; Jaźwiński, Jarosław; Kamieński, Bohdan; Senkara, Elżbieta

2014-03-01

Complexation of tetrakis(μ2-N,N'-diphenylformamidinato-N,N')-di-rhodium(II) with ligands containing nitrile, isonitrile, amine, hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups has been studied in liquid and solid phases using (1)H, (13)C and (15)N NMR, (13)C and (15)N cross polarisation-magic angle spinning NMR, and absorption spectroscopy in the visible range. The complexation was monitored using various NMR physicochemical parameters, such as chemical shifts, longitudinal relaxation times T1 , and NOE enhancements. Rhodium(II) tetraformamidinate selectively bonded only unbranched amine (propan-1-amine), pentanenitrile, and (1-isocyanoethyl)benzene. No complexation occurred in the case of ligands having hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups, and more expanded amine molecules such as butan-2-amine and 1-azabicyclo[2.2.2]octane. Such features were opposite to those observed in rhodium(II) tetracarboxylates, forming adducts with all kind of ligands. Special attention was focused on the analysis of Δδ parameters, defined as a chemical shift difference between signal in adduct and corresponding signal in free ligand. In the case of (1)H NMR, Δδ values were either negative in adducts of rhodium(II) tetraformamidinate or positive in adducts of rhodium(II) tetracarboxylates. Experimental findings were supported by density functional theory molecular modelling and gauge independent atomic orbitals chemical shift calculations. The calculation of chemical shifts combined with scaling procedure allowed to reproduce qualitatively Δδ parameters. Copyright © 2013 John Wiley & Sons, Ltd.

Experimental and analytical variation in human urine in 1H NMR spectroscopy-based metabolic phenotyping studies.

Science.gov (United States)

Maher, Anthony D; Zirah, Séverine F M; Holmes, Elaine; Nicholson, Jeremy K

2007-07-15

1H NMR spectroscopy potentially provides a robust approach for high-throughput metabolic screening of biofluids such as urine and plasma, but sample handling and preparation need careful optimization to ensure that spectra accurately report biological status or disease state. We have investigated the effects of storage temperature and time on the 1H NMR spectral profiles of human urine from two participants, collected three times a day on four different days. These were analyzed using modern chemometric methods. Analytical and preparation variation (tested between -40 degrees C and room temperature) and time of storage (to 24 h) were found to be much less influential than biological variation in sample classification. Statistical total correlation spectroscopy and discriminant function methods were used to identify the specific metabolites that were hypervariable due to preparation and biology. Significant intraindividual variation in metabolite profiles were observed even for urine collected on the same day and after at least 6 h fasting. The effect of long-term storage at different temperatures was also investigated, showing urine is stable if frozen for at least 3 months and that storage at room temperature for long periods (1-3 months) results in a metabolic profile explained by bacterial activity. Presampling (e.g., previous day) intake of food and medicine can also strongly influence the urinary metabolic profiles indicating that collective detailed participant historical meta data are important for interpretation of metabolic phenotypes and for avoiding false biomarker discovery.

Use of NMR spectroscopy in combination with pattern recognition techniques for elucidation of origin and adulteration of foodstuffs

Energy Technology Data Exchange (ETDEWEB)

Standal, Inger Beate

2009-07-01

Consumers and food authorities are, to an increasing extent, concerned about factors such as the origin of food, how it is produced, and if it is healthy and safe. There are methods for general quality control to map the safety and nutritional value; however there is a need for suitable analytical methods to verify information such as the production method (wild/farmed), geographical origin, species, and process history of foods. This thesis evaluates the applicability of using nuclear magnetic resonance (NMR) spectroscopy combined with pattern recognition techniques for authentication of foodstuffs. Fish and marine oils were chosen as materials. 13C NMR was applied to authenticate marine oils and muscle lipids of both fatty and lean fish, according to production method (wild/farmed), geographical origin, species, and process history. 1H NMR was applied on low molecular weight compounds extracted from cod muscle to authenticate fish according to species and processing conditions. 13C NMR combined with pattern recognition techniques enabled the differentiation of marine oils according to wild/farmed and geographical origin of the raw material. It is suggested that this was mainly due to the different diets of the fish from which the oil was produced. It was also possible to authenticate marine oils according to species, and to say something about the level of mixtures detectable. The Sn-2 position specificity of fatty acids in triacylglycerols was shown to be an important characteristic to separate oils of different species. Esterified fish oil (concentrates) could easily be differentiated from natural fish oil by their 13C NMR profile. (Author)

Enantiodiscrimination of flexible cyclic solutes using NMR spectroscopy in polypeptide chiral mesophases: investigation of cis-decalin and THF.

Science.gov (United States)

Aroulanda, Christie; Lafon, Olivier; Lesot, Philippe

2009-08-06

The conformational dynamics and orientational behavior of two model cyclic molecules, cis-decalin (cis-dec) and tetrahydrofurane (THF), dissolved in weakly ordering, polypeptidic chiral liquid crystals (CLCs) are theoretically discussed and experimentally investigated using deuterium and carbon-13 NMR spectroscopies. The analysis of enantiomeric and enantiotopic discriminations in these compounds is shown to depend on the rate of conformational exchange regime, slow or fast. The slow exchange regime is illustrated through the case of cis-dec at low temperature (243 K). We show that the deuterium NMR spectra in this regime can be qualitatively and quantitatively interpreted by restricting the conformational pathway of cis-dec to two enantiomeric conformers of C(2)-symmetry. The orientational order parameters of these interconverting enantiomers are calculated by matching the (2)H quadrupolar splittings with calculated conformer structures. The fast exchange regime is investigated through the examples of cis-dec at high temperature (356 K) and THF at room temperature (300 K). The (2)H NMR spectra above the coalescence temperature are analyzed by introducing the concept of "average molecular structure". This fictitious structure allows easily identifying NMR equivalences of solutes dissolved in CLC. However, it cannot be applied to determine consistent orientational order parameters. This study emphasizes that enantiotopic discriminations observed for flexible molecules in the fast exchange regime can be quantitatively interpreted only by considering the orientational order of each conformer.

Identification of Imitation Cheese and Imitation Ice Cream Based on Vegetable Fat Using NMR Spectroscopy and Chemometrics

Directory of Open Access Journals (Sweden)

Yulia B. Monakhova

2013-01-01

Full Text Available Vegetable oils and fats may be used as cheap substitutes for milk fat to manufacture imitation cheese or imitation ice cream. In this study, 400 MHz nuclear magnetic resonance (NMR spectroscopy of the fat fraction of the products was used in the context of food surveillance to validate the labeling of milk-based products. For sample preparation, the fat was extracted using an automated Weibull-Stoldt methodology. Using principal component analysis (PCA, imitation products can be easily detected. In both cheese and ice cream, a differentiation according to the type of raw material (milk fat and vegetable fat was possible. The loadings plot shows that imitation products were distinguishable by differences in their fatty acid ratios. Furthermore, a differentiation of several types of cheese (Edamer, Gouda, Emmentaler, and Feta was possible. Quantitative data regarding the composition of the investigated products can also be predicted from the same spectra using partial least squares (PLS regression. The models obtained for 13 compounds in cheese (R2 0.75–0.95 and 17 compounds in ice cream (R2 0.83–0.99 (e.g., fatty acids and esters were suitable for a screening analysis. NMR spectroscopy was judged as suitable for the routine analysis of dairy products based on milk or on vegetable fat substitutes.

Identification of Imitation Cheese and Imitation Ice Cream Based on Vegetable Fat Using NMR Spectroscopy and Chemometrics

Science.gov (United States)

Monakhova, Yulia B.; Godelmann, Rolf; Andlauer, Claudia; Kuballa, Thomas; Lachenmeier, Dirk W.

2013-01-01

Vegetable oils and fats may be used as cheap substitutes for milk fat to manufacture imitation cheese or imitation ice cream. In this study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy of the fat fraction of the products was used in the context of food surveillance to validate the labeling of milk-based products. For sample preparation, the fat was extracted using an automated Weibull-Stoldt methodology. Using principal component analysis (PCA), imitation products can be easily detected. In both cheese and ice cream, a differentiation according to the type of raw material (milk fat and vegetable fat) was possible. The loadings plot shows that imitation products were distinguishable by differences in their fatty acid ratios. Furthermore, a differentiation of several types of cheese (Edamer, Gouda, Emmentaler, and Feta) was possible. Quantitative data regarding the composition of the investigated products can also be predicted from the same spectra using partial least squares (PLS) regression. The models obtained for 13 compounds in cheese (R 2 0.75–0.95) and 17 compounds in ice cream (R 2 0.83–0.99) (e.g., fatty acids and esters) were suitable for a screening analysis. NMR spectroscopy was judged as suitable for the routine analysis of dairy products based on milk or on vegetable fat substitutes. PMID:26904597

Study of crude and plasma-treated heavy oil by low- and high-field 1H NMR

Energy Technology Data Exchange (ETDEWEB)

Honorato, Hercilio D. A.; Silva, Renzo C.; Junior, Valdemar Lacerda; Castro, Eustaquio V. R. de; Freitas, Jair C. C. [Research and Methodology Development Laboratory for Crude Oil Analysis - LabPetro, Department of Chemistry, Federal University of Espirito Santo (Brazil)], email: jairccfreitas@yahoo.com.br; Piumbini, Cleiton K.; Cunha, Alfredo G.; Emmerich, Francisco G. [Department of Physics, Federal University of Espirito Santo (Brazil); Souza, Andre A. de; Bonagamba, Tito J. [Institute of Physics of Sao Carlos, University of Sao Paulo (Brazil)

2010-07-01

This document is intended to describe the combination of H low-field NMR and thermogravimetry (TG), rheological measurement and H high-field NMR to assess the physical and chemical changes that can occur in a heavy crude oil from treatment in a plasma reactor. This research was done using a heavy crude oil, API gravity of 10.1, which was treated in a double dielectric barrier (DDB) plasma reactor using different plasma gases: natural gas (NG), C02 or H2. The low-field HNMR experiments were conducted in a Maran Ultra spectrometer, from Oxford Instruments, at 27.5? C. After rheological analysis, a reduction in the viscosity of the plasma-treated oils in comparison to that of the crude oil was observed. Finally, it was confirmed that the use of H low-field NMR relaxometry and H high-field NMR spectroscopy allowed a separate analysis of the effects of the plasma treatment on the water and oil fractions to be made.

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.

Quality assessment in in vivo NMR spectroscopy: IV. A multicentre trial of test objects and protocols for performance assessment in clinical NMR spectroscopy

DEFF Research Database (Denmark)

Keevil, S.F.; Barbiroli, B; Collins, D.J.

1995-01-01

implemented on commercially available MR systems at ten sites in Europe. At each site, a number of parameters devised by the Concerted Action were measured using prototype test objects. Some of these parameters related to the quality of localisation and others to the overall performance of the spectrometer...... in the development of the Concerted Action's final recommendations for MRS performance assessment, and demonstrate that such assessment provides valuable information in the comparison of spectroscopy data from different sites and in the development of new localisation sequences, and provides a means of quality...... assurance in MRS...

Two-dimensional NMR spectroscopy strongly enhances soil organic matter composition analysis

Science.gov (United States)

Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Hedenström, Mattias; Schleucher, Jürgen

2016-04-01

Soil organic matter (SOM) is the largest terrestrial carbon pool and strongly affects soil properties. With climate change, understanding SOM processes and turnover and how they could be affected by increasing temperatures becomes critical. This is particularly key for organic soils as they represent a huge carbon pool in very sensitive ecosystems, like boreal ecosystems and peatlands. Nevertheless, characterization of SOM molecular composition, which is essential to elucidate soil carbon processes, is not easily achieved, and further advancements in that area are greatly needed. Solid-state one-dimensional (1D) 13C nuclear magnetic resonance (NMR) spectroscopy is often used to characterize its molecular composition, but only provides data on a few major functional groups, which regroup many different molecular fragments. For instance, in the carbohydrates region, signals of all monosaccharides present in many different polymers overlap. This overlap thwarts attempts to identify molecular moieties, resulting in insufficient information to characterize SOM composition. Here we show that two-dimensional (2D) liquid-state 1H-13C NMR spectra provided much richer data on the composition of boreal plant litter and organic surface soil. The 2D spectra indeed resolved overlaps observed in 1D 13C spectra and displayed signals from hundreds of identifiable molecular groups. For example, in the aromatics region, signals from individual lignin units could be recognized. It was hence possible to follow the fate of specific structural moieties in soils. We observed differences between litter and soil samples, and were able to relate them to the decomposition of identifiable moieties. Sample preparation and data acquisition were both simple and fast. Further, using multivariate data analysis, we aimed at linking the detailed chemical fingerprints of SOM to turnover rates in a soil incubation experiment. With the multivariate models, we were able to identify specific molecular

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.

Novel solution conformation of DNA observed in d(GAATTCGAATTC) by two-dimensional NMR spectroscopy

International Nuclear Information System (INIS)

Chary, K.V.R.; Hosur, R.V.; Govil, G.; Zu-kun, T.; Miles, H.T.

1987-01-01

Resonance assignments of nonexchangeable base and sugar protons of the self-complementary dodecanucleotide d(GAATTCGAATTC) have been obtained by using the two-dimensional Fourier transform NMR methods correlated spectroscopy and nuclear Overhauser effect spectroscopy. Conformational details about the sugar pucker, the glycosidic dihedral angle, and the overall secondary structure of the molecule has been derived from the relative intensities of cross peaks in the two-dimensional NMR spectra in aqueous solution. It is observed that d(GAATTCGAATTC) assumes a novel double-helical structure. The solution conformations of the two complementary strands are identical, unlike those observed in a related sequence in the solid state. Most of the five-membered sugar rings adopt an unusual O1'-endo geometry. All the glycosidic dihedral angles are in the anti domain. The AATT segments A2-T5 and A8-T11 show better stacking compared to the rest of the molecule. These features fit into a right-handed DNA model for the above two segments, with the sugar geometries different from the conventional ones. There are important structural variations in the central TCG portion, which is known to show preferences for DNase I activity, and between G1-A2 and G7-A8, which are cleavage points in the EcoRI recognition sequence. The sugar puckers for G1 and G7 are significantly different from the rest of the molecule. Further, in the three segments mentioned above, the sugar phosphate geometry is such that the distances between protons on adjacent nucleotides are much larger than those expected for a right-handed DNA. The authors suggest that such crevices in the DNA structure may act as hot points in initiation of protein recognition

Quality assurance in the pre-analytical phase of human urine samples by (1)H NMR spectroscopy.

Science.gov (United States)

Budde, Kathrin; Gök, Ömer-Necmi; Pietzner, Maik; Meisinger, Christine; Leitzmann, Michael; Nauck, Matthias; Köttgen, Anna; Friedrich, Nele

2016-01-01

Metabolomic approaches investigate changes in metabolite profiles, which may reflect changes in metabolic pathways and provide information correlated with a specific biological process or pathophysiology. High-resolution (1)H NMR spectroscopy is used to identify metabolites in biofluids and tissue samples qualitatively and quantitatively. This pre-analytical study evaluated the effects of storage time and temperature on (1)H NMR spectra from human urine in two settings. Firstly, to evaluate short time effects probably due to acute delay in sample handling and secondly, the effect of prolonged storage up to one month to find markers of sample miss-handling. A number of statistical procedures were used to assess the differences between samples stored under different conditions, including Projection to Latent Structure Discriminant Analysis (PLS-DA), non-parametric testing as well as mixed effect linear regression analysis. The results indicate that human urine samples can be stored at 10 °C for 24 h or at -80 °C for 1 month, as no relevant changes in (1)H NMR fingerprints were observed during these time periods and temperature conditions. However, some metabolites most likely of microbial origin showed alterations during prolonged storage but without facilitating classification. In conclusion, the presented protocol for urine sample handling and semi-automatic metabolite quantification is suitable for large-scale epidemiological studies. Copyright © 2015 Elsevier Inc. All rights reserved.

Structure and assembly of the mouse ASC inflammasome by combined NMR spectroscopy and cryo-electron microscopy

Science.gov (United States)

Sborgi, Lorenzo; Ravotti, Francesco; Dandey, Venkata P.; Dick, Mathias S.; Mazur, Adam; Reckel, Sina; Chami, Mohamed; Scherer, Sebastian; Huber, Matthias; Böckmann, Anja; Egelman, Edward H.; Stahlberg, Henning; Broz, Petr; Meier, Beat H.; Hiller, Sebastian

2015-01-01

Inflammasomes are multiprotein complexes that control the innate immune response by activating caspase-1, thus promoting the secretion of cytokines in response to invading pathogens and endogenous triggers. Assembly of inflammasomes is induced by activation of a receptor protein. Many inflammasome receptors require the adapter protein ASC [apoptosis-associated speck-like protein containing a caspase-recruitment domain (CARD)], which consists of two domains, the N-terminal pyrin domain (PYD) and the C-terminal CARD. Upon activation, ASC forms large oligomeric filaments, which facilitate procaspase-1 recruitment. Here, we characterize the structure and filament formation of mouse ASC in vitro at atomic resolution. Information from cryo-electron microscopy and solid-state NMR spectroscopy is combined in a single structure calculation to obtain the atomic-resolution structure of the ASC filament. Perturbations of NMR resonances upon filament formation monitor the specific binding interfaces of ASC-PYD association. Importantly, NMR experiments show the rigidity of the PYD forming the core of the filament as well as the high mobility of the CARD relative to this core. The findings are validated by structure-based mutagenesis experiments in cultured macrophages. The 3D structure of the mouse ASC-PYD filament is highly similar to the recently determined human ASC-PYD filament, suggesting evolutionary conservation of ASC-dependent inflammasome mechanisms. PMID:26464513

The use of 1H-NMR spectroscopy and refractometry for investigation of the distribution of nonelectrolytes of N-alcohol series between human red blood cells and extracellular medium.

Science.gov (United States)

Kucherenko, Y U; Moiseev, V A

2000-01-01

Comparative analysis of 1H NMR spectroscopy and refractometry with respect to their application for investigating the distribution of nonelectrolytes of n-alcohol series (ethanol, 1,2-propanediol, glycerol) and polyethylene glycols (PEGs) with molecular masses of 400, 600, 1500 between human erythrocytes and extracellular medium was performed. The distribution coefficients (Q) for solutions of ethanol, 1,2-propanediol, glycerol, PEG-400, PEG-600 and PEG-1500 were obtained. The Q values decreased with the increase in the nonelectrolyte molecular mass from 1.23+/-0.12 for ethanol to 0.40+/-0.08 for PEG-1500 (1H NMR spectroscopy) and from 2.6+/-0.12 for ethanol to 0.23+/-0.03 for PEG-1500 (refractometry). It was shown that 1H-NMR high-resolution spectroscopy ensures more precise determination of Q values for nonelectrolytes with low molecular masses; for PEGs with high molecular masses, the accuracy of Q value calculation by this method was about 20%. On the contrary, refractometry can be used for investigating substances with high molecular masses; the error of Q value determination for solution of low-refractive substances, such as ethanol, may be more than 50%.

Ligand screening by saturation-transfer difference (STD) NMR spectroscopy.

Energy Technology Data Exchange (ETDEWEB)

Krishnan, V V

2005-04-26

NMR based methods to screen for high-affinity ligands have become an indispensable tool for designing rationalized drugs, as these offer a combination of good experimental design of the screening process and data interpretation methods, which together provide unprecedented information on the complex nature of protein-ligand interactions. These methods rely on measuring direct changes in the spectral parameters, that are often simpler than the complex experimental procedures used to study structure and dynamics of proteins. The goal of this review article is to provide the basic details of NMR based ligand-screening methods, with particular focus on the saturation transfer difference (STD) experiment. In addition, we provide an overview of other NMR experimental methods and a practical guide on how to go about designing and implementing them.

Interaction between Wine Phenolic Acids and Salivary Proteins by Saturation-Transfer Difference Nuclear Magnetic Resonance Spectroscopy (STD-NMR) and Molecular Dynamics Simulations.

Science.gov (United States)

Ferrer-Gallego, Raúl; Hernández-Hierro, José Miguel; Brás, Natércia F; Vale, Nuno; Gomes, Paula; Mateus, Nuno; de Freitas, Victor; Heredia, Francisco J; Escribano-Bailón, María Teresa

2017-08-09

The interaction between phenolic compounds and salivary proteins is highly related to the astringency perception. Recently, it has been proven the existence of synergisms on the perceived astringency when phenolic acids were tested as mixtures in comparison to individual compounds, maintaining constant the total amount of the stimulus. The interactions between wine phenolic acids and the peptide fragment IB7 12 have been studied by saturation-transfer difference (STD) NMR spectroscopy. This technique provided the dissociation constants and the percentage of interaction between both individual and mixtures of hydroxybenzoic and hydroxycinnamic acids and the model peptide. It is noteworthy that hydroxybenzoic acids showed higher affinity for the peptide than hydroxycinnamic acids. To obtain further insights into the mechanisms of interaction, molecular dynamics simulations have been performed. Results obtained not only showed the ability of these compounds to interact with salivary proteins but also may justify the synergistic effect observed in previous sensory studies.

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.

Touch NMR: An NMR Data Processing Application for the iPad

Science.gov (United States)

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

2014-01-01

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

31P NMR spectroscopy studies of phospholipid metabolism in human melanoma xenograft lines differing in rate of tumour cell proliferation.

