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Ho TT, Tran MT, Cui X, Lin CL, Baek S, Kim WJ, Lee CH, Jin GY, Chae KJ, Choi S. Human-airway surface mesh smoothing based on graph convolutional neural networks. Comput Methods Programs Biomed 2024; 246:108061. [PMID: 38341897 DOI: 10.1016/j.cmpb.2024.108061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/22/2024] [Accepted: 02/05/2024] [Indexed: 02/13/2024]
Abstract
BACKGROUND AND OBJECTIVE A detailed representation of the airway geometry in the respiratory system is critical for predicting precise airflow and pressure behaviors in computed tomography (CT)-image-based computational fluid dynamics (CFD). The CT-image-based geometry often contains artifacts, noise, and discontinuities due to the so-called stair step effect. Hence, an advanced surface smoothing is necessary. The existing smoothing methods based on the Laplacian operator drastically shrink airway geometries, resulting in the loss of information related to smaller branches. This study aims to introduce an unsupervised airway-mesh-smoothing learning (AMSL) method that preserves the original geometry of the three-dimensional (3D) airway for accurate CT-image-based CFD simulations. METHOD The AMSL method jointly trains two graph convolutional neural networks (GCNNs) defined on airway meshes to filter vertex positions and face normal vectors. In addition, it regularizes a combination of loss functions such as reproducibility, smoothness and consistency of vertex positions, and normal vectors. The AMSL adopts the concept of a deep mesh prior model, and it determines the self-similarity for mesh restoration without using a large dataset for training. Images of the airways of 20 subjects were smoothed by the AMSL method, and among them, the data of two subjects were used for the CFD simulations to assess the effect of airway smoothing on flow properties. RESULTS In 18 of 20 benchmark problems, the proposed smoothing method delivered better results compared with the conventional or state-of-the-art deep learning methods. Unlike the traditional smoothing, the AMSL successfully constructed 20 smoothed airways with airway diameters that were consistent with the original CT images. Besides, CFD simulations with the airways obtained by the AMSL method showed much smaller pressure drop and wall shear stress than the results obtained by the traditional method. CONCLUSIONS The airway model constructed by the AMSL method reproduces branch diameters accurately without any shrinkage, especially in the case of smaller airways. The accurate estimation of airway geometry using a smoothing method is critical for estimating flow properties in CFD simulations.
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Affiliation(s)
- Thao Thi Ho
- School of Mechanical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, South Korea
| | - Minh Tam Tran
- School of Mechanical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, South Korea
| | - Xinguang Cui
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Ching-Long Lin
- Department of Mechanical Engineering, IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Stephen Baek
- School of Data Science, University of Virginia, Charlottesville, VA, USA; Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA
| | - Woo Jin Kim
- Department of Internal Medicine and Environmental Health Center, School of Medicine, Kangwon National University Hospital, Kangwon National University, Chuncheon, South Korea
| | - Chang Hyun Lee
- Department of Radiology, College of Medicine, Seoul National University, Seoul National University Hospital, Seoul, South Korea; Department of Radiology, College of Medicine, The University of Iowa, Iowa City, IA, USA
| | - Gong Yong Jin
- Department of Radiology, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
| | - Kum Ju Chae
- Department of Radiology, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
| | - Sanghun Choi
- School of Mechanical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, South Korea.
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Gunasekera S, de Silva C, Ng O, Thomas S, Varcoe R, Barber T. Stenosis to stented: decrease in flow disturbances following stent implantation of a diseased arteriovenous fistula. Biomech Model Mechanobiol 2024; 23:453-468. [PMID: 38063956 DOI: 10.1007/s10237-023-01784-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 10/14/2023] [Indexed: 03/26/2024]
Abstract
The arteriovenous fistula (AVF) is commonly faced with stenosis at the juxta-anastomotic (JXA) region of the vein. Implantation of a flexible nitinol stent across the stenosed JXA has led to the retention of functioning AVFs leading to the resulting AVF geometry being distinctly altered, thereby affecting the haemodynamic environment within it. In this study, large eddy simulations of the flow field within a patient-specific AVF geometry before and after stent implantation were conducted to detail the change in flow features. Although the diseased AVF had much lower flow rates, adverse flow features, such as recirculation zones and swirling flow at the anastomosis, and jet flow at the stenosis site were present. Larger velocity fluctuations (leading to higher turbulent kinetic energy) stemming from these flow features were apparent in the diseased AVF compared to the stented AVF. The unsteadiness at the stenosis created large regions of wall shear stress (WSS) fluctuations downstream of the stenosis site that were not as apparent in the stented AVF geometry. The larger pressure drop across the diseased vein, compared to the stented vein, was primarily caused by the constriction at the stenosis, potentially causing the lower flow rate. Furthermore, the WSS fluctuations in the diseased AVF could lead to further disease progression downstream of the stenosis. The change in bulk flow unsteadiness, pressure drop, and WSS behaviour confirms that the haemodynamic environment of the diseased AVF has substantially improved following the flexible stent implantation.
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Affiliation(s)
- Sanjiv Gunasekera
- School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Charitha de Silva
- School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Olivia Ng
- School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Shannon Thomas
- Department of Vascular Surgery, Prince of Wales Hospital, Randwick, NSW, 2031, Australia
| | - Ramon Varcoe
- Department of Vascular Surgery, Prince of Wales Hospital, Randwick, NSW, 2031, Australia
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
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Enomoto T, Mishima T, Tsuchida M. Blood flow analysis with computational fluid dynamics in the left atrium after left atrial plication: a prospective study. Gen Thorac Cardiovasc Surg 2024; 72:209-215. [PMID: 37550585 DOI: 10.1007/s11748-023-01963-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/17/2023] [Indexed: 08/09/2023]
Abstract
OBJECTIVE This study aimed to evaluate blood flow stagnation in an enlarged left atrium (LA) and prove that left atrial plication (LAP) could alleviate the stagnation. METHODS Five patients with chronic atrial fibrillation who underwent mitral valve surgery followed by LAP for an enlarged LA with a ≥ 60-mm diameter were included. We performed computational fluid dynamics (CFD) analysis using preoperative and postoperative computed tomography and four-dimensional flow magnetic resonance imaging. Additionally, computer graphics were used to create virtual left atrial appendage resection (LAAR) images. We performed CFD analysis to assess blood flow stagnation in the LA for three groups: preoperative, LAAR, and LAP. RESULTS When the average and constant stagnation volumes were both set to 100 preoperatively, the average stagnation volumes of the LAAR and LAP groups were 67.42 ± 18.64 and 35.88 ± 8.20, respectively. The constant stagnation volumes of these groups reduced to 45.01 ± 7.43 and 21.14 ± 7.70, respectively. The LAP group also had significantly lower average and constant stagnation volumes than those in the LAAR group (p = 0.006 and p = 0.033, respectively). CONCLUSIONS Blood flow stagnation was noted in the LAA and enlarged LA. CFD analysis revealed that LAP for the enlarged LA improved blood flow stagnation more than the virtual LAAR alone. CLINICAL TRIAL REGISTRY NUMBER UMIN000049923.
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Affiliation(s)
- Takashi Enomoto
- Division of Thoracic and Cardiovascular Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachidori, Chuo-ku, Niigata, Niigata, 951-8510, Japan.
| | - Takehito Mishima
- Division of Thoracic and Cardiovascular Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachidori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Masanori Tsuchida
- Division of Thoracic and Cardiovascular Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachidori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
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Zhang X, Li F, Rajaraman PK, Comellas AP, Hoffman EA, Lin CL. Investigating distributions of inhaled aerosols in the lungs of post-COVID-19 clusters through a unified imaging and modeling approach. Eur J Pharm Sci 2024; 195:106724. [PMID: 38340875 PMCID: PMC10948263 DOI: 10.1016/j.ejps.2024.106724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024]
Abstract
BACKGROUND Recent studies, based on clinical data, have identified sex and age as significant factors associated with an increased risk of long COVID. These two factors align with the two post-COVID-19 clusters identified by a deep learning algorithm in computed tomography (CT) lung scans: Cluster 1 (C1), comprising predominantly females with small airway diseases, and Cluster 2 (C2), characterized by older individuals with fibrotic-like patterns. This study aims to assess the distributions of inhaled aerosols in these clusters. METHODS 140 COVID survivors examined around 112 days post-diagnosis, along with 105 uninfected, non-smoking healthy controls, were studied. Their demographic data and CT scans at full inspiration and expiration were analyzed using a combined imaging and modeling approach. A subject-specific CT-based computational model analysis was utilized to predict airway resistance and particle deposition among C1 and C2 subjects. The cluster-specific structure and function relationships were explored. RESULTS In C1 subjects, distinctive features included airway narrowing, a reduced homothety ratio of daughter over parent branch diameter, and increased airway resistance. Airway resistance was concentrated in the distal region, with a higher fraction of particle deposition in the proximal airways. On the other hand, C2 subjects exhibited airway dilation, an increased homothety ratio, reduced airway resistance, and a shift of resistance concentration towards the proximal region, allowing for deeper particle penetration into the lungs. CONCLUSIONS This study revealed unique mechanistic phenotypes of airway resistance and particle deposition in the two post-COVID-19 clusters. The implications of these findings for inhaled drug delivery effectiveness and susceptibility to air pollutants were explored.
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Affiliation(s)
- Xuan Zhang
- IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA, USA; Department of Mechanical Engineering, University of Iowa, Iowa City, IA, USA
| | - Frank Li
- IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA, USA; Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - Prathish K Rajaraman
- IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA, USA; Department of Mechanical Engineering, University of Iowa, Iowa City, IA, USA
| | | | - Eric A Hoffman
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA; Department of Radiology, University of Iowa, Iowa City, IA, USA
| | - Ching-Long Lin
- IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA, USA; Department of Mechanical Engineering, University of Iowa, Iowa City, IA, USA; Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA; Department of Radiology, University of Iowa, Iowa City, IA, USA.
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Dhoble S, Kapse A, Ghegade V, Chogale M, Ghodake V, Patravale V, Vora L. Design, development, and technical considerations for dry powder inhaler devices. Drug Discov Today 2024:103954. [PMID: 38531423 DOI: 10.1016/j.drudis.2024.103954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 03/28/2024]
Abstract
The dry powder inhaler (DPI) stands out as a highly patient-friendly and effective pulmonary formulation, surpassing traditional and other pulmonary dosage forms in certain disease conditions. The development of DPI products, however, presents more complexities than that of other dosage forms, particularly in device design and the integration of the drug formulation. This review focuses on the capabilities of DPI devices in pulmonary drug delivery, with a special emphasis on device design and formulation development. It also delves into the principles of deep lung particle deposition and device engineering, and provides a current overview of the market for DPI devices. Furthermore, the review highlights the use of computational fluid dynamics (CFD) in DPI product design and discusses the regulatory environment surrounding these devices.
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Affiliation(s)
- Sagar Dhoble
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai 400019, India
| | - Archana Kapse
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai 400019, India
| | - Vaibhav Ghegade
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai 400019, India
| | - Manasi Chogale
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai 400019, India
| | - Vinod Ghodake
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai 400019, India
| | - Vandana Patravale
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai 400019, India.
| | - Lalitkumar Vora
- School of Pharmacy, Queens University, Belfast, United Kingdom.
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Straccia A, Chassagne F, Barbour MC, Beckman J, Li S, Mahr C, Aliseda A. A Computational Investigation of the Effects of Temporal Synchronization of Left Ventricular Assist Device Speed Modulation with the Cardiac Cycle on Intraventricular Hemodynamics. Ann Biomed Eng 2024:10.1007/s10439-024-03489-x. [PMID: 38517620 DOI: 10.1007/s10439-024-03489-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/07/2024] [Indexed: 03/24/2024]
Abstract
Patients with advanced heart failure are implanted with a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy. Despite advances in pump design, the risk of stroke remains high. LVAD implantation significantly alters intraventricular hemodynamics, where regions of stagnation or elevated shear stresses promote thrombus formation. Third generation pumps incorporate a pulsatility mode that modulates rotational speed of the pump to enhance in-pump washout. We investigated how the timing of the pulsatility mode with the cardiac cycle affects intraventricular hemodynamic factors linked to thrombus formation. Computational fluid dynamics simulations with Lagrangian particle tracking to model platelet behavior in a patient-specific left ventricle captured altered intraventricular hemodynamics due to LVAD implantation. HeartMate 3 incorporates a pulsatility mode that modulates the speed of the pump every two seconds. Four different timings of this pulsatility mode with respect to the cardiac cycle were investigated. A strong jet formed between the mitral valve and inflow cannula. Blood stagnated in the left ventricular outflow tract beneath a closed aortic valve, in the near-wall regions off-axis of the jet, and in a large counterrotating vortex near the anterior wall. Computational results showed good agreement with particle image velocimetry results. Synchronization of the pulsatility mode with peak systole decreased stasis, reflected in the intraventricular washout of virtual contrast and Lagrangian particles over time. Temporal synchronization of HeartMate 3 pulsatility with the cardiac cycle reduces intraventricular stasis and could be beneficial for decreasing thrombogenicity.
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Affiliation(s)
- Angela Straccia
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
| | | | - Michael C Barbour
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Jennifer Beckman
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Song Li
- Institute for Advanced Cardiac Care, Medical City Healthcare, Dallas, TX, USA
| | - Claudius Mahr
- Institute for Advanced Cardiac Care, Medical City Healthcare, Dallas, TX, USA
| | - Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
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Ahmadi P, Dichgans F, Jagau L, Schmidt C, Aizinger V, Gilfedder BS, Fleckenstein JH. Systematic CFD-based evaluation of physical factors influencing the spatiotemporal distribution patterns of microplastic particles in lakes. Sci Total Environ 2024; 917:170218. [PMID: 38280578 DOI: 10.1016/j.scitotenv.2024.170218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/24/2023] [Accepted: 01/14/2024] [Indexed: 01/29/2024]
Abstract
Spatiotemporal distribution patterns of microplastic (MP) particles in lakes hinge on both the physical conditions in the lake and particle properties. Using numerical simulations, we systematically investigated the influence of lake depth and bathymetry, wind and temperature conditions, MP particle release location and timing, as well as particle diameter (10, 20, and 50 μm). Our results indicate that maximum lake depth had the greatest effect on the residence time in the water column, as it determines the settling timescale and occurrence of hydrodynamic complexity such as density-driven flows in the lake. Increasing particle size from 10 to 20 and 50 μm also significantly reduced the residence time making particle size the factor with the second strongest effect on the residence time and, in turn, on the availability of MP particles for uptake by organisms. Changing bathymetry from a uniform to a non-uniform had a less pronounced effect on particle residence time compared to maximum depth and particle size. Release location, wind conditions, and release time had comparably little effect on particle behavior but became more important as MP particle size decreased. The release of the 10 μm MP particles in the deeper lakes with uniform bathymetry during summer with stable thermal stratification, resulted in a nearly month-long turnover phase in the fall in which both settling and rising of particles occurred simultaneously. This was caused by convective heat and water transport during this period. In these scenarios about 2.6 to 5.4 % of the released MP particles were held in or returned to the water layers near the lake surface. While acknowledging the dominant role of lake depth and MP particle size on the particle residence time, this study further emphasizes that it is ultimately a particular combination of different factors and their interactions that shape MP distribution patterns in lakes.
