Article
Mathematics, Interdisciplinary Applications
Sazid Zamal Hoque, D. Vijay Anand, B. S. Patnaik
Summary: Particle-based methods are effective in simulating particle-like suspensions in blood, especially the dynamics of important suspensions like red blood cells (RBCs) in microvasculature. This study used a finite-sized dissipative particle dynamics framework and a discrete model to simulate the dynamics of a pair of RBCs flowing through symmetric and asymmetric bifurcating microfluidic channels. The findings showed that the deformed shape of RBCs matched experimental observations, and in asymmetric bifurcation, RBCs flowed through the low flow rate branch with lateral migration observed. Trade-off and following effects were particularly noticed in symmetric bifurcation.
COMPUTATIONAL PARTICLE MECHANICS
(2022)
Article
Multidisciplinary Sciences
Muhammad Ajaz, Abd Haj Ismail, Muhammad Waqas, Abdul Mosawir Quraishi, Jalal Hasan Baker, Antalov Jagnandan, Mohammad Ayaz Ahmad, Shawn Jagnandan, Haifa I. Alrebdi, Elmuez A. Dawi, Murad Badshah
Summary: This study analyzes the strange hadron transverse momentum spectra in symmetric and asymmetric collision systems, and investigates their dependence on rapidity and event charged-particle multiplicity. The results show that with an increase in event multiplicity, the average transverse flow velocity, freezeout temperatures, and non-extensivity parameter values all increase. The findings provide insights into the physics of collision processes.
Article
Physics, Fluids & Plasmas
Goncalo Coutinho, Ana S. Moita, Massimiliano Rossi, Antonio L. N. Moreira
Summary: This study focuses on the dynamics of platelet-size particles inside RBC flows through straight-square microchannels. The results suggest that RBCs are the main contributor to near-wall particle accumulation and margination.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Biochemical Research Methods
Jinghong Su, Xiaodong Chen, Yongzheng Zhu, Guoqing Hu
Summary: This study presents a fast numerical algorithm and machine learning techniques for analysis and design of inertial microfluidic devices, generating a database of inertial lift forces in straight microchannels and developing a machine learning assisted model to predict particle trajectories quickly and accurately.
Article
Multidisciplinary Sciences
Nathaniel Z. Piety, Julianne Stutz, Nida Yilmaz, Hui Xia, Tatsuro Yoshida, Sergey S. Shevkoplyas
Summary: The study compared the sensitivity of capillary networks versus ektacytometry in assessing the deformability of red blood cells during hypothermic storage. Results showed that capillary networks were more sensitive in detecting differences between storage conditions and overall decline in RBC deformability compared to ektacytometry.
SCIENTIFIC REPORTS
(2021)
Article
Mechanics
A. Chatterjee, A. K. Nayak, B. Weigand
Summary: This study focuses on the electromigration interaction of non-Newtonian fluid in a rectangular micro-capillary under an external electric field, aiming to predict the spatiotemporal dynamics of solute concentration. The solute concentration is optimized through dispersion and a driving force utilizing sequential ionic distribution and local electrical conductivity. Numerical computations are performed for the coupled electro-osmosis/electrophoresis migrated nonlinear equations, and analytical observations and calculations are made for electrical conductivity, velocity, and solutal species. The study also examines the Taylor-Aries dispersion effect and instantaneous dispersion dependent on time regime and flow strength.
Article
Ophthalmology
Srividya Neriyanuri, Phillip Bedggood, R. C. Andrew Symons, Andrew B. Metha
Summary: This study investigated the characteristics of capillary flow in the retina of three healthy individuals using high-resolution adaptive optics ophthalmoscopy. The study revealed significant variability in capillary flow parameters within subjects and within imaged fields. The velocities of erythrocytes were moderately correlated with hematocrit, suggesting a redistribution of plasma between cells with changes in flow.