Science.gov (United States)

Lyng, H; Olsen, D R; Petersen, S B; Rofstad, E K

1995-04-01

The concentration of phospholipid metabolites in tumours has been hypothesized to be related to rate of cell membrane turnover and may reflect rate of cell proliferation. The purpose of the study reported here was to investigate whether 31P NMR resonance ratios involving the phosphomonoester (PME) or phosphodiester (PDE) resonance are correlated to fraction of cells in S-phase or volume-doubling time in experimental tumours. Four human melanoma xenograft lines (BEX-t, HUX-t, SAX-t, WIX-t) were included in the study. The tumours were grown subcutaneously in male BALB/c-nu/nu mice. 31P NMR spectroscopy was performed at a magnetic field strength of 4.7 T. Fraction of cells in S-phase was measured by flow cytometry. Tumour volume-doubling time was determined by Gompertzian analysis of volumetric growth data. BEX-t and SAX-t tumours differed in fraction of cells in S-phase and volume-doubling time, but showed similar 31P NMR resonance ratios. BEX-t and WIX-t tumours showed significantly different 31P NMR resonance ratios but similar fractions of cells in S-phase. The 31P NMR resonance ratios were significantly different for small and large HUX-t tumours even though fraction of cells in S-phase and volume-doubling time did not differ with tumour volume. None of the 31P NMR resonance ratios showed significant increase with increasing fraction of cells in S-phase or significant decrease with increasing tumour volume-doubling time across the four xenograft lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of free fatty acids in pharmaceutical lipids by ¹H NMR and comparison with the classical acid value.

Science.gov (United States)

Skiera, Christina; Steliopoulos, Panagiotis; Kuballa, Thomas; Diehl, Bernd; Holzgrabe, Ulrike

2014-05-01

Indices like acid value, peroxide value, and saponification value play an important role in quality control and identification of lipids. Requirements on these parameters are given by the monographs of the European pharmacopeia. (1)H NMR spectroscopy provides a fast and simple alternative to these classical approaches. In the present work a new (1)H NMR approach to determine the acid value is described. The method was validated using a statistical approach based on a variance components model. The performance under repeatability and in-house reproducibility conditions was assessed. We applied this (1)H NMR assay to a wide range of different fatty oils. A total of 305 oil and fat samples were examined by both the classical and the NMR method. Except for hard fat, the data obtained by the two methods were in good agreement. The (1)H NMR method was adapted to analyse waxes and oleyloleat. Furthermore, the effect of solvent and in the case of castor oil the effect of the oil matrix on line broadening and chemical shift of the carboxyl group signal are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of UV-A and UV-B irradiation on the metabolic profile of aqueous humor in rabbits analyzed by 1H NMR spectroscopy.

Science.gov (United States)

Tessem, May-Britt; Bathen, Tone F; Cejková, Jitka; Midelfart, Anna

2005-03-01

This study was conducted to investigate metabolic changes in aqueous humor from rabbit eyes exposed to either UV-A or -B radiation, by using (1)H nuclear magnetic resonance (NMR) spectroscopy and unsupervised pattern recognition methods. Both eyes of adult albino rabbits were irradiated with UV-A (366 nm, 0.589 J/cm(2)) or UV-B (312 nm, 1.667 J/cm(2)) radiation for 8 minutes, once a day for 5 days. Three days after the last irradiation, samples of aqueous humor were aspirated, and the metabolic profiles analyzed with (1)H NMR spectroscopy. The metabolic concentrations in the exposed and control materials were statistically analyzed and compared, with multivariate methods and one-way ANOVA. UV-B radiation caused statistically significant alterations of betaine, glucose, ascorbate, valine, isoleucine, and formate in the rabbit aqueous humor. By using principal component analysis, the UV-B-irradiated samples were clearly separated from the UV-A-irradiated samples and the control group. No significant metabolic changes were detected in UV-A-irradiated samples. This study demonstrates the potential of using unsupervised pattern recognition methods to extract valuable metabolic information from complex (1)H NMR spectra. UV-B irradiation of rabbit eyes led to significant metabolic changes in the aqueous humor detected 3 days after the last exposure.

Investigating the Hydrolysis Reactions of a Chemical Warfare Agent Surrogate. A Systematic Study using ¹H, ¹³C, ¹⁷O, ¹⁹F, ³¹P, and ³⁵Cl NMR Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Alam, Todd M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wilson, Brendan W. [West Virginia Univ., Morgantown, WV (United States)

2015-07-24

During the summer of 2015, I participated in the DHS HS-STEM fellowship at Sandia National Laboratories (SNL, NM) under the supervision of Dr. Todd M. Alam in his Nuclear Magnetic Resonance (NMR) Spectroscopy research group. While with the group, my main project involved pursing various hydrolysis reactions with Diethyl Chlorophosphate (DECP), a surrogate for the agent Sarin (GB). Specifically, I performed different hydrolysis reactions, monitored and tracked the different phosphorous containing species using phosphorous (³¹P) NMR spectroscopy. With the data collected, I performed kinetics studies mapping the rates of DECP hydrolysis. I also used the NMR of different nuclei such as ¹H, ¹³C, ¹⁷O, and ³⁵Cl to help understand the complexity of the reactions that take place. Finally, my last task at SNL was to work with Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) NMR Spectroscopy optimizing conditions for ¹⁹F- ³¹P filtering NMR experiments.

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

Directory of Open Access Journals (Sweden)

S. Ok

2017-03-01

Full Text Available Adulteration of olive oil using unhealthy substitutes is considered a threat for public health. Low-field (LF proton (1H nuclear magnetic resonance (NMR relaxometry and ultra-violet (UV visible spectroscopy are used to detect adulteration of olive oil. Three different olive oil with different oleoyl acyl contents were mixed with almond, castor, corn, and sesame oils with three volumetric ratios, respectively. In addition, Arbequina olive oil was mixed with canola, flax, grape seed, peanut, soybean, and sunflower seed oils with three volumetric ratios. Transverse magnetization relaxation time (T2 curves were fitted with bi-exponential decaying functions. T2 times of each mixture of olive oils and castor oils, and olive oils and corn oils changed systematically as a function of volumetric ratio. To detect the adulteration in the mixtures with almond and sesame oils, both LF 1H NMR relaxometry and UV-Vis spectroscopy were needed, where UV-Vis-spectroscopy detected the adulteration qualitatively. In the mixtures of Arbequina olive oil and flax, peanut, soybean, and sunflower seed oils, both T21 and T22 values became longer systematically as the content of the olive oil was decreased. The unique UV-Vis maximum absorbance of flax oil at 320.0 nm shows the adulteration of olive oil qualitatively.

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

International Nuclear Information System (INIS)

Ok, S.

2017-01-01

Adulteration of olive oil using unhealthy substitutes is considered a threat for public health. Low-field (LF) proton (1H) nuclear magnetic resonance (NMR) relaxometry and ultra-violet (UV) visible spectroscopy are used to detect adulteration of olive oil. Three different olive oil with different oleoyl acyl contents were mixed with almond, castor, corn, and sesame oils with three volumetric ratios, respectively. In addition, Arbequina olive oil was mixed with canola, flax, grape seed, peanut, soybean, and sunflower seed oils with three volumetric ratios. Transverse magnetization relaxation time (T2) curves were fitted with bi-exponential decaying functions. T2 times of each mixture of olive oils and castor oils, and olive oils and corn oils changed systematically as a function of volumetric ratio. To detect the adulteration in the mixtures with almond and sesame oils, both LF 1H NMR relaxometry and UV-Vis spectroscopy were needed, where UV-Vis-spectroscopy detected the adulteration qualitatively. In the mixtures of Arbequina olive oil and flax, peanut, soybean, and sunflower seed oils, both T21 and T22 values became longer systematically as the content of the olive oil was decreased. The unique UV-Vis maximum absorbance of flax oil at 320.0 nm shows the adulteration of olive oil qualitatively. [es

Two-dimensional NMR spectroscopy links structural moieties of soil organic matter to the temperature sensitivity of its decomposition

Science.gov (United States)

Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Schleucher, Jürgen

2015-04-01

Soil organic matter (SOM) represents a huge carbon pool, specifically in boreal ecosystems. Warming-induced release of large amounts of CO2 from the soil carbon pool might become a significant exacerbating feedback to global warming, if decomposition rates of boreal soils were more sensitive to increased temperatures. Despite a large number of studies dedicated to the topic, it has proven difficult to elucidate how the organo-chemical composition of SOM influences its decomposition, or its quality as a substrate for microbial metabolism. A great part of this challenge results from our inability to achieve a detailed characterization of the complex composition of SOM on the level of molecular structural moieties. 13C nuclear magnetic resonance (NMR) spectroscopy is a common tool to characterize SOM. However, SOM is a very complex mixture and the chemical shift regions distinguished in the 13C NMR spectra often represent many different molecular fragments. For example, in the carbohydrates region, signals of all monosaccharides present in many different polymers overlap. This overlap thwarts attempts to identify molecular moieties, resulting in insufficient information to characterize SOM composition. We applied two-dimensional (2D) NMR to characterize SOM with highly increased resolution. We directly dissolved finely ground litters and forest floors'fibric and humic horizons'of both coniferous and deciduous boreal forests in dimethyl sulfoxide and analyzed the resulting solution with a 2D 1H-13C NMR experiment. In the 2D planes of these spectra, signals of CH groups can be resolved based on their 13C and 1H chemical shifts, hence the resolving power and information content of these NMR spectra is hugely increased. The 2D spectra indeed resolved overlaps observed in 1D 13C spectra, so that hundreds of distinct CH groups could be observed and many molecular fragments could be identified. For instance, in the aromatics region, signals from individual lignin units could

31P NMR Spectroscopy Revealed Adenylate kinase-like Activity and Phosphotransferase-like Activity from F1-ATPase of Escherichia coli

International Nuclear Information System (INIS)

Kim, Hyun Won

2011-01-01

Adenylate kinase-like activity and phosphotransferase-like activity from F 1 -ATPase of Escherichia coli was revealed by 31 P NMR spectroscopy. Incubation of F 1 -ATPase with ADP in the presence of Mg 2+ shows the appearance of 31 P resonances from AMP and Pi, suggesting generation of AMP and ATP by adenylate kinase-like activity and the subsequent hydrolysis to Pi. Incubation of F1-ATPase with ADP in the presence of methanol shows additional peak from methyl phosphate, suggesting phosphotransferase-like activity of F 1 -ATPase. Both adenylate kinase-like activity and phosphotransferase-like activity has not been reported from F 1 -ATPase of Escherichia coli. 31 P NMR could be a valuable tool for the investigation of phosphorous related enzyme

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

1H HRMAS NMR spectroscopy and chemometrics for evaluation of metabolic changes in citrus sinensis Caused by Xanthomonas axonopodis pv. citri

International Nuclear Information System (INIS)

Silva, Lorena M.A.; Alves Filho, Elenilson G.; Choze, Rafael; Liao, Luciano M.; Alcantara, Glaucia B.

2012-01-01

Xanthomonas axonopodis (Xac) bacterium causes one of the most feared and untreatable diseases in citriculture: citrus canker. To understand the response mechanisms of orange trees when attacked by Xac, leaves and fruits of Citrus sinensis were directly evaluated by HRMAS NMR (high resolution magic angle spinning nuclear magnetic resonance) spectroscopy. This technique allows the analysis of samples without laborious pre-treatments and also allows access to important information about chemical composition of samples. The orange tree leaves and fruit peels investigated in this study demonstrated the biochemical changes caused by Xac. Aided by chemometric analysis, the HRMAS NMR results show relevant changes in amino acids, carbohydrates, organic acids and terpenoids content. (author)

Indirectly detected chemical shift correlation NMR spectroscopy in solids under fast magic angle spinning

Energy Technology Data Exchange (ETDEWEB)

Mao, Kanmi [Iowa State Univ., Ames, IA (United States)

2011-01-01

The development of fast magic angle spinning (MAS) opened up an opportunity for the indirect detection of insensitive low-γ nuclei (e.g., ¹³C and ¹⁵N) via the sensitive high-{gamma} nuclei (e.g., ¹H and ¹⁹F) in solid-state NMR, with advanced sensitivity and resolution. In this thesis, new methodology utilizing fast MAS is presented, including through-bond indirectly detected heteronuclear correlation (HETCOR) spectroscopy, which is assisted by multiple RF pulse sequences for ¹H-¹H homonuclear decoupling. Also presented is a simple new strategy for optimization of ¹H-¹H homonuclear decoupling. As applications, various classes of materials, such as catalytic nanoscale materials, biomolecules, and organic complexes, are studied by combining indirect detection and other one-dimensional (1D) and two-dimensional (2D) NMR techniques. Indirectly detected through-bond HETCOR spectroscopy utilizing refocused INEPT (INEPTR) mixing was developed under fast MAS (Chapter 2). The time performance of this approach in ¹H detected 2D ¹H{l_brace}¹³C{r_brace} spectra was significantly improved, by a factor of almost 10, compared to the traditional ¹³C detected experiments, as demonstrated by measuring naturally abundant organic-inorganic mesoporous hybrid materials. The through-bond scheme was demonstrated as a new analytical tool, which provides complementary structural information in solid-state systems in addition to through-space correlation. To further benefit the sensitivity of the INEPT transfer in rigid solids, the combined rotation and multiple-pulse spectroscopy (CRAMPS) was implemented for homonuclear ¹H decoupling under fast MAS (Chapter 3). Several decoupling schemes (PMLG5_m^$\\bar{x}$, PMLG5_mm^$\\bar{x}$x and SAM3) were analyzed to maximize the performance of through-bond transfer based

Hydration kinetics for the alite, belite, and calcium aluminate phase in Portland cements from 27Al and 29Si MAS NMR spectroscopy

DEFF Research Database (Denmark)

Skibsted, Jørgen; Jensen, Ole Mejlhede; Jakobsen, Hans Jørgen

1997-01-01

29Si magic-angle spinning (MAS) NMR spectroscopy is shown to be a valuable tool for obtaining the quantities of alite and belite in hydrated Portland cements. The hydration (1-180 days) of a white Portland cement with 10 wt.% silica fume added is investigated and the degrees of hydration for alite...

Structure and function of the Juxta membrane domain of the human epidermal growth factor receptor by NMR spectroscopy

International Nuclear Information System (INIS)

Choowongkomon, Kiattawee; Carlin, Cathleen; Sonnichsen, Frank D.

2005-10-01

The epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine kinase family involved in the regulation of cellular proliferation and differentiation. Its juxta membrane domain (JX), the region located between the transmembrane and kinase domains, plays important roles in receptor trafficking since both basolateral sorting in polarized epithelial cells and lysosomal sorting signals are identified in this region. In order to understand the regulation of these signals, we characterized the structural properties of recombinant JX domain in dodecyl phosphocholine detergent (DPC) by nuclear magnetic resonance (NMR) spectroscopy. In DPC micelles, structures derived from NMR data showed three amphipathic, helical segments. Two equivalent average structural models on the surface of micelles were obtained that differ only in the relative orientation between the first and second helices. Our data suggests that the activity of sorting signals may be regulated by their membrane association and restricted accessibility in the intact receptor

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.)

Cotranslational structure acquisition of nascent polypeptides monitored by NMR spectroscopy.

Science.gov (United States)

Eichmann, Cédric; Preissler, Steffen; Riek, Roland; Deuerling, Elke

2010-05-18

The folding of proteins in living cells may start during their synthesis when the polypeptides emerge gradually at the ribosomal exit tunnel. However, our current understanding of cotranslational folding processes at the atomic level is limited. We employed NMR spectroscopy to monitor the conformation of the SH3 domain from alpha-spectrin at sequential stages of elongation via in vivo ribosome-arrested (15)N,(13)C-labeled nascent polypeptides. These nascent chains exposed either the entire SH3 domain or C-terminally truncated segments thereof, thus providing snapshots of the translation process. We show that nascent SH3 polypeptides remain unstructured during elongation but fold into a compact, native-like beta-sheet assembly when the entire sequence information is available. Moreover, the ribosome neither imposes major conformational constraints nor significantly interacts with exposed unfolded nascent SH3 domain moieties. Our data provide evidence for a domainwise folding of the SH3 domain on ribosomes without significant population of folding intermediates. The domain follows a thermodynamically favorable pathway in which sequential folding units are stabilized, thus avoiding kinetic traps during the process of cotranslational folding.

NMR structure of the protein NP-247299.1: comparison with the crystal structure

International Nuclear Information System (INIS)

Jaudzems, Kristaps; Geralt, Michael; Serrano, Pedro; Mohanty, Biswaranjan; Horst, Reto; Pedrini, Bill; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

2010-01-01

Comparison of the NMR and crystal structures of a protein determined using largely automated methods has enabled the interpretation of local differences in the highly similar structures. These differences are found in segments of higher B values in the crystal and correlate with dynamic processes on the NMR chemical shift timescale observed in solution. The NMR structure of the protein NP-247299.1 in solution at 313 K has been determined and is compared with the X-ray crystal structure, which was also solved in the Joint Center for Structural Genomics (JCSG) at 100 K and at 1.7 Å resolution. Both structures were obtained using the current largely automated crystallographic and solution NMR methods used by the JCSG. This paper assesses the accuracy and precision of the results from these recently established automated approaches, aiming for quantitative statements about the location of structure variations that may arise from either one of the methods used or from the different environments in solution and in the crystal. To evaluate the possible impact of the different software used for the crystallographic and the NMR structure determinations and analysis, the concept is introduced of reference structures, which are computed using the NMR software with input of upper-limit distance constraints derived from the molecular models representing the results of the two structure determinations. The use of this new approach is explored to quantify global differences that arise from the different methods of structure determination and analysis versus those that represent interesting local variations or dynamics. The near-identity of the protein core in the NMR and crystal structures thus provided a basis for the identification of complementary information from the two different methods. It was thus observed that locally increased crystallographic B values correlate with dynamic structural polymorphisms in solution, including that the solution state of the protein involves

Identification and quantitative determination of carbohydrates in ethanolic extracts of two conifers using 13C NMR spectroscopy.

Science.gov (United States)

Duquesnoy, Emilie; Castola, Vincent; Casanova, Joseph

2008-04-07

We developed a method for the direct identification and quantification of carbohydrates in raw vegetable extracts using (13)C NMR spectroscopy without any preliminary step of precipitation or reduction of the components. This method has been validated (accuracy, precision and response linearity) using pure compounds and artificial mixtures before being applied to authentic ethanolic extracts of pine needles, pine wood and pine cones and fir twigs. We determined that carbohydrates represented from 15% to 35% of the crude extracts in which pinitol was the principal constituent accompanied by arabinitol, mannitol, glucose and fructose.

Robust and transferable quantification of NMR spectral quality using IROC analysis

Science.gov (United States)

Zambrello, Matthew A.; Maciejewski, Mark W.; Schuyler, Adam D.; Weatherby, Gerard; Hoch, Jeffrey C.

2017-12-01

Non-Fourier methods are increasingly utilized in NMR spectroscopy because of their ability to handle nonuniformly-sampled data. However, non-Fourier methods present unique challenges due to their nonlinearity, which can produce nonrandom noise and render conventional metrics for spectral quality such as signal-to-noise ratio unreliable. The lack of robust and transferable metrics (i.e. applicable to methods exhibiting different nonlinearities) has hampered comparison of non-Fourier methods and nonuniform sampling schemes, preventing the identification of best practices. We describe a novel method, in situ receiver operating characteristic analysis (IROC), for characterizing spectral quality based on the Receiver Operating Characteristic curve. IROC utilizes synthetic signals added to empirical data as "ground truth", and provides several robust scalar-valued metrics for spectral quality. This approach avoids problems posed by nonlinear spectral estimates, and provides a versatile quantitative means of characterizing many aspects of spectral quality. We demonstrate applications to parameter optimization in Fourier and non-Fourier spectral estimation, critical comparison of different methods for spectrum analysis, and optimization of nonuniform sampling schemes. The approach will accelerate the discovery of optimal approaches to nonuniform sampling experiment design and non-Fourier spectrum analysis for multidimensional NMR.

Unlike twins: an NMR comparison of two α-synuclein polymorphs featuring different toxicity.

Directory of Open Access Journals (Sweden)

Julia Gath

Full Text Available We structurally compare, using solid-state NMR, two different polymorphs of α-synuclein which, as established recently, display contrasting biochemical properties, toxicity, and tropism for cells. We show that both forms, which can each be produced as a pure polymorph, are greatly different in secondary structure. While β-sheets are the dominating secondary structure elements for both polymorphs, they are markedly divergent in terms of number of elements, as well as their distribution. We demonstrate that all identified β-sheets feature an in-register parallel stacking for both polymorphs. The two forms show a different molecular arrangement in the unit cell and distinct dynamic features, while sharing a highly flexible C-terminal domain. The use of reproducible, well-identified conditions for sample preparation and the recording of identical NMR experiments allows for a direct comparison of the results.