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Affiliation(s)
- Pouyan Ahmadi
- Department of Hydrogeology, Helmholtz-Centre for Environmental Research, UFZ, 04318 Leipzig, Germany.
| | - Franz Dichgans
- Department of Hydrogeology, Helmholtz-Centre for Environmental Research, UFZ, 04318 Leipzig, Germany
| | - Lisa Jagau
- Chair of Scientific Computing, University of Bayreuth, 95440 Bayreuth, Germany
| | - Christian Schmidt
- Department of Hydrogeology, Helmholtz-Centre for Environmental Research, UFZ, 04318 Leipzig, Germany
| | - Vadym Aizinger
- Chair of Scientific Computing, University of Bayreuth, 95440 Bayreuth, Germany
| | - Benjamin S Gilfedder
- Limnological Research Station, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, 95440 Bayreuth, Germany; Department of Hydrology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440 Bayreuth, Germany
| | - Jan H Fleckenstein
- Department of Hydrogeology, Helmholtz-Centre for Environmental Research, UFZ, 04318 Leipzig, Germany; Hydrologic Modelling Unit, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440 Bayreuth, Germany
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Moussa A, Huygens B, Venditti C, Adrover A, Desmet G. On the contribution of the top and bottom walls in micro-pillar array columns and related high-aspect ratio chromatography systems. J Chromatogr A 2024; 1720:464825. [PMID: 38507870 DOI: 10.1016/j.chroma.2024.464825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/15/2024] [Accepted: 03/16/2024] [Indexed: 03/22/2024]
Abstract
We report on a steady-state based, and hence highly accurate numerical modelling study of the effect of the top and bottom wall in the current generation of micro-pillar array columns. These have a mesoporous retention layer that not only covers the pillar walls but also the bottom wall. Our results show that the performance of these columns can in general not be improved by also covering the top wall with the same layer, despite the increased column symmetry this approach would offer. The reason for this is that the local species retardation caused by a retentive layer is much stronger than the pure flow arresting effect of an uncovered wall. At least, this has a crucial impact in high aspect-ratio systems such as micro-pillar array columns because these require a small inter-pillar distance to promote mass transfer together with a large channel depth to enable a sufficiently high flow rate. On the other hand, a notable improvement could be made if micro-pillar array would be produced without having a retentive layer at the bottom. At Péclet number Pe = 50 and aspect ratio AR = 5 for flow-channels, this gain amounts up to about 4.5 h-units at a zone retention factor k'' = 2 and 1.75 h-units at k'' = 16 (gain scales almost linearly with Pe). To verify these results, we also considered another high aspect-ratio system with a simplified geometry: the open-tubular channel with a flat-rectangular cross-section. This led to very similar observations, thus confirming the findings for the micro-pillar array. The results produced in the present study also allow us to conclude that the classic modelling paradigm adopted in chromatography, which is based on the independency and hence additivity of the hCm- and hCs-contributions, can lead to large modelling errors in chromatographic systems with a high aspect-ratio, even when their geometry is so simple as that of a straight open-tubular channel with constant cross-section. Indeed, when both zones are treated independently, the analysis misses how the vertical diffusion through the retentive layer helps suppressing the vertical gradients in the mobile zone. The diffusion through this layer occurs in a ratio of k''Ds/Dm (Dm being the diffusion coefficient in mobile phase zone and Ds being the diffusion coefficient in stationary phase zone), such that at high retention factors this diffusion contribution even becomes the dominant one.
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Affiliation(s)
- Ali Moussa
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Bram Huygens
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
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Kimura N, Imada S, Hori D, Nakamura M. Thoracic endovascular aortic repair for acute aortic dissection complicated by mesenteric malperfusion: an evaluation by computational fluid dynamics. Interdiscip Cardiovasc Thorac Surg 2024:ivae047. [PMID: 38498834 DOI: 10.1093/icvts/ivae047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/27/2023] [Accepted: 03/14/2024] [Indexed: 03/20/2024]
Abstract
Computational fluid dynamics was performed to simulate haemodynamics of type B aortic dissection complicated by mesenteric malperfusion caused by dynamic obstruction in a 70-year-old man. Streamline analysis showed disappearance of antegrade flow in the false lumen of the descending aorta and attenuation of intermittent flap-induced disruption of visceral vessel perfusion after entry coverage. Quantitative analysis showed endovascular repair increased perfusion volume of the coeliac artery and superior mesenteric artery by 55.6%, and 77.4%, respectively. Entry closure with thoracic endovascular prosthesis improved mesenteric malperfusion by attenuating the intermittent flap-induced perfusion disruption.
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Affiliation(s)
- Naoyuki Kimura
- Department of Cardiovascular Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Shuta Imada
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Daijiro Hori
- Department of Cardiovascular Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Masanori Nakamura
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan
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Lee JH, Shim JW, Lim MH, Baek C, Jeon B, Cho M, Park S, Choi DH, Kim BS, Yoon D, Kim YG, Cho SY, Lee KM, Yeo MS, Zo H, Shin SD, Kim S. Towards optimal design of patient isolation units in emergency rooms to prevent airborne virus transmission: From computational fluid dynamics to data-driven modeling. Comput Biol Med 2024; 173:108309. [PMID: 38520923 DOI: 10.1016/j.compbiomed.2024.108309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/26/2024] [Accepted: 03/12/2024] [Indexed: 03/25/2024]
Abstract
BACKGROUND Patient isolation units (PIUs) can be an effective method for effective infection control. Computational fluid dynamics (CFD) is commonly used for PIU design; however, optimizing this design requires extensive computational resources. Our study aims to provide data-driven models to determine the PIU settings, thereby promoting a more rapid design process. METHOD Using CFD simulations, we evaluated various PIU parameters and room conditions to assess the impact of PIU installation on ventilation and isolation. We investigated particle dispersion from coughing subjects and airflow patterns. Machine-learning models were trained using CFD simulation data to estimate the performance and identify significant parameters. RESULTS Physical isolation alone was insufficient to prevent the dispersion of smaller particles. However, a properly installed fan filter unit (FFU) generally enhanced the effectiveness of physical isolation. Ventilation and isolation performance under various conditions were predicted with a mean absolute percentage error of within 13%. The position of the FFU was found to be the most important factor affecting the PIU performance. CONCLUSION Data-driven modeling based on CFD simulations can expedite the PIU design process by offering predictive capabilities and clarifying important performance factors. Reducing the time required to design a PIU is critical when a rapid response is required.
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Affiliation(s)
- Jong Hyeon Lee
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Jae Woo Shim
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Min Hyuk Lim
- Graduate School of Health Science and Technology, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan, Republic of Korea; Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan, Republic of Korea; Department of Transdisciplinary Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Changhoon Baek
- Department of Transdisciplinary Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Innovative Medical Technology Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Medical Research Center, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Byoungjun Jeon
- Innovative Medical Technology Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Office of Hospital Information, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Minwoo Cho
- Department of Transdisciplinary Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Innovative Medical Technology Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Medical Research Center, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Sungwoo Park
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea; Innovative Medical Technology Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Dong Hyun Choi
- Department of Biomedical Engineering, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Byeong Soo Kim
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Dan Yoon
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Young Gyun Kim
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Seung Yeon Cho
- Interdisciplinary Program in Bioengineering, Graduate School, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Kyung-Min Lee
- International Vaccine Institute, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Myoung-Souk Yeo
- Department of Architecture and Architectural Engineering, Seoul National University College of Engineering, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Hangman Zo
- Department of Architecture and Architectural Engineering, Seoul National University College of Engineering, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Sang Do Shin
- Laboratory of Emergency Medical Services, Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Department of Emergency Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Department of Emergency Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, Republic of Korea
| | - Sungwan Kim
- Department of Biomedical Engineering, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, Republic of Korea; Institute of Bioengineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea; Artificial Intelligence Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
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11
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Candreva A, Gallo D, Munhoz D, Rizzini ML, Mizukami T, Seki R, Sakai K, Sonck J, Mazzi V, Ko B, Nørgaard BL, Jensen JM, Maeng M, Otake H, Koo BK, Shinke T, Aben JP, Andreini D, Gallinoro E, Stähli BE, Templin C, Chiastra C, De Bruyne B, Morbiducci U, Collet C. Influence of intracoronary hemodynamic forces on atherosclerotic plaque phenotypes. Int J Cardiol 2024; 399:131668. [PMID: 38141723 DOI: 10.1016/j.ijcard.2023.131668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/21/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
BACKGROUND AND AIMS Coronary hemodynamics impact coronary plaque progression and destabilization. The aim of the present study was to establish the association between focal vs. diffuse intracoronary pressure gradients and wall shear stress (WSS) patterns with atherosclerotic plaque composition. METHODS Prospective, international, single-arm study of patients with chronic coronary syndromes and hemodynamic significant lesions (fractional flow reserve [FFR] ≤ 0.80). Motorized FFR pullback pressure gradient (PPG), optical coherence tomography (OCT), and time-average WSS (TAWSS) and topological shear variation index (TSVI) derived from three-dimensional angiography were obtained. RESULTS One hundred five vessels (median FFR 0.70 [Interquartile range (IQR) 0.56-0.77]) had combined PPG and WSS analyses. TSVI was correlated with PPG (r = 0.47, [95% Confidence Interval (95% CI) 0.30-0.65], p < 0.001). Vessels with a focal CAD (PPG above the median value of 0.67) had significantly higher TAWSS (14.8 [IQR 8.6-24.3] vs. 7.03 [4.8-11.7] Pa, p < 0.001) and TSVI (163.9 [117.6-249.2] vs. 76.8 [23.1-140.9] m-1, p < 0.001). In the 51 vessels with baseline OCT, TSVI was associated with plaque rupture (OR 1.01 [1.00-1.02], p = 0.024), PPG with the extension of lipids (OR 7.78 [6.19-9.77], p = 0.003), with the presence of thin-cap fibroatheroma (OR 2.85 [1.11-7.83], p = 0.024) and plaque rupture (OR 4.94 [1.82 to 13.47], p = 0.002). CONCLUSIONS Focal and diffuse coronary artery disease, defined using coronary physiology, are associated with differential WSS profiles. Pullback pressure gradients and WSS profiles are associated with atherosclerotic plaque phenotypes. Focal disease (as identified by high PPG) and high TSVI are associated with high-risk plaque features. CLINICAL TRIAL REGISTRATION https://clinicaltrials,gov/ct2/show/NCT03782688.
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Affiliation(s)
- Alessandro Candreva
- Department of Cardiology, Zurich University Hospital, Zurich, Switzerland; Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; PoliTo(BIO) Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Diego Gallo
- PoliTo(BIO) Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Daniel Munhoz
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, Italy; Department of internal medicine, University of Campinas (Unicamp), Campinas, Brazil
| | - Maurizio Lodi Rizzini
- PoliTo(BIO) Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Takuya Mizukami
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; Department of Cardiology, Showa University School of Medicine, Tokyo, Japan
| | - Ruiko Seki
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium
| | - Koshiro Sakai
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium
| | - Jeroen Sonck
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, Italy
| | - Valentina Mazzi
- PoliTo(BIO) Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Brian Ko
- Monash Cardiovascular Research Centre, Monash University and Monash Heart, Monash Health, Clayton, Victoria, Australia
| | | | | | - Michael Maeng
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Hiromasa Otake
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; Department of Cardiology, Aichi Medical University, Aichi, Japan
| | - Bon-Kwon Koo
- Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, South Korea
| | - Toshiro Shinke
- Department of Cardiology, Showa University School of Medicine, Tokyo, Japan
| | | | - Daniele Andreini
- Department of Cardiology, IRCCS Ospedale Galeazzi-Sant'Ambrogio, Milan, Italy and Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Emanuele Gallinoro
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; Department of Cardiology, IRCCS Ospedale Galeazzi-Sant'Ambrogio, Milan, Italy and Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Barbara E Stähli
- Department of Cardiology, Zurich University Hospital, Zurich, Switzerland; University of Zurich, Zurich, Switzerland
| | - Christian Templin
- Department of Cardiology, Zurich University Hospital, Zurich, Switzerland
| | - Claudio Chiastra
- PoliTo(BIO) Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Bernard De Bruyne
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium; Department of Cardiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Umberto Morbiducci
- PoliTo(BIO) Med Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Carlos Collet
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium.
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12
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Kumar P, Yan JZ, Rauch N, Dabiri S, Rauch W. Lagrangian solver for coupling hydrodynamics with biokinetic conversion modelling in anaerobic digesters. Water Res 2024; 252:121211. [PMID: 38309059 DOI: 10.1016/j.watres.2024.121211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/14/2024] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
Conventional anaerobic digestion models used in wastewater treatment plants suffer from inaccuracies due to the limited consideration given to hydrodynamics within the digester tank. A solution to this is to combine computational fluid dynamics simulations with anaerobic models. This paper introduces a novel methodology in the form of a software toolbox that implements the standard anaerobic digestion model no.1 in C++ and can interface with particle-based Lagrangian simulations. This method provides significantly more insights into the biochemical conversion process by accounting for the impact of the hydrodynamics on the biochemical reactions. The paper presents the background of the method along with a conceptual and numerical verification. It also presents a case study of a 3D lab scale digester comparing the results from the solver with the standard anaerobic digestion model. This integrated approach can be used by operators and designers for optimisations and also for predictive modelling.
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Affiliation(s)
- Prashant Kumar
- Room 312, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria
| | - Jeremy Z Yan
- Room 312, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria
| | - Nikolaus Rauch
- Room 3N04, Interactive Graphics and Simulation Group, University of Innsbruck, Technikerstrasse 21a, Innsbruck, 6020, Austria
| | - Soroush Dabiri
- Room 312, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria
| | - Wolfgang Rauch
- Room 311, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria.
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Paliwal N, Park HC, Mao Y, Hong SJ, Lee Y, Spragg DD, Calkins H, Trayanova NA. Slow blood-flow in the left atrial appendage is associated with stroke in atrial fibrillation patients. Heliyon 2024; 10:e26858. [PMID: 38449599 PMCID: PMC10915374 DOI: 10.1016/j.heliyon.2024.e26858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 02/16/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024] Open
Abstract
Background Atrial fibrillation (AF) patients are at high risk of stroke with ∼90% clots originating from the left atrial appendage (LAA). Clinical understanding of blood-flow based parameters and their potential association with stroke for AF patients remains poorly understood. We hypothesize that slow blood-flow either in the LA or the LAA could lead to the formation of blood clots and is associated with stroke for AF patients. Methods We retrospectively collected cardiac CT images of paroxysmal AF patients and dichotomized them based on clinical event of previous embolic event into stroke and non-stroke groups. After image segmentation to obtain 3D LA geometry, patient-specific blood-flow analysis was performed to model LA hemodynamics. In terms of geometry, we calculated area of the pulmonary veins (PVs), mitral valve, LA and LAA, orifice area of LAA and volumes of LA and LAA and classified LAA morphologies. For hemodynamic assessment, we quantified blood flow velocity, wall shear stress (WSS, blood-friction on LA wall), oscillatory shear index (OSI, directional change of WSS) and endothelial cell activation potential (ECAP, ratio of OSI and WSS quantifying slow and oscillatory flow) in the LA as well as the LAA. Statistical analysis was performed to compare the parameters between the groups. Results Twenty-seven patients were included in the stroke and 28 in the non-stroke group. Examining geometrical parameters, area of left inferior PV was found to be significantly higher in the stroke group as compared to non-stroke group (p = 0.026). In terms of hemodynamics, stroke group had significantly lower blood velocity (p = 0.027), WSS (p = 0.018) and higher ECAP (p = 0.032) in the LAA as compared to non-stroke group. However, LAA morphologic type did not differ between the two groups. This suggests that stroke patients had significantly slow and oscillatory circulating blood-flow in the LAA, which might expose it to potential thrombogenesis. Conclusion Slow flow in the LAA alone was associated with stroke in this paroxysmal AF cohort. Patient-specific blood-flow analysis can potentially identify such hemodynamic conditions, aiding in clinical stroke risk stratification of AF patients.
