@article {1063,
	title = {Can PISEMA experiments be used to extract structural parameters for mobile beta-barrels?},
	journal = {Journal of Biomolecular Nmr},
	volume = {32},
	number = {2},
	year = {2005},
	note = {ISI Document Delivery No.: 948CRTimes Cited: 4Cited Reference Count: 42},
	month = {Jun},
	pages = {101-111},
	type = {Article},
	abstract = {The effect of mobility on N-15 chemical shift/N-15-H-1 dipolar coupling (PISEMA) solid state NMR experiments applied to macroscopically oriented beta-barrels is assessed using molecular dynamics simulation data of the NalP autotransporter domain embedded in a DMPC bilayer. In agreement with previous findings for alpha-helices, the fast librational motion of the peptide planes is found to have a considerable effect on the calculated PISEMA spectra. In addition, the dependence of the chemical shift anisotropy (CSA) and dipolar coupling parameters on the calculated spectra is evaluated specifically for the beta-barrel case. It is found that the precise choice of the value of the CSA parameters sigma(11), sigma(22) and sigma(33) has only a minor effect, whereas the choice of the CSA parameter theta shifts the position of the peaks by up to 20 ppm and changes the overall shape of the spectrum significantly. As was found for alpha-helices, the choice of the NH bond distance has a large effect on the dipolar coupling constant used for the calculations. Overall, it is found that the alternating beta-strands in the barrel occupy distinct regions of the PISEMA spectra, forming patterns which may prove useful in peak assignment.},
	keywords = {ANGLE-SPINNING NMR, ASSIGNMENT, COAT PROTEIN, CONSTRAINTS, DOMAIN, HELICAL WHEELS, MEMBRANE-PROTEINS, mobility of membrane beta-barrels, MOLECULAR-DYNAMICS SIMULATIONS, mosaic spread, PISEMA, SOLID-STATE NMR, SPECTROSCOPY, time averaging},
	isbn = {0925-2738},
	url = {<Go to ISI>://000230694100001},
	author = {Bleile, D. W. and Scott, W. R. P. and Straus, S. K.}
}
@article {610,
	title = {Influence of F content on the composition of Al-rich synthetic phlogopite: Part II. Probing the structural arrangement of aluminum in tetrahedral and octahedral layers by Al-27 MQMAS and H-1/F-19-Al-27 HETCOR and REDOR experiments},
	journal = {American Mineralogist},
	volume = {88},
	number = {7},
	year = {2003},
	note = {ISI Document Delivery No.: 699FDTimes Cited: 10Cited Reference Count: 28},
	month = {Jul},
	pages = {1046-1054},
	type = {Article},
	abstract = {The influence of F substitution on the local structure of Al in the tetrahedral and octahedral sheets of synthetic Al-rich phlogopite samples with nominal gel compositions of K(Mg3-xAlx)[Al1+xSi3-xO10] (OH)(y)(F)(2-y) between 0.0 less than or equal to x less than or equal to 0.8 and 0.5 less than or equal to y less than or equal to 1.8, was studied by Al-27 MAS, MQMAS, {H-1/F-19} {\textendash}> Al-27 2D CPMAS (HETCOR) and {H-1/F-19} Al-27 REDOR solid-state NMR and by IR spectroscopy. Changes in intensity of the absorption bands in the OH-stretching region of the IR spectra clearly indicate the incorporation of octahedral Al. Signals from the different phases can be separated in the Al-27 MQMAS NMR spectra by generation of an isotropic dimension in F1. The Al-27 quadrupolar parameters of the four phases were estimated from Al-27 MAS NMR spectra obtained at 104.26 and 208.42 MHz. The quadrupolar coupling constant and isotropic chemical shift increases with increasing Al content for the Al-IV site in phlogopite. The Al-VI site shows a clear increase of the asymmetry parameter and C-Q with increasing F content. The estimated Al-27 signal areas show the lowest amount of impurity phases at high OH contents and a stabilization of Al-VI sites by hydroxyl groups. The {H-1} {\textendash}> Al-27 2D CPMAS (HETCOR) NMR experiment at short contact times provides information about site neighborhoods of tetrahedral Al sites and Mg3OH as well as Mg2AlOH sites, whereas magnetization is only transferred to the octahedral At sites from hydroxyl groups in Mg2AlOH sites. The {F-19} {\textendash}> Al-27 2D CPMAS (HETCOR) NMR spectrum is dominated by Al-IV sites coupled to the Mg3F complex in phlogopite. Resonances from Mg2AlF complexes are not observed. Finally, the {H-1/F-19} Al-27 REDOR experiments support the results of the 2D CPMAS (HETCOR) experiments.},