The stoichiometry of synthetic alunite as a function of hydrothermal aging investigated by solid-state NMR spectroscopy, powder X-ray diffraction and infrared spectroscopy

DEFF Research Database (Denmark)

Grube, Elisabeth; Nielsen, Ulla Gro

2015-01-01

The stoichiometry of a series of synthetic alunite (nominally KAl3(SO4)2(OH)6) samples prepared by hydrothermal methods as a function of reaction time (1 – 31 days) has been investigated by powder X-ray diffraction, Fourier transform infrared spectroscopy as well as solid-state 1H and 27Al magic...... of potassium defects present, from 17.261(1) to 17.324(5) Å. Solid-state 27Al MAS NMR revealed a decrease in the defect concentration as a function of time and showed the presence of 7-10 % impurities in the samples....

Forms and Lability of Phosphorus in Algae and Aquatic Macrophytes Characterized by Solution 31P NMR Coupled with Enzymatic Hydrolysis

Science.gov (United States)

Feng, Weiying; Zhu, Yuanrong; Wu, Fengchang; He, Zhongqi; Zhang, Chen; Giesy, John P.

2016-11-01

Solution Phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy coupled with enzymatic hydrolysis (EH) with commercially available phosphatases was used to characterize phosphorus (P) compounds in extracts of the dominant aquatic macrophytes and algae in a eutrophic lake. Total extractable organic P (Po) concentrations ranged from 504 to 1643 mg kg-1 and 2318 to 8395 mg kg-1 for aquatic macrophytes and algae, respectively. Using 31P NMR spectroscopy, 11 Po species were detected in the mono- and diester region. Additionally, orthophosphate, pyrophosphate and phosphonates were also detected. Using EH, phytate-like P was identified as the prevalent class of enzyme-labile Po, followed by labile monoester- and diester-P. Comparison of the NMR and EH data indicated that the distribution pattern of major P forms in the samples determined by the two methods was similar (r = 0.712, p < 0.05). Additional 31P NMR spectroscopic analysis of extracts following EH showed significant decreases in the monoester and pyrophosphate regions, with a corresponding increase in the orthophosphate signal, as compared to unhydrolyzed extracts. Based on these quantity and hydrolysis data, we proposed that recycling of Po in vegetative biomass residues is an important mechanism for long-term self-regulation of available P for algal blooming in eutrophic lakes.

The cerebroprotective effect of dextromethorphan assessed by 1H and 31P NMR spectroscopy during global forebrain ischemia in the rat

International Nuclear Information System (INIS)

Tulleken, C.A.F.; Rijen, P.C. van; Berkelbach van der Sprenkel, J.W.; Verheul, H.B.; Echteld, C.J.A. van; Balasz, R.; Lewis, P.

1991-01-01

Global forebrain ischemia was induced in the rat model by occlusion of both carotid arteries and subsequent lowering of the blood pressure. After 30 minutes of ischemia reperfusion was established. Using 1H and 31P NMR spectroscopy tissue pH values, lactate production, cellular energy index and N-acetyl-aspartate content were determined. The survival rates and histological damage were counted. (author)

Phosphorolytic activity of Escherichia coli glycyl-tRNA synthetase towards its cognate aminoacyl adenylate detected by 31P-NMR spectroscopy and thin-layer chromatography

DEFF Research Database (Denmark)

Led, Jens Jørgen; Switon, Werner K.; Jensen, Kaj Frank

1983-01-01

The catalytic activity of highly purified Escherichia coli glycyl-tRNA synthetase has been studied by 31P-NMR spectroscopy and thin-layer chromatography on poly(ethyleneimine)-cellulose. It was found that this synthetase, besides the activation of its cognate amino acid and the syntheses...

Enzymatic and acidic degradation of high molecular weight dextran into low molecular weight and its characterizations using novel Diffusion-ordered NMR spectroscopy.

Science.gov (United States)

Iqbal, Samina; Marchetti, Roberta; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio

2017-10-01

Low molecular weight fractions were derived from native high molecular weight dextran produced by Leuconostoc mesenteroides KIBGE-IB26. Structural characterization of native and low molecular weight fractions obtained after acidic and enzymatic hydrolysis was done using FTIR and NMR spectroscopy. The molecular weight was estimated using Diffusion Ordered NMR spectroscopy. Native dextran (892kDa) is composed of α-(1→6) glycosidic linkage along with α-(1→3) branching. Major proportion of 528kDa dextran was obtained after prolong enzymatic hydrolysis however, an effective acidic treatment at pH-1.4 up to 02 and 04h of exposure resulted in the formation of 77kDa and 57kDa, respectively. The increment in pH from 1.4 to 1.8 lowered the hydrolysis efficiency and resulted in the formation of 270kDa dextran fraction. The results suggest that derived low molecular weight water soluble fractions can be utilized as a drug delivery carrier along with multiple application relating pharmaceutical industries. Copyright © 2017 Elsevier B.V. All rights reserved.

Solid-state NMR basic principles and practice

CERN Document Server

Apperley, David C; Hodgkinson, Paul

2014-01-01

Nuclear Magnetic Resonance (NMR) has proved to be a uniquely powerful and versatile tool for analyzing and characterizing chemicals and materials of all kinds. This book focuses on the latest developments and applications for "solid-state" NMR, which has found new uses from archaeology to crystallography to biomaterials and pharmaceutical science research. The book will provide materials engineers, analytical chemists, and physicists, in and out of lab, a survey of the techniques and the essential tools of solid-state NMR, together with a practical guide on applications. In this concise introduction to the growing field of solid-state nuclear magnetic resonance spectroscopy The reader will find: * Basic NMR concepts for solids, including guidance on the spin-1/2 nuclei concept * Coverage of the quantum mechanics aspects of solid state NMR and an introduction to the concept of quadrupolar nuclei * An understanding relaxation, exchange and quantitation in NMR * An analysis and interpretation of NMR data, with e...

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...

Two-dimensional NMR spectroscopy as a tool to link soil organic matter composition to ecosystem processes

Science.gov (United States)

Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Schleucher, Jürgen

2014-05-01

Environmental factors (e.g. temperature and moisture) and the size and composition of soil microbial populations are often considered the main drivers of soil organic matter (SOM) mineralization. Less consideration is given to the role of SOM as a substrate for microbial metabolism and the importance of the organo-chemical composition of SOM on decomposition. In addition, a fraction of the SOM is often considered as recalcitrant to mineralization leading to accumulation of SOM. However, recently the concept of intrinsic recalcitrance of SOM to mineralization has been questioned. The challenge in investigating the role of SOM composition on its mineralization to a large extent stems from the difficulties in obtaining high resolution characterization of a very complex matrix. 13C nuclear magnetic resonance (NMR) spectroscopy is a widely used tool to characterize SOM. However, SOM is a very complex mixture and in the resulting 13C NMR spectra, the identified functional groups may represent different molecular fragments that appear in the same spectral region leading to broad peaks. These overlaps defy attempts to identify molecular moieties, and this makes it impossible to derive information at a resolution needed for evaluating e.g. recalcitrance of SOM. Here we applied a method, developed in wood science for the pulp paper industry, to achieve a better characterization of SOM. We directly dissolved finely ground organic layers of boreal forest floors-litters, fibric and humic horizons of both coniferous and broadleaved stands-in dimethyl sulfoxide and analyzed the resulting solution with a two-dimensional (2D) 1H-13C NMR experiment. We will discuss methodological aspects related to the ability to identify and quantify individual molecular moieties in SOM. We will demonstrate how the spectra resolve signals of CH groups in a 2D plane determined by the 13C and 1H chemical shifts, thereby vastly increasing the resolving power and information content of NMR spectra. The

4-Carboxyl-2,6-dinitrophenylazohydroxynaphthalenes tautomerism NMR re-explained and other methods verified

DEFF Research Database (Denmark)

Hristova, Silvia; Angelova, Silvia; Hansen, Poul Erik

2017-01-01

In two consecutive studies the tautomerism in 4-((2-hydroxynaphthalen-1-yl)diazenyl)-3,5-dinitrobenzoic acid and the structurally similar 1-((2-nitrophenyl)diazenyl)naphthalen-2-ol has been considered from viewpoint of theoretical chemistry, UV–Vis spectroscopy and NMR. Although the theoretical...... data (at M062X level) show that both compounds exist only as a keto tautomer, the experiment proves existence of the enol form. The difference in the results obtained by UV–Vis spectroscopy and NMR requires a deeper consideration and verification of the NMR approach, which is based on using model...... compounds to provide the NMR signal pattern of individual tautomers....

Use of NMR as an online sensor in industrial processes

International Nuclear Information System (INIS)

Andrade, Fabiana Diuk de

2012-01-01

Nuclear magnetic resonance (NMR) is one of the most versatile analytical techniques for chemical, biochemical and medical applications. Despite this great success, NMR is seldom used as a tool in industrial applications. The first application of NMR in flowing samples was published in 1951. However, only in the last ten years Flow NMR has gained momentum and new and potential applications have been proposed. In this review we present the historical evolution of flow or online NMR spectroscopy and imaging, and current developments for use in the automation of industrial processes. (author)

Dynamics of solutions and fluid mixtures by NMR

International Nuclear Information System (INIS)

Delpuech, J.J.

1994-01-01

After a short introduction to NMR spectroscopy, with a special emphasis on dynamical aspects, an overview on two fundamental aspects of molecular dynamics, NMR relaxation and its relationship with molecular reorientation, and magnetization transfer phenomena induced by molecular rate processes (dynamic NMR) is presented, followed by specific mechanisms of relaxation encountered in paramagnetic systems or with quadrupolar nuclei. Application fields are then reviewed: solvent exchange on metal ions with a variable pressure NMR approach, applications of field gradients in NMR, aggregation phenomena and micro-heterogeneity in surfactant solutions, polymers and biopolymers in the liquid state, liquid-like molecules in rigid matrices and in soft matter (swollen polymers and gels, fluids in and on inorganic materials, food)

Effect on the content of n-acetylaspartate, total creatine, choline containing compounds, and lactate in the hippocampus of rats exposed to aromatic white spirit for three weeks measured by NMR spectroscopy

DEFF Research Database (Denmark)

Steensgaard, A; Ostergaard, G; Jensen, C V

1996-01-01

parameters in vivo, and to examine the same subjects repeatedly over time. NMR spectroscopy was used to study the effects of organic solvents in rats. Rats were exposed to 0, 400 ppm, or 800 ppm of aromatic white spirit 6 hr/day, 7 days/week for 3 weeks. During the first week, the rats showed signs...... of irritation of mucous membranes, and appeared to be sedated. Both types of effect gradually diminished during the second week. The rats were examined by single volume of interest (VOI) NMR spectroscopy. N-acetylaspartate, creatinine and phosphocreatinine, and choline containing compounds were measured...

High resolution solid-state NMR spectroscopy of the Yersinia pestis outer membrane protein Ail in lipid membranes

International Nuclear Information System (INIS)

Yao, Yong; Dutta, Samit Kumar; Park, Sang Ho; Rai, Ratan; Fujimoto, L. Miya; Bobkov, Andrey A.; Opella, Stanley J.; Marassi, Francesca M.

2017-01-01

The outer membrane protein Ail (Adhesion invasion locus) is one of the most abundant proteins on the cell surface of Yersinia pestis during human infection. Its functions are expressed through interactions with a variety of human host proteins, and are essential for microbial virulence. Structures of Ail have been determined by X-ray diffraction and solution NMR spectroscopy, but those samples contained detergents that interfere with functionality, thus, precluding analysis of the structural basis for Ail’s biological activity. Here, we demonstrate that high-resolution solid-state NMR spectra can be obtained from samples of Ail in detergent-free phospholipid liposomes, prepared with a lipid to protein molar ratio of 100. The spectra, obtained with 13 C or 1 H detection, have very narrow line widths (0.40–0.60 ppm for 13 C, 0.11–0.15 ppm for 1 H, and 0.46–0.64 ppm for 15 N) that are consistent with a high level of sample homogeneity. The spectra enable resonance assignments to be obtained for N, CO, CA and CB atomic sites from 75 out of 156 residues in the sequence of Ail, including 80% of the transmembrane region. The 1 H-detected solid-state NMR 1 H/ 15 N correlation spectra obtained for Ail in liposomes compare very favorably with the solution NMR 1 H/ 15 N TROSY spectra obtained for Ail in nanodiscs prepared with a similar lipid to protein molar ratio. These results set the stage for studies of the molecular basis of the functional interactions of Ail with its protein partners from human host cells, as well as the development of drugs targeting Ail.

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

KAUST Repository

Elbaz, Ayman M.

2015-11-12

There is an increasing interest in the comprehensive study of heavy fuel oil (HFO) due to its growing use in furnaces, boilers, marines, and recently in gas turbines. In this work, the thermal combustion characteristics and chemical composition of HFO were investigated using a range of techniques. Thermogravimetric analysis (TGA) was conducted to study the nonisothermal HFO combustion behavior. Chemical characterization of HFO was accomplished using various standard methods in addition to direct 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) spectroscopy. By analyzing thermogravimetry and differential thermogravimetry (TG/DTG) results, three different reaction regions were identified in the combustion of HFO with air, specifically, low temperature oxidation region (LTO), fuel deposition (FD), and high temperature oxidation (HTO) region. At the high end of the LTO region, a mass transfer resistance (skin effect) was evident. Kinetic analysis in LTO and HTO regions was conducted using two different kinetic models to calculate the apparent activation energy. In both models, HTO activation energies are higher than those for LTO. The FT-ICR MS technique resolved thousands of aromatic and sulfur containing compounds in the HFO sample and provided compositional details for individual molecules of three major class species. The major classes of compounds included species with one sulfur atom (S1), with two sulfur atoms (S2), and purely hydrocarbons (HC). The DBE (double bond equivalent) abundance plots established for S1 and HC provided additional information on their distributions in the HFO sample. The 1H NMR and 13C NMR results revealed that nearly 59% of the 1H nuclei were distributed as paraffinic CH2 and 5% were in aromatic groups. Nearly 21% of 13C nuclei were

Carbon-deuterium rotational-echo double-resonance NMR spectroscopy of lyophilized aspartame formulations.

Science.gov (United States)

Luthra, Suman A; Utz, Marcel; Gorman, Eric M; Pikal, Michael J; Munson, Eric J; Lubach, Joseph W

2012-01-01

In this study, changes in the local conformation of aspartame were observed in annealed lyophilized glasses by monitoring changes in the distance between two labeled sites using C-(2)H rotational-echo double-resonance (REDOR) nuclear magnetic resonance (NMR) spectroscopy. Confirmation that the REDOR experiments were producing accurate distance measurement was ensured by measuring the (13)C-(15)N distance in glycine. The experiment was further verified by measuring the REDOR dephasing curve on (13)C-(2)H methionine. (13)C-(2)H REDOR dephasing curves were then measured on lyophilized aspartame-disaccharide formulations. In aspartame-sucrose formulation, the internuclear distances increased upon annealing, which correlated with decreased chemical reactivity. By contrast, annealing had only a minimal effect on the dephasing curve in aspartame-trehalose formulation. The results show that stability is a function of both mobility and local structure (conformation), even in a small molecule system such as lyophilized aspartame-sucrose. Copyright © 2011 Wiley-Liss, Inc.

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

Solid-state 27Al and 29Si NMR investigations on Si-substituted hydrogarnets

International Nuclear Information System (INIS)

Rivas Mercury, J.M.; Pena, P.; Aza, A.H. de; Turrillas, X.; Sobrados, I.; Sanz, J.

2007-01-01

Partially deuterated Ca 3 Al 2 (SiO 4 ) 3-x (OH) 4x hydrates prepared by a reaction in the presence of D 2 O of synthetic tricalcium aluminate with different amounts of amorphous silica were characterized by 29 Si and 27 Al magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. The 29 Si NMR spectroscopy was used for quantifying the non-reacted silica and the resulting hydrated products. The incorporation of Si into Ca 3 Al 2 (SiO 4 ) 3-x (OH) 4x was followed by 27 Al NMR spectroscopy: Si:OH ratios were determined quantitatively from octahedral Al signals ascribed to Al(OH) 6 and Al(OSi)(OH) 5 environments. The NMR data obtained were consistent with the concentrations of the Al and Si species deduced from transmission electron microscopy energy-dispersive spectrometry and Rietveld analysis of both X-ray and neutron diffraction data

Recommendations for the presentation of NMR structures of proteins and nucleic acids - IUPAC-IUBMB-IUPAB Inter-Union Task Group on the Standardization of Data Bases of Protein and Nucleic Acid Structures Determined by NMR Spectroscopy

International Nuclear Information System (INIS)

Markley, John L.; Bax, Ad; Arata, Yoji; Hilbers, C. W.; Kaptein, Robert; Sykes, Brian D.; Wright, Peter E.; Wuethrich, Kurt

1998-01-01

The recommendations presented here are designed to support easier communication of NMR data and NMR structures of proteins and nucleic acids through unified nomenclature and reporting standards. Much of this document pertains to the reporting of data in journal articles; however, in the interest of the future development of structural biology, it is desirable that the bulk of the reported information be stored in computer-accessible form and be freely accessible to the scientific community in standardized formats for data exchange. These recommendations stem from an IUPAC-IUBMB-IUPAB inter-union venture with the direct involvement of ICSU and CODATA. The Task Group has reviewed previous formal recommendations and has extended them in the light of more recent developments in the field of biomolecular NMR spectroscopy. Drafts of the recommendations presented here have been examined critically by more than 50 specialists in the field and have gone through two rounds of extensive modification to incorporate suggestions and criticisms

Verification of the application of NMR spectroscopy in the reading of the MAGIC-f gel dosimeter; Verificação da aplicação da espectroscopia de RMN na leitura do dosímetro gel MAGIC-f

Energy Technology Data Exchange (ETDEWEB)

Murakami, N.S.; Filipov, D.; Soboll, D.S., E-mail: nayarasaty@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Programa de Pós-Graduação em Engenharia Biomédica; Barison, A.; Alib, S. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Centro de RMN; Petchevistc, P.C.D. [ONCOVILLE Atendimento Oncológico Integral, Curitiba, PR (Brazil)

2017-07-01

This work aims to perform the processing of the MAGIC-f polymeric gel, irradiate it and verify the application of NMR spectroscopy to characterize it. Thus, this would be another method of reading the dosimeter. As an initial study, it was found that NMR spectroscopy can be a very effective method for reading the MAGIC-f gel, showing different signal intensities for each absorbed dose.

Comparison between the efficacy of two cleanup methods for the 1H NMR analysis of food samples contaminated with Cypermethrin

International Nuclear Information System (INIS)

Silva, M.M.; Figueroa-Villar, J.D.; Aguiar, A.P.; Riehl, C.A.S.

2004-01-01

This work aimed to study the use of 1 H NMR for the identification of cypermethrin in cooked foods. 1 H NMR is not commonly used in these cases, because food samples ready for consumption have complex substances, mainly lipids, which usually interfere with the identification of cypermethrin. Thus, we drew a comparison between the most applied method for the treatment of those samples and an alternative route that made possible the use of 1 H NMR in the identification of cypermethrin in a matrix consisting of rice, bean, and chicken, which allows the Forensic work for such cases.(author)

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

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/MS Translator for the Enhanced Simultaneous Analysis of Metabolomics Mixtures by NMR Spectroscopy and Mass Spectrometry: Application to Human Urine.

Science.gov (United States)

Bingol, Kerem; Brüschweiler, Rafael

2015-06-05

A novel metabolite identification strategy is presented for the combined NMR/MS analysis of complex metabolite mixtures. The approach first identifies metabolite candidates from 1D or 2D NMR spectra by NMR database query, which is followed by the determination of the masses (m/z) of their possible ions, adducts, fragments, and characteristic isotope distributions. The expected m/z ratios are then compared with the MS(1) spectrum for the direct assignment of those signals of the mass spectrum that contain information about the same metabolites as the NMR spectra. In this way, the mass spectrum can be assigned with very high confidence, and it provides at the same time validation of the NMR-derived metabolites. The method was first demonstrated on a model mixture, and it was then applied to human urine collected from a pool of healthy individuals. A number of metabolites could be detected that had not been reported previously, further extending the list of known urine metabolites. The new analysis approach, which is termed NMR/MS Translator, is fully automated and takes only a few seconds on a computer workstation. NMR/MS Translator synergistically uses the power of NMR and MS, enhancing the accuracy and efficiency of the identification of those metabolites compiled in databases.

Actinide(IV) and actinide(VI) carbonate speciation studies by PAS and NMR spectroscopies. Yucca Mountain Project: Milestone report 3031-WBS 1.2.3.4.1.3.1

International Nuclear Information System (INIS)

Clark, D.L.; Ekberg, S.A.; Morris, D.E.; Palmer, P.D.; Tait, C.D.

