Results 81 to 90 of about 94,222 (207)

Interaction of Dirac δ$$ \delta $$‐Waves in the Inviscid Levine and Sleeman Chemotaxis Model

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT This article investigates interactions of δ$$ \delta $$‐shock waves in the inviscid Levine and Sleeman chemotaxis model ut−λ(uv)x=0$$ {u}_t-\lambda {(uv)}_x=0 $$, vt−ux=0$$ {v}_t-{u}_x=0 $$. The analysis employs a distributional product and a solution concept that extends the classical solution concept.
Adelino Paiva
wiley   +1 more source

Analytical Solutions for the Cardiac Extracellular‐Membrane‐Intracellular Model

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT The cardiac extracellular‐membrane‐intracellular (EMI) model is a novel mathematical framework for cardiac electrophysiology simulations. The cardiac EMI model provides a more detailed description of the heart's electrical activity compared to traditional monodomain and bidomain models, potentially making it better‐suited for understanding the
Carlos Ballesteros, Alexei Cheviakov, Raymond J. Spiteri   +2 more
wiley   +1 more source

Existence Analysis of a Three‐Species Memristor Drift‐Diffusion System Coupled to Electric Networks

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT The existence of global weak solutions to a partial‐differential‐algebraic system is proved. The system consists of the drift‐diffusion equations for the electron, hole, and oxide vacancy densities in a memristor device, the Poisson equation for the electric potential, and the differential‐algebraic equations for an electric network.
Ansgar Jüngel, Tuấn Tùng Nguyến
wiley   +1 more source

From Stability to Chaos: A Complete Classification of the Damped Klein‐Gordon Dynamics

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT We investigate the transition between stability and chaos in the damped Klein‐Gordon equation, a fundamental model for wave propagation and energy dissipation. Using semigroup methods and spectral criteria, we derive explicit thresholds that determine when the system exhibits asymptotic stability and when it displays strong chaotic dynamics ...
Carlos Lizama, Marina Murillo‐Arcila, Julio Puerta‐Fernández   +2 more
wiley   +1 more source

Dynamic Contrast Enhanced—Magnetic Resonance Fingerprinting (DCE‐MRF) Improves Detection of Induced Vascular Perfusion Reduction in a Mouse Breast Cancer Model

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Dynamic contrast‐enhanced MRI (DCE‐MRI) can assess tumor perfusion using pharmacokinetic models. However, poor DCE‐MRI reproducibility from reliance on conventional T1‐weighted MRI has limited clinical translation. We evaluated whether Dynamic Contrast Enhanced‐Magnetic Resonance Fingerprinting (DCE‐MRF), which directly generates ...
Christina J. MacAskill, Bernadette O. Erokwu, Yuran Zhu, Guanhua Wang, Andrew Dupuis, Barbara J. Schiemann, Gopalakrishnan Ramamurthy, Chetan B. Dhakan, Michael Kavran, Chunying Wu, William P. Schiemann, Yilun Sun, Mark A. Griswold, Xin Yu, Mark D. Pagel, Chris A. Flask   +15 more
wiley   +1 more source

MoCo + ROVir: Synergy Between Respiratory Motion Compensation and Cardiac Receive Region Focusing for Cardiac MRI

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To improve cardiac motion representation and reduce artifacts for cardiac‐ and respiratory‐resolved imaging through a synergistic combination of retrospective cardiac phased array RF focusing and rigid respiratory motion compensation (MoCo).
Zheyuan Hu, Hsu‐Lei Lee, Tianle Cao, Takegawa Yoshida, Lingceng Ma, J. Paul Finn, Kim‐Lien Nguyen, Anthony G. Christodoulou   +7 more
wiley   +1 more source

Free‐Running Three‐Dimensional Cardiac Extracellular Volume Mapping in a Single Scan With Mid‐Scan Contrast Injection

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To develop a new method for free‐running three‐dimensional (3D) extracellular volume mapping of the heart in a single scan with mid‐scan contrast injection. Methods 3D cardiac MR imaging was performed with a single scan that acquired k‐space data continuously using an inversion recovery (IR) sequence with a spoiled gradient‐echo ...
Wonil Lee, Paul Kyu Han, Thibault Marin, Ismaël B. G. Mounime, Didi Chi, Felicitas J. Bijari, Marc D. Normandin, Georges El Fakhri, Chao Ma   +8 more
wiley   +1 more source

Rosette Cardiac MR Fingerprinting for Simultaneous T1, T2, T2*$$ {\mathrm{T}}_2^{\ast } $$, and Fat Fraction Mapping Using a Multi‐Echo Deep Image Prior Reconstruction

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Quantitative mapping of cardiac tissue properties is used clinically in diagnosis and monitoring of a wide variety of cardiac pathologies. Cardiac Magnetic Resonance Fingerprinting (cMRF) enables rapid and simultaneous quantification of multiple parameters in the myocardium from a single scan.
Evan Cummings, Gastao Cruz, Jacob Richardson, Sydney Kaplan, Jesse Hamilton, Nicole Seiberlich   +5 more
wiley   +1 more source

A Numerical Alternative to MR Thermometry for Safety Validation of Multi‐Channel RF Transmit Coils

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose This study proposes a numerical technique to estimate peak local specific absorption rate (SAR) uncertainty of multi‐channel RF coils during the process of safety validation as an alternative to experimental temperature and electric‐field measurements, and demonstrates its use to enable human studies at 10.5 T.
Alireza Sadeghi‐Tarakameh, Simon Schmidt, Matt Waks, Russell L. Lagore, Andrea Grant, Edward Auerbach, Lance DelaBarre, Lasse Knudsen, Christophe Lenglet, Luca Vizioli, Essa Yacoub, Gregor Adriany, Gregory J. Metzger, Kamil Ugurbil, Yigitcan Eryaman   +14 more
wiley   +1 more source

Phase‐Pole‐Free Images and Smooth Coil Sensitivity Maps by Regularized Nonlinear Inversion

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Phase singularities are a common problem in image reconstruction with auto‐calibrated sensitivities due to an inherent ambiguity of the estimation problem. The purpose of this work is to develop a method for detecting and correcting phase poles in non‐linear inverse (NLINV) reconstruction of MR images and coil sensitivity maps ...
Moritz Blumenthal, Martin Uecker
wiley   +1 more source