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
(2023)
Article
Thermodynamics
Jana Kriebel, Ines M. Goncalves, Vitoria Baptista, Maria I. Veiga, Graca Minas, Rui Lima, Susana O. Catarino
Summary: This study evaluated the deformability of healthy red blood cells (RBCs) in contact with 20 nm magnetic iron and non-magnetic cerium nanoparticles using a microfluidic hyperbolic contraction. The results showed that RBCs' deformability index depended on the cells' velocity, and decreased when exposed to nanoparticles, with a greater effect seen for magnetic nanoparticles and longer exposure times. The deformability index exhibited a logarithmic trend with variations depending on nanoparticle properties, concentration, and exposure time. These findings provide valuable insights into the mechanical behavior of RBCs and the potential applications of nanocarriers in targeted drug delivery systems.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Chemistry, Physical
Adlan Merlo, Maxime Berg, Paul Duru, Frederic Risso, Yohan Davit, Sylvie Lorthois
Summary: The study reveals how the physics of blood flow affect the distribution of red blood cells (RBCs) in small vessel networks. Experimental results show that the partitioning of RBCs at bifurcations can affect their distribution at the next bifurcations. Sensitivity analysis based on network models demonstrates that these effects can propagate and have a significant impact on the distribution of RBCs throughout the network. A modified RBC partitioning model is proposed to explain why some networks exhibit a single pattern of RBC preferential location while others exhibit two different patterns. These findings are important for understanding and modeling blood flow in physiological and pathological conditions.
Article
Biochemistry & Molecular Biology
Juliane Hannemann, Debra J. Skene, Benita Middleton, Edzard Schwedhelm, Anika Laing, Rainer Boeger
Summary: Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) interfere with nitric oxide (NO) formation from L-arginine via different mechanisms. The plasma concentrations of L-arginine-related amino acid metabolites show diurnal variation, with L-arginine and homoarginine concentrations having a 12-hour period. ADMA and SDMA show a 24-hour rhythmicity. Night shift work does not significantly affect the central suprachiasmatic nuclei clock timing, melatonin and cortisol levels, or blood pressure patterns.
Article
Engineering, Electrical & Electronic
Kunyu Zuo, Lei Wu
Summary: This paper discusses the stability performance of droop-free controlled islanded microgrid through eigenvalue-based analysis. The paper proposes a modified eigenvalue analysis method to prove the asymptotic stability of the symmetric droop-free controlled microgrid. The analytical eigenvalues with symmetric/asymmetric communication network designs are deduced under the homogenized electrical network. Stability performances of the symmetric/asymmetric designs are assessed using stability margin analysis and vulnerability analysis.
IEEE TRANSACTIONS ON SMART GRID
(2022)
Article
Engineering, Multidisciplinary
Nur Tantiyani Ali Othman, Halimunnisha Sahul Hameed, Masli Irwan Rosli
Summary: In this study, the application of dielectrophoresis (DEP) force in an X-shaped microchannel was explored to improve the efficiency of plasma separation from blood cells. The results showed that under certain conditions, a 100% separation efficiency could be achieved.
JURNAL TEKNOLOGI-SCIENCES & ENGINEERING
(2022)
Article
Computer Science, Information Systems
Whan Choi, Yeong Jun Koh, Chang-Su Kim
Summary: This paper proposes a video frame interpolation network based on both symmetric and asymmetric motion-based warping modules, which can effectively handle linear and non-linear motions as well as occlusions. The combination of symmetric and asymmetric warping results improves the reliability of intermediate frame reconstruction.
Article
Engineering, Biomedical
Qianbin Zhao, Sheng Yan, Boran Zhang, Kai Fan, Jun Zhang, Weihua Li
Summary: There are many non-Newtonian fluids in our daily life, which are viscoelastic and heterogeneous liquids containing cells, ions, metabolites, and hormones. The viscoelasticity of biological fluids is often ignored, but it actually affects the behavior of microparticles. A reliable and easy-to-use on-chip viscoelasticity sensor is therefore highly desired for various applications. In this study, stable non-Newtonian fluid-polyethylene oxide (PEO) solutions were used to investigate the effects of weak fluidic viscoelasticity on microparticle behavior. A database of fluidic patterns for viscoelasticity sensing and relaxation time measurement was established. The sensor was tested with different biological fluids and showed promising results.
CYBORG AND BIONIC SYSTEMS
(2023)
Article
Computer Science, Artificial Intelligence
Amrita Soni, Neha Sharma
Summary: This paper discusses the challenges of optical buffering and large-scale data switching, and introduces the possible solution of the Data Vortex (DV) all optical switch innovations and its enhancements. A new algorithm for simulating the equivalent planar virtual model is proposed, and the performance of ADV is compared under different I/O modes. The results show that EPA ADV has better performance under asymmetric I/O operation.