1994-09-01

Pulsed-laser photoacoustic spectroscopy (PAS) and Fourier-transform nuclear magnetic resonance (NMR) spectroscopy were used to study speciation of actinide(IV) and actinide(VI) ions (Np, Pu, Am) in aqueous carbonate solutions vs of pH, carbonate concentration, actinide content, and temperature. PAS focused on Pu(IV) speciation. Stability fields on a pH (8.4 to 12.0) versus total carbonate content (0.003 to 1.0 M) plot for dilute Pu(IV) carbonate species ([Pu] tot = 1 mM) were mapped. Four plutonium species, with absorption peaks at 486, 492, 500, and 512 nm were found. Loss of a single carbonate ligand does not account for the difference in speciation for the 486 and 492 nm absorption peaks, nor can any of the observed species be identified as colloidal Pu(IV). NMR data have been obtained for UO 2 2+ , PuO 2 2+ and AmO 2 2+ . This report focuses on results for PuO 2 2+ . The ligand exchange reaction between free and coordinated carbonate on the PuO 2 (CO 3 ) 3 4- systems has been examined by variable temperature 13 C NMR spectroscopy. In each of the six different PuO 2 (CO 3 ) 3 4- samples, two NMR signals are present, one for the free carbonate ligand and one for the carbonate ligand coordinated to a paramagnetic plutonium metal center. The single 13 C resonance line for coordinated carbonate is consistent with expectations of a monomeric PuO 2 (CO 3 ) 3 4- species in solution. A modified Carr-Purcell-Meiboom-Gill NMR pulse sequence was used for determining of ligand exchange parameters for paramagnetic actinide complexes. Eyring analysis at standard conditions provided activation parameters of ΔH = 38 KJ/M and ΔS = -60 J/K for the plutonyl triscarbonate system, suggesting an associative transition state for the plutonyl(VI) carbonate complex self-exc

Assessment of metabolic phenotypic variability in children’s urine using 1H NMR spectroscopy

Science.gov (United States)

Maitre, Léa; Lau, Chung-Ho E.; Vizcaino, Esther; Robinson, Oliver; Casas, Maribel; Siskos, Alexandros P.; Want, Elizabeth J.; Athersuch, Toby; Slama, Remy; Vrijheid, Martine; Keun, Hector C.; Coen, Muireann

2017-04-01

The application of metabolic phenotyping in clinical and epidemiological studies is limited by a poor understanding of inter-individual, intra-individual and temporal variability in metabolic phenotypes. Using 1H NMR spectroscopy we characterised short-term variability in urinary metabolites measured from 20 children aged 8-9 years old. Daily spot morning, night-time and pooled (50:50 morning and night-time) urine samples across six days (18 samples per child) were analysed, and 44 metabolites quantified. Intraclass correlation coefficients (ICC) and mixed effect models were applied to assess the reproducibility and biological variance of metabolic phenotypes. Excellent analytical reproducibility and precision was demonstrated for the 1H NMR spectroscopic platform (median CV 7.2%). Pooled samples captured the best inter-individual variability with an ICC of 0.40 (median). Trimethylamine, N-acetyl neuraminic acid, 3-hydroxyisobutyrate, 3-hydroxybutyrate/3-aminoisobutyrate, tyrosine, valine and 3-hydroxyisovalerate exhibited the highest stability with over 50% of variance specific to the child. The pooled sample was shown to capture the most inter-individual variance in the metabolic phenotype, which is of importance for molecular epidemiology study design. A substantial proportion of the variation in the urinary metabolome of children is specific to the individual, underlining the potential of such data to inform clinical and exposome studies conducted early in life.

Chemical shift-based identification of monosaccharide spin-systems with NMR spectroscopy to complement untargeted glycomics.

Science.gov (United States)

Klukowski, Piotr; Schubert, Mario

2018-06-15

A better understanding of oligosaccharides and their wide-ranging functions in almost every aspect of biology and medicine promises to uncover hidden layers of biology and will support the development of better therapies. Elucidating the chemical structure of an unknown oligosaccharide is still a challenge. Efficient tools are required for non-targeted glycomics. Chemical shifts are a rich source of information about the topology and configuration of biomolecules, whose potential is however not fully explored for oligosaccharides. We hypothesize that the chemical shifts of each monosaccharide are unique for each saccharide type with a certain linkage pattern, so that correlated data measured by NMR spectroscopy can be used to identify the chemical nature of a carbohydrate. We present here an efficient search algorithm, GlycoNMRSearch, that matches either a subset or the entire set of chemical shifts of an unidentified monosaccharide spin system to all spin systems in an NMR database. The search output is much more precise than earlier search functions and highly similar matches suggest the chemical structure of the spin system within the oligosaccharide. Thus searching for connected chemical shift correlations within all electronically available NMR data of oligosaccharides is a very efficient way of identifying the chemical structure of unknown oligosaccharides. With an improved database in the future, GlycoNMRSearch will be even more efficient deducing chemical structures of oligosaccharides and there is a high chance that it becomes an indispensable technique for glycomics. The search algorithm presented here, together with a graphical user interface, is available at http://glyconmrsearch.santos.pwr.edu.pl. Supplementary data are available at Bioinformatics online.

Characteristics and degradation of carbon and phosphorus from aquatic macrophytes in lakes: Insights from solid-state 13C NMR and solution 31P NMR spectroscopy

International Nuclear Information System (INIS)

Liu, Shasha; Zhu, Yuanrong; Meng, Wei; He, Zhongqi; Feng, Weiying; Zhang, Chen; Giesy, John P.

2016-01-01

Water extractable organic matter (WEOM) derived from macrophytes plays an important role in biogeochemical cycling of nutrients, including carbon (C), nitrogen (N) and phosphorus (P) in lakes. However, reports of their composition and degradation in natural waters are scarce. Therefore, compositions and degradation of WEOM derived from six aquatic macrophytes species of Tai Lake, China, were investigated by use of solid-state 13 C NMR and solution 31 P NMR spectroscopy. Carbohydrates were the predominant constituents of WEOM fractions, followed by carboxylic acid. Orthophosphate (ortho-P) was the dominant form of P (78.7% of total dissolved P) in the water extracts, followed by monoester P (mono-P) (20.6%) and little diester P (0.65%). The proportion of mono-P in total P species increased with the percentage of O-alkyl and O–C–O increasing in the WEOM, which is likely due to degradation and dissolution of biological membranes and RNA from aquatic plants. Whereas the proportion of mono-P decreased with alkyl-C, NCH/OCH 3 and COO/N–C=O increasing, which may be owing to the insoluble compounds including C functional groups of alkyl-C, NCH/OCH 3 and COO/N–C=O, such as aliphatic biopolymers, lignin and peptides. Based on the results of this study and information in the literature about water column and sediment, we propose that WEOM, dominated by polysaccharides, are the most labile and bioavailable component in debris of macrophytes. Additionally, these WEOMs would also be a potential source for bioavailable organic P (e.g., RNA, DNA and phytate) for lakes. - Highlights: • WEOM derived from aquatic macrophytes was characterized. • C and P in WEOM were characterized by solid 13 C NMR and solution 31 P NMR. • Degradation and transformation of macrophyte-derived C and P were investigated. • Macrophyte-derived WEOM are important source for bioavailable nutrients in lakes.

Recommendations of the wwPDB NMR Validation Task Force

Science.gov (United States)

Montelione, Gaetano T.; Nilges, Michael; Bax, Ad; Güntert, Peter; Herrmann, Torsten; Richardson, Jane S.; Schwieters, Charles; Vranken, Wim F.; Vuister, Geerten W.; Wishart, David S.; Berman, Helen M.; Kleywegt, Gerard J.; Markley, John L.

2013-01-01

As methods for analysis of biomolecular structure and dynamics using nuclear magnetic resonance spectroscopy (NMR) continue to advance, the resulting 3D structures, chemical shifts, and other NMR data are broadly impacting biology, chemistry, and medicine. Structure model assessment is a critical area of NMR methods development, and is an essential component of the process of making these structures accessible and useful to the wider scientific community. For these reasons, the Worldwide Protein Data Bank (wwPDB) has convened an NMR Validation Task Force (NMR-VTF) to work with the wwPDB partners in developing metrics and policies for biomolecular NMR data harvesting, structure representation, and structure quality assessment. This paper summarizes the recommendations of the NMR-VTF, and lays the groundwork for future work in developing standards and metrics for biomolecular NMR structure quality assessment. PMID:24010715

Structural investigations of flavonol glycosides from sea buckthorn (Hippophaë rhamnoides) pomace by NMR spectroscopy and HPLC-ESI-MS(n).

Science.gov (United States)

Rösch, Daniel; Krumbein, Angelika; Mügge, Clemens; Kroh, Lothar W

2004-06-30

Four flavonol glycosides were isolated from an extract of sea buckthorn pomace (Hippophaë rhamnoides) by Sephadex LH-20 gel chromatography and semipreparative HPLC. Their structures were elucidated by hydrolysis studies, ESI-MS(n), UV, and (1)H and (13)C NMR spectroscopy. The occurrence of the major flavonol glycoside kaempferol 3-O-beta-sophoroside-7-O-alpha-rhamnoside in sea buckthorn is described here for the first time. A further 21 flavonol glycosides of Sephadex LH-20 fractions of sea buckthorn pomace were characterized by HPLC-DAD-ESI-MS. The characteristic MS-MS and MS(3) fragmentation pattern of flavonol glycosides previously identified in sea buckthorn juice and of flavonol glycosides identified by NMR spectroscopy gave valuable indications for their identification. The results demonstrate that loss of the sugar moiety from C-7 of the aglycon is more favored than fission of the glycosidic linkage at the C-3 position. Thus, most of the compounds identified were 7-rhamnosides of isorhamnetin, kaempferol, and quercetin, which exhibit different substitution patterns at the C-3 position, mainly glucosides, rutinosides, and sophorosides. In addition, numerous flavonol glycosides were detected lacking a sugar moiety at C-7. Finally, eight flavonol derivatives were identified that are acylated by hydroxybenzoic or hydoxycinnamic acids.

Applications of high resolution 3H NMR spectroscopy

International Nuclear Information System (INIS)

Williams, P.G.

1987-10-01

The advantages of tritium as an NMR nucleus are pointed out. Examples of its use are given, including labelled toluene, hydrogenation of β-methylstyrene, and maltose and its binding proteins. 7 refs., 2 figs

NMR investigation of coal extracts

Energy Technology Data Exchange (ETDEWEB)

Lang, I; Sebor, G [Ceskoslovenska Akademie Ved, Prague. Hornicky Ustav; Sebor, G Jr; Hajek, M; Mostecky, J [Vysoka Skola Chemicko-Technologicka, Prague (Czechoslovakia)

1978-07-01

Proton NMR spectroscopy was used for the evaluation of 10% coal extract solutions in deuterated pyridine. Four types of Czechoslovak coal were analyzed. Agreement was found between the aromaticity of coal extracts calculated from /sup 1/H NMR data using Brown's method and Ladner's and Williams' method and the characterization of an average molecule of the coal extract by the number of non-bridge carbon atoms of aromatic rings, by the overall number of aromatic ring carbon atoms and the number of aromatic rings, determined by the Williams and Ferris methods. The methods for calculating carbon distribution from /sup 1/H NMR data, however, contain some constants theoretically estimated or experimentally found using the method which still remain to be verified.

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.

Structural characterization of homogalacturonan by NMR spectroscopy - assignment of reference compounds

DEFF Research Database (Denmark)

Petersen, Bent O.; Meier, Sebastian; Duus, Jens Øllgaard

2008-01-01

Complete assignment of 1H and 13C NMR of six hexagalactopyranuronic acids with varying degree and pattern of methyl esterification is reported. The NMR experiments were run at room temperature using approximately 2 mg of sample making this method convenient for studying the structure...

Synergistic effect of the simultaneous chemometric analysis of {sup 1}H NMR spectroscopic and stable isotope (SNIF-NMR, {sup 18}O, {sup 13}C) data: Application to wine analysis

Energy Technology Data Exchange (ETDEWEB)

Monakhova, Yulia B., E-mail: yul-monakhova@mail.ru [Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Strasse 3, Karlsruhe 76187 (Germany); Bruker Biospin GmbH, Silberstreifen, Rheinstetten 76287 (Germany); Department of Chemistry, Saratov State University, Astrakhanskaya Street 83, Saratov 410012 (Russian Federation); Godelmann, Rolf [Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Strasse 3, Karlsruhe 76187 (Germany); Hermann, Armin [Landesuntersuchungsamt -Institut für Lebensmittelchemie und Arzneimittelprüfung, Emy-Roeder-Straße 1, Mainz 55129 (Germany); Kuballa, Thomas [Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Strasse 3, Karlsruhe 76187 (Germany); Cannet, Claire; Schäfer, Hartmut; Spraul, Manfred [Bruker Biospin GmbH, Silberstreifen, Rheinstetten 76287 (Germany); Rutledge, Douglas N. [AgroParisTech, UMR 1145, Ingénierie Procédés Aliments, 16 rue Claude Bernard, Paris F-75005 (France)

2014-06-23

Highlights: • {sup 1}H NMR profilings of 718 wines were fused with stable isotope analysis data (SNIF-NMR, {sup 18}O, {sup 13}C). • The best improvement was obtained for prediction of the geographical origin of wine. • Certain enhancement was also obtained for the year of vintage (from 88 to 97% for {sup 1}H NMR to 99% for the fused data). • Independent component analysis was used as an alternative chemometric tool for classification. - Abstract: It is known that {sup 1}H NMR spectroscopy represents a good tool for predicting the grape variety, the geographical origin, and the year of vintage of wine. In the present study we have shown that classification models can be improved when {sup 1}H NMR profiles are fused with stable isotope (SNIF-NMR, {sup 18}O, {sup 13}C) data. Variable selection based on clustering of latent variables was performed on {sup 1}H NMR data. Afterwards, the combined data of 718 wine samples from Germany were analyzed using linear discriminant analysis (LDA), partial least squares-discriminant analysis (PLS-DA), factorial discriminant analysis (FDA) and independent components analysis (ICA). Moreover, several specialized multiblock methods (common components and specific weights analysis (ComDim), consensus PCA and consensus PLS-DA) were applied to the data. The best improvement in comparison with {sup 1}H NMR data was obtained for prediction of the geographical origin (up to 100% for the fused data, whereas stable isotope data resulted only in 60–70% correct prediction and {sup 1}H NMR data alone in 82–89% respectively). Certain enhancement was obtained also for the year of vintage (from 88 to 97% for {sup 1}H NMR to 99% for the fused data), whereas in case of grape varieties improved models were not obtained. The combination of {sup 1}H NMR data with stable isotope data improves efficiency of classification models for geographical origin and vintage of wine and can be potentially used for other food products as well.

Observation of immobile regions in natural rubber at ambient temperature by solid-state C-13 CP/MAS NMR spectroscopy

DEFF Research Database (Denmark)

Larsen, F.H.; Rasmussen, T.; Pedersen, Walther Batsberg

1999-01-01

Employing C-13 CP/MAS NMR spectroscopy, the existence of immobile regions in natural rubber (cis-1,4-polyisoprene) corresponding to a few percent of the monomer units has been detected at ambient temperature. For synthetic rubbers no immobile regions have been detected at all. Applying different...... physical and chemical treatments to natural rubber it is shown that mastication, gamma-irradiation, and increasing the temperature, slightly above the ambient, reduce the amount of immobile regions. (C) 1999 Elsevier Science Ltd. All rights reserved....

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

Flow-through lipid nanotube arrays for structure-function studies of membrane proteins by solid-state NMR spectroscopy.

Science.gov (United States)

Chekmenev, Eduard Y; Gor'kov, Peter L; Cross, Timothy A; Alaouie, Ali M; Smirnov, Alex I

2006-10-15

A novel method for studying membrane proteins in a native lipid bilayer environment by solid-state NMR spectroscopy is described and tested. Anodic aluminum oxide (AAO) substrates with flow-through 175 nm wide and 60-mum-long nanopores were employed to form macroscopically aligned peptide-containing lipid bilayers that are fluid and highly hydrated. We demonstrate that the surfaces of both leaflets of such bilayers are fully accessible to aqueous solutes. Thus, high hydration levels as well as pH and desirable ion and/or drug concentrations could be easily maintained and modified as desired in a series of experiments with the same sample. The method allows for membrane protein NMR experiments in a broad pH range that could be extended to as low as 1 and as high as 12 units for a period of up to a few hours and temperatures as high as 70 degrees C without losing the lipid alignment or bilayers from the nanopores. We demonstrate the utility of this method by a solid-state 19.6 T (17)O NMR study of reversible binding effects of mono- and divalent ions on the chemical shift properties of the Leu(10) carbonyl oxygen of transmembrane pore-forming peptide gramicidin A (gA). We further compare the (17)O shifts induced by binding metal ions to the binding of protons in the pH range from 1 to 12 and find a significant difference. This unexpected result points to a difference in mechanisms for ion and proton conduction by the gA pore. We believe that a large number of solid-state NMR-based studies, including structure-function, drug screening, proton exchange, pH, and other titration experiments, will benefit significantly from the method described here.

High resolution solid-state NMR spectroscopy of the Yersinia pestis outer membrane protein Ail in lipid membranes

Energy Technology Data Exchange (ETDEWEB)

Yao, Yong; Dutta, Samit Kumar [Sanford Burnham Prebys Medical Discovery Institute (United States); Park, Sang Ho; Rai, Ratan [University of California San Diego, Department of Chemistry and Biochemistry (United States); Fujimoto, L. Miya; Bobkov, Andrey A. [Sanford Burnham Prebys Medical Discovery Institute (United States); Opella, Stanley J. [University of California San Diego, Department of Chemistry and Biochemistry (United States); Marassi, Francesca M., E-mail: fmarassi@sbp.edu [Sanford Burnham Prebys Medical Discovery Institute (United States)

2017-03-15

The outer membrane protein Ail (Adhesion invasion locus) is one of the most abundant proteins on the cell surface of Yersinia pestis during human infection. Its functions are expressed through interactions with a variety of human host proteins, and are essential for microbial virulence. Structures of Ail have been determined by X-ray diffraction and solution NMR spectroscopy, but those samples contained detergents that interfere with functionality, thus, precluding analysis of the structural basis for Ail’s biological activity. Here, we demonstrate that high-resolution solid-state NMR spectra can be obtained from samples of Ail in detergent-free phospholipid liposomes, prepared with a lipid to protein molar ratio of 100. The spectra, obtained with {sup 13}C or {sup 1}H detection, have very narrow line widths (0.40–0.60 ppm for {sup 13}C, 0.11–0.15 ppm for {sup 1}H, and 0.46–0.64 ppm for {sup 15}N) that are consistent with a high level of sample homogeneity. The spectra enable resonance assignments to be obtained for N, CO, CA and CB atomic sites from 75 out of 156 residues in the sequence of Ail, including 80% of the transmembrane region. The {sup 1}H-detected solid-state NMR {sup 1}H/{sup 15}N correlation spectra obtained for Ail in liposomes compare very favorably with the solution NMR {sup 1}H/{sup 15}N TROSY spectra obtained for Ail in nanodiscs prepared with a similar lipid to protein molar ratio. These results set the stage for studies of the molecular basis of the functional interactions of Ail with its protein partners from human host cells, as well as the development of drugs targeting Ail.

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.

NMR and luminescence spectroscopy study of formation of mixed β-diketonate europium complexes

International Nuclear Information System (INIS)

Kavun, V.Ya.; Kalinovskaya, I.V.; Karasev, V.E.; Chernyshov, B.N.; Steblevskaya, N.I.

1987-01-01

Methods of NMR ('H, 19 F) and luminescent spectroscopy were applied to study ligand substitution in Eu(β-dik) 3 phen-CDCl 3 -(β-dik)' systems, where β-dik-acetylacetone (AA) and hexafluoroacetyl-acetone (HFAA), phen-1.10-phenathroline at different mole ratio (m) of competing ligands (m=AA/HFAA). Formation of mixed Eu(AA) 2 (HFAA)phen and Eu(AA)(HFAA) 2 phen complexes is proved; calculation of the stark structure of 5 D 0 - 7 F j (j=0,1,2) transitions in low-temperature luminescence spectra is conducted for these complexes. It is stated that at minimum HFAA concentration in the solution the latter replaces AA from europium coordination sphere. It is shown that depending on the value in substitution of acidoligands proceeds successfully by the equations Eu(AA) 3 phen+(NHFAA) n → Eu(AA) 3-n → (HFAA) n phen+(NAA) n ; (n=1,2,3)

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

Energy Technology Data Exchange (ETDEWEB)

Mohan, J.T.; Verkade, J.G. [Ames Lab., IA (United States)

1992-11-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Mohan, J.T.; Verkade, J.G. (Ames Lab., IA (United States))

1992-11-01

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

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

Science.gov (United States)

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

2008-07-23

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

New strategy for stable-isotope-aided, multidimensional NMR spectroscopy of DNA oligomers

Energy Technology Data Exchange (ETDEWEB)

Ono, Okira; Tate, Shin-Ichi; Kainosho, Masatsune [Tokyo Metropolitan Univ., Tokyo (Japan)

1994-12-01

Nuclear Magnetic Resonance (NMR) is the most efficient method for determining the solution structures of biomolecules. By applying multidimensional heteronuclear NMR techniques to {sup 13}C/{sup 15}N-labeled proteins, we can determine the solution structures of proteins with molecular mass of 20 to 30kDa at an accuracy similar to that of x-ray crystallography. Improvements in NMR instrumentation and techniques as well as the development of protein engineering methods for labeling proteins have rapidly advanced multidimensional heteronuclear NMR of proteins. In contrast, multidimensional heteronuclear NMR studies of nucleic acids is less advanced because there were no efficient methods for preparing large amounts of labeled DNA/RNA oligomers. In this report, we focused on the chemical synthesis of DNA oligomers labeled at specific residue(s). RNA oligomers with specific labels, which are difficult to synthesize by the enzyme method, can be synthesized by the chemical method. The specific labels are useful for conformational analysis of larger molecules such as protein-nucleic acid complexes.

