The GNAT (General NMR Analysis Toolbox) is a free and open-source software package for processing, visualising, and analysing NMR data. It supersedes the popular DOSY Toolbox, which has a narrower focus on diffusion NMR. Data import of most common formats from the major NMR platforms is supported, as well as a GNAT generic format.
View Article and Find Full Text PDFNuclear magnetic resonance rheology (Rheo-NMR) is a valuable tool for studying the transport of suspended non-colloidal particles, important in many commercial processes. The Rheo-NMR imaging technique directly and quantitatively measures fluid displacement as a function of radial position. However, the high field magnets typically used in these experiments are unsuitable for the industrial environment and significantly hinder the measurement of shear stress.
View Article and Find Full Text PDFWe present an experimental and numerical study of transport in carbonates during dissolution and its upscaling from the pore (∼μm) to core (∼cm) scale. For the experimental part, we use nuclear magnetic resonance (NMR) to probe molecular displacements (propagators) of an aqueous hydrochloric acid (HCl) solution through a Ketton limestone core. A series of propagator profiles are obtained at a large number of spatial points along the core at multiple time-steps during dissolution.
View Article and Find Full Text PDFNMR propagator measurements are widely used for identifying the distribution of molecular displacements over a given observation time, characterising a flowing system. However, where high q-space resolution is required, the experiments are time consuming and therefore unsuited to the study of dynamic systems. Here, it is shown that with an appropriately sampled subset of the q-space points in a high-resolution flow propagator measurement, one can quickly and robustly reconstruct the fully sampled propagator through interpolation of the acquired raw data.
View Article and Find Full Text PDFBackground: Several treatment options exist for type 2 diabetes, but little is known about the factors considered by health care providers (HCPs) and patients in Canada in making therapeutic decisions. This study explores perceptions and practices of HCPs and patients related to add-on (i.e.
View Article and Find Full Text PDFPurpose: Whether improving the efficiency of hospital care will worsen post-discharge outcomes is unclear. We designed this study to evaluate the General Internal Medicine (GIM) Care Transformation Initiative implemented at one of the seven teaching hospitals in the Canadian province of Alberta.
Methods: Controlled before-after study of GIM patients hospitalised at the University of Alberta Hospital (UAH, intervention site, n=1896) or the six other teaching hospitals in Alberta-three in Edmonton (intra-regional controls (IRC), n=4550) and three in Calgary (extra-regional controls (ERC), n=4095).
Diffusion-ordered spectroscopy (DOSY) is one of the most powerful methods for intact mixture analysis by NMR. However, the separation of overlapped spectra by current DOSY methods typically requires a minimum of 30% difference in diffusion coefficient. Here we present a new algorithm (OUTSCORE) that can improve the situation by almost an order of magnitude, allowing the unmixing of severely overlapped species of similar size, by combining least squares fitting with cross-talk minimisation, maximising spectral difference.
View Article and Find Full Text PDFObtaining diffusion coefficients from PFG NMR diffusion (a.k.a DOSY) data is, in the general case, an ill-posed problem.
View Article and Find Full Text PDFAn increase in the resolving power in 2D NMR spectra is obtained by collapsing 2D signals with multiplet structure into 2D singlets. This resolution gain is achieved by combining 2D experiments with pure shift techniques and covariance processing (see picture). The method should be of value in both manual and automated structure determination.
View Article and Find Full Text PDFDiffusion-ordered spectroscopy (DOSY) is an important tool in NMR mixture analysis that has found use in most areas of chemistry, including organic synthesis, drug discovery, and supramolecular chemistry. Typically the aim is to disentangle the overlaid, and often overlapped, NMR spectra of individual mixture components and/or to obtain size and interaction information from their respective diffusion coefficients. The most common processing method, high-resolution DOSY, breaks down where component spectra overlap; here multivariate methods can be very effective, but only for small numbers (2-5) of components.
View Article and Find Full Text PDF