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Affiliation(s)
- Nikhil Paliwal
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD, USA
| | - Hwan-Cheol Park
- Division of Cardiology, Department of Internal Medicine, Hanyang University College of Medicine, Guri City, Republic of Korea
| | - Yuncong Mao
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Su Jin Hong
- Department of Radiology, Hanyang University Guri Hospital, Hanyang University College of Medicine, Republic of Korea
| | - Yonggu Lee
- Division of Cardiology, Department of Internal Medicine, Hanyang University College of Medicine, Guri City, Republic of Korea
| | - David D. Spragg
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hugh Calkins
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Natalia A. Trayanova
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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Zablah JE, Shorofsky MJ, Cao K, Mukherjee D. Computational Fluid Dynamic Assessment of Patients with Congenital Heart Disease from 3D Rotational Angiography. Pediatr Cardiol 2024:10.1007/s00246-024-03443-7. [PMID: 38489092 DOI: 10.1007/s00246-024-03443-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/02/2024] [Indexed: 03/17/2024]
Abstract
For congenital heart disease patients, multiple imaging modalities are needed to discern anatomy and functional information such as differential blood flow. During cardiac catheterization, 3D rotational angiography (3DRA) can provide CTA-like images, enabling anatomical information and intraprocedural guidance. We seek to establish whether unique aspects of this technique can also generate quantitative functional blood flow information. We propose that systematic integration of 3DRA imaging, catheter hemodynamic information, and computational fluid dynamics (CFD), can provide quantitative information regarding blood flow dynamics and energetics, without additional imaging or procedures. We report a single center retrospective feasibility study comprising four patients with 3DRA imaging and a complete set of hemodynamic data. 3DRA was processed and segmented to reconstruct vascular regions of interest (ROI), and a computational grid for CFD modeling of blood flow through the ROI was generated. Blood flow was simulated by integrating catheter hemodynamic data to devise boundary conditions at vascular ROI inlets and outlets. The 3DRA-based workflow successfully generated key computational outputs commonly used for cardiovascular applications, including flow patterns, distribution fractions, wall shear stress. Computational outputs obtained were as detailed and resolved as those obtained from more commonly used CT or MR angiography. Accuracy was confirmed by comparing computed flow distributions with measurements for 2 cases, showing less than 2.0% error from the measured data. Systematic integration of catheter hemodynamic information, 3DRA imaging, and CFD modeling, provides an effective and feasible alternative to obtain important quantitative blood flow information and visualization, without additional imaging.
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Affiliation(s)
- Jenny E Zablah
- Children's Hospital of Colorado Heart Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Michael J Shorofsky
- Children's Hospital of Colorado Heart Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kelly Cao
- Biomedical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Debanjan Mukherjee
- Paul M Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA.
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15
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Malatos S, Fazzini L, Raptis A, Nana P, Kouvelos G, Tasso P, Gallo D, Morbiducci U, Xenos MA, Giannoukas A, Matsagkas M. Evaluation of hemodynamic properties after chimney and fenestrated endovascular aneurysm repair. Ann Vasc Surg 2024:S0890-5096(24)00093-1. [PMID: 38492732 DOI: 10.1016/j.avsg.2023.12.084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/14/2023] [Accepted: 12/16/2023] [Indexed: 03/18/2024]
Abstract
OBJECTIVES Fenestrated (FEVAR) and chimney (ChEVAR) endovascular aortic repair have been applied in anatomically suitable complex aortic aneurysms. However, local hemodynamic changes may occur after repair. This study aimed to compare FEVAR's and ChEVAR's hemodynamic properties, focusing on visceral arteries. METHODS Pre- and post-operative computed tomography angiographies (CTAs) have been used to reconstruct patient-based models. Data of three patients, for each modality, were analyzed. Following geometric reconstruction, computational fluid dynamics (CFD) simulations were used to extract near-wall and intravascular hemodynamic indicators, as pressure drops, velocity, wall shear stress (WSS), time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT) and local normalized helicity (LNH). RESULTS An overall improvement in hemodynamics was detected after repair, with either technique. Preoperatively, a disturbed pro-thrombotic WSS profile was recorded in several zones of the sac. The LNH results showed a better organization of the helical structures at post-operative setting, decreasing thrombus formation, with both modalities. Similarly, TAWSS increased and OSI decreased post-operatively, signaling non-disturbed blood flow. The RRT was locally reduced. The flow in visceral arteries tended to be more streamlined in ChEVAR, compared to evident recirculation regions at renal and superior mesenteric artery fenestrations (p=0.06). CONCLUSION ChEVAR and FEVAR seem to improve hemodynamics towards normal values with a reduction of recirculation zones in the main graft and aortic branches. Visceral artery flow comparison revealed that ChEVAR tended to present lower recirculation regions at parallel grafts' entries while FEVAR showed less intense flow regurgitation in visceral stents.
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Affiliation(s)
- Stavros Malatos
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece.
| | - Laura Fazzini
- Department of Mechanical and Aerospace Engineering, Biomedical engineering, Politecnico di Torino, Torino, Italy.
| | - Anastasios Raptis
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece.
| | - Petroula Nana
- Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
| | - George Kouvelos
- Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
| | - Paola Tasso
- Department of Mechanical and Aerospace Engineering, Biomedical engineering, Politecnico di Torino, Torino, Italy.
| | - Diego Gallo
- Department of Mechanical and Aerospace Engineering, Biomedical engineering, Politecnico di Torino, Torino, Italy.
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Biomedical engineering, Politecnico di Torino, Torino, Italy.
| | - Michail A Xenos
- Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece; Department of Mathematics, Section of Applied and Computational Mathematics, University of Ioannina, Ioannina, Greece.
| | - Athanasios Giannoukas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece; Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Miltiadis Matsagkas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece; Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
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Sicard RM, Frank-Ito DO. Parameter characteristics in intranasal drug delivery: A key to targeting medications to the olfactory airspace. Clin Biomech (Bristol, Avon) 2024; 114:106231. [PMID: 38507865 DOI: 10.1016/j.clinbiomech.2024.106231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 02/23/2024] [Accepted: 03/12/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND The nose is a viable pathway for topical drug delivery to the olfactory cleft for treatment of obstructive smell loss and nose-to-brain drug delivery. This study investigates how variations in nasal vestibule morphology influence intranasal spray drug transport to the olfactory cleft and olfactory roof/bulb regions. METHODS The unilateral nasal vestibule morphology in three healthy subjects with healthy normal nasal anatomy was classified as Elongated (Subject DN001), Notched (Subject DN002), and Standard (Subject DN003). Computational fluid and particle dynamics modelling were used to simulate nasal airflow and drug particle transport to the olfactory cleft and olfactory roof/bulb regions in each subject-specific nasal cavity. To evaluate highest drug depositions in these regions, the particle transport simulations involved extensive parameter combination analyses: 6 inspiratory flow rates mimicking resting to sniffing (10-50 L/min); 5 spray release locations (Top, Bottom, Central, Lateral, and Medial); 5 head positions (Upright, Tilted Forward, Tilted Back, Supine, and Mygind); 3 particle velocities (1, 5, and 10 m/s); 350,000 μm-particles (1-100 μm) and 346,500 nanoparticles (10-990 nm). FINDINGS Particle size groups with highest depositions in olfactory cleft: DN001 left = 28.4% at 11-20 μm, right = 75.3% at 6-10 μm; DN002 left = 16.8% at 1-5 μm, right = 45.3% at 30-40 nm; DN003 left = 29.1% at 21-30 μm, right = 15.9% at 6-10 μm. Highest depositions in olfactory roof/bulb: DN001 left = 6.5% at 11-20 μm, right = 26.4% at 11-20 μm; DN002 left = 3.6% at 1-5 μm, right = 2.6% at 1-5 μm; DN003 left = 2.8% at 21-30 μm, right = 1.7% at 31-40 μm. INTERPRETATION DN001 (Elongated nasal vestibule) had the most deposition in the olfactory regions. Micron-particles size groups generally had better deposition in the olfactory regions.
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Affiliation(s)
- Ryan M Sicard
- Department of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, NC, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Dennis O Frank-Ito
- Department of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, NC, USA; Computational Biology & Bioinformatics PhD Program, Duke University, Durham, NC, USA; Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA.
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Yu M, Li Y, Zhao M, Huang Z, Zhou N, Jin H. Computational fluid dynamics investigation on the irrigation of a real root canal with a side-vented needle. BMC Oral Health 2024; 24:321. [PMID: 38461300 PMCID: PMC10924978 DOI: 10.1186/s12903-024-03966-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 02/01/2024] [Indexed: 03/11/2024] Open
Abstract
BACKGROUND Root canal therapy is one of the main treatments for root canal diseases, and effective irrigation is the key to successful treatment. Side-vented needle is one of the commonly used needle types in clinic. In the real root canal, due to the influence of the curvature of the root canal, the irrigation flow field in different needle directions shows obvious differences. At the same time, changes in root canal curvature and working depth will lead to changes in irrigation efficiency and the flow field. Both the mainstream of the irrigation flow and the shear stress near the wall changes significant. Consequently, either the replacement in the root canal or the removal efficiency of the smear layers is apparently modified. MATERIALS AND METHODS In this paper, the permanent root canal of the maxillary first molar prepared until 15/04 were scanned by micro-CT, and then imported into the software for 3D reconstruction. The key parameters of flushing efficiency of 30G side needle at different working depths of 4.75 mm, 5 mm, 5.25 mm and 5.5 mm were compared. Meanwhile, the simulated models with different curvatures of 0°, 5°, 10°, 20° and 30° based on the real root canal were reconstructed to investigate the curvature effect on the irrigation efficiency. RESULTS The results show that moderate working depth (such as 4.75 mm and 5.25 mm in present paper) helps to improve the replacement capacity of irrigation flow. At the same time, the apical pressure decreased as the working depth increased. The curvature of the root canal seriously affects the removal depth of the smear layers of the root canal. A root canal with a large curvature (especially 20° and 30°) can significantly improve the difficulty of irrigation. CONCLUSIONS (1) Moderate working depth helps to improve the displacement capacity, the ERD of the irrigation flow is generally improved at the working depths of 4.75 mm and 5.25 mm, and the apical pressure will decrease with the increase of working depth. (2) The large curvature of the root canal can significantly improve the difficulty of irrigation. The curvature of the root canal can severely influence the removal depth of the smear layer on the wall. It can be found both the span and the depth of the ESS for little curvatures (5° and 10°) root canals are higher than those for large curvatures (20° and 30°).
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Affiliation(s)
- Mingzhou Yu
- School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, 310027, People's Republic of China
- Aerosol Science and Technology Laboratory, China Jiliang University, Hangzhou, 310018, People's Republic of China
| | - Yi Li
- Aerosol Science and Technology Laboratory, China Jiliang University, Hangzhou, 310018, People's Republic of China
| | - Mengdie Zhao
- Aerosol Science and Technology Laboratory, China Jiliang University, Hangzhou, 310018, People's Republic of China
| | - Zhengqiu Huang
- Aerosol Science and Technology Laboratory, China Jiliang University, Hangzhou, 310018, People's Republic of China
| | - Na Zhou
- Aerosol Science and Technology Laboratory, China Jiliang University, Hangzhou, 310018, People's Republic of China.
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, 310006, People's Republic of China.
| | - Hanhui Jin
- School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, 310027, People's Republic of China.
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, People's Republic of China.
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Chidyagwai SG, Kaplan MS, Jensen CW, Chen JS, Chamberlain RC, Hill KD, Barker PCA, Slesnick TC, Randles A. Surgical Modulation of Pulmonary Artery Shear Stress: A Patient-Specific CFD Analysis of the Norwood Procedure. Cardiovasc Eng Technol 2024:10.1007/s13239-024-00724-3. [PMID: 38459240 DOI: 10.1007/s13239-024-00724-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 02/19/2024] [Indexed: 03/10/2024]
Abstract
PURPOSR This study created 3D CFD models of the Norwood procedure for hypoplastic left heart syndrome (HLHS) using standard angiography and echocardiogram data to investigate the impact of shunt characteristics on pulmonary artery (PA) hemodynamics. Leveraging routine clinical data offers advantages such as availability and cost-effectiveness without subjecting patients to additional invasive procedures. METHODS Patient-specific geometries of the intrathoracic arteries of two Norwood patients were generated from biplane cineangiograms. "Virtual surgery" was then performed to simulate the hemodynamics of alternative PA shunt configurations, including shunt type (modified Blalock-Thomas-Taussig shunt (mBTTS) vs. right ventricle-to-pulmonary artery shunt (RVPAS)), shunt diameter, and pulmonary artery anastomosis angle. Left-right pulmonary flow differential, Qp/Qs, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were evaluated. RESULTS There was strong agreement between clinically measured data and CFD model output throughout the patient-specific models. Geometries with a RVPAS tended toward more balanced left-right pulmonary flow, lower Qp/Qs, and greater TAWSS and OSI than models with a mBTTS. For both shunt types, larger shunts resulted in a higher Qp/Qs and higher TAWSS, with minimal effect on OSI. Low TAWSS areas correlated with regions of low flow and changing the PA-shunt anastomosis angle to face toward low TAWSS regions increased TAWSS. CONCLUSION Excellent correlation between clinically measured and CFD model data shows that 3D CFD models of HLHS Norwood can be developed using standard angiography and echocardiographic data. The CFD analysis also revealed consistent changes in PA TAWSS, flow differential, and OSI as a function of shunt characteristics.
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Affiliation(s)
- Simbarashe G Chidyagwai
- Department of Biomedical Engineering, Duke University, 534 Research Drive, 27708, Durham, NC, USA
| | - Michael S Kaplan
- Department of Biomedical Engineering, Duke University, 534 Research Drive, 27708, Durham, NC, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
| | - Christopher W Jensen
- Department of Biomedical Engineering, Duke University, 534 Research Drive, 27708, Durham, NC, USA
- Division of Cardiovascular and Thoracic Surgery, Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - James S Chen
- Department of Biomedical Engineering, Duke University, 534 Research Drive, 27708, Durham, NC, USA
| | - Reid C Chamberlain
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Kevin D Hill
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Piers C A Barker
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Timothy C Slesnick
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Amanda Randles
- Department of Biomedical Engineering, Duke University, 534 Research Drive, 27708, Durham, NC, USA.