Introducing NMR to a General Chemistry Audience: A Structural-Based Instrumental Laboratory Relating Lewis Structures, Molecular Models, and [superscript 13]C NMR Data

Science.gov (United States)

Pulliam, Curtis R.; Pfeiffer, William F.; Thomas, Alyssa C.

2015-01-01

This paper describes a first-year general chemistry laboratory that uses NMR spectroscopy and model building to emphasize molecular shape and structure. It is appropriate for either a traditional or an atoms-first curriculum. Students learn the basis of structure and the use of NMR data through a cooperative learning hands-on laboratory…

NMR Evidence for the Topologically Nontrivial Nature in a Family of Half-Heusler Compounds

KAUST Repository

Zhang, Xiaoming

2016-03-16

Spin-orbit coupling (SOC) is expected to partly determine the topologically nontrivial electronic structure of heavy half-Heusler ternary compounds. However, to date, attempts to experimentally observe either the strength of SOC or how it modifies the bulk band structure have been unsuccessful. By using bulk-sensitive nuclear magnetic resonance (NMR) spectroscopy combined with first-principles calculations, we reveal that 209Bi NMR isotropic shifts scale with relativity in terms of the strength of SOC and average atomic numbers, indicating strong relativistic effects on NMR parameters. According to first-principles calculations, we further claim that nuclear magnetic shieldings from relativistic p1/2 states and paramagnetic contributions from low-lying unoccupied p3/2 states are both sensitive to the details of band structures tuned by relativity, which explains why the hidden relativistic effects on band structure can be revealed by 209Bi NMR isotropic shifts in topologically nontrivial half-Heusler compounds. Used in complement to surface-sensitive methods, such as angle resolved photon electron spectroscopy and scanning tunneling spectroscopy, NMR can provide valuable information on bulk electronic states.

NMR Evidence for the Topologically Nontrivial Nature in a Family of Half-Heusler Compounds

KAUST Repository

Zhang, Xiaoming; Hou, Zhipeng; Wang, Yue; Xu, Guizhou; Shi, Chenglong; Liu, EnKe; Xi, Xuekui; Wang, Wenhong; Wu, Guangheng; Zhang, Xixiang

2016-01-01

Spin-orbit coupling (SOC) is expected to partly determine the topologically nontrivial electronic structure of heavy half-Heusler ternary compounds. However, to date, attempts to experimentally observe either the strength of SOC or how it modifies the bulk band structure have been unsuccessful. By using bulk-sensitive nuclear magnetic resonance (NMR) spectroscopy combined with first-principles calculations, we reveal that 209Bi NMR isotropic shifts scale with relativity in terms of the strength of SOC and average atomic numbers, indicating strong relativistic effects on NMR parameters. According to first-principles calculations, we further claim that nuclear magnetic shieldings from relativistic p1/2 states and paramagnetic contributions from low-lying unoccupied p3/2 states are both sensitive to the details of band structures tuned by relativity, which explains why the hidden relativistic effects on band structure can be revealed by 209Bi NMR isotropic shifts in topologically nontrivial half-Heusler compounds. Used in complement to surface-sensitive methods, such as angle resolved photon electron spectroscopy and scanning tunneling spectroscopy, NMR can provide valuable information on bulk electronic states.

Fourier transform and its application to 1D and 2D NMR

International Nuclear Information System (INIS)

Canet, D.

1988-01-01

In this review article, the following points are developed: Pulsed NMR and Fourier transform; Fourier transform and two-dimensional spectroscopy; Mathematical properties of Fourier transform; Fourier transform of a sine function- one dimensional NMR; Fourier transform of a product of sine functions - two-dimensional NMR; Data manipulations in the time domain; Numerical Fourier transform [fr

Study of the catalytic system, ethylbenzene-aluminum bromide, by the methods of NMR and EPR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Lipovich, V.G.; Bazhenova, A.P.; Kalabin, G.A.; Laperdina, T.G.; Latysheva, L.E.; Saraev, V.V.

1981-01-01

By the methods of NMR, EPR, and deuterium exchange it was shown that in the presence of air or oxygen in the system, ethylbenzene (I)-A1Br/sub 3/, disproportionation processes are activated, as a result of which in the /sup 1/H and /sup 13/ C NMR spectra new signals for the alkyl group of I and a signal for benzene alone appear. With accumulation in the composite layer of the catalytic system of a sufficient quantity of triethylbenzene, its protonation occurs with formation of the 2,4,6-triethylbenzenium ion. Interconversion of the two types of EPR signals, registerable on admission of air into the I-A1Br/sub 3/ system, occurs because of positional isomerization of the forming di- and triethylbenzenes. It was shown that in the presence of air in the system I-isopropylbenzene-A1Br/sub 3/, the degree of deuterium exchange between a-positions of alkyl groups is increased by 10-15% by comparison with the degassed system.

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.

Observation by flow 1H NMR and dimerization kinetics and products of reactive ortho-quinodimethanes and benzocyclobutadiene

International Nuclear Information System (INIS)

Fischer, D.

1990-01-01

The reactive o-quinodimethanes, 1,2-dimethylene-1,2-dihydronaphthalene (9) and o-xylylene (1) were observed by flow 1 H NMR spectroscopy at room temperature. The 1 H NMR spectrum of 9 was obtained in the absence of precursor and dimers. However, the 1 H NMR spectrum of the more reactive 1, generated in a similar manner from [o-((trimethylsilyl)methyl)benzyl]trimethylammonium iodide (5.) could be obtained only in the presence of its stable [4 + 2] and [4 + 4] dimers. The dimerization kinetics of 3-methyl- (5'), 3,6-dimethyl- (11), 3-isopropyl- (12), and 3,6-diisoproply-1,2-xylylene (13) in acetonitrile (CH 3 CN) were studied by stopped-flow UV-visible spectroscopy. Fluoride ion induced 1,2-elimination from 2-elimination from 2-trimethylsilylbenzocyclobutenyl-1 mesylate (26) was used to generate the reactive molecule benzocyclobutadiene (1') in CD 3 CN, which was observed by flow 1 H NMR spectroscopy at room temperature. The 1 H NMR spectrum (in CD 3 CN) of 1,2-dimethylene-1,2-dihydrothiophene (1 double-prime), obtained by fluoride ion induced 1,4-elimination from 3-(trimethylammoniummethyl)-2-(trimethylsilylmethyl)thiophene iodine was observed by flow 1 H NMR spectroscopy at room temperature. The dimerization rate of 1 double-prime in CH 3 CN, generated in the same manner, was measured by UV-visible spectroscopy. 166 refs., 7 figs., 7 tabs

Characterization of new materials in chromatography and fuel cell development by modern NMR techniques; Charakterisierung neuer Materialien in der Chromatographie und Brennstoffzellen-Forschung mit Hilfe moderner NMR-Techniken

Energy Technology Data Exchange (ETDEWEB)

Schauff, S.

2007-12-28

New materials, suitable for the application in reversed phase liquid chromatography and fuel cell membranes, were characterized regarding their structure and dynamic properties using solid-state and suspended-state NMR spectroscopy. Both methods were found to be suitable to study the dynamic behaviour, the first to observe intrinsic mobilities of phosphonic acids, the second to monitor interaction processes taking place in a chromatography-like system. Several phosphonic acids, which are promising materials for high temperature fuel cell membranes, were investigated with respect to proton mobility and transport applying various solid-state NMR methods. In addition, water uptake and its effects on anhydride formation were studied on samples that were equilibrated with saturated salt solutions. For PVPA substantial, reversible anhydride formation was found, while MePA did not show condensation. These results show that the relation between hydrogen bond strength and proton mobility is complex. In particular, this work demonstrates that the application of simple 1D 1H and 2H NMR experiments provides easy access to information about proton/deuteron mobility on short time scales, needed for an identification of materials with high intrinsic proton conductivities. Stationary phases for reversed phase liquid chomatography were characterized by solid-state NMR spectroscopy, and their influence on different analytes was studied using suspendedstate HR-MAS NMR spectroscopy. Suspended-state HR-MAS NMR spectroscopy showed to be suitable to model the separation process of analytes on chromatographic sorbents. For this, the stationary phase was suspended in a solution of analyte dissolved in mobile phase. MePhSucc showed a peak doubling of the CH2 group in presence of monomeric C18 phase, leading to the coexistence of a narrow and a broadened peak. Thus, the dynamic interactions of MePhSucc towards the stationary phase, and under the influence of the mobile phase, could be

Assignment strategies in homonuclear three-dimensional 1H NMR spectra of proteins

International Nuclear Information System (INIS)

Vuister, G.W.; Boelens, R.; Padilla, A.; Kleywegt, G.J.; Kaptein, R.

1990-01-01

The increase in dimensionality of three-dimensional (3D) NMR greatly enhances the spectral resolution in comparison to 2D NMR. It alleviates the problem of resonance overlap and may extend the range of molecules amenable to structure determination by high-resolution NMR spectroscopy. Here, the authors present strategies for the assignment of protein resonances from homonuclear nonselective 3D NOE-HOHAHA spectra. A notation for connectivities between protons, corresponding to cross peaks in 3D spectra, is introduced. They show how spin systems can be identified by tracing cross-peak patterns in cross sections perpendicular to the three frequency axes. The observable 3D sequential connectivities in proteins are tabulated, and estimates for the relative intensities of the corresponding cross peaks are given for α-helical and β-sheet conformations. Intensities of the cross peaks in the 3D spectrum of pike III paravalbumin follow the predictions. The sequential-assignment procedure is illustrated for loop regions, extended and α-helical conformations for the residues Ala 54-Leu 63 of paravalbumin. NOEs that were not previously identified in 2D spectra of paravalbumin due to overlap are found

Identification and quantitation of 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) in human urine by 1H NMR spectroscopy. Application to five cases of intoxication.

Science.gov (United States)

Liu, Jonathan; Decatur, John; Proni, Gloria; Champeil, Elise

2010-01-30

Identification of 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) in five cases of intoxication using nuclear magnetic resonance (NMR) spectroscopy of human urine is reported. A new water suppression technique PURGE (Presaturation Utilizing Relaxation Gradients and Echoes) was used. A calibration curve was obtained using spiked samples. The method gave a linear response (correlation coefficient of 0.992) over the range 0.01-1mg/mL. Subsequently, quantitation of the amount of MDMA present in the samples was performed. The benefit and reliability of NMR investigations of human urine for cases of intoxication with MDMA are discussed. Published by Elsevier Ireland Ltd.

Comparison between the efficacy of two cleanup methods for the {sup 1}H NMR analysis of food samples contaminated with Cypermethrin

Energy Technology Data Exchange (ETDEWEB)

Silva, M.M.; Figueroa-Villar, J.D.; Aguiar, A.P. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Dept. de Quimica; Riehl, C.A.S. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Analitica]. E-mail: riehl@iq.ufrj

2004-07-01

This work aimed to study the use of {sup 1}H NMR for the identification of cypermethrin in cooked foods. {sup 1}H NMR is not commonly used in these cases, because food samples ready for consumption have complex substances, mainly lipids, which usually interfere with the identification of cypermethrin. Thus, we drew a comparison between the most applied method for the treatment of those samples and an alternative route that made possible the use of {sup 1}H NMR in the identification of cypermethrin in a matrix consisting of rice, bean, and chicken, which allows the Forensic work for such cases.(author)

Solid-State NMR and DFT Studies on the Formation of Well-Defined Silica-Supported Tantallaaziridines: From Synthesis to Catalytic Application

KAUST Repository

Hamzaoui, Bilel; Pelletier, Jeremie; Abou-Hamad, Edy; Chen, Yin; El Eter, Mohamad; Chermak, Edrisse; Cavallo, Luigi; Basset, Jean-Marie

2016-01-01

spectroscopy, elemental analysis, and 1H,13C HETCOR and DQ TQ solid-state (SS) NMR spectroscopy. The formation mechanism, by β-H abstraction, was investigated by SS NMR spectroscopy and supported by DFT calculations. The C-H activation of the dimethylamide

Holistic control of Herbal Teas and Tinctures Based on sage ( L. for compounds with Beneficial and Adverse Effects using NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Stephan G. Walch

2012-01-01

Full Text Available A methodology that utilizes 1 H-NMR spectroscopy has been developed to simultaneously analyze toxic terpenes (thujone and camphor, major polyphenolic compounds, the total antioxidant capacity (ORAC and the Folin-Ciocalteu (FC index in foods and medicines containing sage. The quantitative determination of rosmarinic acid (limit of detection (LOD = 10 mg/L and total thujone (LOD = 0.35 mg/L was possible using direct integration of the signals. For other parameters (derivatives of rosmarinic acid, carnosol and flavone glycosides, ORAC and FC index, chemometric regression models obtained separately for alcohol-based tinctures (R 2 = 0.94-0.98 and aqueous tea infusions (R 2 = 0.79-0.99 were suitable for screening analysis. The relative standard deviations for authentic samples were below 10%. The developed methodology was applied for the analysis of a wide variety of sage products (n = 108. The total thujone content in aqueous tea infusions was found to be in the range of not detectable (nd to 37.5 mg/L (average 9.2 mg/L, while tinctures contained higher levels (range nd–-409 mg/L, average 107 mg/L. The camphor content varied from 2.1 to 43.7 mg/L in aqueous infusions and from not detectable to 748 mg/L in tinctures (averages were 14.1 and 206 mg/L, respectively. Phenolic compounds were also detected in the majority of the investigated products. 1 H-NMR spectroscopy was proven to have the ability to holistically control all important adverse and beneficial compounds in sage products in a single experiment, considerably saving time, resources and costs as NMR replaces four separate methodologies that were previously needed to analyze the same parameters.

1H diffusion-weighted, 13C and 17O NMR spectroscopy: methodological developments to study brain structure and function in vivo

International Nuclear Information System (INIS)

Najac, Chloe

2014-01-01

Magnetic Resonance Spectroscopy is a unique tool that allows acquiring brain biochemical profiles and quantifying many cellular parameters in vivo. During this thesis, three different techniques have been developed: (i) 1 H diffusion-weighted, (ii) carbon-13 ( 13 C) and (iii) oxygen-17 ( 17 O) NMR spectroscopy to study brain structure and function in vivo. Brain metabolites are cell-specific endogenous tracers of the intracellular space whose translational diffusion depends on many cellular properties (e.g.: cytosol viscosity and intracellular restriction). Studying the variation of the diffusion coefficient (ADC) as a function of diffusion time (td) allows untangling and quantifying those parameters. In particular, measuring metabolites ADC at long diffusion times gives information about the metabolites compartmentation in cells. In a first study, we measured neuronal and astrocytic metabolites ADC over a large time window (from 80 ms to 1 s) in a large voxel in the macaque brain. No dependence of all metabolites ADC on td was observed suggesting that metabolites primarily diffuse in neuronal (dendrites and axons) and astrocytic processes and are not confined inside the cell body and organelles (nucleus, mitochondria). The large size of the voxel, due to low detection sensitivity, did not allow us to study metabolites compartmentation in pure white (WM) and grey matters (GM). Therefore, we performed a new study in the human brain. Results showed that in both WM and GM metabolites diffuse in fiber-like cell structure. Finally, using an even larger time window (up to 2 s) in the macaque brain and analytical models mimicking the cell structure, we estimated the length of neuronal (∼110 μm) and astrocytic (∼70 μm) processes. ATP (adenosine triphosphate), the main source of energy in the organism, is produced thanks to glucose oxidation inside the mitochondria. 13 C NMR spectroscopy is a well-known technique to study brain energy metabolism and can be used to

Metabolic characterization of Palatinate German white wines according to sensory attributes, varieties, and vintages using NMR spectroscopy and multivariate data analyses

Energy Technology Data Exchange (ETDEWEB)

Ali, Kashif; Maltese, Federica [Leiden University, Division of Pharmacognosy, Section Metabolomics, Institute of Biology (Netherlands); Toepfer, Reinhard [Institute for Grapevine Breeding Geilweilerhof, Julius Kuehn Institute (JKI), Federal Research Centre for Cultivated Plants (Germany); Choi, Young Hae, E-mail: y.choi@chem.leidenuniv.nl; Verpoorte, Robert [Leiden University, Division of Pharmacognosy, Section Metabolomics, Institute of Biology (Netherlands)

2011-04-15

{sup 1}H NMR (nuclear magnetic resonance spectroscopy) has been used for metabolomic analysis of 'Riesling' and 'Mueller-Thurgau' white wines from the German Palatinate region. Diverse two-dimensional NMR techniques have been applied for the identification of metabolites, including phenolics. It is shown that sensory analysis correlates with NMR-based metabolic profiles of wine. {sup 1}H NMR data in combination with multivariate data analysis methods, like principal component analysis (PCA), partial least squares projections to latent structures (PLS), and bidirectional orthogonal projections to latent structures (O2PLS) analysis, were employed in an attempt to identify the metabolites responsible for the taste of wine, using a non-targeted approach. The high quality wines were characterized by elevated levels of compounds like proline, 2,3-butanediol, malate, quercetin, and catechin. Characterization of wine based on type and vintage was also done using orthogonal projections to latent structures (OPLS) analysis. 'Riesling' wines were characterized by higher levels of catechin, caftarate, valine, proline, malate, and citrate whereas compounds like quercetin, resveratrol, gallate, leucine, threonine, succinate, and lactate, were found discriminating for 'Mueller-Thurgau'. The wines from 2006 vintage were dominated by leucine, phenylalanine, citrate, malate, and phenolics, while valine, proline, alanine, and succinate were predominantly present in the 2007 vintage. Based on these results, it can be postulated the NMR-based metabolomics offers an easy and comprehensive analysis of wine and in combination with multivariate data analyses can be used to investigate the source of the wines and to predict certain sensory aspects of wine.

Metabolic characterization of Palatinate German white wines according to sensory attributes, varieties, and vintages using NMR spectroscopy and multivariate data analyses

International Nuclear Information System (INIS)

Ali, Kashif; Maltese, Federica; Toepfer, Reinhard; Choi, Young Hae; Verpoorte, Robert

2011-01-01

1 H NMR (nuclear magnetic resonance spectroscopy) has been used for metabolomic analysis of ‘Riesling’ and ‘Mueller-Thurgau’ white wines from the German Palatinate region. Diverse two-dimensional NMR techniques have been applied for the identification of metabolites, including phenolics. It is shown that sensory analysis correlates with NMR-based metabolic profiles of wine. 1 H NMR data in combination with multivariate data analysis methods, like principal component analysis (PCA), partial least squares projections to latent structures (PLS), and bidirectional orthogonal projections to latent structures (O2PLS) analysis, were employed in an attempt to identify the metabolites responsible for the taste of wine, using a non-targeted approach. The high quality wines were characterized by elevated levels of compounds like proline, 2,3-butanediol, malate, quercetin, and catechin. Characterization of wine based on type and vintage was also done using orthogonal projections to latent structures (OPLS) analysis. ‘Riesling’ wines were characterized by higher levels of catechin, caftarate, valine, proline, malate, and citrate whereas compounds like quercetin, resveratrol, gallate, leucine, threonine, succinate, and lactate, were found discriminating for ‘Mueller-Thurgau’. The wines from 2006 vintage were dominated by leucine, phenylalanine, citrate, malate, and phenolics, while valine, proline, alanine, and succinate were predominantly present in the 2007 vintage. Based on these results, it can be postulated the NMR-based metabolomics offers an easy and comprehensive analysis of wine and in combination with multivariate data analyses can be used to investigate the source of the wines and to predict certain sensory aspects of wine.

Fast 2D NMR Spectroscopy for In vivo Monitoring of Bacterial Metabolism in Complex Mixtures

Directory of Open Access Journals (Sweden)

Rupashree Dass

2017-07-01

Full Text Available The biological toolbox is full of techniques developed originally for analytical chemistry. Among them, spectroscopic experiments are very important source of atomic-level structural information. Nuclear magnetic resonance (NMR spectroscopy, although very advanced in chemical and biophysical applications, has been used in microbiology only in a limited manner. So far, mostly one-dimensional 1H experiments have been reported in studies of bacterial metabolism monitored in situ. However, low spectral resolution and limited information on molecular topology limits the usability of these methods. These problems are particularly evident in the case of complex mixtures, where spectral peaks originating from many compounds overlap and make the interpretation of changes in a spectrum difficult or even impossible. Often a suite of two-dimensional (2D NMR experiments is used to improve resolution and extract structural information from internuclear correlations. However, for dynamically changing sample, like bacterial culture, the time-consuming sampling of so-called indirect time dimensions in 2D experiments is inefficient. Here, we propose the technique known from analytical chemistry and structural biology of proteins, i.e., time-resolved non-uniform sampling. The method allows application of 2D (and multi-D experiments in the case of quickly varying samples. The indirect dimension here is sparsely sampled resulting in significant reduction of experimental time. Compared to conventional approach based on a series of 1D measurements, this method provides extraordinary resolution and is a real-time approach to process monitoring. In this study, we demonstrate the usability of the method on a sample of Escherichia coli culture affected by ampicillin and on a sample of Propionibacterium acnes, an acne causing bacterium, mixed with a dose of face tonic, which is a complicated, multi-component mixture providing complex NMR spectrum. Through our experiments

Two-dimensional nuclear magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Bax, A.; Lerner, L.

