We revisit the definition of the diffusion coefficient for light transport in scattering and absorbing media. From an asymptotic analysis of the transport equation, we present a novel derivation of the diffusion coefficient, which is restricted neither to low absorption nor to a situation in which the specific intensity is quasi-isotropic. Our result agrees with previous expressions of the diffusion coefficient in the appropriate limit. Using numerical simulations, we discuss the implications of the proper choice of the diffusion coefficient for time-dependent transport.
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http://dx.doi.org/10.1364/josaa.20.000678 | DOI Listing |
Radiologie (Heidelb)
January 2025
Department of Radiology, Bezmialem Vakıf University, Istanbul, Turkey.
Purpose: To determine whether there is a difference in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values in white matter pathways in the subacute period after COVID-19 infection and to evaluate the correlation between diffusion tensor imaging (DTI) metrics and laboratory findings.
Material And Methods: The study included 64 healthy controls and 91 patients. Patients were classified as group 1 (all patients, n = 91), group 2 (outpatients, n = 58), or group 3 (inpatients, n = 33).
Acta Radiol
January 2025
Radiology Department, Third Affiliated Hospital of Zhengzhou University, Zhengzhou City, PR China.
Background: Cerebral infarction is one of the most common diseases. Diffusion tensor imaging (DTI) has been used to evaluate for crossed cerebellar diaschisis (CCD) to observe the expression of repulsive guidance molecule a (RGMa), the axonal regeneration as well as the effect on neural functional recovery in the middle cerebral artery occlusion (MCAO) rat model.
Purpose: To certify the expression pattern of RGMa in cerebral infarction and the mechanism of CCD to provide a new target for clinical therapy.
J Phys Chem B
January 2025
Engineering Research Center of Membrane and Water Treatment of MOE, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
Polyamide (PA) membranes are widely utilized in desalination and water treatment applications, yet the mechanisms underlying water transport within these amorphous polymer materials remain insufficiently understood. To gain more insight into these problems on a microscopic scale, we employ molecular dynamics (MD) simulations to analyze the relationship between the structural properties and the water permeation behavior of PA membranes. Two distinct atomistic models of PA membranes are developed by controlling their degrees of cross-linking (DC).
View Article and Find Full Text PDFBrain Imaging Behav
January 2025
Macquarie Medical School, Macquarie University, Sydney, NSW, Australia.
Magnetic resonance imaging (MRI) is frequently used to monitor disease progression in multiple sclerosis (MS). This study aims to systematically evaluate the correlation between MRI measures and histopathological changes, including demyelination, axonal loss, and gliosis, in the central nervous system of MS patients. We systematically reviewed post-mortem histological studies evaluating myelin density, axonal loss, and gliosis using quantitative imaging in MS.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
January 2025
The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China.
Purpose: The study explores the role of multimodal imaging techniques, such as [F]F-PSMA-1007 PET/CT and multiparametric MRI (mpMRI), in predicting the ISUP (International Society of Urological Pathology) grading of prostate cancer. The goal is to enhance diagnostic accuracy and improve clinical decision-making by integrating these advanced imaging modalities with clinical variables. In particular, the study investigates the application of few-shot learning to address the challenge of limited data in prostate cancer imaging, which is often a common issue in medical research.
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