	keywords = {ANGLE-SPINNING NMR, DOUBLE-RESONANCE, F-19 MAS-NMR, FLUORINE, HIGH-FIELD, NMR, QUADRUPOLAR NUCLEI, SI-29, SOLID-STATE NMR, SPECTRA, SUBSTITUTION},
	isbn = {0003-004X},
	url = {<Go to ISI>://000184045300013},
	author = {Fechtelkord, M. and Behrens, H. and Holtz, F. and Bretherton, J. L. and Fyfe, C. A. and Groat, L. A. and Raudsepp, M.}
}
@article {5079,
	title = {Solid-state NMR detection, characterization, and quantification of the multiple aluminum environments in US-Y catalysts by Al-27 MAS and MQMAS experiments at very high field},
	journal = {Journal of the American Chemical Society},
	volume = {123},
	number = {22},
	year = {2001},
	note = {ISI Document Delivery No.: 438ETTimes Cited: 47Cited Reference Count: 25},
	month = {Jun},
	pages = {5285-5291},
	type = {Article},
	abstract = {The detection of all of the aluminum present in steamed zeolite H-Y catalysts by Al-27 MAS NMR at 14.4 T (600 MHz for H-1) end 18.8T (800 MHz for H-1) is reported. Further, it is shown that it is possible Al MAS and MQMAS NMR measurements to clearly identify four separate aluminum environments which are characteristic of these materials and to unambiguously assign their coordinations. Average chemical shift and quadrupolar coupling parameters are used to accurately simulate the Al-27 MAS NMR spectra at 9.4 T (400 MHz for H-1), 14.4 T (600 MHz for H-1) and 18.8 T (800 MHz for H-1) in terms of these four aluminum environments. In addition, these:average chemical shift and quadrupolar coupling parameters are used to calculate peak positions in the Al-27 MQMAS isotropic dimension that are in good agreement with the experimental data acquired at 9.4 and 18.8 T.},
	keywords = {ACID SITES, ANGLE-SPINNING NMR, QUADRUPOLAR NUCLEI, SPECTROSCOPY, zeolites},
	isbn = {0002-7863},
	url = {<Go to ISI>://000169041300015},
	author = {Fyfe, C. A. and Bretherton, J. L. and Lam, L. Y.}
}
@article {4812,
	title = {Detection of the {\textquoteright}invisible aluminium{\textquoteright} and characterisation of the multiple aluminium environments in zeolite USY by high-field solid-state NMR},
	journal = {Chemical Communications},
	number = {17},
	year = {2000},
	note = {ISI Document Delivery No.: 347EQTimes Cited: 32Cited Reference Count: 16},
	pages = {1575-1576},
	type = {Article},
	abstract = {The detection of all of the aluminium present in steamed zeolite H-Y catalysts by Al-27 MAS NMR at high field (18.8 T, 800 MHz for H-1) is reported; further, it is shown that it is possible by Al-27 MAS and MQMAS measurements to clearly identify four separate aluminium environments characteristic of these materials and to unambiguously assign their coordinations.},
	keywords = {ACID SITES, AL-27 NMR, ANGLE-SPINNING NMR, H-Y ZEOLITES},
	isbn = {1359-7345},
	url = {<Go to ISI>://000088914800008},
	author = {Fyfe, C. A. and Bretherton, J. L. and Lam, L. Y.}
}
@article {4549,
	title = {Characterization of Na5P3O10 polymorphs by Na-23 MAS, Na-23 MQMAS, and P-31 MAS NMR spectroscopy},
	journal = {Inorganic Chemistry},
	volume = {38},
	number = {1},
	year = {1999},
	note = {ISI Document Delivery No.: 157MUTimes Cited: 20Cited Reference Count: 42},
	month = {Jan},
	pages = {84-92},
	type = {Article},