1986-01-01

Great spectral simplification can be obtained by spreading the conventional one-dimensional nuclear magnetic resonance (NMR) spectrum in two independent frequency dimensions. This so-called two-dimensional NMR spectroscopy removes spectral overlap, facilitates spectral assignment, and provides a wealth of additional information. For example, conformational information related to interproton distances is available from resonance intensities in certain types of two-dimensional experiments. Another method generates 1 H NMR spectra of a preselected fragment of the molecule, suppressing resonances from other regions and greatly simplifying spectral appearance. Two-dimensional NMR spectroscopy can also be applied to the study of 13 C and 15 N, not only providing valuable connectivity information but also improving sensitivity of 13 C and 15 N detection by up to two orders of magnitude. 45 references, 10 figures

Characterization of cover crops by NMR spectroscopy: impacts on soil carbon, nitrogen and phosphorus under tillage regimes

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Arminda Moreira de Carvalho

Full Text Available The objective of this study was to investigate the chemical composition of cover crops by solid-state CPMAS 13C NMR spectroscopy and its effects on carbon, nitrogen and phosphorus in a Typic Acrustox. Cover crops (Crotalaria juncea, Canavalia brasiliensis, Cajanus cajan, Mucuna pruriens and Raphanus sativus and natural fallow were studied in rotation with maize under conventional and no-tillage regimes. Tissues of Crotalaria juncea, Canavalia brasiliensis, Mucuna pruriens and Raphanus sativus were analyzed using CPMAS 13C NMR spectroscopy. Soil samples were collected at the end of the growing season of the cover crops (September 2002 and during the grain filling period in corn from 0-5 and 5-10 cm layers. Cajanus cajan presented the lowest content of polysaccharides and along with Mucuna pruriens presented the highest percentage of aromatic carbon compounds, reflecting the slow decomposition of highly lignified material. Carbon stocks were higher in the superficial soil layer and under no-tillage due to the accumulation and slower decomposition of plant tissues under these conditions. Increases in the C/N ratio of the soil with Mucuna pruriens and the C/P ratio with Cajanus cajan in the dry season were also related to slower rates of decomposition, caused by the large concentration of aromatic compounds in the tissues of these species. The higher C/P ratios found at 0-5 cm layer are due to higher values of P (Mehlich-1 at 5-10 cm (25 mg kg-1 layer and the higher concentration of carbon in the superficial soil layer as a result of the accumulation of plant residues.

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.

Solid-state NMR analysis of membrane proteins and protein aggregates by proton detected spectroscopy

International Nuclear Information System (INIS)

Zhou, Donghua H.; Nieuwkoop, Andrew J.; Berthold, Deborah A.; Comellas, Gemma; Sperling, Lindsay J.; Tang, Ming; Shah, Gautam J.; Brea, Elliott J.; Lemkau, Luisel R.; Rienstra, Chad M.

2012-01-01

Solid-state NMR has emerged as an important tool for structural biology and chemistry, capable of solving atomic-resolution structures for proteins in membrane-bound and aggregated states. Proton detection methods have been recently realized under fast magic-angle spinning conditions, providing large sensitivity enhancements for efficient examination of uniformly labeled proteins. The first and often most challenging step of protein structure determination by NMR is the site-specific resonance assignment. Here we demonstrate resonance assignments based on high-sensitivity proton-detected three-dimensional experiments for samples of different physical states, including a fully-protonated small protein (GB1, 6 kDa), a deuterated microcrystalline protein (DsbA, 21 kDa), a membrane protein (DsbB, 20 kDa) prepared in a lipid environment, and the extended core of a fibrillar protein (α-synuclein, 14 kDa). In our implementation of these experiments, including CONH, CO(CA)NH, CANH, CA(CO)NH, CBCANH, and CBCA(CO)NH, dipolar-based polarization transfer methods have been chosen for optimal efficiency for relatively high protonation levels (full protonation or 100 % amide proton), fast magic-angle spinning conditions (40 kHz) and moderate proton decoupling power levels. Each H–N pair correlates exclusively to either intra- or inter-residue carbons, but not both, to maximize spectral resolution. Experiment time can be reduced by at least a factor of 10 by using proton detection in comparison to carbon detection. These high-sensitivity experiments are especially important for membrane proteins, which often have rather low expression yield. Proton-detection based experiments are expected to play an important role in accelerating protein structure elucidation by solid-state NMR with the improved sensitivity and resolution.

NMR-Based Metabolomic Study on Isatis tinctoria: Comparison of Different Accessions, Harvesting Dates, and the Effect of Repeated Harvesting.

Science.gov (United States)

Guldbrandsen, Niels; Kostidis, Sarantos; Schäfer, Hartmut; De Mieri, Maria; Spraul, Manfred; Skaltsounis, Alexios-Leandros; Mikros, Emmanuel; Hamburger, Matthias

2015-05-22

Isatis tinctoria is an ancient dye and medicinal plant with potent anti-inflammatory and antiallergic properties. Metabolic differences were investigated by NMR spectroscopy of accessions from different origins that were grown under identical conditions on experimental plots. For these accessions, metabolite profiles at different harvesting dates were analyzed, and single and repeatedly harvested plants were compared. Leaf samples were shock-frozen in liquid N2 immediately after being harvested, freeze-dried, and cryomilled prior to extraction. Extracts were prepared by pressurized liquid extraction with ethyl acetate and 70% aqueous methanol. NMR spectra were analyzed using a combination of different methods of multivariate data analysis such as principal component analysis (PCA), canonical analysis (CA), and k-nearest neighbor concept (k-NN). Accessions and harvesting dates were well separated in the PCA/CA/k-NN analysis in both extracts. Pairwise statistical total correlation spectroscopy (STOCSY) revealed unsaturated fatty acids, porphyrins, carbohydrates, indole derivatives, isoprenoids, phenylpropanoids, and minor aromatic compounds as the cause of these differences. In addition, the metabolite profile was affected by the repeated harvest regime, causing a decrease of 1,5-anhydroglucitol, sucrose, unsaturated fatty acids, porphyrins, isoprenoids, and a flavonoid.

Analytical challenges in drug counterfeiting and falsification-The NMR approach.

Science.gov (United States)

Holzgrabe, Ulrike; Malet-Martino, Myriam

2011-06-25

Counterfeiting of products is a global problem. As long as clothes, clocks, leather wear, etc. are faked there is no danger, but when it comes to drugs, counterfeiting can be life-threatening. In the last years sub-standard active pharmaceutical ingredients (APIs) were found more often even though the use of the quality-ensuring methods of international pharmacopoeias should have detected additional impurities and the low content of the API. Methods orthogonal to the separating methods used in the pharmacopoeias are necessary to find counterfeits. Beside Raman and NIR spectroscopies as well as powder X-ray analysis, NMR spectroscopy being a primary ratio method of measurement is highly suitable to identify and quantify a drug and its related substances as well as to recognize a drug of sub-standard quality. DOSY experiments are suitable to identify the ingredients of formulations and therefore to identify wrong and/or additional ingredients. This review gives an overview of the application of quantitative NMR spectroscopy and DOSY NMR in anticounterfeiting. Copyright © 2010 Elsevier B.V. All rights reserved.

Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic 1H NMR spectroscopy.

Science.gov (United States)

Culf, A S; Cuperlović-Culf, M; Ouellette, R J

2009-02-01

Highly coloured Janovsky complexes have been known for over 120 years, being used in many colourimetric analytical procedures. In this present study, two novel and stable nitrocyclohexadienyl spirobicyclic, zwitterionic Janovsky anionic hydantoin sigma-complexes, rac-1,3-diisopropyl-6-nitro-2,4-dioxo-1,3-diazaspiro[4.5]deca-6,9-dien-8-ylideneazinate, ammonium internal salt (1) and 1,3-diisopropyl-2,4-dioxo-1,3-diazaspiro[4.5]deca-6,9-dien-8-ylideneazinate, ammonium internal salt (2) have been prepared and characterised by NMR, electrospray ionization mass spectrometry (ESI-MS) and UV/visible methods. For the p-mononitro-substituted complex (2), we discovered chemical exchange behaviour using 1D saturation transfer and 2D exchange spectroscopy (EXSY) (1)H NMR techniques. The coalescence temperature was determined to be 62 degrees C in d(3)-acetonitrile. Analysis of these data provided a Gibbs free energy of activation, DeltaG double dagger, of + 67 kJ mole(-1), a rate constant, k, coalescence of 220 Hz and an equilibrium constant, K(eqm), of 0.98 as estimates of the exchange process in this solvent. Of the two mechanisms proposed for this fluxional behaviour, ring opening to a substituted benzene or proton exchange, a further theoretical modelling study of 1D (1)H NMR spectra was able to confirm that simple proton exchange between the two nitrogen sites of the hydantoin ring provided an accurate simulation of the observed experimental evidence. Interestingly, the o,p-dinitro-substituted complex (1) did not show any chemical exchange behaviour up to 150 degrees C in d(3)-acetonitrile (to 75 degrees C) and d(6)-dimethyl sulfoxide (DMSO). Molecular modelling at the MM2 level suggests that steric collisions of an N-acyl isopropyl substituent of the hydantoin ring with the ortho-nitro group of the spirofused cyclohexadienyl ring prevents the proposed proton exchange mechanism occurring in this case. 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.

1H NMR Spectroscopy and Multivariate Analysis of Monovarietal EVOOs as a Tool for Modulating Coratina-Based Blends

Directory of Open Access Journals (Sweden)

Laura Del Coco

2014-04-01

Full Text Available Coratina cultivar-based olives are very common among 100% Italian extra virgin olive oils (EVOOs. Often, the very spicy character of this cultivar, mostly due to the high polyphenols concentration, requires blending with other “sweetener” oils. In this work, monovarietal EVOO samples from the Coratina cultivar (Apulia, Italy were investigated and compared with monovarietal EVOO from native or recently introduced Apulian (Italy cultivars (Ogliarola Garganica, Ogliarola Barese, Cima di Mola, Peranzana, Picholine, from Calabria (Italy (Carolea and Rossanese and from other Mediterranean countries, such as Spain (Picual and Greece (Kalamata and Koroneiki by 1H NMR spectroscopy and multivariate analysis (principal component analysis (PCA. In this regard, NMR signals could allow a first qualitative evaluation of the chemical composition of EVOO and, in particular, of its minor component content (phenols and aldehydes, an intrinsic behavior of EVOO taste, related to the cultivar and geographical origins. Moreover, this study offers an opportunity to address blended EVOOs tastes by using oils from a specific region or country of origin.

Non-invasive measurement of brain glycogen by NMR spectroscopy and its application to the study of brain metabolism

Science.gov (United States)

Tesfaye, Nolawit; Seaquist, Elizabeth R.; Öz, Gülin

2011-01-01

Glycogen is the reservoir for glucose in the brain. Beyond the general agreement that glycogen serves as an energy source in the central nervous system, its exact role in brain energy metabolism has yet to be elucidated. Experiments performed in cell and tissue culture and animals have shown that glycogen content is affected by several factors including glucose, insulin, neurotransmitters, and neuronal activation. The study of in vivo glycogen metabolism has been hindered by the inability to measure glycogen non-invasively, but in the past several years, the development of a non-invasive localized 13C nuclear magnetic resonance (NMR) spectroscopy method has enabled the study of glycogen metabolism in the conscious human. With this technique, 13C-glucose is administered intravenously and its incorporation into and wash-out from brain glycogen is tracked. One application of this method has been to the study of brain glycogen metabolism in humans during hypoglycemia: data have shown that mobilization of brain glycogen is augmented during hypoglycemia and, after a single episode of hypoglycemia, glycogen synthesis rate is increased, suggesting that glycogen stores rebound to levels greater than baseline. Such studies suggest glycogen may serve as a potential energy reservoir in hypoglycemia and may participate in the brain's adaptation to recurrent hypoglycemia and eventual development of hypoglycemia unawareness. Beyond this focused area of study, 13C NMR spectroscopy has a broad potential for application in the study of brain glycogen metabolism and carries the promise of a better understanding of the role of brain glycogen in diabetes and other conditions. PMID:21732401

LEGO-NMR spectroscopy: a method to visualize individual subunits in large heteromeric complexes.

Science.gov (United States)

Mund, Markus; Overbeck, Jan H; Ullmann, Janina; Sprangers, Remco

2013-10-18

Seeing the big picture: Asymmetric macromolecular complexes that are NMR active in only a subset of their subunits can be prepared, thus decreasing NMR spectral complexity. For the hetero heptameric LSm1-7 and LSm2-8 rings NMR spectra of the individual subunits of the complete complex are obtained, showing a conserved RNA binding site. This LEGO-NMR technique makes large asymmetric complexes accessible to detailed NMR spectroscopic studies. © 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of Creative Commons the Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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

From Traditional Resource to Global Commodities:-A Comparison of Rhodiola Species Using NMR Spectroscopy-Metabolomics and HPTLC.

Science.gov (United States)

Booker, Anthony; Zhai, Lixiang; Gkouva, Christina; Li, Shuyuan; Heinrich, Michael

2016-01-01

The fast developing international trade of products based on traditional knowledge and their value chains has become an important aspect of the ethnopharmacological debate. The structure and diversity of value chains and their impact on the phytochemical composition of herbal medicinal products, as well as the underlying government policies and regulations, have been overlooked in the debate about quality problems in transnational trade. Rhodiola species, including Rhodiola rosea L. and Rhodiola crenulata (Hook. f. & Thomson) H. Ohba, are used as traditional herbal medicines. Faced with resource depletion and environment destruction, R. rosea and R. crenulata are becoming endangered, making them more economically valuable to collectors and middlemen, and also increasing the risk of adulteration and low quality. Rhodiola products have been subject to adulteration and we recently assessed 39 commercial products for their composition and quality. However, the range of Rhodiola species potentially implicated has not been assessed. Also, the ability of selected analytical techniques in differentiating these species is not known yet. Using a strategy previously developed by our group, we compare the phytochemical differences among Rhodiola raw materials available on the market to provide a practical method for the identification of different Rhodiola species from Europe and Asia and the detection of potential adulterants. Nuclear magnetic resonance spectroscopy coupled with multivariate analysis software and high performance thin layer chromatography techniques were used to analyse the samples. Rosavin and rosarin were mainly present in R. rosea but also in Rosea sachalinensis Borris. 30% of the Rhodiola samples purchased from the Chinese market were adulterated by other Rhodiola spp. The utilization of a combined platform based on (1)H-NMR and HPTLC methods resulted in an integrated analysis of different Rhodiola species. We identified adulteration at the earliest stage

Comparison among Magnus/Floquet/Fer expansion schemes in solid-state NMR

Science.gov (United States)

Takegoshi, K.; Miyazawa, Norihiro; Sharma, Kshama; Madhu, P. K.

2015-04-01

We here revisit expansion schemes used in nuclear magnetic resonance (NMR) for the calculation of effective Hamiltonians and propagators, namely, Magnus, Floquet, and Fer expansions. While all the expansion schemes are powerful methods there are subtle differences among them. To understand the differences, we performed explicit calculation for heteronuclear dipolar decoupling, cross-polarization, and rotary-resonance experiments in solid-state NMR. As the propagator from the Fer expansion takes the form of a product of sub-propagators, it enables us to appreciate effects of time-evolution under Hamiltonians with different orders separately. While 0th-order average Hamiltonian is the same for the three expansion schemes with the three cases examined, there is a case that the 2nd-order term for the Magnus/Floquet expansion is different from that obtained with the Fer expansion. The difference arises due to the separation of the 0th-order term in the Fer expansion. The separation enables us to appreciate time-evolution under the 0th-order average Hamiltonian, however, for that purpose, we use a so-called left-running Fer expansion. Comparison between the left-running Fer expansion and the Magnus expansion indicates that the sign of the odd orders in Magnus may better be reversed if one would like to consider its effect in order.

Comparison among Magnus/Floquet/Fer expansion schemes in solid-state NMR

International Nuclear Information System (INIS)

Takegoshi, K.; Miyazawa, Norihiro; Sharma, Kshama; Madhu, P. K.

2015-01-01

We here revisit expansion schemes used in nuclear magnetic resonance (NMR) for the calculation of effective Hamiltonians and propagators, namely, Magnus, Floquet, and Fer expansions. While all the expansion schemes are powerful methods there are subtle differences among them. To understand the differences, we performed explicit calculation for heteronuclear dipolar decoupling, cross-polarization, and rotary-resonance experiments in solid-state NMR. As the propagator from the Fer expansion takes the form of a product of sub-propagators, it enables us to appreciate effects of time-evolution under Hamiltonians with different orders separately. While 0th-order average Hamiltonian is the same for the three expansion schemes with the three cases examined, there is a case that the 2nd-order term for the Magnus/Floquet expansion is different from that obtained with the Fer expansion. The difference arises due to the separation of the 0th-order term in the Fer expansion. The separation enables us to appreciate time-evolution under the 0th-order average Hamiltonian, however, for that purpose, we use a so-called left-running Fer expansion. Comparison between the left-running Fer expansion and the Magnus expansion indicates that the sign of the odd orders in Magnus may better be reversed if one would like to consider its effect in order

Comparison among Magnus/Floquet/Fer expansion schemes in solid-state NMR

Energy Technology Data Exchange (ETDEWEB)

Takegoshi, K., E-mail: takeyan@kuchem.kyoto-u.ac.jp; Miyazawa, Norihiro [Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto (Japan); Sharma, Kshama [TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500 075 (India); Madhu, P. K. [TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500 075 (India); Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)

2015-04-07

We here revisit expansion schemes used in nuclear magnetic resonance (NMR) for the calculation of effective Hamiltonians and propagators, namely, Magnus, Floquet, and Fer expansions. While all the expansion schemes are powerful methods there are subtle differences among them. To understand the differences, we performed explicit calculation for heteronuclear dipolar decoupling, cross-polarization, and rotary-resonance experiments in solid-state NMR. As the propagator from the Fer expansion takes the form of a product of sub-propagators, it enables us to appreciate effects of time-evolution under Hamiltonians with different orders separately. While 0th-order average Hamiltonian is the same for the three expansion schemes with the three cases examined, there is a case that the 2nd-order term for the Magnus/Floquet expansion is different from that obtained with the Fer expansion. The difference arises due to the separation of the 0th-order term in the Fer expansion. The separation enables us to appreciate time-evolution under the 0th-order average Hamiltonian, however, for that purpose, we use a so-called left-running Fer expansion. Comparison between the left-running Fer expansion and the Magnus expansion indicates that the sign of the odd orders in Magnus may better be reversed if one would like to consider its effect in order.

Comparison of the computational NMR chemical shifts of choline with the experimental data

International Nuclear Information System (INIS)

Alcorn, C; Cuperlovic-Culf, M; Ghandi, K

2012-01-01

One of the main biological markers of the presence of cancer in living patients is an over-expression of total choline (tCho), which is the sum of free choline and its derivatives. 1 H Magnetic Resonance Spectroscopy, or H-MRS, enables the quantification of tCho via its proton spectra, and thus has the potential to be a diagnostic tool for the presence of cancer and an accurate early indicator of the response of cancer to treatment. However, it remains difficult to quantify individual choline derivatives, since they share a large structural similarity ((CH 3 ) 3 -N + -CH 2 -CH 2 -O-), of which the strongest signal detectable by MRS is that of the choline h ead group : the three methyl groups bonded to the nitrogen. This work used ACENet, a high performance computing system, to attempt to model the NMR parameters of choline derivatives, with the focus of this report being free choline. Optimized structures were determined using Density Functional Theory and the B3LYP electron correlation functional. The Polarizable Continuum Model was used to evaluate solvent effects. The Gauge-Invariant Atomic Orbital method was found to be the superior method for calculating the NMR parameters of cholines.

Determination and Comparison of Seed Oil Triacylglycerol Composition of Various Soybeans (Glycine max (L. Using 1H-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Won Woo Kim

2013-11-01

Full Text Available Seed oil triacylglycerol (TAG composition of 32 soybean varieties were determined and compared using 1H-NMR. The contents of linolenic (Ln, linoleic (L, and oleic (O ranged from 10.7% to 19.3%, 37.4%–50.1%, and 15.7%–34.1%, respectively. As is evident, linoleic acid was the major fatty acid of soybean oil. Compositional differences among the varieties were observed. Natural oils containing unsaturated groups have been regarded as important nutrient and cosmetic ingredients because of their various biological activities. The TAG profiles of the soy bean oils could be useful for distinguishing the origin of seeds and controlling the quality of soybean oils. To the best of our knowledge, this is the first study in which the TAG composition of various soybean oils has been analyzed using the 1H-NMR method.

Determination and comparison of seed oil triacylglycerol composition of various soybeans (Glycine max (L.)) using ¹H-NMR spectroscopy.

Science.gov (United States)

Kim, Won Woo; Rho, Ho Sik; Hong, Yong Deog; Yeom, Myung Hun; Shin, Song Seok; Yi, Jun Gon; Lee, Min-Seuk; Park, Hye Yoon; Cho, Dong Ha

2013-11-21

Seed oil triacylglycerol (TAG) composition of 32 soybean varieties were determined and compared using ¹H-NMR. The contents of linolenic (Ln), linoleic (L), and oleic (O) ranged from 10.7% to 19.3%, 37.4%-50.1%, and 15.7%-34.1%, respectively. As is evident, linoleic acid was the major fatty acid of soybean oil. Compositional differences among the varieties were observed. Natural oils containing unsaturated groups have been regarded as important nutrient and cosmetic ingredients because of their various biological activities. The TAG profiles of the soy bean oils could be useful for distinguishing the origin of seeds and controlling the quality of soybean oils. To the best of our knowledge, this is the first study in which the TAG composition of various soybean oils has been analyzed using the ¹H-NMR method.