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19
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Wiśniewski K, Tyfa Z, Reorowicz P, Brandel MG, Adel T, Obidowski D, Jóźwik K, Levy ML. Numerical flow experiment for assessing predictors for cerebrovascular accidents in patients with PHACES syndrome. Sci Rep 2024; 14:5161. [PMID: 38431727 PMCID: PMC10908848 DOI: 10.1038/s41598-024-55345-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 02/22/2024] [Indexed: 03/05/2024] Open
Abstract
There is an increased risk of cerebrovascular accidents (CVA) in individuals with PHACES, yet the precise causes are not well understood. In this analysis, we aimed to examine the role of arteriopathy in PHACES syndrome as a potential contributor to CVA. We analyzed clinical and radiological data from 282 patients with suspected PHACES syndrome. We analyzed clinical features, including the presence of infantile hemangioma and radiological features based on magnetic resonance angiography or computed tomography angiography, in individuals with PHACES syndrome according to the Garzon criteria. To analyze intravascular blood flow, we conducted a simulation based on the Fluid-Structure Interaction (FSI) method, utilizing radiological data. The collected data underwent statistical analysis. Twenty patients with PHACES syndrome were included. CVAs were noted in 6 cases. Hypoplasia (p = 0.03), severe tortuosity (p < 0.01), absence of at least one main cerebral artery (p < 0.01), and presence of persistent arteries (p = 0.01) were associated with CVAs, with severe tortuosity being the strongest predictor. The in-silico analysis showed that the combination of hypoplasia and severe tortuosity resulted in a strongly thrombogenic environment. Severe tortuosity, combined with hypoplasia, is sufficient to create a hemodynamic environment conducive to thrombus formation and should be considered high-risk for cerebrovascular accidents (CVAs) in PHACES patients.
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Affiliation(s)
- Karol Wiśniewski
- Department of Neurosurgery, University of California, San Diego-Rady Children's Hospital, San Diego, CA, 92123, USA.
- Department of Neurosurgery and Neurooncology, Medical University of Lodz, Barlicki University Hospital, Kopcińskiego 22, 90-153, Lodz, Poland.
- Institute of Turbomachinery, Lodz University of Technology, 219/223 Wolczanska Str., 90-924, Lodz, Poland.
| | - Zbigniew Tyfa
- Institute of Turbomachinery, Lodz University of Technology, 219/223 Wolczanska Str., 90-924, Lodz, Poland
| | - Piotr Reorowicz
- Institute of Turbomachinery, Lodz University of Technology, 219/223 Wolczanska Str., 90-924, Lodz, Poland
| | - Michael G Brandel
- Department of Neurosurgery, University of California, San Diego-Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Thomas Adel
- Department of Neurosurgery, University of California, San Diego-Rady Children's Hospital, San Diego, CA, 92123, USA
- Medical University of Vienna, Spitalgasse 23 Str., 1090, Wien, Austria
| | - Damian Obidowski
- Institute of Turbomachinery, Lodz University of Technology, 219/223 Wolczanska Str., 90-924, Lodz, Poland
| | - Krzysztof Jóźwik
- Institute of Turbomachinery, Lodz University of Technology, 219/223 Wolczanska Str., 90-924, Lodz, Poland
| | - Michael L Levy
- Department of Neurosurgery, University of California, San Diego-Rady Children's Hospital, San Diego, CA, 92123, USA
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20
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Wickramarachchi A, Gregory SD, Burrell AJC, Khamooshi M. Flow characterization of Maquet and Bio-Medicus multi-stage drainage cannulae during venoarterial extracorporeal membrane oxygenation. Comput Biol Med 2024; 171:108135. [PMID: 38373368 DOI: 10.1016/j.compbiomed.2024.108135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/15/2024] [Accepted: 02/12/2024] [Indexed: 02/21/2024]
Abstract
BACKGROUND Drainage cannulae extract blood from a patient during venoarterial extracorporeal membrane oxygenation (VA ECMO), a treatment that temporarily supports patients undergoing severe heart and/or lung dysfunction. Currently, the two most commonly used multi-stage drainage cannulae are manufactured by Maquet and Bio-Medicus, but their designs vary in many aspects which impacts the generated flow dynamics. Therefore, this study aimed to use computational fluid dynamics (CFD) to explore the flow characteristics of the aforementioned cannulae and their impact on complications such as thrombosis. METHODS The Maquet and Bio-Medicus cannulae were 3D modelled within a patient-specific geometry of the venous vasculature taken from a computed tomography scan of a patient undergoing VA ECMO. A drainage flow rate of 4 L/min was assigned to each cannula. Lastly, a stress blended eddy simulation turbulence model was employed to resolve bulk flow turbulence. RESULTS The proximal row of side holes in both cannulae generated high intensity counter-rotating vortices, thus generating supraphysiological shear. These proximal rows were also responsible for the majority of flow extraction in both cannulae (>1.6 L/min). Despite identical simulation settings, each cannulae had differing impacts on global flow dynamics. For instance, the Bio-Medicus model produced a total stagnant blood volume of 25.6 ml, compared to 17.8 ml the Maquet cannula, thereby increasing the risk of thrombosis. CONCLUSIONS Overall, our results demonstrate that differences in design clearly impact flow dynamics and risk of complications. Therefore, further work in optimizing cannula design may be beneficial to prevent harmful flow characteristics.
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Affiliation(s)
- Avishka Wickramarachchi
- Cardio-Respiratory Engineering and Technology Laboratory, Department of Mechanical and Aerospace Engineering, Monash University, 631 Blackburn Road, Clayton, VIC, Australia.
| | - Shaun D Gregory
- Cardio-Respiratory Engineering and Technology Laboratory, Department of Mechanical and Aerospace Engineering, Monash University, 631 Blackburn Road, Clayton, VIC, Australia
| | - Aidan J C Burrell
- Department of Intensive Care, Alfred Hospital, 55 Commercial Road, Melbourne, VIC, Australia; Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, VIC, Australia
| | - Mehrdad Khamooshi
- Cardio-Respiratory Engineering and Technology Laboratory, Department of Mechanical and Aerospace Engineering, Monash University, 631 Blackburn Road, Clayton, VIC, Australia
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21
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Hou C, Lu Y, Ma Y, Li Q, Liu C, Lu M, Cao C, Liu J. Investigation of the predictive value of a novel algorithm based on coronary CT angiography regarding fractional flow reserve and revascularization in patients with stable coronary artery disease. Heart Vessels 2024; 39:195-205. [PMID: 37897523 DOI: 10.1007/s00380-023-02324-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 09/28/2023] [Indexed: 10/30/2023]
Abstract
Fractional flow reserve (FFR) has been established as a gold standard for functional coronary ischemia. At present, the FFR can be calculated from coronary computed tomography angiography (CCTA) images (CT-FFR). Previous studies have suggested that CT-FFR outperforms CCTA and invasive coronary angiography (ICA) in determining hemodynamic significance of stenoses. Recently, a novel automatical algorithm of CT-FFR called RuiXin-FFR has been developed. The present study is designed to investigate the predictive value of this algorithm and its value in therapeutic decision making. The present study retrospectively included 166 patients with stable coronary artery disease (CAD) who underwent CCTA screening and diagnostic ICA examination at Peking University People's Hospital, in 73 of whom wire-derived FFR was also measured. CT-FFR analyses were performed with a dedicated software. All patients were followed up for at least 1 year. We validated the accuracy of RuiXin-FFR with invasive FFR as the standard of reference, and investigated the role of RuiXin-FFR in predicting treatment strategy and long-term prognosis. The mean age of the patients was 63.3 years with 63.9% male. The CT-FFR showed a moderate correlation with wire-derived FFR (r = 0.542, p < 0.0001) and diagnostic accuracy of 87.6% to predict myocardial ischemia (AUC: 0.839, 95% CI 0.728-0.950), which was significantly higher than CCTA and ICA. In the multivariate logistic regression analysis, CT-FFR ≤ 0.80 was an independent predictor of undergoing coronary revascularization (OR: 45.54, 95% CI 12.03-172.38, p < 0.0001), whereas CT-FFR > 0.80 was an independent predictor of non-obstructive CAD (OR: 14.67, 95% CI 5.42-39.72, p < 0.0001). Reserving ICA and revascularization for vessels with positive CT-FFR could have reduced the rate of ICA by 29.6%, lowered the rate of ICA in vessels without stenosis > 50% by 11.7%, and increased the rate of revascularization in patients receiving ICA by 21.2%. The average follow-up was 23.7 months, and major adverse cardiovascular events (MACE) occurred in 11 patients. The rate of MACE was significantly lower in patients with CT-FFR > 0.80. The new algorithm of CT-FFR can be used to predict the invasive FFR. The RuiXin-FFR can also provide useful information for the screening of patients in whom further ICA is indeed needed and prognosis evaluation.
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Affiliation(s)
- Chang Hou
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Yahui Lu
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Yuliang Ma
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Qi Li
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Chuanfen Liu
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Mingyu Lu
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Chengfu Cao
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China
| | - Jian Liu
- Department of Cardiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China.
- Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Peking University People's Hospital, Beijing, China.
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22
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Dasnoy S, Illartin M, Queffelec J, Nkunku A, Peerboom C. Combined Effect of Shaking Orbit and Vial Orientation on the Agitation-Induced Aggregation of Proteins. J Pharm Sci 2024; 113:669-679. [PMID: 37611666 DOI: 10.1016/j.xphs.2023.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023]
Abstract
Orbital shaking in a glass vial is a commonly used forced degradation test to evaluate protein propensity for agitation-induced aggregation. Vial shaking in horizontal orientation has been widely recommended to maximize the air-liquid interface area while ensuring solution contact with the stopper. We evaluated the impact of shaking orbit diameter and frequency, and glass vial orientation (horizontal versus vertical) on the aggregation of three proteins prepared in surfactant-free formulation buffers. As soon as an orbit-specific frequency threshold was reached, an increase in turbidity was observed for the three proteins in vertical orientation only when using a 3 mm agitation orbit, and in horizontal orientation only when using a 30 mm agitation orbit. Orthogonal analyses confirmed turbidity was linked to protein aggregation. The most turbid samples had a visually more homogeneous appearance in vertical than in horizontal orientation, in line with the predicted dispersion of air and liquid phases obtained from computational fluid dynamics agitation simulations. Both shaking orbits were used to assess the performance of nonionic surfactants. We show that the propensity of a protein to aggregate in a vial agitated in horizontal or vertical orientation depends on the shaking orbit, and confirm that Brij® 58 and FM1000 prevent proteins from agitation-induced aggregation at lower concentrations than polysorbate 80.
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Affiliation(s)
| | - Marion Illartin
- UCB Pharma, Chemin du Foriest, 1420 Braine-l'Alleud, Belgium; Institut Mines-Télécom (IMT) Mines Albi, Allée des Sciences, 81000 Albi, France
| | - Julie Queffelec
- UCB Pharma, Chemin du Foriest, 1420 Braine-l'Alleud, Belgium; Institut Mines-Télécom (IMT) Mines Albi, Allée des Sciences, 81000 Albi, France
| | - Aubrey Nkunku
- UCB Pharma, Chemin du Foriest, 1420 Braine-l'Alleud, Belgium; ALTEN Belgium, Chaussée de Charleroi 112, 1060 Bruxelles, Belgium
| | - Claude Peerboom
- UCB Pharma, Chemin du Foriest, 1420 Braine-l'Alleud, Belgium
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23
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Manchester EL, Pirola S, Pirola S, Mastroiacovo G, Polvani G, Pontone G, Xu XY. Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics. Comput Biol Med 2024; 171:108123. [PMID: 38354498 DOI: 10.1016/j.compbiomed.2024.108123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/05/2024] [Accepted: 02/04/2024] [Indexed: 02/16/2024]
Abstract
Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects have yet to be evaluated in either bioprosthetic or aortic valve neocuspidization valve types in patient-specific settings. The aim of this study is to better understand turbulence production in the aorta and evaluate its effects on laminar and turbulent wall shear stress. Four patients with aortic valve disease were treated with either bioprosthetic valves (n=2) or aortic valve neocuspidization valvular repair (n=2). Aortic geometries were segmented from magnetic resonance images (MRI), and 4D flow MRI was used to derive physiological inlet and outlet boundary conditions. Pulsatile large-eddy simulations were performed to capture the full range of laminar, transitional and turbulence characteristics in the aorta. Turbulence was produced in all aortas with highest levels occurring during systolic deceleration. In the ascending aorta, turbulence production is attributed to a combination of valvular skew, valvular eccentricity, and ascending aortic dilation. In the proximal descending thoracic aorta, turbulence production is dependent on the type of arch-descending aorta connection (e.g., a narrowing or sharp bend) which induces flow separation. Laminar and turbulent wall shear stresses are of similar magnitude throughout late systolic deceleration and diastole, although turbulent wall shear stress magnitudes exceed laminar wall shear stresses between 27.3% and 61.1% of the cardiac cycle. This emphasises the significance of including turbulent wall shear stress to improve our comprehension of progressive arterial wall diseases. The findings of this study recommend that aortic valve treatments should prioritise minimising valvular eccentricity and skew in order to mitigate turbulence generation.
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Affiliation(s)
- Emily Louise Manchester
- Department of Chemical Engineering, Imperial College London, London, United Kingdom; Department of Fluids and Environment, The University of Manchester, Manchester, United Kingdom.
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, United Kingdom; Department of BioMechanical Engineering, Delft University of Technology, Delft, Netherlands.
| | - Sergio Pirola
- Department of Cardiovascular Surgery, Centro Cardiologico Monzino IRCCS, Milan, Italy
| | - Giorgio Mastroiacovo
- Department of Cardiovascular Surgery, Centro Cardiologico Monzino IRCCS, Milan, Italy
| | - Gianluca Polvani
- Department of Cardiovascular Surgery, Centro Cardiologico Monzino IRCCS, Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Gianluca Pontone
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy; Department of Perioperative Cardiology and Cardiovascular Imaging, Centro Cardiologico Monzino IRCCS, Milan, Italy
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom.
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24
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Su C, Yan H, Wang S, Ren L, Ren B, Yin J. The study of DIEA three dimensional reconstruction technique based on CTA in preoperative perforator selection. J Plast Reconstr Aesthet Surg 2024; 90:189-191. [PMID: 38394832 DOI: 10.1016/j.bjps.2024.01.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/16/2023] [Accepted: 01/29/2024] [Indexed: 02/25/2024]
Abstract
Preoperative selection of perforator is one of the key steps for successful surgery. The purpose of this study is to simulate the selection process of the perforator of the flap using the 3D models of the deep inferior epigastric artery (DIEA). A retrospective study was performed of women who underwent deep inferior epigastric perforator flap breast reconstruction from January 2011 to July 2021. Construct 3D models of the DIEA using computerized tomography angiography images, and then computational fluid dynamics simulations were performed. Correlation and regression analyses were used to analyze the geometric and hemodynamic parameters. Statistical analysis suggested that the outlet flow was positively correlated with the inlet area (r = 0.338, p = 0.000), outlet area (r = 0.840, p = 0.000), the average radius of the perforator (r = 0.592, p = 0.000), and negatively correlated with the length of perforator(r = -0.210, p = 0.024). The results of linear regression analysis showed that the outlet area (p = 0.000), the average radius (p = 0.000), and the length (p = 0.044) of the perforator were the influencing factors on outlet flow. In multiple perforators analysis, there was a significant difference in the total outlet flow among single perforator, double perforators, and triple perforators (p = 0.002). The successful implementation of this experiment provides a new approach for the selection of dominant perforators in the future.