Review
Engineering, Biomedical
Ali Abou-Hassan, Alexandre Barros, Noor Buchholz, Dario Carugo, Francesco Clavica, Petra de Graaf, Julia de La Cruz, Wolfgang Kram, Filipe Mergulhao, Rui L. Reis, Ilya Skovorodkin, Federico Soria, Seppo Vainio, Shaokai Zheng
Summary: Urinary stents and catheters have been associated with infections and discomfort, but research on coatings, pH sensors, and other technologies show promising results in improving urinary implants. Collaboration among stakeholders is deemed essential for future advancements in this field.
EXPERT REVIEW OF MEDICAL DEVICES
(2021)
Editorial Material
Cardiac & Cardiovascular Systems
Dominik Obrist, Hendrik von Tengg-Kobligk
ARQUIVOS BRASILEIROS DE CARDIOLOGIA
(2022)
Article
Mechanics
Hadi Zolfaghari, Rich R. Kerswell, Dominik Obrist, Peter J. Schmid
Summary: This article investigates the influence of instabilities in bileaflet mechanical heart valves on turbulent flow. Using adjoint-based methods, the structural sensitivity of the instabilities is analyzed and their role in disturbance energy growth in the wake of the valves is quantified. The study demonstrates that improving the shape of the leading edge can effectively reduce turbulence.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Cardiac & Cardiovascular Systems
Leonardo Pietrasanta, Shaokai Zheng, Dario De Marinis, David Hasler, Dominik Obrist
Summary: The development of turbulence after transcatheter aortic valve (TAV) implantation may negatively affect the long-term performance and durability of the valves. This study investigated the turbulent flow generated after TAV implantation using experimental and velocimetry techniques. The results suggest that the degree of expansion of the TAV in-situ is related to the onset of turbulence and that a smaller and less regular opening area might introduce flow instabilities that could be detrimental for the long-term performance of the valve.
FRONTIERS IN CARDIOVASCULAR MEDICINE
(2022)
Article
Engineering, Biomedical
Mirunalini Thirugnanasambandam, Sabrina Frey, Yannick Roesch, Alberto Mantegazza, Francesco Clavica, Robert S. Schwartz, Nikola Cesarovic, Dominik Obrist
Summary: Cardiac microvascular obstruction (MVO) is the partial or complete loss of blood perfusion in the myocardial microcirculation caused by acute myocardial infarction. A new catheter-based method called CoFI has been developed to accurately diagnose MVO during acute therapy. Experiments on a porcine MVO model and a benchtop microcirculation model showed that CoFI could identify the increased hydraulic resistance in the affected microvascular bed. Different levels of collateral flow were studied and concepts to differentiate collateral flow from MVO were formulated.
ANNALS OF BIOMEDICAL ENGINEERING
(2022)
Article
Biotechnology & Applied Microbiology
Thomas Martinez, Silje Ekroll Jahren, Armando Walter, Jonathan Chavanne, Francesco Clavica, Lorenzo Ferrari, Paul Philipp Heinisch, Daniela Casoni, Andreas Haeberlin, Markus M. Luedi, Dominik Obrist, Thierry Carrel, Yoan Civet, Yves Perriard
Summary: Although heart transplantation is the preferred treatment for patients with heart failure, employing DEAs to enhance aortic function might be a promising alternative in the future. In an animal study, implantation of a DEA device into the descending aorta demonstrated significant support to the heart, with optimal assistance achieved through specific activation and deactivation timings.
BIOENGINEERING & TRANSLATIONAL MEDICINE
(2023)
Article
Biotechnology & Applied Microbiology
Shaokai Zheng, Pedro Amado, Dominik Obrist, Fiona Burkhard, Francesco Clavica
Summary: In this study, a simple in vitro bladder model was designed to simulate the dynamics of filling and voiding. The physio-mechanical condition of the model was verified using pressure-flow and reflux tests. Encrustation tests with artificial urine on double-J stents were conducted using the model, and the volumes of luminal encrustations were quantified. The results suggest that VUR is an important factor contributing to the dynamics in the upper urinary tract with indwelling stents, emphasizing its significance in future in vitro studies and clinical analyses.
