Article
Mathematics, Applied
Oleg Davydov, Dang Thi Oanh, Ngo Manh Tuong
Summary: We present a geometric stencil selection algorithm for the Laplacian in 3D, which improves upon octant-based selection methods. The algorithm aims to choose a small subset of irregular points surrounding a given point to obtain an accurate numerical differentiation formula. This subset is utilized as an influence set for numerical approximations of the Laplacian using polynomial or kernel-based techniques. Numerical experiments demonstrate the competitiveness of this method in solving the Dirichlet problems for the Poisson equation on various STL models. Discretization nodes are obtained through 3D triangulations, Cartesian grids, or Halton quasi-random sequences.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2023)
Article
Gastroenterology & Hepatology
Henry Han, Leo K. Cheng, Niranchan Paskaranandavadivel
Summary: A high-resolution multi-channel suction electrode array was developed and applied in vivo to record monophasic gastric slow waves, which had a more pronounced recovery phase with a higher gradient compared to biphasic slow waves. The recovery phase analysis of monophasic signals could be performed more efficiently due to the more identifiable recovery phases.
NEUROGASTROENTEROLOGY AND MOTILITY
(2022)
Article
Engineering, Biomedical
Henry Han, Leo K. Cheng, Recep Avci, Niranchan Paskaranandavadivel
Summary: In this study, a new bipolar velocity estimation method was developed to rapidly and efficiently estimate gastric slow wave wavefront velocities with minimal errors. This is of great significance for understanding and studying the coordination mechanism of gastrointestinal motility.
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
(2022)
Article
Biology
Chad E. Eichler, Leo K. Cheng, Niranchan Paskaranandavadivel, Peng Du, Leonard A. Bradshaw, Recep Avci
Summary: The study found that higher density and coverage sensor layouts in magnetogastrography (MGG) improve the utility of tracking slow wave (SW) propagation. Further research is needed to explore the optimal sensor configurations across larger anatomical variations and other SW propagation patterns.
COMPUTERS IN BIOLOGY AND MEDICINE
(2021)
Article
Mathematics, Applied
Xindong Zhang, Lin Yao, Juan Liu
Summary: The article proposes a two-level mesh method for solving the nonlinear Fisher's equation, using global radial basis function method and radial basis function-finite difference method on coarse and fine meshes respectively. The numerical results demonstrate the method is highly effective.
APPLIED MATHEMATICS LETTERS
(2021)
Article
Computer Science, Artificial Intelligence
M. Lalu, K. Phaneendra, Siva Prasad Emineni
Summary: A numerical approach is proposed for differential-difference equations with small and large delays, utilizing non-polynomial spline and singular perturbation theory. The method is validated by tabulating maximum errors in the solution and focusing on the impact of large delays on solution behavior. The study also explores the effect of fitting parameter on solution layer using special mesh configurations.
Article
Engineering, Electrical & Electronic
Igor Tsukerman
Summary: The article examines local approximation errors of finite-difference schemes in electromagnetic analysis and proposes two novel methods for comparison. It concludes that a loss of accuracy for Yee-like schemes at slanted material boundaries is unavoidable.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Guiting Chen, Zhenming Peng, Yalin Li
Summary: The paper proposes a framework for automatically choosing FD parameters to achieve the optimal FD scheme in acoustic wave modeling. Taking computational efficiency into consideration, the framework provides the maximum admissible time step under stability conditions and finds suitable parameters to ensure sufficient wavenumber bandwidth for the FD scheme.
COMPUTERS & GEOSCIENCES
(2022)
Article
Engineering, Multidisciplinary
Aasma Khalid, Abdul Ghaffar, M. Nawaz Naeem, Kottakkaran Sooppy Nisar, Dumitru Baleanu
Summary: This paper describes the precise results obtained by solving 6th and 8th-order nonlinear boundary-value problems using Cubic-Nonpolynomial spline (CNPS) and Cubic-polynomial spline (CPS). A class of numerical techniques is developed to simplify the problem to a new system consisting of 2nd-order BVPs, with comparisons made to exact solutions for accuracy validation. The results show that CNPS and CPS provide more accurate responses compared to other techniques.
