Showing papers in "Solid State Nuclear Magnetic Resonance in 2004"

TL;DR: A new set of methods for transferring spin polarization between different nuclear isotopes in magic-angle-spinning solid-state NMR is demonstrated, particularly attractive for nuclei with low gyromagnetic ratios or for those experiencing strong anisotropic spin interactions, where conventional Hartmann-Hahn cross-polarization is difficult to apply.

TL;DR: A snapshot of the current state of development of (17)O solid-state NMR of biomolecules is provided and the structural sensitivity of the approach to effects such as hydrogen bonding highlighted.

TL;DR: The chemical-shift-anisotropy-based dephasing is particularly useful for distinguishing the signals of di-oxygenated alkyl (O-C-O) carbons, found for instance as anomeric carbons in carbohydrates, from bands of aromatic carbons with similar 13C isotropic chemical shifts.

TL;DR: MRI microscopy images of single biological cells with micron-scale resolution in all three dimensions are reported, including a spiral-shaped array of chloroplasts on the inner surface of the cell wall of a Spirogyra alga.

TL;DR: The overall pore size distributions determined by NMR are in reasonable agreement with the results specified by the manufacturer, or measured by us using the N2 sorption technique.

TL;DR: The proposed experiment, MQ-J-HETCOR, uses multiple quantum magic angle spinning (MQMAS) NMR for elimination of the second-order quadrupolar broadening and INEPT, INEPTR, InEPT+ and DEPT sequences for the polarization transfer.

TL;DR: A very simple method for reducing probehead background signal in one-pulse 1H nuclear magnetic resonance (NMR) spectra is presented and results show background suppression in 1H wideline as well as 1H fast magic-angle spinning (MAS) one-Pulse spectra of clay and polymer samples.

TL;DR: In this article, high-field 11 B MAS NMR gives well-resolved resonances from boron atoms which are 3-and 4-coordinated to oxygen.

TL;DR: The data reveal that substantial amount of the PO(4)(3-) groups at the P2 and P4 sites have been transformed to HPO( 4)(2-) in the authors' octacalcium phosphate sample.

TL;DR: This work presents a research carried out on a 17th century manuscript that appears possible to detect the alteration of the crystalline/amorphous cellulose balance and therefore to get information on some deterioration processes of paper.

TL;DR: The 2H NMR magic-angle spinning technique is compared to the static-powder quadrupole echo (QE) and Jeener-Brockaert pulse sequences for a quantitative investigation of molecular dynamics in solids and is found to be more sensitive to the presence of an inhomogeneous distribution of correlation times.

TL;DR: Compared to melt-cooling, the sol-gel process permits a significant extension of the glass-forming region towards higher alumina contents, and this has been confirmed by extensive ( 27)Al, (31)P and (23)Na MAS NMR as well as (27)Al[(31]P] and (27]Al [(1)H] double resonance experiments.

TL;DR: Electric field gradients (EFG) of 23Na and 27Al in three model fluoride crystalline powders AlF3, Na3AlF6 and Na5Al3F14 were computed using the density functional based electronic structure code WIEN97 and compared to values derived from nuclear magnetic resonance (NMR).

TL;DR: The results show that the tetracycline hydrochloride decreases the resistance of the HPMC network structure against the movement of solvent molecules, and on the other hand the swelling properties of the matrix increase with the amount of drug in the matrix.

TL;DR: Preliminary results were obtained on (87)Sr NMR showing behaviour comparable to (137)Ba NMR, i.e. a broadening of the peaks due to an increasing quadrupolar interaction with the amount of barium distorting the environment of the strontium sites.

TL;DR: The operating principles of a pulsed switched power supply for a fast field-cycling nuclear magnetic resonance spectrometer using a variant of a four-quadrant chopper with a duty cycle that defines the average output current is outlined.

TL;DR: A 3D spin-echo (3D SE) pulse sequence was used on a 4.7 T research MRI system to produce images of extracted human first molar tooth placed in CuSO4 water solution, producing very good contrast allowing to visualize topography of outer and inner surfaces of the tooth.

TL;DR: Solid state (33)S NMR is shown to be a feasible probe that can be applied to this problem that can readily distinguish different sulphur species.

TL;DR: The results show that under the given conditions SFG N MR and PFG NMR can provide tracer diffusion coefficients for 7 Li diffusion down to about 10(-14) and 10(-13) m2/s, respectively.

TL;DR: The (17)O NMR spectra of a partially metamict zircon sample clearly show evidence of bridging oxygens being produced as a consequence of radiation damage, and it is concluded that a 'routine' overnight NMR experiment of 15 h at high field may well be possible.

TL;DR: The dependence of the 1H spin-lattice relaxation time on the magnetic field strength has been determined for linear and cross-linked polyisoprene for Larmor frequencies between 5 kHz and 20 MHz.

TL;DR: In this article, Li-LSX was used to identify the framework oxygen atoms that form the β-cages and demonstrate the sensitivity of the 17O shifts to gas loading.

TL;DR: It is demonstrated that no well-defined peroxidized calcium species are formed in solution, showing that the catalytic role of calcium is likely restricted to the solid state.

TL;DR: NMR relaxometry data can help to identify details in the time course of cement hydration that possibly would be overlooked in other experiments with lower temporal resolution.

TL;DR: A set of homonuclear correlation experiments for half-integer quadrupolar spins in solids, demonstrated and compared, in view of their specific advantages and disadvantages, for 23Na in the model compound Na2SO3.

TL;DR: High-resolution NMR spectra of Tin-119 (and in one case phosphorus-31) shielding tensor data derived from MAS NMR are reported for four other crystalline tin(II) compounds, namely tin diphosphate, tin oxalate, Tin sulphate and calcium tin ethylenediamine tetraacetate.

TL;DR: The model-free approach to the analysis of 1H NMRD data was used to separate the information on the static and dynamic behaviour of the system provided by the dispersion profiles of the systems tested, and all mechanical spectra exhibited the gel like character, and the solid like response was more evident at higher concentrations of calcium cations.

TL;DR: It is demonstrated that the use of fast amplitude-modulated RF pulse trains with constant (FAM-I) and incremented pulse durations (SW-FAM) leads to considerable sensitivity enhancement for the central-transition signal for solid-state NMR spectra of titanium.

TL;DR: A prototype NMR probe for long RF pulse has been constructed and may be used in off-resonance experiments in which long and strong RF pulses are applied to the bigger coil and thereby the problem of the sample overheating is avoided.

TL;DR: An inexpensive spinning speed controller for use in magic-angle solid-state NMR experiments is described which can control the spinning rate to within +/- 0.2 Hz.