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Affiliation(s)
- Cong Su
- The Department of Breast Oncoplastic Surgery, Tianjin Medical University Cancer Institute and Hospital; National Clinical Research Center for Cancer; Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education; Key Laboratory of Cancer Prevention and Treatment, Tianjin; Tianjin's Clinical Research Center for Cancer; The Sino-Russian Joint Research Center for Oncoplastic Breast Surgery, Tianjin 300060, China.
| | - Han Yan
- TMCC, College of Computer Science, Nankai University, No.38 of Tongyan Road, Jinnan District, Tianjin 300381, China.
| | - Shu Wang
- The Department of Breast Oncoplastic Surgery, Tianjin Medical University Cancer Institute and Hospital; National Clinical Research Center for Cancer; Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education; Key Laboratory of Cancer Prevention and Treatment, Tianjin; Tianjin's Clinical Research Center for Cancer; The Sino-Russian Joint Research Center for Oncoplastic Breast Surgery, Tianjin 300060, China.
| | - Lei Ren
- Medical Imaging Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin 300110, China.
| | - Bo Ren
- TMCC, College of Computer Science, Nankai University, No.38 of Tongyan Road, Jinnan District, Tianjin 300381, China.
| | - Jian Yin
- The Department of Breast Oncoplastic Surgery, Tianjin Medical University Cancer Institute and Hospital; National Clinical Research Center for Cancer; Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education; Key Laboratory of Cancer Prevention and Treatment, Tianjin; Tianjin's Clinical Research Center for Cancer; The Sino-Russian Joint Research Center for Oncoplastic Breast Surgery, Tianjin 300060, China.
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25
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Christierson L, Frieberg P, Lala T, Töger J, Liuba P, Revstedt J, Isaksson H, Hakacova N. Validation of fluid-structure interaction simulations of the opening phase of phantom mitral heart valves under physiologically inspired conditions. Comput Biol Med 2024; 171:108033. [PMID: 38430739 DOI: 10.1016/j.compbiomed.2024.108033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/22/2023] [Accepted: 01/26/2024] [Indexed: 03/05/2024]
Abstract
BACKGROUND AND OBJECTIVE Atrioventricular valve disease is a common cause of heart failure, and successful surgical or interventional outcomes are crucial. Patient-specific fluid-structure interaction (FSI) modeling may provide valuable insights into valve dynamics and guidance of valve repair strategies. However, lack of validation has kept FSI modeling from clinical implementation. Therefore, this study aims to validate FSI simulations against in vitro benchmarking data, based on clinically relevant parameters for evaluating heart valve disease. METHODS An FSI model that mimics the left heart was developed. The domain included a deformable mitral valve of different stiffnesses run with different inlet velocities. Five different cases were simulated and compared to in vitro data based on the pressure difference across the valve, the valve opening, and the velocity in the flow domain. RESULTS The simulations underestimate the pressure difference across the valve by 6.8-14 % compared to catheter measurements. Evaluation of the valve opening showed an underprediction of 5.4-7.3 % when compared to cine MRI, 2D Echo, and 3D Echo data. Additionally, the simulated velocity through the valve showed a 7.9-8.4 % underprediction in relation to Doppler Echo measurements. Qualitative assessment of the velocity profile in the ventricle and the streamlines of the flow in the domain showed good agreement of the flow behavior. CONCLUSIONS Parameters relevant to the diagnosis of heart valve disease estimated by FSI simulations showed good agreement when compared to in vitro benchmarking data, with differences small enough not to affect the grading of heart valve disease. The FSI model is thus deemed good enough for further development toward patient-specific cases.
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Affiliation(s)
- Lea Christierson
- Department of Clinical Sciences Lund, Pediatric Heart Center, Skåne University Hospital, Lund University, Lund, Sweden. Address: Barnhjärtcentrum mottagning, Skånes universitetssjukhus, Lasarettsgatan 48, 221 85, Lund, Sweden; Department of Biomedical Engineering, Lund University, Lund, Sweden. Address: Box 118, 221 00, Lund, Sweden.
| | - Petter Frieberg
- Department of Clinical Sciences Lund, Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden. Address: Box 177, 221 00, Lund, Sweden
| | - Tania Lala
- Department of Biomedical Engineering, Lund University, Lund, Sweden. Address: Box 118, 221 00, Lund, Sweden; Department of Clinical Sciences Lund, Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden. Address: Box 177, 221 00, Lund, Sweden
| | - Johannes Töger
- Department of Clinical Sciences Lund, Clinical Physiology, Skåne University Hospital, Lund University, Lund, Sweden. Address: Box 177, 221 00, Lund, Sweden
| | - Petru Liuba
- Department of Clinical Sciences Lund, Pediatric Heart Center, Skåne University Hospital, Lund University, Lund, Sweden. Address: Barnhjärtcentrum mottagning, Skånes universitetssjukhus, Lasarettsgatan 48, 221 85, Lund, Sweden
| | - Johan Revstedt
- Department of Energy Science, Lund University, Lund, Sweden. Address: Box 118, 221 00, Lund, Sweden
| | - Hanna Isaksson
- Department of Biomedical Engineering, Lund University, Lund, Sweden. Address: Box 118, 221 00, Lund, Sweden
| | - Nina Hakacova
- Department of Clinical Sciences Lund, Pediatric Heart Center, Skåne University Hospital, Lund University, Lund, Sweden. Address: Barnhjärtcentrum mottagning, Skånes universitetssjukhus, Lasarettsgatan 48, 221 85, Lund, Sweden
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26
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Satheesan MK, Tsang TW, Wong LT, Mui KW. The air we breathe: Numerical investigation of ventilation strategies to mitigate airborne dispersion of MERS-CoV in inpatient wards. Heliyon 2024; 10:e26159. [PMID: 38404798 PMCID: PMC10884507 DOI: 10.1016/j.heliyon.2024.e26159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 01/03/2024] [Accepted: 02/08/2024] [Indexed: 02/27/2024] Open
Abstract
Ventilation strategies for infection control in hospitals has been predominantly directed towards isolation rooms and operating theatres, with relatively less emphasis on perceived low risk spaces, such as general wards. Typically, the ventilation systems in general wards are intended to optimize patient thermal comfort and energy conservation. The emission of pathogens from exhalation activity, such as sneezing, by an undiagnosed infectious patient admitted to general wards, is a significant concern for infection outbreaks. However, the ventilation guidelines for general wards with respect to infection control are vague. This research article presents a numerical study on the effect of varying air change rates (3 h-1, 6 h-1, 9 h-1, 13 h-1) and exhaust flow rates (10%, 50% of supply air quantity) on the concentration of airborne pathogens in a mechanically ventilated general inpatient ward. The findings imply that the breathing zone directly above the source patient has the highest level of pathogen exposure, followed by the breathing zones at the bedside and adjacent patients close to the source patient. The dispersion of pathogens throughout the ward over time is also apparent. However, a key difference while adopting a lower ACH (3 h-1) and a higher ACH (13 h-1) in this study was that the latter had a significantly lower number of suspended pathogens in the breathing zone than the former. Thus, this research suggests high ventilation rates for general wards, contrary to current ventilation standards. In addition, combining a higher air change rate (13 h-1) with a high exhaust flow rate (50% of supply air) through a local exhaust grille dramatically reduced suspended pathogens within the breathing zone, further mitigating the risk of pathogen exposure for ward users. Therefore, this study presents an effective ventilation technique to dilute and eliminate airborne infectious pathogens, minimizing their concentration and the risk of infection.
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Affiliation(s)
- Manoj Kumar Satheesan
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Tsz Wun Tsang
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Ling Tim Wong
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Kwok Wai Mui
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
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Qiu Y, Ekström S, Valverde-Pérez B, Smets BF, Climent J, Domingo-Félez C, Cuenca RM, Plósz BG. Numerical modelling of surface aeration and N 2O emission in biological water resource recovery. Water Res 2024; 255:121398. [PMID: 38503179 DOI: 10.1016/j.watres.2024.121398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/15/2024] [Accepted: 02/27/2024] [Indexed: 03/21/2024]
Abstract
Biokinetic modelling of N2O production and emission has been extensively studied in the past fifteen years. In contrast, the physical-chemical hydrodynamics of activated sludge reactor design and operation, and their impact on N2O emission, is less well understood. This study addresses knowledge gaps related to the systematic identification and calibration of computational fluid dynamic (CFD) simulation models. Additionally, factors influencing reliable prediction of aeration and N2O emission in surface aerated oxidation ditch-type reactor types are evaluated. The calibrated model accurately predicts liquid sensor measurements obtained in the Lynetten Water Resource Recovery Facility (WRRF), Denmark. Results highlight the equal importance of design and operational boundary conditions, alongside biokinetic parameters, in predicting N2O emission. Insights into the limitations of calibrating gas mass-transfer processes in two-phase CFD models of surface aeration systems are evaluated.
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Affiliation(s)
- Yuge Qiu
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK.
| | - Sara Ekström
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs., Lyngby, Denmark
| | - Borja Valverde-Pérez
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs., Lyngby, Denmark
| | - Barth F Smets
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs., Lyngby, Denmark
| | - Javier Climent
- Department of Mechanical Engineering and Construction, Universitat Jaume I, Av. Vicent Sos Baynat, s/n 12071 Castellón (Spain)
| | - Carlos Domingo-Félez
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs., Lyngby, Denmark
| | - Raúl Martínez Cuenca
- Department of Mechanical Engineering and Construction, Universitat Jaume I, Av. Vicent Sos Baynat, s/n 12071 Castellón (Spain)
| | - Benedek G Plósz
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK; SWING - Department of Built Environment, Oslo Metropolitan University, St Olavs plass 0130, Oslo, Norway
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Rossinelli D, Fourestey G, Killer HE, Neutzner A, Iaccarino G, Remonda L, Berberat J. Large-scale in-silico analysis of CSF dynamics within the subarachnoid space of the optic nerve. Fluids Barriers CNS 2024; 21:20. [PMID: 38419077 PMCID: PMC10900650 DOI: 10.1186/s12987-024-00518-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND Impaired cerebrospinal fluid (CSF) dynamics is involved in the pathophysiology of neurodegenerative diseases of the central nervous system and the optic nerve (ON), including Alzheimer's and Parkinson's disease, as well as frontotemporal dementia. The smallness and intricate architecture of the optic nerve subarachnoid space (ONSAS) hamper accurate measurements of CSF dynamics in this space, and effects of geometrical changes due to pathophysiological processes remain unclear. The aim of this study is to investigate CSF dynamics and its response to structural alterations of the ONSAS, from first principles, with supercomputers. METHODS Large-scale in-silico investigations were performed by means of computational fluid dynamics (CFD) analysis. High-order direct numerical simulations (DNS) have been carried out on ONSAS geometry at a resolution of 1.625 μm/pixel. Morphological changes on the ONSAS microstructure have been examined in relation to CSF pressure gradient (CSFPG) and wall strain rate, a quantitative proxy for mass transfer of solutes. RESULTS A physiological flow speed of 0.5 mm/s is achieved by imposing a hydrostatic pressure gradient of 0.37-0.67 Pa/mm across the ONSAS structure. At constant volumetric rate, the relationship between pressure gradient and CSF-accessible volume is well captured by an exponential curve. The ONSAS microstructure exhibits superior mass transfer compared to other geometrical shapes considered. An ONSAS featuring no microstructure displays a threefold smaller surface area, and a 17-fold decrease in mass transfer rate. Moreover, ONSAS trabeculae seem key players in mass transfer. CONCLUSIONS The present analysis suggests that a pressure drop of 0.1-0.2 mmHg over 4 cm is sufficient to steadily drive CSF through the entire subarachnoid space. Despite low hydraulic resistance, great heterogeneity in flow speeds puts certain areas of the ONSAS at risk of stagnation. Alterations of the ONSAS architecture aimed at mimicking pathological conditions highlight direct relationships between CSF volume and drainage capability. Compared to the morphological manipulations considered herein, the original ONSAS architecture seems optimized towards providing maximum mass transfer across a wide range of pressure gradients and volumetric rates, with emphasis on trabecular structures. This might shed light on pathophysiological processes leading to damage associated with insufficient CSF flow in patients with optic nerve compartment syndrome.
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Affiliation(s)
- Diego Rossinelli
- Institute for Computational and Mathematical Engineering (ICME), Center for Turbulence Research, Stanford University, Stanford, CA, 94305-3024, USA.
| | - Gilles Fourestey
- Scientific IT & Application Support (SCITAS), Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | | | - Albert Neutzner
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Gianluca Iaccarino
- Institute for Computational and Mathematical Engineering (ICME), Center for Turbulence Research, Stanford University, Stanford, CA, 94305-3024, USA
| | - Luca Remonda
- Institute of Neuroradiology, Kantonsspital Aarau, 5000, Aarau, Switzerland
| | - Jatta Berberat
- Institute of Neuroradiology, Kantonsspital Aarau, 5000, Aarau, Switzerland
- Geriatric Psychiatry, Department of Psychiatry, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
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Su B, Palahnuk H, Harbaugh T, Rizk E, Hazard W, Chan A, Bernstein J, Weinsaft JW, Manning KB. Numerical Study on the Impact of Central Venous Catheter Placement on Blood Flow in the Cavo-Atrial Junction. Ann Biomed Eng 2024:10.1007/s10439-024-03463-7. [PMID: 38407724 DOI: 10.1007/s10439-024-03463-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
An in silico study is performed to investigate fluid dynamic effects of central venous catheter (CVC) placement within patient-specific cavo-atrial junctions. Prior studies show the CVC infusing a liquid, but this study focuses on the placement without any liquid emerging from the CVC. A 7 or 15-French double-lumen CVC is placed virtually in two patient-specific models; the CVC tip location is altered to understand its effect on the venous flow field. Results show that the CVC impact is trivial on flow in the superior vena cava when the catheter-to-vein ratio ranges from 0.15 to 0.33. Results further demonstrate that when the CVC tip is directly in the right atrium, flow vortices in the right atrium result in elevated wall shear stress near the tip hole. A recirculation region characterizes a spatially variable flow field inside the CVC side hole. Furthermore, flow stagnation is present near the internal side hole corners but an elevated wall shear stress near the curvature of the side hole's exit. These results suggest that optimal CVC tip location is within the superior vena cava, so as to lower the potential for platelet activation due to elevated shear stresses and that CVC geometry and location depth in the central vein significantly influences the local CVC fluid dynamics. A thrombosis model also shows thrombus formation at the side hole and tip hole. After modifying the catheter design, the hemodynamics change, which alter thrombus formation. Future studies are warranted to study CVC design and placement location in an effort to minimize CVC-induced thrombosis incidence.
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Affiliation(s)
- Boyang Su
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Hannah Palahnuk
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Thaddeus Harbaugh
- Department of Neurosurgery, Penn State College of Medicine, Hershey, PA, USA
| | - Elias Rizk
- Department of Neurosurgery, Penn State College of Medicine, Hershey, PA, USA
| | - Will Hazard
- Department of Neurosurgery, Penn State College of Medicine, Hershey, PA, USA
| | - Angel Chan
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
- Department of Medicine (Cardiology), Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jonathan Bernstein
- Division of Pediatric Hematology/Oncology, Penn State Hershey Children's Hospital, Hershey, PA, USA
| | - Jonathan W Weinsaft
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
- Department of Medicine (Cardiology), Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Radiology (Cardiothoracic Imaging), Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA.
- Department of Surgery, Penn State College of Medicine, Hershey, PA, USA.
