Article
Engineering, Biomedical
Alain Berod, Christophe Chnafa, Simon Mendez, Franck Nicoud
Summary: Numerical computations of hemodynamics inside intracranial aneurysms treated by endovascular braided devices such as flow-diverters contribute to understanding and improving such treatment procedures. Nevertheless, these simulations yield high computational and meshing costs due to the heterogeneity of length scales between the dense weave of the fine struts of the device and the arterial volume.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING
(2022)
Article
Thermodynamics
Hanwei Wang, Kai Luo, Chuang Huang, Aihong Zou, Daijin Li, Kan Qin
Summary: This paper investigates the flow characteristics within partial admission radial inflow turbines using three-dimensional computational fluid dynamics method. Different flow conditions under various partial admission ratios are analyzed, and the suitability of existing partial admission loss models is questioned.
Article
Biophysics
M. O. Khan, V. Toro Arana, M. Najafi, D. E. MacDonald, T. Natarajan, K. Valen-Sendstad, D. A. Steinman
Summary: High-fidelity computational fluid dynamics (HF-CFD) reveals the potential for high-frequency flow instabilities in intracranial aneurysms. While high SPI values do not significantly predict rupture status, it is important not to overlook these instabilities for a better understanding of the dynamic mechanical forces on aneurysm walls.
JOURNAL OF BIOMECHANICS
(2021)
Article
Health Care Sciences & Services
Denis Tikhvinskii, Julia Kuianova, Dmitrii Kislitsin, Kirill Orlov, Anton Gorbatykh, Daniil Parshin
Summary: This study retrospectively analyzed neurosurgical treatments for occlusion of cerebral aneurysms using flow-diverters and investigated the hemodynamic factors affecting stent endothelization. Various geometric approaches were considered for virtual deployment of flow-diverters. A comparative analysis of hemodynamic parameters was conducted on four clinical cases, which revealed statistically proven shear stress thresholds for in stent stenosis and insufficient endothelialization leading to non-occlusion of the aneurysm.
JOURNAL OF PERSONALIZED MEDICINE
(2022)
Article
Engineering, Biomedical
Yoke Rung Wong, Chi Wei Ong, Alyssa LiYu Toh, Einly Lim, Pei Ho, Hwa Liang Leo
Summary: A novel method for measuring the real-time input flow impedance of thoracic aorta aneurysm (TAA) was developed in this study. The unique features of real-time input flow impedance were extracted to correlate with TAA formation. The proposed fluid mechanics model has the potential to analyze aneurysmal diseases in real-time.
BIOMEDICAL SIGNAL PROCESSING AND CONTROL
(2021)
Article
Neuroimaging
Mehdi Najafi, Nicole M. Cancelliere, Olivier Brina, Pierre Bouillot, Maria Vargas, Benedicte Ma Delattre, Vitor M. Pereira, David A. Steinman
Summary: The study tested the impact of relying on generalized inflow rates and found that adjusting the generalized waveform shape with patient-specific Qavg can achieve near-perfect agreement and improve OSI correlations.
JOURNAL OF NEUROINTERVENTIONAL SURGERY
(2021)
Article
Engineering, Petroleum
Nasser Sabet, Mazda Irani, Hassan Hassanzadeh
Summary: The use of horizontal wells to improve oil production rates has become common practice. Inflow control devices (ICDs) are now widely used to mitigate water (or gas) coning. By using numerical simulations and formulating results into correlations, operators can ensure prototypes are suitable for specific problems.
Article
Clinical Neurology
Takeshi Miyata, Hiroharu Kataoka, Kampei Shimizu, Akihiro Okada, Takanobu Yagi, Hirotoshi Imamura, Masaomi Koyanagi, Ryota Ishibashi, Masanori Goto, Nobuyuki Sakai, Taketo Hatano, Masaki Chin, Koichi Iwasaki, Susumu Miyamoto
Summary: This study investigated the factors influencing the growth of intracranial aneurysms (IAs) at the middle cerebral artery (MCA) bifurcations. The morphology and hemodynamic environment of the MCA are associated with the growth and rupture of IAs. Parameters such as volume, shape, diameter, and angle configurations are closely correlated with the growth and rupture of MCA IAs.
