Download or read book Red Blood Cell Aggregation Characterization written by Rym Mehri and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Red blood cells (RBCs) are the most abundant cells in human blood, representing 40 to 45% of the blood volume (hematocrit). These cells have the particular ability to deform and bridge together to form aggregates under very low shear rates. The theory and mechanics behind aggregation are, however, not yet completely understood. The purpose of this work is to provide a novel method to analyze, understand and mimic blood behaviour in microcirculation. The main objective is to develop a methodology to quantify and characterize RBC aggregates and hence enhance the current understanding of the non-Newtonian behaviour of blood at the microscale. For this purpose, suspensions of porcine blood and human blood are tested in vitro in a Poly-di-methylsiloxane (PDMS) microchannel to characterize RBC aggregates within these two types of blood. These microchannels are fabricated using standard photolithography methods. Experiments are performed using a micro Particle Image Velocimetry ( PIV) system for shear rate measurements coupled with a high speed camera for the flow visualization. Corresponding numerical simulations are conducted using a research Computational Fluid Dynamic (CFD) solver, Nek5000, based on the spectral element method solution to the incompressible non-Newtonian Navier-Stokes equations. RBC aggregate sizes are quantified in controlled and measurable shear rate environments for 5, 10 and 15% hematocrit. Aggregate sizes are determined using image processing techniques. Velocity fields of the blood flow are measured experimentally and compared to numerical simulations using simple non-Newtonian models (Power law and Carreau models). This work establishes for the first time a relationship between RBC aggregate sizes and corresponding shear rates in a microfluidic environment as well as one between RBC aggregate sizes and apparent blood viscosity at body temperature in a microfluidic controlled environment. The results of the investigation can be used to help develop new numerical models for non-Newtonian blood flow, provide a better understanding of the mechanics of RBC aggregation and help determine aggregate behaviour in clinical settings such as for degenerative diseases like diabetes and heart disease.
Download or read book Physical Characterization of Red Blood Cell Aggregation written by Daniel Flormann and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Red Blood Cell Aggregation Dynamics with Doppler Ultrasound written by Zhao Qin and published by . This book was released on 1997 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Red Blood Cell Aggregation Characterization written by Curtis James Karns Armstrong and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The presence of red blood cell (RBC) aggregation is confirmed to be a rheological phenomenon implicating abnormal physiological conditions in vivo. However, there is presently no existing technology able to analyze, characterize and detect aggregation in vivo. The Laboratoire de Mécanique et d'Acoustique (LMA, UMR 7031), Centre National de la Recherche Scientifique (CNRS) at Aix-Marseille Universite (AMU) is developing a technology to measure blood aggregation in vivo using ultrasound backscattering techniques. In doing so it aims to allow disease prevention and disease recognition. The methodology developed at LMA is currently being compared to previous methodologies used to quantify RBC aggregation. Further study is needed to compare the methodologies used in LMA to microscopic imaging techniques, which are considered the gold standard in aggregation characterization. This thesis focuses on the development of a microfluidic device dedicated to the visualization of RBC aggregation. The device is capable of low compliance to ensure repeatability of the flow rate, with good optical clarity. The device's co-flow properties and capabilities were tested and analyzed to ensure a proper comparison of methodologies could be conducted. Once completed, the incorporation of an ultrasound transducer to the setup, will be done in France to directly compare the methodologies developed by LMA and confirm the models derived by Franceschini et al. In order to develop the microfluidic chip, this thesis considers an overview of the methodology for characterizing RBC aggregation, the fabrication and compliant verification of a novel Norland Optical Adhesive microfluidic chip, and the shear rate calibration of the microfluidic device using Dextran 70 and Dextran 500. The NOA63 microfluidic device was calibrated to flow factors based on a shearing flow ratio of 25:1. The Norland Optical Adhesive microfluidic device had a much lower level of compliance in comparison to the gold standard of PDMS. The NOA63 device was found to be 51% less compliant than its counter part of PDMS. The device was calibrated to control shear rates from around 60s-1 to 0.01s-1. Multiple concentrations of Dextran 70 and Dextran 500 in human blood samples at 10% hematocrit were tested to characterize the shear rate in the blood layer. Aggregates were found to align themselves parallel to the flow and were observed to haven anisotropic shapes. All results from this thesis are being used to support the development of an ultrasound device capable of measuring blood aggregation in vivo.