ALEXANDRIA ENGINEERING JOURNAL
(2021)
Article
Engineering, Geological
Mrinal Bhaumik, Tarun Naskar
Summary: A non-uniform dispersive staggered grid scheme is proposed to accurately model soil properties in ground exploration techniques. This method significantly reduces computing time without sacrificing accuracy and is superior to traditional uniform and velocity dependent grid approaches.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
S. Clain, D. Lopes, R. M. S. Pereira
Summary: An arbitrary order finite difference method for curved boundary domains with Cartesian grid is proposed, which can handle Dirichlet, Neumann or Robin conditions in a universal manner. The method introduces the Reconstruction Off-site Data (ROD) method to transfer information from the physical boundary to the computational domain through polynomial functions. Three major advantages include simple description of the physical boundary with Robin condition, no requirement for analytical expressions, and splitting the boundary treatment and resolution of the interior problem into two independent parts. Numerical evidence shows the method's capability to reach at least 6th-order accuracy with arbitrary smooth domains.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Geochemistry & Geophysics
Jun Wang, Yongxin Gao, Wei Guan, Hengshan Hu
Summary: Experimental and theoretical studies have shown that a slow compressional wave in a fluid-saturated porous medium can generate a seismoelectric signal, providing a feasible method for detecting the properties of the slow compressional wave.
Article
Mathematics, Applied
Michael Chapwanya, Phindile Dumani
Summary: This paper investigates the physiological structure of microbial communities in natural environments, which is typically a response to changes in internal and external conditions. The study includes a spatio-temporal bacterioplankton-nutrient interaction model that considers the quiescent stage. The paper explores the conditions for microbial population oscillations and the existence of traveling wavefronts in the proposed reaction-diffusion model, supported by qualitative analysis and simulations.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Computer Science, Interdisciplinary Applications
Kushal Dhar Dwivedi, Jagdev Singh
Summary: A new finite difference collocation algorithm utilizing Fibonacci polynomial was introduced and applied to a super diffusion problem and two sub-diffusion problems with exact solutions. It was demonstrated that the numerical error obtained from this method is more accurate than previously existing methods. The study also solved a fractional order reaction advection sub-diffusion equation and discussed the effects of parameter changes in the model with graphical representation.
MATHEMATICS AND COMPUTERS IN SIMULATION
(2021)
Article
Physics, Multidisciplinary
Sergey R. Kamaletdinov, Ian H. Hutchinson, Ivan Y. Vasko, Anton Artemyev, Ajay Lotekar, Forrest Mozer
Summary: Observations show a large number of slow electron holes with speeds clustered near the local minimum of double-humped velocity distribution functions of background ions, which can avoid acceleration under certain circumstances according to theoretical calculations. The origin of these slow electron holes remains elusive, but the agreement between observation and theory regarding the conditions for their existence is remarkable.
PHYSICAL REVIEW LETTERS
(2021)
Article
Gastroenterology & Hepatology
Zahra Aghababaie, Leo K. Cheng, Niranchan Paskaranandavadivel, Recep Avci, Chih-Hsiang Alexander Chan, Ashton Matthee, Satya Amirapu, Samuel J. Asirvatham, Gianrico Farrugia, Arthur Beyder, Gregory O'Grady, Timothy R. Angeli-Gordon
Summary: This study introduces gastric ablation as a new tool for modulating gastric bioelectrical activation, including eliminating both normal and abnormal pacemaker sites underlying gastric dysrhythmias. Targeted radiofrequency ablation successfully eliminated these pacemaker sites without disrupting the surrounding conduction capability or tissue structure. Gastric ablation presents a powerful new research tool for modulating gastric electrical activation and may hold therapeutic potential for disorders of gastric function.
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
(2022)
Article
Computer Science, Interdisciplinary Applications
Luman Wang, Avinash Malik, Partha S. Roop, Leo K. Cheng, Niranchan Paskaranandavadivel
Summary: This paper presents a closed-loop Gastric Electrical Stimulator (GES) design framework that can sense and modulate dysrhythmic patterns in the gastrointestinal tract. The efficacy of the design framework is validated using an ICC network model to mimic experimental recordings.
COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE
(2022)
Article
Engineering, Biomedical
Jaime E. Lara, Leo K. Cheng, Oliver Roehrle, Niranchan Paskaranandavadivel
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
(2022)
Article
Engineering, Biomedical
Sachira Kuruppu, Leo K. Cheng, Poul M. F. Nielsen, Thiranja P. Babarenda Gamage, Recep Avci, Timothy R. Angeli, Niranchan Paskaranandavadivel
Summary: This study developed a method to quantify strain fields from in vivo intestinal motility recordings and successfully reduced tracking error accumulation through the use of a nonlinear optimization scheme. The method was able to map intestinal activity and analyze intestinal contractions quantitatively, providing significant insights into the regulatory mechanisms of intestinal motility.
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
(2022)
Article
Engineering, Biomedical
Henry Han, Leo K. Cheng, Recep Avci, Niranchan Paskaranandavadivel
Summary: In this study, a new bipolar velocity estimation method was developed to rapidly and efficiently estimate gastric slow wave wavefront velocities with minimal errors. This is of great significance for understanding and studying the coordination mechanism of gastrointestinal motility.