Theoretical NMR spectroscopy of N-heterocyclic carbenes and their metal complexes

KAUST Repository

Falivene, Laura

2016-12-26

Recent theoretical analysis of the NMR properties of free N-heterocyclic carbenes (NHC) and Metal-NHC complexes has complemented experiments, allowing the establishment of structure/property relationships and the rationalization of otherwise surprising experimental results. In this review, the main conclusions from recent literature are discussed, with the aim to offer a vision of the potential of theoretical analyses of NMR properties.

High sensitivity 1H-NMR spectroscopy of homeopathic remedies made in water

Science.gov (United States)

Anick, David J

2004-01-01

Background The efficacy of homeopathy is controversial. Homeopathic remedies are made via iterated shaking and dilution, in ethanol or in water, from a starting substance. Remedies of potency 12 C or higher are ultra-dilute (UD), i.e. contain zero molecules of the starting material. Various hypotheses have been advanced to explain how a UD remedy might be different from unprepared solvent. One such hypothesis posits that a remedy contains stable clusters, i.e. localized regions where one or more hydrogen bonds remain fixed on a long time scale. High sensitivity proton nuclear magnetic resonance spectroscopy has not previously been used to look for evidence of differences between UD remedies and controls. Methods Homeopathic remedies made in water were studied via high sensitivity proton nuclear magnetic resonance spectroscopy. A total of 57 remedy samples representing six starting materials and spanning a variety of potencies from 6 C to 10 M were tested along with 46 controls. Results By presaturating on the water peak, signals could be reliably detected that represented H-containing species at concentrations as low as 5 μM. There were 35 positions where a discrete signal was seen in one or more of the 103 spectra, which should theoretically have been absent from the spectrum of pure water. Of these 35, fifteen were identified as machine-generated artifacts, eight were identified as trace levels of organic contaminants, and twelve were unexplained. Of the unexplained signals, six were seen in just one spectrum each. None of the artifacts or unexplained signals occurred more frequently in remedies than in controls, using a p < .05 cutoff. Some commercially prepared samples were found to contain traces of one or more of these small organic molecules: ethanol, acetate, formate, methanol, and acetone. Conclusion No discrete signals suggesting a difference between remedies and controls were seen, via high sensitivity 1H-NMR spectroscopy. The results failed to support

Discrimination of Aurantii Fructus Immaturus and Fructus Poniciri Trifoliatae Immaturus by Flow Injection UV Spectroscopy (FIUV) and 1H NMR using Partial Least-squares Discriminant Analysis (PLS-DA)

Science.gov (United States)

Two simple fingerprinting methods, flow-injection UV spectroscopy (FIUV) and 1H nuclear magnetic resonance (NMR), for discrimination of Aurantii FructusImmaturus and Fructus Poniciri TrifoliataeImmaturususing were described. Both methods were combined with partial least-squares discriminant analysis...

Spectroscopy 101: A Practical Introduction to Spectroscopy and Analysis for Undergraduate Organic Chemistry Laboratories

Science.gov (United States)

Morrill, Lucas A.; Kammeyer, Jacquelin K.; Garg, Neil K.

2017-01-01

An undergraduate organic chemistry laboratory that provides an introduction to various spectroscopic techniques is reported. Whereas organic spectroscopy is most often learned and practiced in the context of reaction analyses, this laboratory experiment allows students to become comfortable with [superscript 1]H NMR, [superscript 13]C NMR, and IR…

Characteristics and degradation of carbon and phosphorus from aquatic macrophytes in lakes: Insights from solid-state {sup 13}C NMR and solution {sup 31}P NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Liu, Shasha [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhu, Yuanrong, E-mail: zhuyuanrong07@mails.ucas.ac.cn [State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Meng, Wei, E-mail: mengwei@craes.org.cn [State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); He, Zhongqi [USDA-ARS Southern Regional Research Center, 1100 Robert E Lee Blvd, New Orleans, LA 70124 (United States); Feng, Weiying [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhang, Chen [State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Giesy, John P. [State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Department of Biomedical and Veterinary Biosciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan (Canada)

2016-02-01

Water extractable organic matter (WEOM) derived from macrophytes plays an important role in biogeochemical cycling of nutrients, including carbon (C), nitrogen (N) and phosphorus (P) in lakes. However, reports of their composition and degradation in natural waters are scarce. Therefore, compositions and degradation of WEOM derived from six aquatic macrophytes species of Tai Lake, China, were investigated by use of solid-state {sup 13}C NMR and solution {sup 31}P NMR spectroscopy. Carbohydrates were the predominant constituents of WEOM fractions, followed by carboxylic acid. Orthophosphate (ortho-P) was the dominant form of P (78.7% of total dissolved P) in the water extracts, followed by monoester P (mono-P) (20.6%) and little diester P (0.65%). The proportion of mono-P in total P species increased with the percentage of O-alkyl and O–C–O increasing in the WEOM, which is likely due to degradation and dissolution of biological membranes and RNA from aquatic plants. Whereas the proportion of mono-P decreased with alkyl-C, NCH/OCH{sub 3} and COO/N–C=O increasing, which may be owing to the insoluble compounds including C functional groups of alkyl-C, NCH/OCH{sub 3} and COO/N–C=O, such as aliphatic biopolymers, lignin and peptides. Based on the results of this study and information in the literature about water column and sediment, we propose that WEOM, dominated by polysaccharides, are the most labile and bioavailable component in debris of macrophytes. Additionally, these WEOMs would also be a potential source for bioavailable organic P (e.g., RNA, DNA and phytate) for lakes. - Highlights: • WEOM derived from aquatic macrophytes was characterized. • C and P in WEOM were characterized by solid {sup 13}C NMR and solution {sup 31}P NMR. • Degradation and transformation of macrophyte-derived C and P were investigated. • Macrophyte-derived WEOM are important source for bioavailable nutrients in lakes.

Amorphous surface layer versus transient amorphous precursor phase in bone - A case study investigated by solid-state NMR spectroscopy.

Science.gov (United States)

Von Euw, Stanislas; Ajili, Widad; Chan-Chang, Tsou-Hsi-Camille; Delices, Annette; Laurent, Guillaume; Babonneau, Florence; Nassif, Nadine; Azaïs, Thierry

2017-09-01

The presence of an amorphous surface layer that coats a crystalline core has been proposed for many biominerals, including bone mineral. In parallel, transient amorphous precursor phases have been proposed in various biomineralization processes, including bone biomineralization. Here we propose a methodology to investigate the origin of these amorphous environments taking the bone tissue as a key example. This study relies on the investigation of a bone tissue sample and its comparison with synthetic calcium phosphate samples, including a stoichiometric apatite, an amorphous calcium phosphate sample, and two different biomimetic apatites. To reveal if the amorphous environments in bone originate from an amorphous surface layer or a transient amorphous precursor phase, a combined solid-state nuclear magnetic resonance (NMR) experiment has been used. The latter consists of a double cross polarization 1 H→ 31 P→ 1 H pulse sequence followed by a 1 H magnetization exchange pulse sequence. The presence of an amorphous surface layer has been investigated through the study of the biomimetic apatites; while the presence of a transient amorphous precursor phase in the form of amorphous calcium phosphate particles has been mimicked with the help of a physical mixture of stoichiometric apatite and amorphous calcium phosphate. The NMR results show that the amorphous and the crystalline environments detected in our bone tissue sample belong to the same particle. The presence of an amorphous surface layer that coats the apatitic core of bone apatite particles has been unambiguously confirmed, and it is certain that this amorphous surface layer has strong implication on bone tissue biogenesis and regeneration. Questions still persist on the structural organization of bone and biomimetic apatites. The existing model proposes a core/shell structure, with an amorphous surface layer coating a crystalline bulk. The accuracy of this model is still debated because amorphous calcium

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.

Process of Fragment-Based Lead Discovery—A Perspective from NMR

Directory of Open Access Journals (Sweden)

Rongsheng Ma

2016-07-01

Full Text Available Fragment-based lead discovery (FBLD has proven fruitful during the past two decades for a variety of targets, even challenging protein–protein interaction (PPI systems. Nuclear magnetic resonance (NMR spectroscopy plays a vital role, from initial fragment-based screening to lead generation, because of its power to probe the intrinsically weak interactions between targets and low-molecular-weight fragments. Here, we review the NMR FBLD process from initial library construction to lead generation. We describe technical aspects regarding fragment library design, ligand- and protein-observed screening, and protein–ligand structure model generation. For weak binders, the initial hit-to-lead evolution can be guided by structural information retrieved from NMR spectroscopy, including chemical shift perturbation, transferred pseudocontact shifts, and paramagnetic relaxation enhancement. This perspective examines structure-guided optimization from weak fragment screening hits to potent leads for challenging PPI targets.

Mechanisms of Action of (Methacrylates in Hemolytic Activity, in Vivo Toxicity and Dipalmitoylphosphatidylcholine (DPPC Liposomes Determined Using NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Seiichiro Fujisawa

2012-01-01

Full Text Available We investigated the quantitative structure-activity relationships between hemolytic activity (log 1/H50 or in vivo mouse intraperitoneal (ip LD50 using reported data for α,β-unsaturated carbonyl compounds such as (methacrylate monomers and their 13C-NMR β-carbon chemical shift (δ. The log 1/H50 value for methacrylates was linearly correlated with the δCβ value. That for (methacrylates was linearly correlated with log P, an index of lipophilicity. The ipLD50 for (methacrylates was linearly correlated with δCβ but not with log P. For (methacrylates, the δCβ value, which is dependent on the π-electron density on the β-carbon, was linearly correlated with PM3-based theoretical parameters (chemical hardness, η; electronegativity, χ; electrophilicity, ω, whereas log P was linearly correlated with heat of formation (HF. Also, the interaction between (methacrylates and DPPC liposomes in cell membrane molecular models was investigated using 1H-NMR spectroscopy and differential scanning calorimetry (DSC. The log 1/H50 value was related to the difference in chemical shift (ΔδHa (Ha: H (trans attached to the β-carbon between the free monomer and the DPPC liposome-bound monomer. Monomer-induced DSC phase transition properties were related to HF for monomers. NMR chemical shifts may represent a valuable parameter for investigating the biological mechanisms of action of (methacrylates.

Surface characterization of hydrophobic core-shell QDs using NMR techniques

Science.gov (United States)

Zhang, Chengqi; Zeng, Birong; Palui, Goutam; Mattoussi, Hedi

2018-02-01

Using a few solution phase NMR spectroscopy techniques, including 1H NMR and 31P NMR, we have characterized the organic shell on CdSe-ZnS core-shell quantum dots and tracked changes in its composition when the QD dispersions are subjected to varying degrees of purification. Combining solution phase NMR with diffusion ordered spectroscopy (DOSY), we were able to distinguish between freely diffusing ligands in the sample from those bound on the surfaces. Additionally, matrix assisted laser desorption ionization (MALDI) and FTIR measurements were used to provide complementary and supporting information on the organic ligand coating for these nanocrystals. We found that the organic shell is dominated by monomeric or oligomeric n-hexylphosphonic acid (HPA), along with small portion of 1-hexadecyl amine (HDA). The presence of TOP/TOPO (tri-n-octylphosphine / tri-noctylphosphine oxide) molecules is much smaller, even though large excess of TOP/TOPO were used during the QD growth. These results indicate that HPA (alkyl phosphonate) exhibits the strongest coordination affinity to ZnS-rich QD surfaces grown using the high temperature injection route.

Comparison of photoacoustic spectroscopy, conventional absorption spectroscopy, and potentiometry as probes of lanthanide speciation

International Nuclear Information System (INIS)

Torres, R.A.; Palmer, C.E.A.; Baisden, P.A.; Russo, R.E.; Silva, R.J.

1990-01-01

The authors measured the stability constants of praseodymium acetate and oxydiacetate complexes by laser-induced photoacoustic spectroscopy, conventional UV-visible absorption spectroscopy, and pH titration. For the spectroscopic studies, changes in the free Pr absorption peaks at 468 and 481 nm were monitored at varying ligand concentrations. The total Pr concentration was 1 x 10 -4 M in solutions used for the photoacoustic studies and 0.02 M for conventional spectroscopy. For the pH titrations, we used solutions whose Pr concentrations varied from 5 x 10 -3 to 5 x 10 -2 M, with total ligand-to-metal ratios ranging from 1 to 10. A comparison of the results obtained by the three techniques demonstrates that photoacoustic spectroscopy can give the same information about metal-ligand speciation as more conventional methods. It is particularly suited to those situations where the other techniques are insensitive because of limited metal concentrations

Intra- versus Intermolecular Hydrogen Bonding: Solvent-Dependent Conformational Preferences of a Common Supramolecular Binding Motif from 1 H NMR and Vibrational Circular Dichroism Spectra.

Science.gov (United States)

Demarque, Daniel P; Merten, Christian

2017-12-19

When predicting binding properties of small molecules or larger supramolecular aggregates, intra- and intermolecular hydrogen bonds are often considered the most important factor. Spectroscopic techniques such as 1 H NMR spectroscopy are typically utilized to characterize such binding events, but interpretation is often qualitative and follows chemical intuition. In this study, we compare the effects of intramolecular hydrogen bonding and solvation on two chiral 2,6-pyridinediyl-dialkylamides. In comparison with 1 H NMR spectroscopy, vibrational circular dichroism (VCD) spectroscopy proved to be more sensitive to conformational changes. In fact, the change of the solvent from CDCl 3 to [D 6 ]DMSO generates mirror-image VCD spectra for the same enantiomer. Here, the common sense that the sterically less hindered group is more prone to solvation proved to be wrong according predicted VCD spectra, which clearly show that both asymmetric amide hydrogens are equally likely to be solvated, but never simultaneously. The competition between intra- and intermolecular hydrogen bonding and their importance for a correct prediction of spectral properties are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-state {sup 27}Al and {sup 29}Si NMR investigations on Si-substituted hydrogarnets

Energy Technology Data Exchange (ETDEWEB)

Rivas Mercury, J.M. [Instituto de Ceramica y Vidrio, CSIC, Kelsen, 5, 28049 Cantoblanco-Madrid (Spain); Pena, P. [Instituto de Ceramica y Vidrio, CSIC, Kelsen, 5, 28049 Cantoblanco-Madrid (Spain)]. E-mail: ppena@icv.csic.es; Aza, A.H. de [Instituto de Ceramica y Vidrio, CSIC, Kelsen, 5, 28049 Cantoblanco-Madrid (Spain); Turrillas, X. [Instituto de Ciencias de la Construccion Eduardo Torroja, CSIC, Serrano Galvache, 4, 28033 Madrid (Spain); Sobrados, I. [Instituto de Ciencia de Materiales, CSIC, Sor Juana Ines de la Cruz, 3, 28049 Cantoblanco-Madrid (Spain); Sanz, J. [Instituto de Ciencia de Materiales, CSIC, Sor Juana Ines de la Cruz, 3, 28049 Cantoblanco-Madrid (Spain)

2007-02-15

Partially deuterated Ca{sub 3}Al{sub 2}(SiO{sub 4}){sub 3-x}(OH){sub 4x} hydrates prepared by a reaction in the presence of D{sub 2}O of synthetic tricalcium aluminate with different amounts of amorphous silica were characterized by {sup 29}Si and {sup 27}Al magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. The {sup 29}Si NMR spectroscopy was used for quantifying the non-reacted silica and the resulting hydrated products. The incorporation of Si into Ca{sub 3}Al{sub 2}(SiO{sub 4}){sub 3-x}(OH){sub 4x} was followed by {sup 27}Al NMR spectroscopy: Si:OH ratios were determined quantitatively from octahedral Al signals ascribed to Al(OH){sub 6} and Al(OSi)(OH){sub 5} environments. The NMR data obtained were consistent with the concentrations of the Al and Si species deduced from transmission electron microscopy energy-dispersive spectrometry and Rietveld analysis of both X-ray and neutron diffraction data.

Nuclear magnetic resonance apparatus having semitoroidal RF coil for use in topical NMR and NMR imaging

International Nuclear Information System (INIS)

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

1984-01-01

An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, to enable NMR measurements to be taken from selected regions inside an object, particularly human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other electric field interactions. The coil may be combined with a like orthogonal coil and suitably driven to provide a circularly polarised field; or it may be used in conjunction with a concentrically nested smaller semitoroidal coil to move the maximum field further from the coil assembly. (author)

Binding events of (S )-N -(3-oxo-octanoyl)-homoserine lactone with agrobacterium tumefaciens mutant cells studied by saturation transfer difference NMR

Energy Technology Data Exchange (ETDEWEB)

Cabeca, Luis Fernando; Pomini, Armando Mateus; Cruz, Pedro Luiz R.; Marsaioli, Anita J. [University of Campinas (UNICAMP), SP (Brazil). Chemistry Inst.

2011-07-01

Quorum-sensing is a widely studied communication phenomenon in bacteria, which involves the production and detection of signaling substances in relation with cell density and colony behavior. Herein, the membrane binding interactions of the signal (S)-N-(3-oxo-octanoyl)-HSL with A. tumefaciens NTL4(pZLR4) cells were studied using saturation transfer difference NMR spectroscopy (STD-NMR). The substance epitope map was obtained showing that the hydrophobic acyl chain is the most important interacting site for the signal and the cell membrane. Results were interpreted upon comparisons with a simpler system, using liposomes as membrane models. Some insights on the use of b-cyclodextrin as acyl-HSL carrier were also provided. (author)

Molecular Dynamics and Morphology of High Performance Elastomers and Fibers by Solid State NMR

Science.gov (United States)

2016-06-30

nuclear magnetic resonance (ssNMR) spectroscopy to investigate the chemical structure and physical state of the residual phosphorous in PBO fiber...ssNMR) spectroscopy to investigate the chemical structure and physical state of the residual phosphorous in PBO fiber, which has been long suspected to...Jason Cain, Jian H. Yu, David Veysset, Keith A. Nelson . Probing the Influence of Molecular Dynamics of Matrix Elastomers on Ballistic Impact Back-face

Reaction titration: a convenient method for titering reactive hydride agents (Red-Al, LiAlH4, DIBALH, L-Selectride, NaH, and KH) by No-D NMR spectroscopy.

Science.gov (United States)

Hoye, Thomas R; Aspaas, Andrew W; Eklov, Brian M; Ryba, Troy D

2005-05-26

The concentration of reactive metal hydride (Met-H) reducing agents can be determined (in < or = 20 min) using No-D NMR spectroscopy. The method involves (i) reacting Met-H with an excess of p-methoxybenzaldehyde, (ii) quenching with excess acetic acid, (iii) recording the No-D NMR spectrum of this homogeneous mixture, and (iv) deducing the concentration of Met-H from the % conversion (as measured by integration). By a conceptually related method, the titer of the basic alkali metal hydrides KH and NaH can also be determined.

13C and 31P NMR study of gluconeogenesis: utilization of 13C-labeled substrates by perfused liver from streptozotocin-diabetic and untreated rats

International Nuclear Information System (INIS)

Cohen, S.M.

1987-01-01

The metabolism of 13 C-labeled substrates was followed by 13 C and 31 P NMR in perfused liver from the streptozotocin-treated rat model of insulin-dependent diabetes. Comparison was made with perfused liver from untreated littermates, fasted either 24 or 12 h. The major routes of pyruvate metabolism were followed by a 13 C NMR approach that provided for the determination of the metabolic fate of several substances simultaneously. The rate of gluconeogenesis was 2-4-fold greater and β-hydroxybutyrate production was 50% greater in liver from the chronically diabetic rats as compared with the control groups. Large differences in the distribution of 13 C label in hepatic alanine were measured between diabetic and control groups. The biosyntheses of 13 C-labeled glutathione and N-carbamoylaspartate were monitored in time-resolved 13 C NMR spectra of perfused liver. Assignments for the resonances of glutathione and N-carbamoylaspartate were made with the aid of 13 C NMR studies of perchloric acid extracts of the freeze-clamped livers. 13 C NMR spectroscopy of the perfusates provided a convenient, rapid assay of the rate of oxidation of [2- 13 C]ethanol, the hepatic output of [2- 13 ]acetaldehyde, and the accumulation of [2- 13 C]acetate in the perfusate. By 31 P NMR spectroscopy, carbamoyl phosphate was measured in all diabetic livers and an unusual P,P'-diesterified pyrophosphate was observed in one-fourth of the diabetic livers examined. Neither of these phosphorylated metabolites was detected in control liver. Both 13 C and 31 P NMR were useful in defining changes in hepatic metabolism in experimental diabetes

Application of high-field n.m.r. spectroscopy to the structural elucidation of natural products. The structure of rubellin, a noval bufadienolide glycoside from Urginea rubella

International Nuclear Information System (INIS)

Steyn, P.S.; Van Heerden, F.R.; Vleggaar, R.

