Sökning: "diffusion measurements"

Visar resultat 1 - 5 av 395 avhandlingar innehållade orden diffusion measurements.

  1. 1. Diffusion in Bone Tissue

    Författare :Gustav Lindberg; Hållfasthetslära; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bone growth; diffusion; stress enhanced; finite element method; steady-state; periosteal membrane; diffusion in bovine bone; diffusion experiment; Conductivity measurement; Fick’s law; Fourier series; Kalman filter; transient solution;

    Sammanfattning : In order to prevent or modify the processes of bone degeneration the modeling and remodeling of bone tissue must be better understood. In this thesis it is assumed that the primary condition leading to bone growth is a change of the chemical environment caused by transport of matter resulting from stress driven diffusion. LÄS MER

  3. 2. Pushing diffusion MRI towards new dimensions

    Författare :Joao Martins; Fysikalisk kemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NMR; MRI; diffusion; relaxation; multidimensional diffusion MRI; relaxation-diffusion correlations; Laplace NMR; porous media; tissue microstructure; heterogeneity; anisotropy;

    Sammanfattning : Diffusion-MRI techniques allow the non-invasive investigation of microstructural changes in living tissues. However, a detailed interpretation of the data is complicated by the fact that multiple microscopic environments with varying diffusion properties all contribute to the measured signal. LÄS MER

  4. 3. Applications of diffusion MRI: Tensor-valued encoding, time-dependent diffusion, and histological validation

    Författare :Jan Brabec; Lund Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; diffusion MRI; meningioma; glioma; brain tumors; intracranial tumors; undulations; restricted diffusion; time dependence; spherical b-tensor encoding; linear b-tensor encoding; histogram analysis; anisotropic kurtosis; isotropic kurtosis; hyperintensity; conspicuity; white matter; detection; diffusion spectrum; consistency; type; grade; axon diameter; axonal trajectories; Fysicumarkivet A:2022:Brabec;

    Sammanfattning : Diffusion MRI (dMRI) sensitizes the MR signal to the diffusion of water molecules at the microscopic level and thereby non-invasively probes tissue microstructure. This is relevant when determining biological properties of tissues, for example, cancer type and its malignancy. LÄS MER

  5. 4. Quantitative methods for diffusion measurements in fluorescence microscopy

    Författare :Marco Longfils; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cross-validation.; single particle tracking; Confocal laser scanning microscopy; raster scan; correlation spectroscopy; mixture models; diffusion;

    Sammanfattning : In this work, statistical methods are developed for mapping mass transport locally based on images collected using a confocal laser scanning microscope. Besides presenting raster image correlation spectroscopy as an established method in fluorescence microscopy, we introduce a single particle tracking method which takes advantage of the raster scanning of the image in a confocal microscope. LÄS MER

  7. 5. Investigation of Water Mobility using Diffusion-Sensitive MRI: The Role of q-Space Imaging, High b-Values and Diffusion Time

    Författare :Jimmy Lätt; Lund Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MRI; kurtosis; high b-value; diffusion; diffusion time; NMR; q-space;

    Sammanfattning : Nuclear magnetic resonance (NMR) diffusometry provides important information about molecular motion on a microscopic scale. The advantage of NMR diffusometry is its ability to characterise microstructures non-invasively. This has made the method important not only in chemistry, biochemistry and materials science, but also in medicine. LÄS MER