Bulletin of the American Physical Society
70th Annual Meeting of the APS Division of Fluid Dynamics
Volume 62, Number 14
Sunday–Tuesday, November 19–21, 2017; Denver, Colorado
Session A11: Medical DevicesBio Fluids: Internal
|
Hide Abstracts |
Chair: Ali Azadani, University of Denver Room: 504 |
Sunday, November 19, 2017 8:00AM - 8:13AM |
A11.00001: 4D pressure MRI: validation through in-vitro experiments and simulations. Daniele Schiavazzi, Omid Amili, Filippo Coletti Advances in MRI scan technology and recently developed acquisition sequences have led to the development of 4D flow MRI, a protocol capable of characterizing in-vivo hemodynamics in patients. Thus, the availability of phase-averaged time-resolved three-dimensional blood velocities has opened new opportunities for computing a wide spectrum of totally non-invasive hemodynamic indicators. In this regard, relative pressures play a particularly important role, as they are routinely employed in the clinic to detect cardiovascular abnormalities (e.g., in peripheral artery disease, valve stenosis, hypertension, etc.). In the first part of the talk, we discuss how the relative pressures can be robustly computed through the solution of a pressure Poisson equation and how noise in the velocities affects their estimate. Routine application of these techniques in the clinic, require however a thorough validation on multiple patients/anatomies and systematic comparisons with in-vitro and simulated representations. Thus, the second part of the talk illustrates the use of numerical simulation and in-vitro experimental protocols to validate these indicators with reference to aortic and cerebral vascular anatomies. [Preview Abstract] |
Sunday, November 19, 2017 8:13AM - 8:26AM |
A11.00002: CFD modeling of catheter-based Chemofilter device for filtering chemotherapy drugs from venous flow Nazanin Maani, Daryl Yee, Michael Nosonovsky, Julia Greer, Steven Hetts, Vitaliy Rayz \textbf{Purpose:} Intra-arterial chemotherapy, a procedure where drugs are injected into arteries supplying a tumor, may cause systemic toxicity. The Chemofilter device, deployed in a vein downstream of the tumor, can chemically filter the excessive drugs from the circulation. In our study, CFD modeling of blood flow through the Chemofilter is used to optimize its hemodynamic performance. \textbf{Methods: }The Chemofilter consists of a porous membrane attached to a stent-like frame of the RX Accunet distal protection filters used for capturing blood clots. The membrane is formed by a lattice of symmetric micro-cells. This design provides a large surface area for the drug binding, and allows blood cells to pass through the lattice. A two-scale modeling approach is used, where the flow through individual micro-cells is simulated to determine the lattice permeability and then the entire device is modeled as a porous membrane. \textbf{Results:} The simulations detected regions of flow stagnation and recirculation caused by the membrane and its supporting frame. The effect of the membrane's leading angle on the velocity and pressure fields was determined. The device optimization will help the efficacy of drug absorption, while the risk of blood clotting reduces. [Preview Abstract] |
Sunday, November 19, 2017 8:26AM - 8:39AM |
A11.00003: The Hydrodynamics of Needle-Free Intradermal Jet Injection Jonathan Simmons, Jeremy Marston, Paul Fisher, Kate Broderick Needle-free methods of drug delivery circumvent the drawbacks associated with the use of hypodermic needles such as needle-stick injuries, needle-phobia, cross contamination and disposal. Furthermore, pioneering DNA-based vaccines that aim to treat cancer and fight infectious diseases, such as HIV, Ebola and Zika, require precise deposition into the skin to target the immune response producing cells found only in the epidermis and dermis. Intradermal (ID) delivery can be achieved using a needle and the Mantoux technique but this requires a highly skilled technician and so extensive use of DNA vaccines calls for an alternative method of delivery. One option is jet injection which has been employed in mass vaccination programs for intramuscular or subcutaneous delivery and is used by some diabetic patients to inject insulin. In this talk I will present results from our ongoing ex-vivo experimental study into ID jet injection. Ultra-high-speed imaging is used to visualize the process of the jet exiting the nozzle and striking excised skin. A skin bleb grows as liquid is deposited within the skin. I will discuss how the control parameters, such as the rheological profile of the liquid and the stand-off distance, influence the volume of liquid successfully delivered intradermally. [Preview Abstract] |
