Complex tissue microstructure involving various types of cells and their membranes can deviate the movement of water molecules from the typical Gaussian diffusion. This deviation can be quantified using excess kurtosis to characterize tissue structural complexity. However, true kurtosis measurements can be obscured by complex white matter configurations such as fiber crossing, bending, and branching, which are ubiquitous in the brain. In this paper, we extend diffusion kurtosis imaging (DKI) to allow characterization of diffusional kurtosis in microstructural environments that are oriented heterogeneously. Our method, called microscopic DKI (DKI), fits a cylindrically symmetric kurtosis model to the spherical mean of the diffusion signal as a function of diffusion weighting. The spherical mean, computed for each -shell, is invariant to the fiber orientation distribution and is a function of per-axon microstructural properties. Experimental results indicate that DKI yields significantly higher consistency in quantifying microstructure than the conventional DKI in the presence of orientation heterogeneity.
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http://dx.doi.org/10.1007/978-3-030-32248-9_62 | DOI Listing |
Chaos
January 2025
Department of Applied Mathematics, College of Applied Sciences, Kyung Hee University, Yongin 17104, Republic of Korea.
Investment in resources is essential for facilitating information dissemination in real-world contexts, and comprehending the influence of resource allocation on information dissemination is, thus, crucial for the efficacy of collaborative networks. Nonetheless, current studies on information dissemination frequently fail to clarify the complex interplay between information distribution and resources in network contexts. In this work, we establish a resource-based information dissemination model to identify the complex interplay by examining the propagation threshold and equilibriums.
View Article and Find Full Text PDFChaos
January 2025
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Spirals are a special class of excitable waves that have its significance in the understanding of cardiac arrests and neuronal transduction. In a theoretical model of the chemical Belousov-Zhabotinsky reaction system, we explore the dynamics of the spatiotemporal patterns that emerge out of competing reaction and diffusion phenomena. By modifying the existing mathematical models of the reaction kinetics, we have been able to explore the explicit effect of hydrogen ion concentration in the system, so as to achieve various regimes of wave activity, from stable spirals to oscillation death.
View Article and Find Full Text PDFChaos
January 2025
Centre for Complex Systems, School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.
Since groundbreaking works in the 1980s it is well-known that simple deterministic dynamical systems can display intermittent dynamics and weak chaos leading to anomalous diffusion. A paradigmatic example is the Pomeau-Manneville (PM) map which, suitably lifted onto the whole real line, was shown to generate superdiffusion that can be reproduced by stochastic Lévy walks (LWs). Here, we report that this matching only holds for parameter values of the PM map that are of Lebesgue measure zero in its two-dimensional parameter space.
View Article and Find Full Text PDFNeurology
February 2025
Department of Neurology, Department of Stroke, University Hospital Cleveland Medical Center, Case Western Reserve University, Cleveland, OH.
Background And Objectives: Although previous trials have established the efficacy and safety of endovascular thrombectomy (EVT) in large ischemic core strokes, most of them excluded patients with extracranial internal carotid artery (e-ICA) occlusion. We aimed to compare outcomes in patients with e-ICA occlusion and large ischemic core infarcts treated with EVT vs medical management (MM).
Methods: This was a secondary analysis of the SELECT2 trial, a randomized controlled trial conducted at 31 international sites.
Blood
January 2025
University of Chicago, Chicago, Illinois, United States.
Most diffuse large B-cell lymphoma (DLBCL) patients treated with immunotherapies such as bispecific antibodies (BsAb) or chimeric antigen receptor (CAR) T cells fail to achieve durable treatment responses, underscoring the need for a deeper understanding of mechanisms that regulate the immune environment and response to treatment. Here, an integrative, multi-omic approach was applied to multiple large independent datasets in order to characterize DLBCL immune environments, and to define their association with tumor cell-intrinsic genomic alterations and outcomes to CD19-directed CAR T-cell and CD20 x CD3 BsAb therapies. This approach effectively segregated DLBCLs into four immune quadrants (IQ) defined by cell-of-origin and immune-related gene set expression scores.
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