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
(2022)
Article
Biotechnology & Applied Microbiology
Shaokai Zheng, Dominik Obrist, Fiona Burkhard, Francesco Clavica
Summary: This study investigates the influence of side hole and stent lumen diameter on flux and shear stress levels using experimental and numerical methods. The results show that reducing the side hole diameter increases shear stress levels but decreases flux. Reducing the stent lumen diameter impedes flow and side hole flux. The design of stent inlet/outlet plays a key role in regulating flow characteristics.
BIOENGINEERING & TRANSLATIONAL MEDICINE
(2023)
Review
Cardiac & Cardiovascular Systems
Anselm W. Stark, Andreas A. Giannopoulos, Alexander Pugachev, Isaac Shiri, Andreas Haeberlin, Lorenz Raber, Dominik Obrist, Christoph Grani
Summary: This systematic review examines the role of computational fluid dynamics (CFD) simulations in the assessment of anomalous aortic origin of a coronary artery (AAOCA). The review found that CFD simulations offer a noninvasive alternative for patient-specific hemodynamic analysis in AAOCA. However, both dedicated and general-purpose CFD models have limitations and further research is needed to accurately simulate the pathophysiological changes in AAOCA.
JOURNAL OF CARDIOVASCULAR DEVELOPMENT AND DISEASE
(2023)
Article
Engineering, Biomedical
Silje Ekroll Jahren, Caglayan Demirel, Karoline-Marie Bornemann, Pascal Corso, Stefan Stortecky, Dominik Obrist
Summary: This pilot study aimed to investigate the differences in aortic root geometry between patients with transcatheter heart valve thrombosis (THVT) and those without THVT after transcatheter aortic valve implantation (TAVI). It was found that THVT patients had lower right coronary artery height and larger sinotubular junction (STJ) and ascending aorta (AAo) diameters. Computational models demonstrated that larger STJ and AAo diameters potentially increase backflow rate, decrease velocity in the sinus, and increase systolic turbulent dissipation rate in the AAo.
APL BIOENGINEERING
(2023)
Article
Biotechnology & Applied Microbiology
Yannick Rosch, Thorald Stolte, Miriam Weisskopf, Sabrina Frey, Rob Schwartz, Nikola Cesarovic, Dominik Obrist
Summary: This study investigated the influence of microvascular obstruction on myocardial infarction patients and explored improved treatment methods using an in vitro model. The findings provide important insights for enhancing treatment of patients with MVO.
BIOENGINEERING & TRANSLATIONAL MEDICINE
(2023)
Letter
Pediatrics
Marc-Alexander Oestreich, Robin Hanni, Florian Wyler, Anne-Christianne Kentgens, Sophie Yammine, Dominik Obrist, Philipp Latzin, Kathryn A. Ramsey
PEDIATRIC PULMONOLOGY
(2023)
Article
Medicine, Research & Experimental
Shaokai Zheng, Dario Carugo, Ali Mosayyebi, Ben Turney, Fiona Burkhard, Dirk Lange, Dominik Obrist, Sarah Waters, Francesco Clavica
Summary: The upper urinary tract (UUT) is essential in the human urogenital system, and dysfunction and complications can occur due to various reasons such as congenital anomalies and diseases. Fluid mechanical modeling plays a pivotal role in addressing scientific and clinical challenges related to the UUT, aiming to provide physiologically meaningful models.
WIRES MECHANISMS OF DISEASE
(2021)
Proceedings Paper
Automation & Control Systems
J. Chavanne, F. Clavica, T. Martinez, Y. Civet, D. Obrist, Y. Perriard
Summary: The lumped parameter model and mock circulation loop are commonly used tools in biomedical research to simulate the cardiac system for studying assist devices. The proposed model aims to study the influence of geometrical parameters and electrical activation of a dielectric elastomer actuator left ventricle assist device to optimize energy provision. Through the model, it has been demonstrated that the actuator, with appropriate activation, can release 4 to 5% of the heart's energy.
2021 IEEE/ASME INTERNATIONAL CONFERENCE ON ADVANCED INTELLIGENT MECHATRONICS (AIM)
(2021)