Described here are systems and methods for reconstructing images from multi-level sampled data acquired with a magnetic resonance imaging (MRI) system. An alternating direction method-of multipliers (ADMM) strategy is implemented for sparse reconstruction of multi-level sampled data, and which decomposes the reconstruction problem into simpler subproblems and enables certain operations to be computed once offline and recycled during the reconstruction process rather than repeated at every iteration. As one example, the described reconstruction technique enables sparse reconstruction of 3D contrast-enhanced MR angiogram time-series in just several minutes rather than the several hours previously required.

Described here are systems and methods for reconstructing images from multi-level sampled data acquired with a magnetic resonance imaging (MRI) system. An alternating direction method-of multipliers (ADMM) strategy is implemented for sparse reconstruction of multi-level sampled data, and which decomposes the reconstruction problem into simpler subproblems and enables certain operations to be computed once offline and recycled during the reconstruction process rather than repeated at every iteration. As one example, the described reconstruction technique enables sparse reconstruction of 3D contrast-enhanced MR angiogram time-series in just several minutes rather than the several hours previously required.

The presence of hydrocarbons in a subsurface formation fluid may be inferred from a determined salt concentration. A sodium nuclear magnetic resonance (NMR) measurement of a subsurface formation is obtained and a salt concentration of the fluid in the subsurface formation is determined from the sodium NMR measurement. Various operations may be performed using the determined salt concentration such as tracking injected water, monitoring flood fronts, improving reserves estimation, and designing enhanced oil recovery. A sodium index may be determined and used in conjunction with one or more other logs to determine a saturation of the subsurface formation. The one or more other logs may include a resistivity log, a dielectric log, a capture cross section (sigma) log, and a proton NMR log. Differentiation between bound water and free water can also be achieved using the sodium nuclear magnetic resonance measurement.

The presence of hydrocarbons in a subsurface formation fluid may be inferred from a determined salt concentration. A sodium nuclear magnetic resonance (NMR) measurement of a subsurface formation is obtained and a salt concentration of the fluid in the subsurface formation is determined from the sodium NMR measurement. Various operations may be performed using the determined salt concentration such as tracking injected water, monitoring flood fronts, improving reserves estimation, and designing enhanced oil recovery. A sodium index may be determined and used in conjunction with one or more other logs to determine a saturation of the subsurface formation. The one or more other logs may include a resistivity log, a dielectric log, a capture cross section (sigma) log, and a proton NMR log. Differentiation between bound water and free water can also be achieved using the sodium nuclear magnetic resonance measurement.

A method and imaging system is provided that can control a magnetic gradient system and an RF system of an MRI system according to a calibration pulse sequence to acquire positive readout gradient (RO+) data and negative readout gradient (RO−) data. The RO+ data and the RQ− data are assembled to form complete image data sets for the RO+ data and the RQ™ data and the RO+ data and the RO− data are combined to generate the calibration data that is ghost-corrected, substantially free of ghost artifacts, or having reduced ghost artifacts compared to traditionally-acquired calibration data. Reconstruction coefficients are derived from the calibration data. The magnetic gradient system and the RF system are controlled according to an imaging pulse sequence to acquire image data and the image data is reconstructed into an image of the subject using the reconstruction coefficients.

Apparatus and methods for characterizing hydrocarbons in a subterranean formation include obtaining a sample of the subterranean formation; measuring, uphole, the porosity of the sample; using a nuclear magnetic resonance (NMR) tool downhole in the borehole, sending NMR pulse sequences configured for formation pore size and measuring NMR signals that characterize the formation at a location in the formation; analyzing the signals to find a gas porosity of the formation at the location; and determining a hydrogen index (HI.sub.g) of the subterranean formation from the gas porosity and from the porosity of the sample. The obtained HI.sub.g may then be used in conjunction with downhole NMR measurements to find corrected gas porosities at locations of the formation.

Apparatus and methods for characterizing hydrocarbons in a subterranean formation include obtaining a sample of the subterranean formation; measuring, uphole, the porosity of the sample; using a nuclear magnetic resonance (NMR) tool downhole in the borehole, sending NMR pulse sequences configured for formation pore size and measuring NMR signals that characterize the formation at a location in the formation; analyzing the signals to find a gas porosity of the formation at the location; and determining a hydrogen index (HI.sub.g) of the subterranean formation from the gas porosity and from the porosity of the sample. The obtained HI.sub.g may then be used in conjunction with downhole NMR measurements to find corrected gas porosities at locations of the formation.

Described herein are salts of 3-[(dimethylamino)methyl]-N-{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide, in particular that of formula (I):

##STR00001##

wherein HA is naphthalene-1,5-disulfonic acid, naphthalene-2-sulfonic acid, oxalic acid, benzenesulfonic acid, or sulfuric acid, or hydrates thereof, and crystalline forms thereof characterized by the powder X-ray diffraction diagram and the 13C CP/MAS NMR solid state spectrum. Also described are compositions, methods of use and preparation thereof.

Described herein are salts of 3-[(dimethylamino)methyl]-N-{2-[4-(hydroxycarbamoyl)phenoxy]ethyl}-1-benzofuran-2-carboxamide, in particular that of formula (I):

##STR00001##

wherein HA is naphthalene-1,5-disulfonic acid, naphthalene-2-sulfonic acid, oxalic acid, benzenesulfonic acid, or sulfuric acid, or hydrates thereof, and crystalline forms thereof characterized by the powder X-ray diffraction diagram and the 13C CP/MAS NMR solid state spectrum. Also described are compositions, methods of use and preparation thereof.

A transmission line array is used for explosive/contraband detection using nuclear quadrupole resonance in which the array is driven in-phase with synchrony frequency-swept signals. Each of the balanced transmission lines is fed with a low power swept frequency source and stimulated emissions are picked out with a directional coupler. Location is provided using a cross grid array or a phase detector is used for each balanced line, with phase determining the distance to the sensed substance.