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30
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Sinko PD, Parker L, Prahl Wittberg L, Bergström CAS. Estimation of the concentration boundary layer adjacent to a flat surface using computational fluid dynamics. Int J Pharm 2024; 653:123870. [PMID: 38401511 DOI: 10.1016/j.ijpharm.2024.123870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 01/28/2024] [Accepted: 01/29/2024] [Indexed: 02/26/2024]
Abstract
Dissolution-permeation (D/P) experiments are widely used during preclinical development due to producing results with better predictability than traditional monophasic experiments. However, it is difficult to compare absorption across in vitro setups given the propensity to only report apparent permeability. We therefore developed an approach to predict the concentration boundary layer for any D/P device by using computational fluid dynamics (CFD). The Navier-Stokes and continuity equation in 2D were solved numerically in MATLAB and by finite element methods in COMSOL v6.1 to predict the momentum [Formula: see text] and concentration ηg boundary layer for a flow over a flat plate, i.e. the classical Blasius boundary layer flow. A MATLAB algorithm was developed to calculate the edge of either boundary layer. The methodology to determine the concentration boundary layer based on Blasius's analysis provided an accurate estimate for both [Formula: see text] and ηg, resulting in, [Formula: see text] , at high Schmidt numbers (Sc ∼ 1000) within 14 % of the Blasius solution and 6.6 % of the accepted Schmidt number correlation ( [Formula: see text] ). The methodology based on the Blasius analysis of the concentration boundary layer using velocity and concentration profiles computed using CFD presented herein will enable characterization/analysis of complex D/P apparatuses used in preclinical development, where an analytical solution may not be available.
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Affiliation(s)
- Patrick D Sinko
- Department of Pharmacy, Uppsala Biomedical Center, Uppsala University, 751 23 Uppsala, Sweden
| | - Louis Parker
- FLOW, Department of Engineering Mechanics, Royal Institute of Technology, KTH, Osquars Backe 18, SE-100 44 Stockholm, Sweden
| | - Lisa Prahl Wittberg
- FLOW, Department of Engineering Mechanics, Royal Institute of Technology, KTH, Osquars Backe 18, SE-100 44 Stockholm, Sweden
| | - Christel A S Bergström
- Department of Pharmacy, Uppsala Biomedical Center, Uppsala University, 751 23 Uppsala, Sweden.
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Yin Y, Wang Z, Ma M, Zhang J, Xu Y, Li L, Ge M. Coupling vibration analysis of heat exchanger tube bundles under different stiffness conditions. Sci Rep 2024; 14:3953. [PMID: 38368432 PMCID: PMC10874426 DOI: 10.1038/s41598-024-53855-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/06/2024] [Indexed: 02/19/2024] Open
Abstract
A two-dimensional tube bundles fluid-structure coupling model was developed using the CFD approach, with a rigid body motion equation and the Newmark integral method. The numerical simulations were performed to determine the vibration coupling properties between various tube bundles of stiffness. Take the corner square tube bundles with a pitch ratio of 1.28 as the research object. The influence of adjacent tubes with different stiffness on the vibration of the central target tube was analyzed. The research results show that the vibration characteristic of tube bundles is affected by the flow field dominant frequency and the inherent frequency of tube bundles. The vibration of adjacent tube bundles significantly impacts the amplitude and frequency of the central target tube. The equal stiffness and large stiffness tubes upstream or downstream inhibit the vibration displacement of the target tube to some extent. The low-stiffness tubes upstream or downstream significantly enhanced the amplitude of the target tube. The findings can be used to provide a basis for reasonable design and vibration suppression of shell-and-tube heat exchangers.
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Affiliation(s)
- Yifang Yin
- College of Mechanical Science and Engineering, Northeast Petroleum University, Daqing, 163318, Heilongjiang, China
| | - Zunce Wang
- College of Mechanical Science and Engineering, Northeast Petroleum University, Daqing, 163318, Heilongjiang, China
- Heilongjiang Key Laboratory of Petroleum and Petrochemical Multiphase Treatment and Pollution Prevention, Daqing, 163318, Heilongjiang, China
| | - Mingyue Ma
- National Observation and Research Station of Coastal Ecological Environments in Macao, Macao Environmental Research Institute, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao SAR, 999078, China
| | - Jinglong Zhang
- College of Mechanical Science and Engineering, Northeast Petroleum University, Daqing, 163318, Heilongjiang, China.
- Heilongjiang Key Laboratory of Petroleum and Petrochemical Multiphase Treatment and Pollution Prevention, Daqing, 163318, Heilongjiang, China.
| | - Yan Xu
- College of Mechanical Science and Engineering, Northeast Petroleum University, Daqing, 163318, Heilongjiang, China.
- Heilongjiang Key Laboratory of Petroleum and Petrochemical Multiphase Treatment and Pollution Prevention, Daqing, 163318, Heilongjiang, China.
| | - Lidong Li
- College of Mechanical Science and Engineering, Northeast Petroleum University, Daqing, 163318, Heilongjiang, China
| | - Mingming Ge
- National Observation and Research Station of Coastal Ecological Environments in Macao, Macao Environmental Research Institute, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao SAR, 999078, China.
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Nair PJ, Pfaller MR, Dual SA, McElhinney DB, Ennis DB, Marsden AL. Non-invasive Estimation of Pressure Drop Across Aortic Coarctations: Validation of 0D and 3D Computational Models with In Vivo Measurements. Ann Biomed Eng 2024:10.1007/s10439-024-03457-5. [PMID: 38341399 DOI: 10.1007/s10439-024-03457-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/20/2024] [Indexed: 02/12/2024]
Abstract
Blood pressure gradient ([Formula: see text]) across an aortic coarctation (CoA) is an important measurement to diagnose CoA severity and gauge treatment efficacy. Invasive cardiac catheterization is currently the gold-standard method for measuring blood pressure. The objective of this study was to evaluate the accuracy of [Formula: see text] estimates derived non-invasively using patient-specific 0D and 3D deformable wall simulations. Medical imaging and routine clinical measurements were used to create patient-specific models of patients with CoA (N = 17). 0D simulations were performed first and used to tune boundary conditions and initialize 3D simulations. [Formula: see text] across the CoA estimated using both 0D and 3D simulations were compared to invasive catheter-based pressure measurements for validation. The 0D simulations were extremely efficient ([Formula: see text] 15 s computation time) compared to 3D simulations ([Formula: see text] 30 h computation time on a cluster). However, the 0D [Formula: see text] estimates, unsurprisingly, had larger mean errors when compared to catheterization than 3D estimates (12.1 ± 9.9 mmHg vs 5.3 ± 5.4 mmHg). In particular, the 0D model performance degraded in cases where the CoA was adjacent to a bifurcation. The 0D model classified patients with severe CoA requiring intervention (defined as [Formula: see text] [Formula: see text] 20 mmHg) with 76% accuracy and 3D simulations improved this to 88%. Overall, a combined approach, using 0D models to efficiently tune and launch 3D models, offers the best combination of speed and accuracy for non-invasive classification of CoA severity.
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Affiliation(s)
- Priya J Nair
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Martin R Pfaller
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Seraina A Dual
- Department of Biomedical Signaling and Health Systems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Doff B McElhinney
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Daniel B Ennis
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Department of Radiology, Stanford University, Stanford, CA, USA
- Division of Radiology, VA Palo Alto Healthcare System, Palo Alto, CA, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA.
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA.
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA.
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.
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Li J, Yang Y, Sun Z, Peng K, Liu K, Xu P, Li J, Wei X, He X. Integrated evaluation of biomechanical and biological properties of the biomimetic structural bone scaffold: Biomechanics, simulation analysis, and osteogenesis. Mater Today Bio 2024; 24:100934. [PMID: 38234458 PMCID: PMC10792490 DOI: 10.1016/j.mtbio.2023.100934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/19/2024] Open
Abstract
A porous structure is essential for bone implants because it increases the bone ingrowth space and improves mechanical and biological properties. The biomimetically designed porous Voronoi scaffold can reconstruct the structure and function of cancellous bone; however, its comprehensive properties need to be investigated further. In this study, algorithms based on scaling factors were used to design the Voronoi scaffolds. Classic approaches, such as computer-aided design and the implicit surface method, have been used to design Diamond, Gyroid, and I-WP scaffolds as controls. All scaffolds were prepared by selective laser melting of titanium alloys and three-dimensional printing. Mechanical tests, finite element analysis, and in vitro and in vivo experiments were performed to investigate the biomechanical, cytologic, and osteogenic performance of the scaffolds, while computational fluid dynamics simulations were used to explore the underlying mechanisms. Diamond scaffolds have a better loading capacity, and the mechanical behaviors and fluid flow of Voronoi scaffolds are similar to those of the human trabecular bone. Cells showed more proliferation and distribution on the Diamond and Voronoi scaffolds and exhibited evident differentiation on Gyroid and Voronoi scaffolds. Bone formation was apparent on the inner part of the Gyroid, the outer part of the I-WP, and the entire Diamond and Voronoi scaffolds. The hydrodynamic properties and stimulus response of cells influenced by the porous structure account for the varied biological performance of the scaffolds. The Voronoi scaffolds with bionic mechanical behavior and an appropriate hydrodynamic response exhibit evident cell growth and osteogenesis, making them preferable for porous structural bone implants.
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Affiliation(s)
- Jialiang Li
- Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710014, China
| | - Yubing Yang
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710000, China
| | - Zhongwei Sun
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, Nanjing, 210096, China
| | - Kan Peng
- Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710014, China
| | - Kaixin Liu
- Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710014, China
| | - Peng Xu
- Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710014, China
| | - Jun Li
- Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710014, China
| | - Xinyu Wei
- Department of Health Management, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710000, China
| | - Xijing He
- Department of Orthopedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710000, China
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Caddy HT, Thomas HJ, Kelsey LJ, Smith KJ, Doyle BJ, Green DJ. Comparison of computational fluid dynamics with transcranial Doppler ultrasound in response to physiological stimuli. Biomech Model Mechanobiol 2024; 23:255-269. [PMID: 37805938 PMCID: PMC10902019 DOI: 10.1007/s10237-023-01772-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023]
Abstract
Cerebrovascular haemodynamics are sensitive to multiple physiological stimuli that require synergistic response to maintain adequate perfusion. Understanding haemodynamic changes within cerebral arteries is important to inform how the brain regulates perfusion; however, methods for direct measurement of cerebral haemodynamics in these environments are challenging. The aim of this study was to assess velocity waveform metrics obtained using transcranial Doppler (TCD) with flow-conserving subject-specific three-dimensional (3D) simulations using computational fluid dynamics (CFD). Twelve healthy participants underwent head and neck imaging with 3 T magnetic resonance angiography. Velocity waveforms in the middle cerebral artery were measured with TCD ultrasound, while diameter and velocity were measured using duplex ultrasound in the internal carotid and vertebral arteries to calculate incoming cerebral flow at rest, during hypercapnia and exercise. CFD simulations were developed for each condition, with velocity waveform metrics extracted in the same insonation region as TCD. Exposure to stimuli induced significant changes in cardiorespiratory measures across all participants. Measured absolute TCD velocities were significantly higher than those calculated from CFD (P range < 0.001-0.004), and these data were not correlated across conditions (r range 0.030-0.377, P range 0.227-0.925). However, relative changes in systolic and time-averaged velocity from resting levels exhibited significant positive correlations when the distinct techniques were compared (r range 0.577-0.770, P range 0.003-0.049). Our data indicate that while absolute measures of cerebral velocity differ between TCD and 3D CFD simulation, physiological changes from resting levels in systolic and time-averaged velocity are significantly correlated between techniques.
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Affiliation(s)
- Harrison T Caddy
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Hannah J Thomas
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Engineering, The University of Western Australia, Perth, Australia
| | - Kurt J Smith
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
- Cerebrovascular Health, Exercise, and Environmental Research Sciences Laboratory, University of Victoria, Victoria, Canada
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia.
- School of Engineering, The University of Western Australia, Perth, Australia.
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
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Han X, Zou X, Luo J, Wu J, Deng B. Residence time and the concentration of microorganism in the ozone contactor: a CFD simulation on chamber deflectors. Environ Sci Pollut Res Int 2024; 31:11164-11177. [PMID: 38217804 DOI: 10.1007/s11356-024-31909-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 01/03/2024] [Indexed: 01/15/2024]
Abstract
Disinfection is an important step in deep drinking water treatment technology. This study applies computational fluid dynamics to investigate and optimize the hydrodynamics inside the ozone contactor. ANSYS Fluent was used to solve all the control equations. A step method is used to simulate the residence time distribution. The mean residence time is simulated under the Eulerian framework. The deflectors are installed in chambers to direct flow. The deflectors allow for a more uniform flow and a longer mean residence time within the contactor. The baffling factor showed that the deflectors could reduce the short-circuit effect in the contactor and improve the disinfection efficiency by 34.6% compared to the original reactor. The Morrill factor coefficient is improved by 22.8% compared to the original reactor. According to the Aral-Demirel index, contactors with deflectors are significantly better than other baffle-type contactors. The presence of the deflectors increased the microbial inactivation efficiency from 95.3 to 96.5%. The optimal deflector height should be controlled between 30 and 60 mm.
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Affiliation(s)
- Xiucheng Han
- Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, People's Republic of China
| | - Xiaonan Zou
- Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, People's Republic of China
| | - Jiajia Luo
- Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, People's Republic of China
| | - Jiming Wu
- Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, People's Republic of China
| | - Baoqing Deng
- Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, People's Republic of China.
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36
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Antoniadis M, Blum M, Ussat M, Laufs U, Lenk K. Standardized angiographic projections allow evaluation of coronary artery side branches with quantitative flow ratio (QFR). Int J Cardiol Heart Vasc 2024; 50:101349. [PMID: 38322018 PMCID: PMC10844669 DOI: 10.1016/j.ijcha.2024.101349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/16/2024] [Accepted: 01/23/2024] [Indexed: 02/08/2024]
Abstract
Quantitative flow ratio (QFR) is a novel, software-based noninvasive method for the quantitative evaluation of coronary physiology. QFR results correlate with invasive FFR measurements in the three main epicardial coronary arteries. However, QFR data for the evaluation of coronary side branches (SB) are scarce. The evaluation of QFR-performance of SB was retrospective and prospective. Eighty-seven patients with suspected chronic coronary syndrome, who received angiography using routine core lab projections, were retrospectively analyzed. On the second part 37 patients, who received angiography using recommended standardized coronary angiography projections, were prospectively analyzed. Quantitative analysis was performed for SB with a maximum lumen diameter proximal of ≥2 mm based on quantitative coronary angiography (QCA) by two certified experts with the software QAngio XA 3D 3.2. Using routine projections, QFR computation in 55 % of the SB were obtained (123 out of 224). Using standardized projections, 85 % of SB were computed by QFR (64 out of 75; p < 0.001 vs routine projections). The fluoroscopy time for recommended projections was not significantly different as opposed to routine projections (3.75 ± 2.2 vs. 4.58 ± 3.00 min, p = 2.6986). Using the standardized projections was associated with a higher amount of contrast medium (53.44 ± 24.23 vs. 87.95 ± 43.73 ml, p < 0.01), longer overall procedure time (23.23 ± 16.35 vs. 36.14 ± 17.21 min, p < 0.01) and a higher dose area product (1152.28 ± 576.70 vs. 2540.68 ± 1774.07 cGycm2, p < 0.01). Our study shows that the blood flow of the vast majority of coronary SB can be determined non-invasively by QFR in addition to the main epicardial coronary arteries when standardized projections are used.