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
(2022)
Review
Gastroenterology & Hepatology
Nipuni D. Nagahawatte, Leo K. Cheng, Recep Avci, Timothy R. Angeli-Gordon, Niranchan Paskaranandavadivel
Summary: Small intestine pacing has therapeutic potential in treating disorders such as short bowel syndrome and obesity. This systematic review proposes standardized protocols to maximize research outcomes and aims to translate research findings to human clinical validation.
NEUROGASTROENTEROLOGY AND MOTILITY
(2023)
Article
Gastroenterology & Hepatology
Nipuni D. Nagahawatte, Recep Avci, Niranchan Paskaranandavadivel, Timothy R. Angeli-Gordon, Leo K. Cheng
Summary: The study presents a high-resolution framework for simultaneous pacing and response mapping of the small intestine. A novel surface-contact electrode array was developed and applied in vivo on pigs, achieving successful pacing and mapping of the pacing response. The study identified effective pacing parameters for slow-wave entrainment in the jejunum and showed no tissue damage from the pacing.
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
(2023)
Article
Biology
Nipuni D. Nagahawatte, Niranchan Paskaranandavadivel, Laura R. Bear, Recep Avci, Leo K. Cheng
Summary: Electroceuticals offer clinical solutions for various disorders and a new signal processing framework has been developed to isolate and suppress stimulation artifacts in bio-electrical recordings. The autoregression method showed superior artifact removal in experimental recordings compared to linear interpolation and weighted mean approaches.
COMPUTERS IN BIOLOGY AND MEDICINE
(2023)
Article
Engineering, Biomedical
Chad E. Drake, Leo K. Cheng, Niranchan Paskaranandavadivel, Saeed Alighaleh, Timothy R. Angeli-Gordon, Peng Du, Leonard A. Bradshaw, Recep Avci
Summary: Bioelectric slow waves regulate gastrointestinal motility, and disordered activity is linked to motility disorders. A method for reconstructing 3D stomach geometry from coil localization was developed and validated using anatomically realistic models and in-vivo pig studies. The proposed method could enable investigation of novel analysis techniques.
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
(2023)
Article
Gastroenterology & Hepatology
Lukasz Wiklendt, Reizal Mohd Rosli, Raghu Kumar, Niranchan Paskaranandavadivel, Peter A. Bampton, Lyn Maslen, Marcello Costa, Simon J. Brookes, Greg O'Grady, Phil G. Dinning
Summary: Patients with IBS-D have altered colonic motility and reduced prevalence of the retrograde cyclic motor pattern compared with healthy adults. The reduction in retrograde propagation may lead to premature rectal filling and result in postprandial urgency and diarrhea.
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
(2023)
Article
Gastroenterology & Hepatology
Chris Varghese, Xavier Harvey, Armen A. Gharibans, Peng Du, Rowan Collinson, Ian P. Bissett, Cathy M. Stinear, Greg O'Grady, Niranchan Paskaranandavadivel
Summary: By developing a high-density electromyography (HD-EMG) probe in conjunction with trans-sacral magnetic stimulation (TSMS), we have created a novel diagnostic tool for assessing anorectal function. The spatiotemporal evaluation of magnetically stimulated motor-evoked potentials correlated well with symptoms, offering a feasible, safe, and patient-tolerable method for evaluating pudendal nerve and external anal sphincter function.
COLORECTAL DISEASE
(2023)
Article
Biology
Chad E. Drake, Leo K. Cheng, Nicole D. Muszynski, Suseela Somarajan, Niranchan Paskaranandavadivel, Timothy R. Angeli-Gordon, Peng Du, Leonard A. Bradshaw, Recep Avci
Summary: This article introduces a novel method for measuring gastric motility using bioelectric slow waves and biomagnetic slow waves. The feasibility of the method was verified by conducting experiments on two anesthetized pigs, which showed that the method enables quantitative spatial co-registration of gastric activity and analysis based on anatomical structures.
COMPUTERS IN BIOLOGY AND MEDICINE
(2023)
Article
Engineering, Biomedical
Saeed Hosseini, Recep Avci, Niranchan Paskaranandavadivel, Vinod Suresh, Leo K. Cheng
Summary: This study quantified the regional properties of gastric motility from free-breathing dynamic MRI data. A stomach centerline was generated as a reference axis, and contractions were visualized as spatio-temporal contraction maps. The motility properties varied in different regions of the stomach.
IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY
(2023)
Meeting Abstract
Gastroenterology & Hepatology
Chris Varghese, Anthony Y. Lin, Niranchan Paskaranandavadivel, Sean Ho Beom Seo, Peng Du, Philip Dinning, Ian P. Bissett, Gregory O'Grady
Meeting Abstract
Gastroenterology & Hepatology
Saeed Alighaleh, Leo K. Cheng, Gregory O. Grady, Adam Bartlett, Niranchan Paskaranandavadivel