Download or read book Red Blood Cell Aggregation written by Oguz Baskurt and published by CRC Press. This book was released on 2011-09-28 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Red blood cells in humans-and most other mammals-have a tendency to form aggregates with a characteristic face-to-face morphology, similar to a stack of coins. Known as rouleaux, these aggregates are a normally occurring phenomenon and have a major impact on blood rheology. What is the underlying mechanism that produces this pattern? Does this real
Download or read book Red blood cell aggregation rheological and microstructural characteristics written by Efstathios C. Kaliviotis and published by . This book was released on 2009 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bioengineering in Cell and Tissue Research written by Gerhard M. Artmann and published by Springer Science & Business Media. This book was released on 2008-04-09 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cutting edge research in cell and tissue research abounds in this review of the latest technological developments in the area. The chapters are written by excellent scientists on advanced, frontier technology and address scientific questions that require considerable engineering brainpower. The aim is to provide students and scientists working in academia and industry new information on bioengineering in cell and tissue research to enhance their understanding and innovation.
Download or read book Red Blood Cells at the Mount of Truth Highlights of the 22nd Meeting of the European Red Cell Research Society written by Anna Bogdanova and published by Frontiers Media SA. This book was released on 2021-01-06 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Red Blood Cell Aggregation written by Oguz Baskurt and published by CRC Press. This book was released on 2011-09-28 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Red blood cells in humans—and most other mammals—have a tendency to form aggregates with a characteristic face-to-face morphology, similar to a stack of coins. Known as rouleaux, these aggregates are a normally occurring phenomenon and have a major impact on blood rheology. What is the underlying mechanism that produces this pattern? Does this really happen in blood circulation? And do these rouleaux formations have a useful function? The first book to offer a comprehensive review of the subject, Red Blood Cell Aggregation tackles these and other questions related to red blood cell (RBC) aggregates. The book covers basic, clinical, and physiological aspects of this important biophysical phenomenon and integrates these areas with concepts in bioengineering. It brings together state-of-the-art research on the determinants, mechanisms, and measurement and effects of RBC aggregation as well as on variations and comparative aspects. After an introductory overview, the book outlines factors and conditions that affect RBC aggregation. It presents the two hypotheses—the bridging model and the depletion model—that provide potential mechanisms for the adhesive forces that lead to the regular packing of the cells in rouleaux formations. The book also reviews the methods used to quantify RBC aggregation in vitro, focusing on their importance in clinical practice. Chapters discuss the effect of RBC aggregation on the in vitro rheology of blood as well as on tube flow. The book also looks at what happens in the circulation when red blood cells aggregate and examines variations due to physiological and pathophysiological challenges. The concluding chapter explores the formation of red blood cell aggregates in other mammals. Written by leading researchers in the field, this is an invaluable resource for basic science, medical, and clinical researchers; graduate students; and clinicians interested in mammalian red blood cells.
Download or read book Preparation Characterization and Rheological Properties of Star shaped Poly ethylene Glycol with a Cholane Core and Study of Its Effect on Red Blood Cell Aggregation written by Florence Janvier and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistics written by Gudmund R. Iversen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 751 pages. Available in PDF, EPUB and Kindle. Book excerpt: An imaginative introduction to statistics, reorienting the course towards an understanding of statistical thinking and its meaning and use in daily life and work. Gudmund Iversen and Mary Gergen bring their years of experience and insight into teaching the subject, incorporating such innovations and insights as a sustained emphasis on the process of statistical analysis and what statistics can and cannot do as well as careful exposition of the ideas of developing statistical and graphical literacy. In the spirit of contemporary pedagogy and by using technology, the authors break down the traditional barriers of statistical formulas and lengthy computations encountered by students without strong quantitative skills. Further, formulas are grouped at the end of each chapter along with related problems, and, with only algebra as a prerequisite, the book is ideal for students in the liberal arts and the behavioural and social sciences.