JOURNAL OF NEUROSURGERY
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Mariya S. Pravdivtseva, Eva Peschke, Thomas Lindner, Fritz Wodarg, Johannes Hensler, Dominik Gabbert, Inga Voges, Philipp Berg, Alex J. Barker, Olav Jansen, Jan-Bernd Hovener
Summary: Flow models of intracranial aneurysms can effectively test the efficiency of flow modulation devices with 4D flow MRI. The models, created from human radiological data and printed with stereolithography, demonstrated similar flow characteristics and minimal geometric variation across different printing layer thicknesses. The deployment of FMDs in the models resulted in reduced mean velocity within the aneurysms, indicating potential for non-invasive evaluation of treatment effects.
Article
Clinical Neurology
Shintaro Nakajima, Shinichiro Sugiyama, Hidenori Oishi, Kenichi Sato, Yasushi Matsumoto, Kuniyasu Niizuma, Miki Fujimura, Teiji Tominaga
Summary: The study demonstrated the usefulness of CFD analysis in diagnosing atherosclerotic changes in large CCAs, which may affect therapeutic response following flow diversion. Post-CFD visualization showed that intra-aneurysmal swirling flow prolonged blood residence time under conditions of small inlet flow rates compared to aneurysmal volume.
Review
Neuroimaging
Cem Bilgin, Yigit Can Senol, Hassan Kobeissi, Atakan Orscelik, Sherief Ghozy, Alexander A. Oliver, Ramanathan Kadirvel, Waleed Brinjikji, David F. Kallmes
Summary: This meta-analysis investigates and compares the clinical outcomes of uncoated Phenox and coated Phenox HPC flow diverters. The results show that Phenox HPC is equally as safe and effective as non-coated Phenox devices. Additionally, the study suggests that prasugrel monotherapy might effectively prevent ischemic complications in patients treated with Phenox HPC flow diverters.
JOURNAL OF NEUROINTERVENTIONAL SURGERY
(2023)
Article
Engineering, Biomedical
Alain Berod, Fernando Mut, Juan Cebral, Simon Mendez, Christophe Chnafa, Franck Nicoud
Summary: The study applies a heterogeneous model developed by Berod et al to evaluate the hemodynamic effects of endovascular prostheses on cerebral aneurysms. The model shows good agreement with the actual treatment outcomes and successfully reproduces the jetting-type flows generated downstream of the struts.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING
(2023)
Article
Engineering, Mechanical
Anand P. Darji, Beena D. Baloni, Chetan S. Mistry
Summary: This study investigates the endwall flow in a low-speed low-pressure linear turbine cascade vane using numerical simulations. Different secondary flow patterns are analyzed, and a suitable turbulence model is selected. The computational results are validated against experimental data and show good agreement. The study also examines the influence of flow incidence and turbulence intensity on the endwall flow field.
JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME
(2023)
Article
Computer Science, Interdisciplinary Applications
Asal Sadeh, Admin Kazemi, Moharam Bahramkhoo, M. Barzegar Gerdroodbary
Summary: Blood hematocrit, porosity, and blood viscosity have significant impacts on the risk of aneurysm rupture, and computational fluid dynamic simulations are reliable tools for recognizing high-risk regions and assessing aneurysm status.
INTERNATIONAL JOURNAL OF MODERN PHYSICS C
(2023)
Article
Surgery
Michael O. Falster, Sarah K. Garland, Louisa R. Jorm, C. Barry Beiles, Anthony J. Freeman, Art Sedrakyan, Oluwadamisola T. Sotade, Ramon L. Varcoe
Summary: This study compares the rates of mortality, rupture, and secondary intervention in patients undergoing endovascular repair of intact abdominal aortic aneurysms using different endograft devices. The results show that the overall long-term safety profiles of major endograft devices are similar. However, there may be differences in rates of secondary intervention, with higher rates observed in patients receiving Medtronic and Gore devices.
EUROPEAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY
(2023)
Article
Gastroenterology & Hepatology
Kenji Kikuchi, Hyeongtak Noh, Keiko Numayama-Tsuruta, Takuji Ishikawa
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
(2020)
Article
Mechanics
Junichi Manabe, Toshihiro Omori, Takuji Ishikawa
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
Hitomu Matsui, Toshihiro Omori, Takuji Ishikawa
JOURNAL OF FLUID MECHANICS
(2020)
Review
Cell Biology
Takuji Ishikawa, Hironori Ueno, Toshihiro Omori, Kenji Kikuchi
Summary: This article explores the roles of cilia and centrosomes in eukaryotic cells and their dynamics, motions, and forces at the molecular, organelle, and tissue levels. The structure and function of cilia and centrosomes are closely related, requiring a comprehensive understanding from the molecular level to the tissue level.
