Diffusion-weighted magnetic resonance imaging (DW-MRI) is a novel imaging technique that reflects microscopic water diffusion using a pair of strong diffusion gradients. It was developed to map the apparent diffusion coefficient (ADC) (1). Parallel to the development of DW-MRI, there have been advances in Dynamic contrast-enhanced MRI (DCEMRI). Using the MRI signal and pharmacokinetic models, p...

The technique of fluorescence recovery after photobleaching is used to perform an extensive study of the lateral diffusion of a phospholipid probe in the binary mixture dimyristoylphosphatidylcholine/cholesterol, above the melting temperature of the phospholipid. In the regions of the phase diagram where a single liquid phase exists, diffusion can be quantitatively described by free volume theo...

In the theory of the ceramic densification process the starting point is that the material transport consists mainly of diffusion processes. At least three different contributions are however distingutshable : volume diffusion, grain boundary diffusion and surface difksionl. For volume diffusion it has been shown tbeorctica& that in ionic compounds an optimal delusion rate can bc obtained by ap...

The permeability of the swimbladder to gas was measured as the conductance to oxygen in seven species of fish. The low over-all conductance resides in the low diffusion constant, K, of the middle layer of the wall (submucosa) while the outer and inner layers (tunica externa and mucosa) have diffusion constants similar to other vertebrate tissues. The low diffusion constant is due to a low diffu...

BACKGROUND AND PURPOSE This study was designed to analyze whether early diffusion-weighted imaging (DWI) provides reliable quantitative information for the prediction of stroke patients at risk of malignant brain infarct. METHODS We selected 28 patients with a middle cerebral artery (MCA) infarct and proven MCA or carotid T occlusion on DWI and MRI angiography performed within 14 hours after ...

OBJECTIVE To compare the accuracy of Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and CT perfusion to detect established infarction in acute anterior circulation stroke. METHODS We performed an observational study in 59 acute anterior circulation ischemic stroke patients who underwent brain noncontrast CT, CT perfusion, and MRI within 100 minutes from CT imaging. ASPECTS s...

Deformation mechanisms involving mass transport by stress driven diffusion influence a large number of technological problems. We study the formation of undulations on surfaces of stressed films at high temperature by exploring the deformation kinetics governed by volume and surface diffusion. A governing equation is derived that gives the amplitude change of such surfaces as a function of time...

In this paper, a nonlinear control volume finite element (CVFE) scheme for a degenerate Keller– Segel model with anisotropic and heterogeneous diffusion tensors is proposed and analyzed. In this scheme, degrees of freedom are assigned to vertices of a primal triangular mesh, as in finite element methods. The diffusion term which involves an anisotropic and heterogeneous tensor is discretized on...

Rendering refraction in volume visualization requires smoothly distributed normals to synthesize good quality visual representations. Such refractive visualizations are more susceptible to noise in the data than visualizations that do not involve refraction. In this paper, we present the first study to investigate convolution and diffusion methods with respect to this problem, highlighting the ...

The self-diffusion of myoglobin in concentrated solutions was investigated up to volume fractions of 0.4 by neutron back-scattering spectroscopy. The quasi-elastic spectrum can be decomposed into two Lorentz curves: (1) a narrow line, where the width increases with Q, which is assigned to translational diffusion, and (2) a broad Q-independent line, reflecting proteininternal motions. The appare...