Time saving in 13C spin-lattice relaxation measurements by inversion-recovery

Canet, Daniel; Levy, George C.; Peat, I. R.

doi:10.1016/0022-2364(75)90238-3

Cited by 245 publications

(135 citation statements)

References 3 publications

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“…The total LV myocardial mass (TMM) was determined by counting all myocardial pixels, and calculating the voxel mass (m v ) from the voxel size (1.17 ⅐ 1.17 ⅐ 10 mm 3 ) and myocardial specific gravity of 1.05 g/cm 3 . R 1 values were calculated pixel-by-pixel from the SI vs. TI dependence, applying three-parameter, nonlinear, least-squares curve-fitting (40,41):…”

Section: Image Processing and Generation Of The Pimmentioning

confidence: 99%

Percent infarct mapping: An R₁‐map‐based CE‐MRI method for determining myocardial viability distribution

Surányi

Kiss

Brott

et al. 2006

Magnetic Resonance in Med

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Section: Image Processing and Generation Of The Pimmentioning

confidence: 99%

Percent infarct mapping: An R₁‐map‐based CE‐MRI method for determining myocardial viability distribution

Surányi

Kiss

Brott

et al. 2006

Magnetic Resonance in Med

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“…T, values were determined on the perfused samples by the FIRFT method (5). The FIRFT technique was thoroughly compared with the standard, slower inversion-recovery method (25) on Pi solutions to ensure that identical relaxation values could be obtained with the former.…”

Section: Relaxation Measurementsmentioning

confidence: 99%

³¹P Relaxation Responses Associated with N₂/O₂ Diffusion in Soybean Nodule Cortical Cells and Excised Cortical Tissue

Pfeffer

Kumosinski²,

MacFall³

et al. 1992

Plant Physiol.

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N2-fixing Bradyrhizobium japonicum nodules and cortical tissue derived from these nodules were examined in vivo by 31P nuclear magnetic resonance (NMR) spectroscopy. Perfusion of the viable nodules and excised cortical tissue with 02 followed by N2 or Ar caused a loss of orthophosphate (Pi) resonance magnetization associated with the major portion of acidic Pi (5 0.9 ppm, pH 5.5) residing in the cortical cells. Soybean nodules contain three cortical cell layers (44% of the nodule volume) (28), an outer cortex, an endodermis, and an inner cortex. The inner cortex functions as a diffusion barrier to balance inward oxygen flux with bacteroid respiratory oxygen demand (15,20,31,32). Tjepkema and Yocum (29) and later Witty et al. (34) verified that the oxygen concentration decreased across the cortical layer until it reached a minimum at the inner cortex, the presumed major barrier to gas diffusion. Numerous investigators (2,7,8,11,27,28) have examined the diffusion of 02 through this barrier and have proposed that the sites of entry are air spaces filled with water the depth of which can be varied through expansion or contraction of the adjacent inner cortex cells. On the other hand, Witty and coworkers (26, 34) have speculated that cell expansion into the intercellular space is responsible for restricting the passage of 02 into the inner nodule in response to diminished respiration. VandenBosch et al. (30) and Bradley et al. (3) observed a unique glycoprotein in the infection thread matrix and intercellular space of pea nodules. Further investigation of this material in soybean nodules by James and coworkers (9) demonstrated that its elaboration was greatly enhanced in the presence of oxygen. These authors (9) hypothesized that this 'occlusion protein' is responsible for increasing 02 diffusion resistance in the cortical cell layer by blocking the intercellular air spaces.At present the nature of the oxygen-regulating miechanism(s) associated with the cortical layer is controversial. In this and the accompanying paper (12), we describe relaxation data obtained from 31P NMR spectroscopy and 'H magnetic resonance imaging studies that suggest that increasing viscosity resulting from the production of cortical cell glycoprotein may be associated with enhanced 02 diffusion resistance in soybean (Glycine max) nodules. MATERIALS AND METHODS

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“…[8] simplifies to When T, = T, or A = 1 then the spectral density for the rigid isotropic case is recovered.…”

Section: Theorymentioning

confidence: 99%

“…They also constitute valuable tools as coating antigens in enzyme-linked immunosorbent assays (ELISA). In this technique, the water-soluble glycopolymers are adsorbed by hydrophobic interactions to 'presented at the XVIth International Carbohydrate Symposium, Paris, France, July [5][6][7][8][9][10]1992.…”

Section: Introductionmentioning

confidence: 99%

Global and internal molecular dynamics of poly(acrylamide-co-allyl 2-acetamido-2-deoxy-D-glucopyranoside) glycopolymers from ¹³C NMR relaxation studies

Roy¹,

Tropper²,

Williams³

et al. 1993

Can. J. Chem.