Sunday, November 19, 2017 8:39AM - 8:52AM |
A11.00004: Microfluidic model experiments on the injectability of monoclonal antibody solutions Charles Duchene, Vasco Filipe, Mostafa Nakach, Sylvain Huille, Anke Lindner Autoinjection devices that allow patients to self-administer medicine are becoming used more frequently; however, this advance comes with an increased need for precision in the injection process. The rare occurrence of protein aggregates in solutions of monoclonal antibodies constitutes a threat to the reliability of such devices. Here we study the flow of protein solutions containing aggregates in microfluidic model systems, mimicking injection devices, to gain fundamental understanding of the catastrophic clogging of constrictions of given size. We form aggregates by mechanically shaking or heating antibody solutions and then inject these solutions into microfluidic channels with varying types of constrictions. Geometrical clogging occurs when aggregates reach the size of the constriction and can in some cases be undone by increasing the applied pressure. We perform systematic experiments varying the relative aggregate size and the flow rate or applied pressure. The mechanical deformation of aggregates during their passage through constrictions is investigated to gain a better understanding of the clogging and unclogging mechanisms. [Preview Abstract] |
Sunday, November 19, 2017 8:52AM - 9:05AM |
A11.00005: Investigation of Flow Structures Downstream of SAPIEN 3, CoreValve, and PERIMOUNT Magna Using Particle Image Velocimetry Mohammed Barakat, Corinne Lengsfeld, Danny Dvir, Ali Azadani Transcatheter aortic valves provide superior systolic hemodynamic performance in terms of valvular pressure gradient and effective orifice area compared with equivalent size surgical bioprostheses. However, in depth investigation of the flow field structures is of interest to examine the flow field characteristics and provide experimental evidence necessary for validation of computational models. The goal of this study was to compare flow field characteristics of the three most commonly used transcatheter and surgical valves using phase-locked particle image velocimetry (PIV). 26mm SAPIEN 3, 26mm CoreValve, and 25mm PERIMOUNT Magna were examined in a pulse duplicator with input parameters matching ISO-5840. A 2D PIV system was used to obtain the velocity fields. Flow velocity and shear stress were obtained during the entire cardiac cycle. In-vitro testing showed that mean gradient was lowest for SAPIEN 3, followed by CoreValve and PERIMOUNT Magna. In all the valves, the peak jet velocity and maximum viscous shear stress were 2 m/s and 2 MPa, respectively. In conclusion, PIV was used to investigate flow field downstream of the three bioprostheses. Viscous shear stress was low and consequently shear-induced thrombotic trauma or shear-induced damage to red blood cells is unlikely. [Preview Abstract] |
Sunday, November 19, 2017 9:05AM - 9:18AM |
A11.00006: Augment clinical measurement using a constraint-based esophageal model Wenjun Kou, Shashank Acharya, Peter Kahrilas, Neelesh Patankar, John Pandolfino Quantifying the mechanical properties of the esophageal wall is crucial to understanding impairments of trans-esophageal flow characteristic of several esophageal diseases. However, these data are unavailable owing to technological limitations of current clinical diagnostic instruments that instead display esophageal luminal cross sectional area based on intraluminal impedance change. In this work, we developed an esophageal model to predict bolus flow and the wall property based on clinical measurements. The model used the constraint-based immersed-boundary method developed previously by our group. Specifically, we first approximate the time-dependent wall geometry based on impedance planimetry data on luminal cross sectional area. We then fed these along with pressure data into the model and computed wall tension based on simulated pressure and flow fields, and the material property based on the strain-stress relationship. As examples, we applied this model to augment FLIP (Functional Luminal Imaging Probe) measurements in three clinical cases: a normal subject, achalasia, and eosinophilic esophagitis (EoE). Our findings suggest that the wall stiffness was greatest in the EoE case, followed by the achalasia case, and then the normal. [Preview Abstract] |
