Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"restricted diffusion"”.
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Electrostatic effects on the restricted diffusion of macromolecules
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981.
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High-Resolution Nuclear Magnetic Resonance Microspectroscopy
… predictions were shown regarding the effects of restricted diffusion in microcoils. Diffusion-ordered spectroscopy (DOSY) experiments, which allow spectral simplification arising from differences in diffusion coefficient, coupled with conventional chemical shift and scalar coupling differences, …
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Exploring Tissue Microstructure in Healthy and Diseased Lung Tissue
… divided into two parts. The first part examines diffusion in a number of human lung samples, while the second deals with diffusion in the more simplified environment of a single capillary tube. In the lung study we examine various types of lung samples: healthy and diseased) at a variety of …
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Multiscale Tortuous Diffusion in Anion- and Cation-Exchange Membranes: Exploration of Counterions, Water Content, and Polymer Functionality
… (PFG) NMR diffusometry. Water diffusion in both AEMs and CEMs exhibit specific trends as a function of water uptake (wt%), indicating morphological similarities across common chemical structures. Furthermore, restricted diffusion reveals micron-scale heterogeneity of the …
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Anomalous diffusion in anisotropic media
… was investigated by pulsed field gradient diffusion NMR and complementary deuterium line shape analysis. Restricted diffusion was studied in two lyotropic lamellar systems, the first consisting of crosslinked flat lamellae in anisotropic hydrogels and the second consisting of spherically …
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Automated Quality Assurance for Magnetic Resonance Imaging with Extensions to Diffusion Tensor Imaging
… this date, no QA procedure has been reported for Diffusion Tensor Imaging (DTI). Therefore, the secondary goal of this thesis was to develop a DTI QA procedure that assess two of the associated features used most in diagnosis, namely, diffusion anisotropy and the direction of primary diffusion. To …
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Magnetic resonance microscopy
… second part of this work studied the effects of restricted diffusion on the appearance of magnetic resonance microscopy images. A scaling law was used to predict the onset of motional narrowing effects for given values of diffusion, length, gradient strength, and gyromagnetic ratio. Barriers to …
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Development and physical characterisation of polyethylene glycol glycerides-based gel formulations for macromolecule delivery
… low water contents are characterised by highly restricted diffusion of water molecules in the gels, while water-rich and lipid-rich phases are present in the gels with medium to high water contents. The ordered liquid crystalline structures with lipid-rich and water-rich domains provide …
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Investigation of the actin-membrane interaction at the leading edge and its influence on membrane diffusion
… of protruding fish keratocytes functions as a diffusion^M barrier for lipid dyes.^M The aim of the here presented thesis was to continue this project and to study the actin-membrane interaction at the leading edge, using the diffusion barrier^M as an initial read-out method. First it was …
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Characterising Heterogeneity of Glioblastoma using Multi-parametric Magnetic Resonance Imaging
… sub-region with decreased isotropic diffusion and increased anisotropic diffusion was associated with progression-free survival (PFS, hazard ratio [HR] = 1.08, P < 0.001) and overall survival (OS, HR = 1.36, P < 0.001) in multivariate models. II. Using a thresholding method, two low …
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NMR Applications in Soft Materials Science: Correlation of Structure, Dynamics, and Transport
… of ²³Na solid-state NMR, ¹H/²H PFG NMR diffusion, relaxation and grazing-incidence small-angle X-ray scattering. Our results show that the liquid crystalline domains in these materials undergo a transition from columnar to bicontinuous cubic phases with a simple increase in humidity, …
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Novel approaches to MRI of glioma
… as well as changes in the tissue microstructure. Diffusion-Weighted Imaging (DWI) and the apparent diffusion coefficient (ADC), have been extensively studied as potential imaging biomarkers for cellularity and tissue architecture. However, several studies have shown partial overlap in the measured …