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."C spin-lattice and spin-spin relaxation times and nuclear Overhauser enhancements have been used to examine the molecular dynamics of the a-(1) and P-(2) anomeric forms of poly(acry1amide-co-ally1 2-acetamido-2-deoxy-D-glucopyranoside) glycopolymers. The timescale of motions and the spatial restriction of these motions were determined by using various forms of the "model-free" approach. It is shown that the motions of the C-H vectors of the polymer backbone may be described by a scaled Lorentzian spectral density function, giving rise to an effective correlation time for overall tumbling. The temperature dependence of this correlation time suggests that the overall motion is dependent on viscosity. The overall motion of the polymer molecules is shown to be anisotropic in nature by including the spinspin relaxation data in the analysis. The N-acetyl methyl and sugar hydroxymethyl (Ch) groups exhibit internal motions. The activation energies associated with these internal motions are derived. The difference in relaxation rates between the a and p anomeric forms, though small, suggests that the motions of the sugar ring may be different for the two systems. This conclusion is supported by potential energy contour map calculations, which indicate that the P anomer (2) has almost twice the conformational flexibility of the a anomer (1).RENE ROY, FRANCOIS D. TROPPER, ANTONY J. WILLIAMS et JEAN-ROBERT BRISSON. Can. J. Chem. 71, 1995Chem. 71, (1993.On a utilisk les temps de relaxation spin-rCseau et spin-spin en RMN du "C ainsi que des expCriences d'effets Overhauser nucleaires pour Ctudier la dynamique moleculaire des fonnes anomkres a (1) et P (2) des glycopolymkres poly(acry1amide- co-2-acetarnido-2-dCsoxy-~-glucopyranoside d'allyle). On a determink l'ordre de grandeur des vitesses des mouvements et de la restriction spaciale de ces mouvements en faisant appel i diverses fonnes de l'approche ((non-modklisCe)).On a montrC que l'on peut dkcrire les mouvement des vecteurs C-H de la structure de polymkre par une fonction de Lorentz de densite spectrale qui donne lieu B une correlation efficace du temps de renversement global. La relation entre la temperature et ce temps de corrClation suggkre que le mouvement global depend de la viscositC. En incluant les donnCes de relaxation spin-spin dans l'analyse, on montre que le mouvement global de la mol&cule est naturellement anisotrope. Les groupes N-acCtylmCthyle et hydromethyle (Ch) du sucre presentent des mouvements internes. On a dCduit les energies d'activation associees ii ces mouvements internes. Les differences dans les vitesses de relaxation entre les formes anomkres a et p, mcme si elles sont faibles, suggkrent que les mouvements du cycle du sucre peuvent ktre diffkrents pour les deux systkmes. Cette conclusion est en accord avec les calculs des cartes de contour de 1'Cnergie potentielle qui indiquent que la flexibilitk de l'anomkre P (2) est deux fois plus grandes que celle de l'anomkre a (1).[Traduit par la redaction]

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Time saving in 13C spin-lattice relaxation measurements by inversion-recovery

Cited by 245 publications

References 3 publications

Percent infarct mapping: An R₁‐map‐based CE‐MRI method for determining myocardial viability distribution

Percent infarct mapping: An R₁‐map‐based CE‐MRI method for determining myocardial viability distribution

³¹P Relaxation Responses Associated with N₂/O₂ Diffusion in Soybean Nodule Cortical Cells and Excised Cortical Tissue

Global and internal molecular dynamics of poly(acrylamide-co-allyl 2-acetamido-2-deoxy-D-glucopyranoside) glycopolymers from ¹³C NMR relaxation studies

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Time saving in 13C spin-lattice relaxation measurements by inversion-recovery

Cited by 245 publications

References 3 publications

Percent infarct mapping: An R1‐map‐based CE‐MRI method for determining myocardial viability distribution

Percent infarct mapping: An R1‐map‐based CE‐MRI method for determining myocardial viability distribution

31P Relaxation Responses Associated with N2/O2 Diffusion in Soybean Nodule Cortical Cells and Excised Cortical Tissue

Global and internal molecular dynamics of poly(acrylamide-co-allyl 2-acetamido-2-deoxy-D-glucopyranoside) glycopolymers from 13C NMR relaxation studies

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Percent infarct mapping: An R₁‐map‐based CE‐MRI method for determining myocardial viability distribution

Percent infarct mapping: An R₁‐map‐based CE‐MRI method for determining myocardial viability distribution

³¹P Relaxation Responses Associated with N₂/O₂ Diffusion in Soybean Nodule Cortical Cells and Excised Cortical Tissue

Global and internal molecular dynamics of poly(acrylamide-co-allyl 2-acetamido-2-deoxy-D-glucopyranoside) glycopolymers from ¹³C NMR relaxation studies