نتایج جستجو برای: diffusivity

تعداد نتایج: 8606  

Journal: :AJNR. American journal of neuroradiology 2015
M Mascalchi N Toschi M Giannelli A Ginestroni R Della Nave E Nicolai A Bianchi C Tessa E Salvatore M Aiello A Soricelli S Diciotti

BACKGROUND AND PURPOSE The ability of DTI to track the progression of microstructural damage in patients with inherited ataxias has not been explored so far. We performed a longitudinal DTI study in patients with spinocerebellar ataxia type 2. MATERIALS AND METHODS Ten patients with spinocerebellar ataxia type 2 and 16 healthy age-matched controls were examined twice with DTI (mean time betwe...

2002
DONALD B. DINGWELL

Dingwell, D.B., 1990. Effects of structural relaxation on cationic tracer diffusion in silicate melts. Chem. Geol., 82: 209-216. The glass transition in silicate melts is a curve in time-temperature space marking the transition of the melt structure from an unrelaxed, disequilibrium glass to a relaxed, equilibrium liquid. Tracer diffusivity data obtained in glasses vs. liquids cannot be compare...

Monir Taherkhani Peyman Pourafshary,

  Diffusivity equation commonly used for pressure distribution prediction in porous media results from substituting equation of state and continuity equation in Navier-Stokes momentum equation. From mathematical point of view this equation format shows infinite propagation speed for pressure pulse through porous media, which is physically impossible. This issue may caused by numerous assumption...

In this study rhubarb stem slices were dried as single layers with thickness of 3 mm in the inlet air temperature range of 50-70  and air velocity of 1 ± 0.2 m/s in a laboratory scale cabinet dryer. The effect of drying air temperature on the drying characteristics was determined and the relationship between the drying parameters with temperature and moisture content was examined. Moisture tran...

2007
Douglas M. Ruthven

The formal solution to the diffusion equation for transient adsorption in a semiinfinite medium with a strongly concentration dependent diffusivity, originally derived by Fujita ( 3 , has been extended to desorption. Profiles for adsorption and desorption are compared and simplified asymptotic expressions which are useful when the diffusivity ratio is large are derived. The effect of a strongly...

2010
Patrick Freund Claudia Wheeler-Kingshott Jonathan Jackson David Miller Alan Thompson Olga Ciccarelli

BACKGROUND The aim of this study was to determine whether the diffusion tensor-derived radial diffusivity and axial diffusivity, measured in the cortico-spinal tract in the cervical cord, predict clinical recovery after a cord relapse in patients with multiple sclerosis, and change over time. METHODS Fourteen patients were clinically assessed at the onset of a cervical cord relapse and after ...

Journal: :AJNR. American journal of neuroradiology 2015
A Tietze M B Hansen L Østergaard S N Jespersen R Sangill T E Lund M Geneser M Hjelm B Hansen

BACKGROUND AND PURPOSE Diffusional kurtosis imaging is an MR imaging technique that provides microstructural information in biologic systems. Its application in clinical studies, however, is hampered by long acquisition and postprocessing times. We evaluated a new and fast (2 minutes 46 seconds) diffusional kurtosis imaging method with regard to glioma grading, compared it with conventional dif...

2004
Y.Liu A. Mandelis N. Baddour C. H. Wang

A method to image near-surface hardness profiles of heat-treated case-hardened steels using laser infrared photothermal radiometric phase imaging is described. It is shown that thermophysical and mechanical transverse inhomogeneity profiles in industrial case hardened steel samples are well correlated. Phase surface scanning imaging leads to a practical criterion for assessing transverse hardne...

Journal: :NeuroImage 2011
Eric C. Klawiter Robert E. Schmidt Kathryn Trinkaus Hsiao-Fang Liang Matthew D. Budde Robert T. Naismith Sheng-Kwei Song Anne H. Cross Tammie L. Benzinger

OBJECTIVE Correlation of diffusion tensor imaging (DTI) with histochemical staining for demyelination and axonal damage in multiple sclerosis (MS) ex vivo human cervical spinal cords. BACKGROUND In MS, demyelination, axonal degeneration, and inflammation contribute to disease pathogenesis to variable degrees. Based upon in vivo animal studies with acute injury and histopathologic correlation,...

Journal: :AJNR. American journal of neuroradiology 2017
X Ou C M Glasier R H Ramakrishnaiah A Kanfi A C Rowell R T Pivik A Andres M A Cleves T M Badger

BACKGROUND AND PURPOSE Studies on infants and children born preterm have shown that adequate gestational length is critical for brain white matter development. Less is known regarding how variations in gestational age at birth in term infants and children affect white matter development, which was evaluated in this study. MATERIALS AND METHODS Using DTI tract-based spatial statistics methods,...

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