Sunday, November 19, 2017 9:18AM - 9:31AM |
A11.00007: Analysis of High Speed Jets Produced by a Servo Tube Driven Liquid Jet Injector Rocco Portaro, Hoi Dick Ng In today's healthcare environment many types of medication must be administered through the use of hypodermic needles. Although this practice has been in use for many years, drawbacks such as accidental needle stick injuries, transmission of deadly viruses and bio-hazardous waste are still present. This study focuses on improving a needle free technology known as liquid jet injection, through the implementation of a linear servo tube actuator for the construction of a fully closed loop liquid jet injection system. This device has the ability to deliver both micro- and macro- molecules, high viscosity fluids whilst providing real time control of the jet pressure profile for accurate depth and dispersion control. The experiments are conducted using a prototype that consists of a 3 kW servo tube actuator, coupled to a specially designed injection head allowing nozzle size and injection volume to be varied. The device is controlled via a high speed servo amplifier and FPGA. The high speed jets emanating from the injector are assessed via high speed photography and through the use of a force transducer. Preliminary results indicate that the system allows for accurate shaping of the jet pressure profile, making it possible to target different tissue depths/types accurately. [Preview Abstract] |
Sunday, November 19, 2017 9:31AM - 9:44AM |
A11.00008: Large-Eddy Simulation of Flows Through a Novel Vascular Access Device for Hemodialysis Access Aleksandr Obabko, Eduard Tsyrulnykov, Robert Rainsberger, Alvaro V. Torreira, Hassan Nagib, Anil Agarwal, Paul F. Fischer The preferred vascular access in patients on hemodialysis (HD) is an arteriovenous (AV) fistula or graft. The majority of the HD patients in the US are dialyzed with an AV fistula where two needles are used for cannulation in most cases. However, this approach can be painfully invasive, extremely difficult to gain access in patients with challenging geometry of vascular access, and is often inadequate to provide optimal blood flow. This work attempts to address the shortcomings of the above procedure and introduces a novel cannulation device that allows less painful easy single access to difficult vessel geometries, and have a potential of improvement of overall increase in efficacy of HD and enhanced patient experience. We present the preliminary Nek5000 large-eddy simulations results of the flows through the device that employs a single 18-gauge needle for cannulation and is able to provide blood flow rates up to 600 ml/min. The range of flow rates and Reynolds numbers up to Re=2,600 are considered and blood recirculation rates are computed. [Preview Abstract] |
Sunday, November 19, 2017 9:44AM - 9:57AM |
A11.00009: Self-separation of blood plasma from whole blood during the capillary flow in microchannel. Bharath Babu Nunna, Shiqiang Zhuang, Eon Soo Lee Self-separation of blood plasma from whole blood in microchannels is of great importance due to the enormous range of applications in healthcare and diagnostics. Blood is a multiphase complex fluid, composed of cells suspended in blood plasma. RBCs are the suspended particles whose shape changes during the flow of blood. The primary constituents of blood are erythrocytes or red blood cells (RBCs), leukocytes or white blood cells (WBCs), thrombocytes or platelets and blood plasma. The existence of RBCs in blood makes the blood a non-Newtonian fluid. The current study of separation of blood plasma from whole blood during self-driven flows in a single microchannel without bifurcation, by enhancing the capillary effects. The change in the capillary effect results in a change in contact angle which directly influences the capillary flow. The flow velocity directly influences the net force acting on the RBCs and influence the separation process. The experiments are performed on the PDMS microchannels with different contact angles by altering the surface characteristics using plasma treatment. The change in the separation length is studied during the capillary flow of blood in microchannel. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700