1986-01-01

The structure and absolute configuration of rubellin, the major toxic principle of Urginea rubella, was determined by application of high-field 1 H n.m.r. spectroscopy. Rubellin proved to be a bufadienolide glycoside with the carbohydrate moiety doubly linked to the aglycone at the 2α- and 3β- positions

Development of a superconducting bulk magnet for NMR and MRI.

Science.gov (United States)

Nakamura, Takashi; Tamada, Daiki; Yanagi, Yousuke; Itoh, Yoshitaka; Nemoto, Takahiro; Utumi, Hiroaki; Kose, Katsumi

2015-10-01

A superconducting bulk magnet composed of six vertically stacked annular single-domain c-axis-oriented Eu-Ba-Cu-O crystals was energized to 4.74 T using a conventional superconducting magnet for high-resolution NMR spectroscopy. Shim coils, gradient coils, and radio frequency coils for high resolution NMR and MRI were installed in the 23 mm-diameter room-temperature bore of the bulk magnet. A 6.9 ppm peak-to-peak homogeneous region suitable for MRI was achieved in the central cylindrical region (6.2 mm diameter, 9.1 mm length) of the bulk magnet by using a single layer shim coil. A 21 Hz spectral resolution that can be used for high resolution NMR spectroscopy was obtained in the central cylindrical region (1.3 mm diameter, 4 mm length) of the bulk magnet by using a multichannel shim coil. A clear 3D MR image dataset of a chemically fixed mouse fetus with (50 μm)(3) voxel resolution was obtained in 5.5 h. We therefore concluded that the cryogen-free superconducting bulk magnet developed in this study is useful for high-resolution desktop NMR, MRI and mobile NMR device. Copyright © 2015 Elsevier Inc. All rights reserved.

Quantitative NMR spectroscopy of binary liquid mixtures (aldehyde + alcohol) Part I: Acetaldehyde + (methanol or ethanol or 1-propanol)

International Nuclear Information System (INIS)

Jaubert, Silke; Maurer, Gerd

2014-01-01

Highlights: • Formation of hemiacetal/poly(oxymethylene) hemiacetals in liquid binary mixtures. • Acetaldehyde and a low molecular alcohol (methanol or ethanol or 1-propanol). • Quantitative 13 C NMR spectroscopy at temperatures between (255 and 295) K. • Hemiacetals are the predominant species. • (Acetaldehyde + methanol (50 + 50)) at 255 K: hemiacetal (polymers) >80% (≈10%). -- Abstract: Aldehydes react with alcohols to hemiacetals and poly(oxymethylene) hemiacetals. The chemical reaction equilibria of such reactions, in particular in the liquid state, can have an essential influence on the thermodynamic properties and related phenomena like, for example, on the vapour + liquid phase equilibrium. Therefore, thermodynamic models that aim to describe quantitatively such phase equilibria have to consider the chemical reaction equilibrium in the coexisting phases. This is well known in the literature for systems such as, for example, formaldehyde and methanol. However, experimental information on the chemical reaction equilibria in mixtures with other aldehydes (than formaldehyde) and alcohols is extremely scarce. Therefore, quantitative NMR spectroscopy was used to investigate the chemical reaction equilibria in binary mixtures of acetaldehyde and a single alcohol (here either methanol, ethanol or 1-propanol) at temperatures between (255 and 295) K. The results reveal that the majority of the constituents of the mixture is present as hemiacetal and the first two poly(oxymethylene) hemiacetals: in an equimolar mixture of (acetaldehyde + methanol or ethanol or 1-propanol), between about 90% at T = 255 K and about 75% at 295 K. The mole-fraction based chemical reaction equilibrium constants for the formation of those species were determined and some derived properties are reported

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

Science.gov (United States)

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

2013-10-01

Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and 31P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse 31P NMR linewidth and inverse Raman PO43-ν1 bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3-10.3 wt% CO32- range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the 31P NMR chemical shift frequency and the Raman phosphate ν1 band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals.

A complete vibrational study on a potential environmental toxicant agent, the 3,3',4,4'-tetrachloroazobenzene combining the FTIR, FTRaman, UV-Visible and NMR spectroscopies with DFT calculations.

Science.gov (United States)

Castillo, María V; Pergomet, Jorgelina L; Carnavale, Gustavo A; Davies, Lilian; Zinczuk, Juan; Brandán, Silvia A

2015-01-05

In this study 3,3',4,4'-tetrachloroazobenzene (TCAB) was prepared and then characterized by infrared, Raman, multidimensional nuclear magnetic resonance (NMR) and ultraviolet-visible spectroscopies. The density functional theory (DFT) together with the 6-31G(*) and 6-311++G(**) basis sets were used to study the structures and vibrational properties of the two cis and trans isomers of TCAB. The harmonic vibrational wavenumbers for the optimized geometries were calculated at the same theory levels. A complete assignment of all the observed bands in the vibrational spectra of TCAB was performed combining the DFT calculations with the scaled quantum mechanical force field (SQMFF) methodology. The molecular electrostatic potentials, atomic charges, bond orders and frontier orbitals for the two isomers of TCAB were compared and analyzed. The comparison of the theoretical ultraviolet-visible spectrum with the corresponding experimental demonstrates a good concordance while the calculated (1)H and (13)C chemicals shifts are in good conformity with the corresponding experimental NMR spectra of TCAB in solution. The npp(*) transitions for both forms were studied by natural bond orbital (NBO) while the topological properties were calculated by employing Bader's Atoms in the Molecules (AIM) theory. This study shows that the cis and trans isomers exhibit different structural and vibrational properties and absorption bands. Copyright © 2014. Published by Elsevier B.V.

Unraveling a phosphorylation event in a folded protein by NMR spectroscopy: phosphorylation of the Pin1 WW domain by PKA

International Nuclear Information System (INIS)

Smet-Nocca, Caroline; Launay, Hélène; Wieruszeski, Jean-Michel; Lippens, Guy; Landrieu, Isabelle

2013-01-01

The Pin1 protein plays a critical role in the functional regulation of the hyperphosphorylated neuronal Tau protein in Alzheimer’s disease and is by itself regulated by phosphorylation. We have used Nuclear Magnetic Resonance (NMR) spectroscopy to both identify the PKA phosphorylation site in the Pin1 WW domain and investigate the functional consequences of this phosphorylation. Detection and identification of phosphorylation on serine/threonine residues in a globular protein, while mostly occurring in solvent-exposed flexible loops, does not lead to chemical shift changes as obvious as in disordered proteins and hence does not necessarily shift the resonances outside the spectrum of the folded protein. Other complications were encountered to characterize the extent of the phosphorylation, as part of the 1 H, 15 N amide resonances around the phosphorylation site are specifically broadened in the unphosphorylated state. Despite these obstacles, NMR spectroscopy was an efficient tool to confirm phosphorylation on S16 of the WW domain and to quantify the level of phosphorylation. Based on this analytical characterization, we show that WW phosphorylation on S16 abolishes its binding capacity to a phosphorylated Tau peptide. A reduced conformational heterogeneity and flexibility of the phospho-binding loop upon S16 phosphorylation could account for part of the decreased affinity for its phosphorylated partner. Additionally, a structural model of the phospho-WW obtained by molecular dynamics simulation and energy minimization suggests that the phosphate moiety of phospho-S16 could compete with the phospho-substrate.

A guide to the identification of metabolites in NMR-based metabonomics/metabolomics experiments.

Science.gov (United States)

Dona, Anthony C; Kyriakides, Michael; Scott, Flora; Shephard, Elizabeth A; Varshavi, Dorsa; Veselkov, Kirill; Everett, Jeremy R

2016-01-01

Metabonomics/metabolomics is an important science for the understanding of biological systems and the prediction of their behaviour, through the profiling of metabolites. Two technologies are routinely used in order to analyse metabolite profiles in biological fluids: nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), the latter typically with hyphenation to a chromatography system such as liquid chromatography (LC), in a configuration known as LC-MS. With both NMR and MS-based detection technologies, the identification of the metabolites in the biological sample remains a significant obstacle and bottleneck. This article provides guidance on methods for metabolite identification in biological fluids using NMR spectroscopy, and is illustrated with examples from recent studies on mice.

A guide to the identification of metabolites in NMR-based metabonomics/metabolomics experiments

Directory of Open Access Journals (Sweden)

Anthony C. Dona

2016-01-01

Full Text Available Metabonomics/metabolomics is an important science for the understanding of biological systems and the prediction of their behaviour, through the profiling of metabolites. Two technologies are routinely used in order to analyse metabolite profiles in biological fluids: nuclear magnetic resonance (NMR spectroscopy and mass spectrometry (MS, the latter typically with hyphenation to a chromatography system such as liquid chromatography (LC, in a configuration known as LC–MS. With both NMR and MS-based detection technologies, the identification of the metabolites in the biological sample remains a significant obstacle and bottleneck. This article provides guidance on methods for metabolite identification in biological fluids using NMR spectroscopy, and is illustrated with examples from recent studies on mice.

Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

Energy Technology Data Exchange (ETDEWEB)

Foerstendorf, Harald; Mueller, Katharina; Steudtner, Robin [eds.

2012-07-01

The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

International Nuclear Information System (INIS)

Foerstendorf, Harald; Mueller, Katharina; Steudtner, Robin

2012-01-01

The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

Target immobilization as a strategy for NMR-based fragment screening: comparison of TINS, STD, and SPR for fragment hit identification.

Science.gov (United States)

Kobayashi, Masakazu; Retra, Kim; Figaroa, Francis; Hollander, Johan G; Ab, Eiso; Heetebrij, Robert J; Irth, Hubertus; Siegal, Gregg

2010-09-01

Fragment-based drug discovery (FBDD) has become a widely accepted tool that is complementary to high-throughput screening (HTS) in developing small-molecule inhibitors of pharmaceutical targets. Because a fragment campaign can only be as successful as the hit matter found, it is critical that the first stage of the process be optimized. Here the authors compare the 3 most commonly used methods for hit discovery in FBDD: high concentration screening (HCS), solution ligand-observed nuclear magnetic resonance (NMR), and surface plasmon resonance (SPR). They selected the commonly used saturation transfer difference (STD) NMR spectroscopy and the proprietary target immobilized NMR screening (TINS) as representative of the array of possible NMR methods. Using a target typical of FBDD campaigns, the authors find that HCS and TINS are the most sensitive to weak interactions. They also find a good correlation between TINS and STD for tighter binding ligands, but the ability of STD to detect ligands with affinity weaker than 1 mM K(D) is limited. Similarly, they find that SPR detection is most suited to ligands that bind with K(D) better than 1 mM. However, the good correlation between SPR and potency in a bioassay makes this a good method for hit validation and characterization studies.

13C and 31P NMR [Nuclear Magnetic Resonance] studies of prostate tumor metabolism

International Nuclear Information System (INIS)

Sillerud, L.O.; Halliday, K.R.; Freyer, J.P; Griffey, R.H.; Fenoglio-Preiser, C.

1989-01-01

The current research on prostate cancer by NMR spectroscopy and microscopy will most significantly contribute to tumor diagnosis and characterization only if sound biochemical models of tumor metabolism are established and tested. Prior searches focused on universal markers of malignancy, have to date, revealed no universal markers by any method. It is unlikely that NMRS will succeed where other methods have failed, however, NMR spectroscopy does provide a non-invasive means to analyze multiple compounds simultaneously in vivo. In order to fully evaluate the ability of NMRS to differentiate non-malignant from malignant tissues it is necessary to determine sufficient multiple parameters from specific, well-diagnosed, histological tumor types that, in comparison to normal tissue and non-neoplastic, non-normal pathologies from which the given neoplasm must be differentiated, one has enough degrees of freedom to make a mathematically and statistically significant determination. Confounding factors may consist of tumor heterogeneity arising from regional variations in differentiation, ischemia, necrosis, hemorrhage, inflammation and the presence of intermingled normal tissue. One related aspect of our work is the development of { 13 C}- 1 H metabolic imaging of 13 C for metabolic characterization, with enhanced spatial localization (46). This should markedly extend the range of potential clinical NMR uses because the spatial variation in prostate metabolism may prove to be just as important in tumor diagnoses as bulk (volume-averaged) properties themselves. It is our hope that NMRS and spectroscopic imaging will reveal a sound correlation between prostate metabolism and tumor properties that will be clinically straightforward and useful for diagnosis

Process spectroscopy in microemulsions—setup and multi-spectral approach for reaction monitoring of a homogeneous hydroformylation process

Science.gov (United States)

Meyer, K.; Ruiken, J.-P.; Illner, M.; Paul, A.; Müller, D.; Esche, E.; Wozny, G.; Maiwald, M.

2017-03-01

Reaction monitoring in disperse systems, such as emulsions, is of significant technical importance in various disciplines like biotechnological engineering, chemical industry, food science, and a growing number other technical fields. These systems pose several challenges when it comes to process analytics, such as heterogeneity of mixtures, changes in optical behavior, and low optical activity. Concerning this, online nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for process monitoring in complex reaction mixtures due to its unique direct comparison abilities, while at the same time being non-invasive and independent of optical properties of the sample. In this study the applicability of online-spectroscopic methods on the homogeneously catalyzed hydroformylation system of 1-dodecene to tridecanal is investigated, which is operated in a mini-plant scale at Technische Universität Berlin. The design of a laboratory setup for process-like calibration experiments is presented, including a 500 MHz online NMR spectrometer, a benchtop NMR device with 43 MHz proton frequency as well as two Raman probes and a flow cell assembly for an ultraviolet and visible light (UV/VIS) spectrometer. Results of high-resolution online NMR spectroscopy are shown and technical as well as process-specific problems observed during the measurements are discussed.

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.

Determination of rate constants of N-alkylation of primary amines by 1H NMR spectroscopy.

Science.gov (United States)

Li, Chenghong

2013-09-05

Macromolecules containing N-diazeniumdiolates of secondary amines are proposed scaffolds for controlled nitrogen oxide (NO) release medical applications. Preparation of these compounds often involves converting primary amine groups to secondary amine groups through N-alkylation. However, N-alkylation results in not only secondary amines but tertiary amines as well. Only N-diazeniumdiolates of secondary amines are suitable for controlled NO release; therefore, the yield of secondary amines is crucial to the total NO load of the carrier. In this paper, (1)H NMR spectroscopy was used to estimate the rate constants for formation of secondary amine (k1) and tertiary amine (k2) for alkylation reagents such as propylene oxide (PO), methyl acrylate (MA), and acrylonitrile (ACN). At room temperature, the ratio of k2/k1 for the three reactions was found to be around 0.50, 0.026, and 0.0072.

SIMPSON: A general simulation program for solid-state NMR spectroscopy

Science.gov (United States)

Bak, Mads; Rasmussen, Jimmy T.; Nielsen, Niels Chr.

2011-12-01

A computer program for fast and accurate numerical simulation of solid-state NMR experiments is described. The program is designed to emulate a NMR spectrometer by letting the user specify high-level NMR concepts such as spin systems, nuclear spin interactions, RF irradiation, free precession, phase cycling, coherence-order filtering, and implicit/explicit acquisition. These elements are implemented using the Tel scripting language to ensure a minimum of programming overhead and direct interpretation without the need for compilation, while maintaining the flexibility of a full-featured programming language. Basicly, there are no intrinsic limitations to the number of spins, types of interactions, sample conditions (static or spinning, powders, uniaxially oriented molecules, single crystals, or solutions), and the complexity or number of spectral dimensions for the pulse sequence. The applicability ranges from simple ID experiments to advanced multiple-pulse and multiple-dimensional experiments, series of simulations, parameter scans, complex data manipulation/visualization, and iterative fitting of simulated to experimental spectra. A major effort has been devoted to optimizing the computation speed using state-of-the-art algorithms for the time-consuming parts of the calculations implemented in the core of the program using the C programming language. Modification and maintenance of the program are facilitated by releasing the program as open source software (General Public License) currently at http://nmr.imsb.au.dk. The general features of the program are demonstrated by numerical simulations of various aspects for REDOR, rotational resonance, DRAMA, DRAWS, HORROR, C7, TEDOR, POST-C7, CW decoupling, TPPM, F-SLG, SLF, SEMA-CP, PISEMA, RFDR, QCPMG-MAS, and MQ-MAS experiments.

The use of deuterium n.m.r. spectroscopy in mechanistic studies of exchange reactions of ethers on supported metal catalysts

International Nuclear Information System (INIS)

Campbell, J.A.; Kemball, Charles; McDougall, G.S.

1987-01-01

Exchange reactions of diethyl ether (DEE) and tetrahydrofuran (THF) with deuterium have been studied over supported nickel, palladium, platinum, and rhodium catalysts. Products from most of the systems were analysed by deuterium n.m.r. spectroscopy (55.28 MHz) which gave quantitative results about the distribution of deuterium in the exchanged ethers. The results confirm earlier conclusions about the mechanism of the exchange of DEE and provide new evidence about the reactions of THF. Some hydrogenolysis occurred simultaneously with exchange of THF over both nickel and platinum. (author)

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.

Nuclear magnetic resonance spectroscopy for determining the functional content of organic aerosols: A review

International Nuclear Information System (INIS)

Chalbot, Marie-Cecile G.; Kavouras, Ilias G.

2014-01-01

The knowledge deficit of organic aerosol (OA) composition has been identified as the most important factor limiting our understanding of the atmospheric fate and implications of aerosol. The efforts to chemically characterize OA include the increasing utilization of nuclear magnetic resonance spectroscopy (NMR). Since 1998, the functional composition of different types, sizes and fractions of OA has been studied with one-dimensional, two-dimensional and solid state proton and carbon-13 NMR. This led to the use of functional group ratios to reconcile the most important sources of OA, including secondary organic aerosol and initial source apportionment using positive matrix factorization. Future research efforts may be directed towards the optimization of experimental parameters, detailed NMR experiments and analysis by pattern recognition methods to identify the chemical components, determination of the NMR fingerprints of OA sources and solid state NMR to study the content of OA as a whole. - Highlights: • Organic aerosol composition by 1 H- and 13 C-NMR spectroscopy. • NMR fingerprints of specific sources, types and sizes of organic aerosol. • Source reconciliation and apportionment using NMR spectroscopy. • Research priorities towards understanding organic aerosol composition and origin. - This review presents the recent advances on the characterization of organic aerosol composition using nuclear magnetic resonance spectroscopy

Quality of spelt pasta enriched with eggs and identification of eggs using 13C MAS NMR spectroscopy

Directory of Open Access Journals (Sweden)

Filipović Jelena S.

2015-01-01

Full Text Available This paper deals with the characteristics of spelt pasta enriched with eggs. Eggs were added to spelt farina in the quantity of 0, 124 or 248 g/kg (equivalent to 0, 3 or 6 eggs, respectively. Post-hoc Tukey’s HSD test at 95% confidence limit showed significant differences between various samples. Relatively low coefficients of variation have been obtained for each applied assay (1.25-12.42%, which confirmed the high accuracy measurements and statistically significant results. Standard score analysis is applied for accessing the contribution of eggs content to spelt pasta quality. Maximum scores regarding quality (0.89 and chemical characteristics (0.70, have been obtained for 6 eggs spelt pasta formulation. It is also shown that the presence of eggs in pasta can be clearly confirmed by 13C MAS NMR spectroscopy. Simultaneous increase in area of peak positioned at 29.5 and 176 ppm is directly associated with the increase in the content of added eggs in the corresponding samples. Pertinent data point at positive contribution of eggs to the spelt pasta and also that NMR spectrum can be used in the egg quantity control. [Projekat Ministarstva nauke Republike Srbije, br. TRI 46005 i br. TR 31029

Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy

Science.gov (United States)

2009-01-01

Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline calcium (alumino-)silicate hydrate (Al-CSH) forms as a precursor solid to the cement mineral tobermorite. Rate constants for tobermorite growth were found to be k = 0.6 (± 0.1) × 10-5 s-1 for a solution:solid of 10:1 and 1.6 (± 0.8) × 10-4 s-1 for a solution:solid of 5:1 (batch mode; T = 150°C). This data indicates that reaction rates for tobermorite growth are faster when the solution volume is reduced by half, suggesting that rates are dependent on solution saturation and that the Gibbs free energy is the reaction driver. However, calculated solution saturation indexes for Al-CSH and tobermorite differ by less than one log unit, which is within the measured uncertainty. Based on this data, we consider both heterogeneous nucleation as the thermodynamic driver and internal restructuring as possible mechanistic pathways for growth. We also use NMR spectroscopy to characterize the site symmetry and bonding environment of Al and Si in a reacted tobermorite sample. We find two [4]Al coordination structures at δiso = 59.9 ppm and 66.3 ppm with quadrupolar product parameters (PQ) of 0.21 MHz and 0.10 MHz (± 0.08) from 27Al 3Q-MAS NMR and speculate on the Al occupancy of framework sites by probing the protonation environment of Al metal centers using 27Al{1H}CP-MAS NMR. PMID:19144195

NMR spectroscopy of muscle proteins; Spektroskopia MRJ bialek miesniowych

Energy Technology Data Exchange (ETDEWEB)

Slosarek, G. [Inst. Fizyki, Univ. A. Mickiewicza, Poznan (Poland)

1995-12-31

Author reviews various experimental techniques used for study of the structure of muscle proteins. Difficulties of application of NMR are described. Studies of the influence of Ca{sup 2+} on flexibility of actin polymer are presented. 11 refs, 3 figs.