SEMINARS IN CELL & DEVELOPMENTAL BIOLOGY
(2021)
Article
Mechanics
Hitomu Matsui, Toshihiro Omori, Takuji Ishikawa
Article
Pharmacology & Pharmacy
Kenji Kikuchi, Shunsuke Shigeta, Keiko Numayama-Tsuruta, Takuji Ishikawa
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2020)
Article
Multidisciplinary Sciences
Toshihiro Omori, Hiroaki Ito, Takuji Ishikawa
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2020)
Article
Physics, Fluids & Plasmas
Tomoki Oyama, Shunichi Ishida, Kohei Maeyama, Taimei Miyagawa, Yohsuke Imai
Summary: The study focuses on the effects of clustered contractions propagating along a circular channel on fluid flow, finding that clustered contractions cause retrograde flow and fluid trapping in the upstream and downstream regions of the cluster. Flow rate is not proportional to the number of peristaltic waves, particularly for large contraction ratios.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Physics, Fluids & Plasmas
Shunichi Ishida, Ryota Matsumoto, Daiki Matsunaga, Yohsuke Imai
Summary: In this study, a lattice Boltzmann simulation was used to investigate the crystal-like structure of deformable particles in a wall-bounded shear flow. It was found that this crystal structure can be effectively utilized for the segregation of capsules of different sizes. The movement of the smaller capsules varied significantly with the size ratio, and their behavior changed from diffusive to advective depending on the ratio.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Mechanics
Kohei Maeyama, Shunichi Ishida, Yohsuke Imai
Summary: Peristaltic pumping is the primary mechanism of food transport in the human intestine. This study investigates the peristaltic transport of a power-law fluid with a low behavior index, and finds that inertia effects can increase the discharge flow rate, while the sharpness of the contraction wave can affect the symmetry of the flow field. The results suggest that an isolated contraction wave with a shorter wavelength can transport intestinal contents more quickly when the contents have low consistency indices or when the contraction wave has a large propagation velocity.
Article
Multidisciplinary Sciences
Rika Ebara, Shunichi Ishida, Taimei Miyagawa, Yohsuke Imai
Summary: The amplitude and frequency of peristaltic contractions have a significant impact on gastric mixing and emptying. Increasing or decreasing the amplitude affects mixing strength and emptying rate, with higher amplitude increasing the emptying rate and lower amplitude decreasing it. The emptying rate also increases with the peristaltic frequency. The closest contraction wave to the pylorus and subsequent waves promote gastric emptying. It is important to maintain these parameters within normal ranges for healthy gastric function.
JOURNAL OF THE ROYAL SOCIETY INTERFACE
(2023)
Article
Multidisciplinary Sciences
Haruki Yoshida, Shunichi Ishida, Taiki Yamamoto, Takayuki Ishikawa, Yuichi Nagata, Kazuhito Takeuchi, Hironori Ueno, Yohsuke Imai
Summary: In this study, computational fluid dynamics was used to investigate the effects of cilia-induced surface velocity on cerebrospinal fluid (CSF) flow. The results showed that ciliary motility disorder could delay CSF exchange in the lateral ventricles.
JOURNAL OF THE ROYAL SOCIETY INTERFACE
(2022)
Article
Physiology
Tim Hsu-Han Wang, Timothy R. Angeli, Shunichi Ishida, Peng Du, Armen Gharibans, Niranchan Paskaranandavadivel, Yohsuke Imai, Taimei Miyagawa, Thomas L. Abell, Gianrico Farrugia, Leo K. Cheng, Gregory O'Grady
Summary: Loss of interstitial cells of Cajal (ICC) and aging are associated with higher gastric slow wave velocity, but the exact reasons for these relationships are still unknown. Increased slow wave velocity may modulate gastric emptying higher, although in gastroparesis other pathological factors must dominate to prevent emptying.
PHYSIOLOGICAL REPORTS
(2021)
Review
Engineering, Biomedical
Takuji Ishikawa, Toshihiro Omori, Kenji Kikuchi
APL BIOENGINEERING
(2020)
Article
Physics, Fluids & Plasmas
Zhihan Huang, Toshihiro Omori, Takuji Ishikawa