	abstract = {The two anhydrous polymorphs of Na5P3O10 have been characterized by Na-23 and P-31 MAS NMR spectroscopy, The Na-23 multiple-quantum (MQ) MAS NMR spectrum of the low-temperature form (phase II) displays three resonances for which the quadrupole coupling parameters and isotropic chemical shifts have been accurately determined from the MAS NMR spectra of the central transition. Thereby, discrepancies between recently reported Na-23 MQMAS spectra of this phase and the crystal structure have been clarified. The Na-23 resonances observed for the low-temperature form are assigned to the crystallographically nonequivalent Na sites in the crystal structure using point-monopole calculations of the electric-field gradient tensors. Three Na-23 resonances have also been observed for the high-temperature form (phase I), with two signals having very similar quadrupolar couplings and isotropic chemical shifts indicating similar coordination environments for the corresponding Na sites, in disagreement with the reported single-crystal structure. Point-monopole calculations of the electric-field gradient tensors based on the crystal structure fail to reproduce the experimental values. The P-31 chemical shielding anisotropies, obtained from P-31 MAS NMR spectra, show that the terminal P atoms of the P3O105- ions have a negative shielding anisotropy parameter (delta(sigma) = delta(iso) - delta(33)) in agreement with similar observations reported for diphosphates. This characteristic feature has been used in the assignment of the three P-31 resonances observed for the hexahydrate Na5P3O10. 6H(2)O.},
	keywords = {2-SPIN SYSTEMS, ANGLE-SPINNING NMR, CHEMICAL SHIELDING, CONDENSED PHOSPHATES, DIPOLAR, NUCLEAR-MAGNETIC-RESONANCE, QUADRUPOLAR NUCLEI, SODIUM TRIPHOSPHATE, SOLID-STATE, SPECTRA, TENSORS},
	isbn = {0020-1669},
	url = {<Go to ISI>://000078066900013},
	author = {Fyfe, C. A. and Altenschildesche, H. M. Z. and Skibsted, J.}
}
@article {4550,
	title = {A comparison of NMR distance determinations in the solid state by cross polarization, REDOR, and TEDOR techniques},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {77},
	number = {11},
	year = {1999},
	note = {ISI Document Delivery No.: 253FETimes Cited: 14Cited Reference Count: 64},
	month = {Nov},
	pages = {1984-1993},
	type = {Article},
	abstract = {Solid-state NMR distance determinations using Hartmann-Hahn cross polarization between spin-1/2 nuclei (F-19/Si-29) are reported. F-19 {\textendash}> Si-29 polarization transfer for the T-1 silicon site in the clathrasil octadecasil shows an oscillatory behaviour as a function of the contact time. These oscillations were observed for non-spinning powder samples and also for different spinning speeds at the various MAS sideband matching conditions. Three analytical functions that allow efficient nonlinear least-square regression analyses of the experimental data to determine the internuclear distances for non-spinning powder samples as well as at the +/-1 and +/-2 MAS sideband matching conditions are reported. Using these functions, a F-19-Si-29 distance of 2.53 +/- 0.04 Angstrom was determined for the T-1 silicon in octadecasil from fitting of the oscillatory behaviour. This distance is in good agreement with that known from the X-ray structure and the previous F-19/Si-29 REDOR and TEDOR distance measurements. The advantages and limits of the different dipolar-based NMR techniques for heteronuclear distance determinations are examined and discussed.},
	keywords = {ANGLE-SPINNING NMR, cross polarization (CP), DISTANCE, distances F-19-Si-29, HELICAL PEPTIDE, HETERONUCLEAR DIPOLAR, interactions, INTERATOMIC, LOCK, NMR distance measurements, NUCLEAR-MAGNETIC-RESONANCE, octadecasil, PROTON-ENHANCED NMR, REDOR, ROTATIONAL-ECHO, SEQUENCES, SPIN-1/2 NUCLEI, TEDOR, TRANSIENT OSCILLATIONS},
	isbn = {0008-4042},
	url = {<Go to ISI>://000083545300032},
	author = {Fyfe, C. A. and Lewis, A. R. and Chezeau, J. M.}
}