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Affiliation(s)
| | | | - M. Ussat
- Department of Cardiology, Leipzig University Hospital, Leipzig, Germany
| | - U. Laufs
- Department of Cardiology, Leipzig University Hospital, Leipzig, Germany
| | - K. Lenk
- Department of Cardiology, Leipzig University Hospital, Leipzig, Germany
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Jayathungage Don TD, Safaei S, Maso Talou GD, Russell PS, Phillips ARJ, Reynolds HM. Computational fluid dynamic modeling of the lymphatic system: a review of existing models and future directions. Biomech Model Mechanobiol 2024; 23:3-22. [PMID: 37902894 PMCID: PMC10901951 DOI: 10.1007/s10237-023-01780-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/02/2023] [Indexed: 11/01/2023]
Abstract
Historically, research into the lymphatic system has been overlooked due to both a lack of knowledge and limited recognition of its importance. In the last decade however, lymphatic research has gained substantial momentum and has included the development of a variety of computational models to aid understanding of this complex system. This article reviews existing computational fluid dynamic models of the lymphatics covering each structural component including the initial lymphatics, pre-collecting and collecting vessels, and lymph nodes. This is followed by a summary of limitations and gaps in existing computational models and reasons that development in this field has been hindered to date. Over the next decade, efforts to further characterize lymphatic anatomy and physiology are anticipated to provide key data to further inform and validate lymphatic fluid dynamic models. Development of more comprehensive multiscale- and multi-physics computational models has the potential to significantly enhance the understanding of lymphatic function in both health and disease.
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Affiliation(s)
| | - Soroush Safaei
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Gonzalo D Maso Talou
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Peter S Russell
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Anthony R J Phillips
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Hayley M Reynolds
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
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38
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Lodi Rizzini M, Candreva A, Mazzi V, Pagnoni M, Chiastra C, Aben JP, Fournier S, Cook S, Muller O, De Bruyne B, Mizukami T, Collet C, Gallo D, Morbiducci U. Blood Flow Energy Identifies Coronary Lesions Culprit of Future Myocardial Infarction. Ann Biomed Eng 2024; 52:226-238. [PMID: 37733110 DOI: 10.1007/s10439-023-03362-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/02/2023] [Indexed: 09/22/2023]
Abstract
The present study establishes a link between blood flow energy transformations in coronary atherosclerotic lesions and clinical outcomes. The predictive capacity for future myocardial infarction (MI) was compared with that of established quantitative coronary angiography (QCA)-derived predictors. Angiography-based computational fluid dynamics (CFD) simulations were performed on 80 human coronary lesions culprit of MI within 5 years and 108 non-culprit lesions for future MI. Blood flow energy transformations were assessed in the converging flow segment of the lesion as ratios of kinetic and rotational energy values (KER and RER, respectively) at the QCA-identified minimum lumen area and proximal lesion sections. The anatomical and functional lesion severity were evaluated with QCA to derive percentage area stenosis (%AS), vessel fractional flow reserve (vFFR), and translesional vFFR (ΔvFFR). Wall shear stress profiles were investigated in terms of topological shear variation index (TSVI). KER and RER predicted MI at 5 years (AUC = 0.73, 95% CI 0.65-0.80, and AUC = 0.76, 95% CI 0.70-0.83, respectively; p < 0.0001 for both). The predictive capacity for future MI of KER and RER was significantly stronger than vFFR (p = 0.0391 and p = 0.0045, respectively). RER predictive capacity was significantly stronger than %AS and ΔvFFR (p = 0.0041 and p = 0.0059, respectively). The predictive capacity for future MI of KER and RER did not differ significantly from TSVI. Blood flow kinetic and rotational energy transformations were significant predictors for MI at 5 years (p < 0.0001). The findings of this study support the hypothesis of a biomechanical contribution to the process of plaque destabilization/rupture leading to MI.
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Affiliation(s)
- Maurizio Lodi Rizzini
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Alessandro Candreva
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
- Department of Cardiology, Zurich University Hospital, Zurich, Switzerland
| | - Valentina Mazzi
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Mattia Pagnoni
- Department of Cardiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Claudio Chiastra
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | | | - Stephane Fournier
- Department of Cardiology, Lausanne University Hospital, Lausanne, Switzerland
- Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, Italy
| | - Stephane Cook
- Department of Cardiology, HFR Fribourg, Fribourg, Switzerland
| | - Olivier Muller
- Department of Cardiology, Lausanne University Hospital, Lausanne, Switzerland
| | | | | | - Carlos Collet
- Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium
| | - Diego Gallo
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy.
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Yan JZ, Kumar P, Rauch W. Effect of turbulent diffusion in modeling anaerobic digestion. Bioresour Technol 2024; 393:130068. [PMID: 37984665 DOI: 10.1016/j.biortech.2023.130068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 11/22/2023]
Abstract
In this study, the impact of turbulent diffusion on mixing of biochemical reaction models is explored by implementing and validating different models. An original codebase called CHAD (Coupled Hydrodynamics and Anaerobic Digestion) is extended to incorporate turbulent diffusion and validate it against results from OpenFOAM with 2D Rayleigh-Taylor Instability and lid-driven cavity simulations. The models are then tested for the applications with Anaerobic Digestion - a widely used wastewater treatment method. The findings demonstrate that the implemented models accurately capture turbulent diffusion when provided with an accurate flow field. Specifically, a minor effect of chemical turbulent diffusion on biochemical reactions within the anaerobic digestion tank is observed, while thermal turbulent diffusion significantly influences mixing. By successfully implementing turbulent diffusion models in CHAD, its capabilities for more accurate anaerobic digestion simulations are enhanced, aiding in optimizing the design and operation of anaerobic digestion reactors in real-world wastewater treatment applications.
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Affiliation(s)
- Jeremy Z Yan
- Environmental Engineering Department, University of Innsbruck, Technikerstraße 13, Room 312, 6020 Innsbruck, Austria
| | - Prashant Kumar
- Environmental Engineering Department, University of Innsbruck, Technikerstraße 13, Room 312, 6020 Innsbruck, Austria
| | - Wolfgang Rauch
- Environmental Engineering Department, University of Innsbruck, Technikerstraße 13, Room 312, 6020 Innsbruck, Austria.
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40
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Zhou C, Ding Y, Ye L. Study on infection risk in a negative pressure ward under different fresh airflow patterns based on a radiation air conditioning system. Environ Sci Pollut Res Int 2024; 31:14135-14155. [PMID: 38270763 DOI: 10.1007/s11356-024-32037-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 01/12/2024] [Indexed: 01/26/2024]
Abstract
COVID-19 and other respiratory infectious viruses are highly contagious, and patients need to be treated in negative pressure wards. At present, many negative pressure wards use independent air conditioning equipment, but independent air conditioning equipment has problems such as indoor air circulation flow, condensate water accumulation, and improper filter maintenance, which increase the risk of infection for healthcare workers and patients. The radiation air conditioning system relies on the radiation ceiling to control the indoor temperature and uses new air to control the indoor humidity and air quality. The problems caused by the use of independent air conditioning equipment should be avoided. This paper studies the thermal comfort, contaminant distribution characteristics, contaminant removal efficiency, and accessibility of supply air in a negative pressure ward with a radiation air conditioning system under three airflow patterns. In addition, the negative pressure ward was divided into 12 areas, and the infection probability of healthcare workers in different areas was analyzed. The results show that the application of radiation air conditioning systems in negative pressure wards can ensure the thermal comfort of patients. Stratum ventilation and ceiling-attached jets have similar effects in protecting healthcare workers; both can effectively reduce the contaminant concentrations and the risk of infection of healthcare workers. Ceiling-attached jets decreases the contaminant concentrations by 10.73%, increases the contaminant removal efficiency by 12.50%, and decreases the infection probability of healthcare workers staying indoors for 10 min by 23.18%, compared with downward ventilation.
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Affiliation(s)
- Chonggang Zhou
- School of Civil Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Panyu District, Guangzhou City, 510006, Guangdong Province, China
| | - Yunfei Ding
- School of Civil Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Panyu District, Guangzhou City, 510006, Guangdong Province, China.
| | - Lifei Ye
- School of Civil Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Panyu District, Guangzhou City, 510006, Guangdong Province, China
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41
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Sakamoto K, Iwamoto Y, Ogawa K, Tamura K, Ito C, Iwata M, Sakamoto A, Shine M, Nishi Y, Uraoka M, Nagaoka T, Honjo M, Funamizu N, Takada Y. Impact of the inferior vena cava morphology on fluid dynamics of the hepatic veins. Surg Today 2024; 54:205-209. [PMID: 37516666 DOI: 10.1007/s00595-023-02733-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/16/2023] [Indexed: 07/31/2023]
Abstract
We reported previously that a large vertical interval between the hepatic segment of the inferior vena cava (IVC) and right atrium (RA), referred to as the IVC-RA gap, was associated with more intraoperative bleeding during hemi-hepatectomy. We conducted a computational fluid dynamics (CFD) study to clarify the impact of fluid dynamics resulting from morphologic variations around the liver. The subjects were 10 patients/donors with a large IVC-RA gap and 10 patients/donors with a small IVC-RA gap. Three-dimensional reconstructions of the IVC and hepatic vessels were created from CT images for the CFD study. Median pressure in the middle hepatic vein was significantly higher in the large-gap group than in the small-gap group (P = 0.008). Differences in hepatic vein pressure caused by morphologic variation in the IVC might be one of the mechanisms of intraoperative bleeding from the hepatic veins.
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Affiliation(s)
- Katsunori Sakamoto
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan.
| | - Yukiharu Iwamoto
- Department of Mechanical Engineering, Ehime University Graduate School of Science and Engineering, 3 Bunkyo-Cho, Matsuyama, Ehime, 790-8577, Japan
| | - Kohei Ogawa
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Kei Tamura
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Chihiro Ito
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Miku Iwata
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Akimasa Sakamoto
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Mikiya Shine
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Yusuke Nishi
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Mio Uraoka
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Tomoyuki Nagaoka
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Masahiko Honjo
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Naotake Funamizu
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Yasutsugu Takada
- Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, 454 Kou, Shitsukawa, Toon, Ehime, 791-0295, Japan
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Parkash R, Chauhan N, Chauhan RP. Application of CFD modeling for indoor radon and thoron dispersion study: A review. J Environ Radioact 2024; 272:107368. [PMID: 38183868 DOI: 10.1016/j.jenvrad.2023.107368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/30/2023] [Accepted: 12/31/2023] [Indexed: 01/08/2024]
Abstract
This paper provides an in-depth discussion of the CFD implications to the design/study of interior environments and an overview of the most widely used CFD model for indoor radon and thoron dispersion study. For the design and analysis of indoor environments, CFD is a powerful tool that enables simulation and measurement-based validation. Simulating an indoor environment involves deliberate thought and skilful management of complicated boundary conditions. User and CFD programs can develop results through gradual effort that can be relied upon and applied to the design and study of indoor environments. Radon and thoron are natural radioactive gases and play a crucial role in accurately assessing the radioactive hazard within an indoor environment. This review comprise the work related to measurement and CFD modeling on these radioactive pollutant for indoors.Highlighting the current state of environmental radioactive pollutants and potentially identified areas that require further attention or research regarding investigating factors affecting indoor radioactive pollutants.
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Affiliation(s)
- Rajat Parkash
- Department of Physics, National Institute of Technology, Kurukshetra, 136119, Haryana, India.
| | - Neetika Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra, 136119, Haryana, India.
| | - R P Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra, 136119, Haryana, India
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Huo M, Giridharan GA, Sethu P, Qu P, Qin K, Wang Y. Numerical simulation analysis of multi-scale computational fluid dynamics on hemodynamic parameters modulated by pulsatile working modes for the centrifugal and axial left ventricular assist devices. Comput Biol Med 2024; 169:107788. [PMID: 38091724 DOI: 10.1016/j.compbiomed.2023.107788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 11/08/2023] [Accepted: 11/28/2023] [Indexed: 02/08/2024]
Abstract
Continuous flow (CF) left ventricular assist devices (LVAD) operate at a constant speed mode, which could result in increased risk of adverse events due to reduced vascular pulsatility. Consequently, pump speed modulation algorithms have been proposed to augment vascular pulsatility. However, the quantitative local hemodynamic effects on the aorta when the pump is operating with speed modulation using different types of CF-LVADs are still under investigation. The computational fluid dynamics (CFD) study was conducted to quantitatively elucidate the hemodynamic effects on a clinical patient-specific aortic model under different speed patterns of CF-LVADs. Pressure distribution, wall shear stress (WSS), time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and velocity were calculated to compare their differences at constant and pulsatile speeds under centrifugal and axial LVAD support. Results showed that pulse pressure on the aorta was significantly larger under pulsatile speed mode than that under constant speed mode for both CF-LVADs, indicating enhanced aorta pulsatility, as well as the higher peak blood flow velocity on some representative slices of aorta. Pulsatile speed modulation enhanced peak WSS compared to constant speed; high TAWSS region appeared near the branch of left common carotid artery and distal aorta regardless of speed modes and CF-LVADs but these regions also had low OSI; RRT was almost the same for all the cases. This study may provide a basis for the scientific and reasonable selection of the pulsatile speed patterns of CF-LVADs for treating heart failure patients.
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Affiliation(s)
- Mingming Huo
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, China
| | | | - Palaniappan Sethu
- Division of Cardiovascular Disease, Department of Medicine, School of Medicine and Department of Biomedical Engineering, School of Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Peng Qu
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Dalian, China
| | - Kairong Qin
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Dalian, China
| | - Yu Wang
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Dalian, China.
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Wang K, Armour CH, Gibbs RGJ, Xu XY. A numerical study of the effect of thrombus breakdown on predicted thrombus formation and growth. Biomech Model Mechanobiol 2024; 23:61-71. [PMID: 37566172 PMCID: PMC10901920 DOI: 10.1007/s10237-023-01757-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/22/2023] [Indexed: 08/12/2023]
Abstract
Thrombosis is a complex biological process which involves many biochemical reactions and is influenced by blood flow. Various computational models have been developed to simulate natural thrombosis in diseases such as aortic dissection (AD), and device-induced thrombosis in blood-contacting biomedical devices. While most hemodynamics-based models consider the role of low shear stress in the initiation and growth of thrombus, they often ignore the effect of thrombus breakdown induced by elevated shear stress. In this study, a new shear stress-induced thrombus breakdown function is proposed and implemented in our previously published thrombosis model. The performance of the refined model is assessed by quantitative comparison with experimental data on thrombus formation in a backward-facing step geometry, and qualitative comparison with in vivo data obtained from an AD patient. Our results show that incorporating thrombus breakdown improves accuracy in predicted thrombus volume and captures the same pattern of thrombus evolution as measured experimentally and in vivo. In the backward-facing step geometry, thrombus breakdown impedes growth over the step and downstream, allowing a stable thrombus to be reached more quickly. Moreover, the predicted thrombus volume, height and length are in better agreement with the experimental measurements compared to the original model which does not consider thrombus breakdown. In the patient-specific AD, the refined model outperforms the original model in predicting the extent and location of thrombosis. In conclusion, the effect of thrombus breakdown is not negligible and should be included in computational models of thrombosis.
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Affiliation(s)
- Kaihong Wang
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Chlöe H Armour
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Richard G J Gibbs
- Regional Vascular Unit, St Mary's Hospital, Imperial College Healthcare National Health Service Trust, Imperial College London, London, UK
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK.
