Showing papers in "Journal of Magnetic Resonance in 1983"

TL;DR: In this paper, the correlation of 1H and 15N chemical shifts based on zero and double quantum NMR is discussed. And the indirect determination of nitrogen shifts from the proton signals provides a dramatic gain in sensitivity over direct observation of 15N signals, and examples are given of applications of the methods to samples with natural abundance 15N concentration and to a sample of 0.7 mM 65% 15N enriched tRNA in H2O.

TL;DR: In this paper, the effects of the proton irradiation sequence by means of a train of spin rotation operators, the overall effect at the end of the cycle being calculated by explicit matrix multiplication, the offset dependence of this proton response determined the residual splitting of the carbon-13 resonance and hence the effectiveness of the decoupling.

TL;DR: New pulse sequences for solvent suppression in Fourier transform NMR are derived and evaluated, and the most satisfactory sequences consist of equally spaced hard pulses with lengths in the ratio of binomial coefficients and phases alternating between 0 and 180°.

TL;DR: In this article, a new scheme for low-power broadband heteronuclear decoupling is described, based on the use of a composite radiofrequency pulse sequence 90°( + X ) 180°(− X ) 270°(+ X ), incorporated into a repeated cycle or supercycle.

TL;DR: In this article, the authors proposed an approach to homonuclear broadband decoupling for semiselective heteronuclear J spectroscopy, where all protons which are not directly attached to a 13C nucleus experience an effect as if a nonselective 180" pulse were applied, while protons bonded to a r3C nucleus are not affected.

TL;DR: In this article, a phase-cycling scheme is proposed to prevent spectral distortion due to misset pulse lengths, and the theoretical single pulse and echo distortion factors are demonstrated to differ from those which were determined for quadrupolar echo spectroscopy.

TL;DR: In this article, a propagator representation is used for visualizing the mean features of molecular diffusion in biporous systems as, e.g., a powder sample of zeolite crystallites.

TL;DR: In this paper, it was shown that the π refocusing pulses can be cycled through all four phases as described by Bodenhausen et al. (J. Magn. Reson. 16, 467 (1974)) for inversion-recovery T1 measurements.

TL;DR: In this paper, it is shown that the cross-relaxation rates between pairs of bound ligand protons and between a ligand proton and a proton of the protein in the ligand-protein complex can be determined directly and with ease from the initial slopes of the time dependent transferred nuclear Overhauser effect (TRNOE), thus enabling distance ratios between any two such pairs of protons or, if one of the interproton distances is known, interpropton distances to be calculated (on the assumption of a single correlation time for all the corresponding

TL;DR: The methode de transfert de coherence relayee was introduced in this paper for analyser des systemes de spins couples, and ses avantages dans l'analyse des spectres de complexes de proteines sont analyses.

TL;DR: In this paper, the powder spectrum was modified to enable its application to a wider range of systems, such as quadrupolar, dipolar, and anisotropic chemical or Knight shift interactions.

TL;DR: In this article, three modified polarization transfer techniques, INEPT+, DEPT+, and DEPT++, are introduced for the elimination of distortions in proton-coupled spectra of low-gyromagnetic-ratio spins.

TL;DR: In this paper, the authors proposed a new method of obtaining proton NMR spectra of dilute solutes in H20, which suppresses the intense water resonance by more than three orders of magnitude.

TL;DR: In this paper, a new two-dimensional approach for obtaining the anisotropy information is proposed, where the spinning axis of the sample is flipped from 90 to 54.7° between the evolution and detection periods.

TL;DR: The 13C CP-MAS experiment as discussed by the authors is the most widely applied solid state NMR experiment in recent years, but it suffers from a limitation that it eliminates the potentially useful information embodied in the chemical shift anisotropy pattern.

TL;DR: In this article, a low-pass J filtering technique was proposed to suppress neighbor peaks in the relayed correlation spectra of glucose in an equilibrated mixt. of a and b anomers.

TL;DR: In this paper, the use of multiple tuned radiofrequency coils is described as a method for obtaining absolute in vivo metabolite concentrations explicitly from high resolution chemical shift spectra and zeugmatographic spin images recorded using pulse Fourier transform NMR.

TL;DR: In this paper, a simple procedure is described for constructing composite pulses of arbitrary flip angle which are compensated to an arbitrarily high degree for pulse imperfections, and the performance of some population inversion pulse sequences is tested experimentally.

TL;DR: In this article, an algorithme simple for decrire les valeurs dependant du temps d'un systeme de spin sans relaxation durant l'experience d'impulsions multiples is presented.

TL;DR: In this article, the errors involved in using DEPT over the normal range of aliphatic and aromatic 1J13C-1H, values are assessed by analyzing DEPT with variable time delay periods using the Heisenberg quantum picture approach.

TL;DR: In this article, a theoretical analysis of correlated motions for methine (CH), methylene (CH 2 ), and methyl (CH 3 ) groups for the situation when the 'H magnetization vectors are initially placed in the transverse plane of the doubly rotating frame and are allowed to precess freely for (2 J ) −1 sec, where J is the single-bond 1 H-13 C coupling constant, prior to the carbon polarization transfer vectors being placed in a transverse planes.

TL;DR: In this paper, the authors propose a method to compensate for telles imperfections by constriction d'impulsions melangees, i.e., constrains of impulsions that se trouvent souvent imparfaites.

TL;DR: In this article, the double-quantum frequency (6, + 6x) was measured in a two-dimensional NMR experiment where the doublequantum coherence was allowed to evolve for a variable period t, (4, 5).