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Fu Y, Bian X, Zou R, Jin R, Leng X, Fan F, Wei S, Cui X, Xiang J, Guan S. Hemodynamic alterations of flow diverters on aneurysms at the fetal posterior communicating artery: A simulation study using CFD to compare the surpass streamline, pipeline flex, and tubridge devices. J Neuroradiol 2024; 51:74-81. [PMID: 37442272 DOI: 10.1016/j.neurad.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 07/03/2023] [Accepted: 07/10/2023] [Indexed: 07/15/2023]
Abstract
PURPOSE Traditional flow diverters (FDs) for treating aneurysms at the fetal posterior communicating artery are unsatisfactory. Surpass Streamline is a novel FD with different mesh characteristics; however, the outcomes for such aneurysms remain unclear. This study aimed to compare hemodynamic alterations induced by Surpass Streamline, Pipeline Flex, and Tubridge devices and explore possible strategies for aneurysms at the fetal posterior communicating artery. METHODS Two simulated aneurysms (Case 1, Case 2) were constructed from digital subtraction angiography (DSA). The three FDs were virtually deployed, and hemodynamic analysis based on computational fluid dynamics was performed. Hemodynamic parameters, including the sac-averaged velocity magnitude (Velocity), high-flow volume (HFV), and wall shear stress (WSS), were compared between each FD and the untreated model (control). Surpass Streamline was performed in real life for two aneurysms and the clinical outcomes were collected for analysis. RESULTS Compared to the control, the Surpass resulted in the most significant reduction in flow. In Case 1, the Velocity, HFV, and WSS were reduced by 51.6%, 78.1%, and 64.3%, respectively. In Case 2, the Velocity, HFV, and WSS were reduced by 48.0%, 81.1%, and 65.3%, respectively. Tubridge showed slightly larger changes in hemodynamic parameters than Pipeline. In addition, our analysis suggested that metal coverage was correlated with the WSS, Velocity, and HFV. The postoperative DSA showed that the aneurysm was nearly occluded in Case 1 and decreased in Case 2. CONCLUSION Compared to that with the Pipeline and Tubridge, the Surpass resulted in the greatest reduction in hemodynamic parameters and might be effective for aneurysms at the fetal posterior communicating artery. Virtual FD deployment and computational fluid dynamics analysis may be used to predict the treatment outcomes.
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Affiliation(s)
- Yu Fu
- Department of Neurointervention Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xin Bian
- ArteryFlow Technology Co., Ltd., Hangzhou, China
| | - Rong Zou
- ArteryFlow Technology Co., Ltd., Hangzhou, China
| | - Rongbo Jin
- ArteryFlow Technology Co., Ltd., Hangzhou, China
| | | | - Feng Fan
- Department of Neurointervention Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Sen Wei
- Department of Neurointervention Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xuan Cui
- Department of Neurointervention Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | - Sheng Guan
- Department of Neurointervention Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
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Nuhash MM, Karim MR, Bhuiyan AA. The impact of tube bundle layout on the thermal and fluidic behaviour of liquid lead-bismuth eutectic in a helical-coiled once-through steam generator. Heliyon 2024; 10:e24149. [PMID: 38293457 PMCID: PMC10826161 DOI: 10.1016/j.heliyon.2024.e24149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/01/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
This study introduces a numerical model to assess the thermal and frictional properties of LBE crossflow over tube bundles on the shell side of a Helical-coiled Once-Through Steam Generator (H-OTSG) considering different arrangements, including inline, obliquely staggered, triangular, and rotated square configurations. The k-ω SST turbulence model combined with Kays turbulent Prandtl number model is utilized to develop the numerical model. The simulation results have been validated against experimental data and empirical correlations. The layouts of the tube bundles significantly influence the generation of transverse flow, vortical structures and rate of heat transfer in the flow domain. The maximum Nusselt number of 8.2 is observed for the triangular layout as significant crossflow is induced, which is a 10% increase compared to the inline arrangement where the Nusselt number is 7.45. Triangle layouts also exhibit a higher friction factor of 0.45, marking a 20% increase compared to the 0.45 friction factor observed in the inline arrangement. Increasing the oblique angle usually reduces the heat transfer rate and friction factor. Yet, at a 45-degree layout, higher turbulence intensity results in a Nu of 7.05, surpassing 6.93 observed at 30° but falling short of 7.15 at 15°. Nu decreases for rotated square arrangements, but a friction factor greater than the inline arrangement is observed at higher diagonal pitches. The Thermal Enhancement Factor (THEF) is employed to assess the thermal effectiveness of the different tube bundle layouts, and the maximum THEF of 1.1 is observed for the layout with an oblique angle of 45°. Favorable THEF values of 1.06 and 1.05 are recorded for the triangular layout and 30-degree oblique angle, respectively. This numerical study will assist the design and development of LBE H-OTSG.
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Affiliation(s)
- Mashrur Muntasir Nuhash
- Department of Mechanical and Production Engineering (MPE), Islamic University of Technology (IUT), Board Bazar, Gazipur, 1704, Bangladesh
| | - Md. Rezwanul Karim
- Department of Mechanical and Production Engineering (MPE), Islamic University of Technology (IUT), Board Bazar, Gazipur, 1704, Bangladesh
| | - Arafat A. Bhuiyan
- Department of Mechanical and Production Engineering (MPE), Islamic University of Technology (IUT), Board Bazar, Gazipur, 1704, Bangladesh
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Martin T, El Hage G, Chaalala C, Peeters JB, Bojanowski MW. Hemodynamic factors of spontaneous vertebral artery dissecting aneurysms assessed with numerical and deep learning algorithms: Role of blood pressure and asymmetry. Neurochirurgie 2024; 70:101519. [PMID: 38280371 DOI: 10.1016/j.neuchi.2023.101519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 01/29/2024]
Abstract
BACKGROUND AND OBJECTIVES The pathophysiology of spontaneous vertebral artery dissecting aneurysms (SVADA) is poorly understood. Our goal is to investigate the hemodynamic factors contributing to their formation using computational fluid dynamics (CFD) and deep learning algorithms. METHODS We have developed software that can use patient imagery as input to recreate the vertebrobasilar arterial system, both with and without SVADA, which we used in a series of three patients. To obtain the kinematic blood flow data before and after the aneurysm forms, we utilized numerical methods to solve the complex Navier-Stokes partial differential equations. This was accomplished through the application of a finite volume solver (OpenFoam/Helyx OS). Additionally, we trained a neural ordinary differential equation (NODE) to learn and replicate the dynamical streamlines obtained from the computational fluid dynamics (CFD) simulations. RESULTS In all three cases, we observed that the equilibrium of blood pressure distributions across the VAs, at a specific vertical level, accurately predicted the future SVADA location. In the two cases where there was a dominant VA, the dissection occurred on the dominant artery where blood pressure was lower compared to the contralateral side. The SVADA sac was characterized by reduced wall shear stress (WSS) and decreased velocity magnitude related to increased turbulence. The presence of a high WSS gradient at the boundary of the SVADA may explain its extension. Streamlines generated by CFD were learned with a neural ordinary differential equation (NODE) capable of capturing the system's dynamics to output meaningful predictions of the flow vector field upon aneurysm formation. CONCLUSION In our series, asymmetry in the vertebrobasilar blood pressure distributions at and proximal to the site of the future SVADA accurately predicted its location in all patients. Deep learning algorithms can be trained to model blood flow patterns within biological systems, offering an alternative to the computationally intensive CFD. This technology has the potential to find practical applications in clinical settings.
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Affiliation(s)
- Tristan Martin
- Division of Neurosurgery, Department of Surgery, University of Montreal Hospital Center 1000, rue St-Denis Montréal, QC H2X 0C, Canada
| | - Gilles El Hage
- Division of Neurosurgery, Department of Surgery, University of Montreal Hospital Center 1000, rue St-Denis Montréal, QC H2X 0C, Canada
| | - Chiraz Chaalala
- Division of Neurosurgery, Department of Surgery, University of Montreal Hospital Center 1000, rue St-Denis Montréal, QC H2X 0C, Canada
| | - Jean-Baptiste Peeters
- Division of Neurosurgery, Department of Surgery, University of Montreal Hospital Center 1000, rue St-Denis Montréal, QC H2X 0C, Canada
| | - Michel W Bojanowski
- Division of Neurosurgery, Department of Surgery, University of Montreal Hospital Center 1000, rue St-Denis Montréal, QC H2X 0C, Canada.
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48
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Chaugule V, Dos Reis LG, Fletcher DF, Young PM, Traini D, Soria J. A counter-swirl design concept for dry powder inhalers. Int J Pharm 2024; 650:123694. [PMID: 38081562 DOI: 10.1016/j.ijpharm.2023.123694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/06/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
A swirling airflow is incorporated in several dry powder inhalers (DPIs) for effective powder de-agglomeration. This commonly requires the use of a flow-straightening grid in the DPI to reduce drug deposition loss caused by large lateral spreading of the emerging aerosol. Here, we propose a novel grid-free DPI design concept that improves the aerosol flow characteristics and reduces the aforementioned drug loss. The basis of this design is the implementation of a secondary airflow that swirls in the opposite direction (counter-swirl) to that of a primary swirling airflow. In-vitro deposition, computational fluid dynamics simulations and particle image velocimetry measurements are used to evaluate the counter-swirl DPI aerosol performance and flow characteristics. In comparison with a baseline-DPI that has only a primary swirling airflow, the counter-swirl DPI has 20% less deposition of the emitted drug dose in the induction port and pre-separator of a next generation impactor (NGI). This occurs as a result of the lower flow-swirl generated from the counter-swirl DPI which eliminates the axial reverse flow outside of the mouthpiece and substantially reduces lateral spreading in the exiting aerosol. Modifications to the counter-swirl DPI design were made to prevent drug loss from the secondary airflow tangential inlets, which involved the addition of wall perforations in the tangential inlets and the separation of the primary and secondary swirling airflows by an annular channel. These modified DPI devices were successful in that aspect but had higher flow-swirl than that in the counter-swirl DPI and thus had higher drug mass retained in the device and deposited in the induction port and pre-separator of the NGI. The fine particle fraction in the aerosols generated from all the counter-swirl-based DPIs and the baseline-DPI are found to be statistically similar to each other.
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Affiliation(s)
- Vishal Chaugule
- Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC), Department of Mechanical and Aerospace Engineering, Monash University, Clayton Campus, Melbourne, Australia
| | | | - David F Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
| | - Paul M Young
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, Australia; Department of Marketing, Macquarie Business School, Macquarie University, Australia
| | - Daniela Traini
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, Australia; Macquarie Medical School, Department of Biological Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Australia
| | - Julio Soria
- Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC), Department of Mechanical and Aerospace Engineering, Monash University, Clayton Campus, Melbourne, Australia.
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49
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Moussa A, Huygens B, Venditti C, Adrover A, Desmet G. Theoretical computation of the band broadening in micro-pillar array columns. J Chromatogr A 2024; 1715:464607. [PMID: 38154258 DOI: 10.1016/j.chroma.2023.464607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/08/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023]
Abstract
We have investigated the possibility to establish a theoretical plate height expression for the band broadening in the most widely used micro-pillar array column format, i.e., a cylindrical pillar array wherein the pillar walls and the channel bottom are coated with a thin layer of meso‑porous material. Assuming isotropic diffusion in the shell-layer, it was found that the vertical diffusive transport along the porous shell-layer covering the pillar walls significantly suppresses the band broadening originating from the vertical migration velocity gradients. As the vertical transport in the shell-layer increases linearly with the retention equilibrium constant K, this leads to an anomalous dependency on the retention factor. Indeed, instead of increasing with k'' and following the classic (1+ak''+bk''2)/(1 + k'')2-dependency governing a classic Taylor-Aris system, the variation of the mobile zone mass transfer resistance term hCm in a 3D pillar array with bottom-wall retention goes through a maximum (resp. factor 1.5 (k''=4) and 2 (k''=16) difference between observed and classic Taylor-Aris behaviour). This effect increases with increasing pillar heights and increasing reduced velocities. Because of this complex k''-dependency, it proves very cumbersome to establish a general plate height equation covering all conditions. Instead, a plate height expression was established that is limited up to k''=4, but remains accurate for higher k''-values for cases where the ratio of pillar height over inter-pillar distance remains below 5. It can however be anticipated the proposed analytical model is only valid in a rather limited range around the presently considered external porosity of ε=0.5.
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Affiliation(s)
- Ali Moussa
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Bram Huygens
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
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Gaidzik F, Korte J, Saalfeld S, Janiga G, Berg P. Image-based hemodynamic simulations for intracranial aneurysms: the impact of complex vasculature. Int J Comput Assist Radiol Surg 2024:10.1007/s11548-023-03045-3. [PMID: 38206468 DOI: 10.1007/s11548-023-03045-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 12/06/2023] [Indexed: 01/12/2024]
Abstract
PURPOSE Hemodynamics play an important role in the assessment of intracranial aneurysm (IA) development and rupture risk. The purpose of this study was to examine the impact of complex vasculatures onto the intra-vessel and intra-aneurysmal blood flow. METHODS Complex segmentation of a subject-specific, 60-outlet and 3-inlet circle of Willis model captured with 7T magnetic resonance imaging was performed. This model was trimmed to a 10-outlet model version. Two patient-specific IAs were added onto both models yielding two pathological versions, and image-based blood flow simulations of the four resulting cases were carried out. To capture the differences between complex and trimmed model, time-averaged and centerline velocities were compared. The assessment of intra-saccular blood flow within the IAs involved the evaluation of wall shear stresses (WSS) at the IA wall and neck inflow rates (NIR). RESULTS Lower flow values are observed in the majority of the complex model. However, at specific locations (left middle cerebral artery 0.5 m/s, left posterior cerebral artery 0.25 m/s), higher flow rates were visible when compared to the trimmed counterpart. Furthermore, at the centerlines the total velocity values reveal differences up to 0.15 m/s. In the IAs, the reduction in the neck inflow rate and WSS in the complex model was observed for the first IA (IA-A δNIRmean = - 0.07ml/s, PCA.l δWSSmean = - 0.05 Pa). The second IA featured an increase in the neck inflow rate and WSS (IA-B δNIRmean = 0.04 ml/s, PCA.l δWSSmean = 0.07 Pa). CONCLUSION Both the magnitude and shape of the flow distribution vary depending on the model's complexity. The magnitude is primarily influenced by the global vessel model, while the shape is determined by the local structure. Furthermore, intra-aneurysmal flow strongly depends on the location in the vessel tree, emphasizing the need for complex model geometries for realistic hemodynamic assessment and rupture risk analysis.
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Affiliation(s)
- Franziska Gaidzik
- Research Campus STIMULATE, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
- Laboratory of Fluid Dynamics and Technical Flows, Forschungscampus STIMULATE, Otto-von-Guericke-University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
| | - Jana Korte
- Research Campus STIMULATE, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- Laboratory of Fluid Dynamics and Technical Flows, Forschungscampus STIMULATE, Otto-von-Guericke-University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Sylvia Saalfeld
- Research Campus STIMULATE, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- Laboratory of Simulation and Graphics, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Gábor Janiga
- Research Campus STIMULATE, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- Laboratory of Fluid Dynamics and Technical Flows, Forschungscampus STIMULATE, Otto-von-Guericke-University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Philipp Berg
- Research Campus STIMULATE, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- Department of Medical Engineering, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
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