Download or read book Gass Atlas of Macular Diseases written by Anita Agarwal and published by Elsevier Health Sciences. This book was released on 2011-12-23 with total page 1357 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fifth Edition of Gass' Atlas of Macular Diseases, by Dr. Anita Agarwal, provides expert diagnostic guidance on macular disorders and quickly brings you up to date on this evolving specialty. Using a case-based approach, it richly depicts a full range of retina and macular diseases, including new infectious, degenerative, and dystrophic conditions. Take advantage of the latest imaging technologies to identify common and rare disorders, and confirm difficult diagnoses with the aid of more than 5,500 high-quality images. Printed in full color for the first time, this edition is accessible online at www.expertconsult.com. "... appropriate for highly ambitious residents, retina fellows and specialists, and general ophthalmologists who are looking for an excellent reference book with a proud lineage and impeccable reputation." Reviewed by ESCRS EuroTimes (European Society of Cataract and Refractive Surgery), Apr 2015 Rely on the same unique, richly illustrated case-descriptive format-encompassing history, clinical examination, and follow-up-that popularized the original book by the late Dr. Donald Gass, the famed ophthalmologist whose clinical expertise set new standards in macular diagnosis. Get expert diagnostic guidance under the new authorship of Dr. Anita Agarwal, a protégé of Dr. Gass who has compiled the ultimate collection of images and hard-to-find case studies. Evaluate macular diseases using the latest techniques including fluorescein angiography, optical coherence tomography (OCT), indocyanine green (ICG), and fundus autofluorescence. Visualize the conditions you're likely to see in practice and confirm your diagnoses by comparing your clinical findings to more than 5,500 images and illustrations (over 3,500 in full color). Search the complete text online, download the illustrations and view a bonus stereoscopic image gallery at www.expertconsult.com.
Download or read book Adhesive Particle Flow written by Jeffery S. Marshall and published by Cambridge University Press. This book was released on 2014-03-31 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is targeted at professionals and graduate students working in disciplines where flow of adhesive particles plays a significant role.
Download or read book Discrete element Model of Red Blood Cell Aggregation in Blood Flow written by Jennifer Kathleene Wright Chesnutt and published by . This book was released on 2009 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Red Blood Cell Functions in Health and Coronary Artery Disease written by Christina Monika Panknin and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Micro Nano Devices for Blood Analysis written by Rui A. Lima and published by MDPI. This book was released on 2019-12-03 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of micro- and nanodevices for blood analysis is an interdisciplinary subject that demands the integration of several research fields, such as biotechnology, medicine, chemistry, informatics, optics, electronics, mechanics, and micro/nanotechnologies. Over the last few decades, there has been a notably fast development in the miniaturization of mechanical microdevices, later known as microelectromechanical systems (MEMS), which combine electrical and mechanical components at a microscale level. The integration of microflow and optical components in MEMS microdevices, as well as the development of micropumps and microvalves, have promoted the interest of several research fields dealing with fluid flow and transport phenomena happening in microscale devices. Microfluidic systems have many advantages over their macroscale counterparts, offering the ability to work with small sample volumes, providing good manipulation and control of samples, decreasing reaction times, and allowing parallel operations in one single step. As a consequence, microdevices offer great potential for the development of portable and point-of-care diagnostic devices, particularly for blood analysis. Moreover, the recent progress in nanotechnology has contributed to its increasing popularity, and has expanded the areas of application of microfluidic devices, including in the manipulation and analysis of flows on the scale of DNA, proteins, and nanoparticles (nanoflows). In this Special Issue, we invited contributions (original research papers, review articles, and brief communications) that focus on the latest advances and challenges in micro- and nanodevices for diagnostics and blood analysis, micro- and nanofluidics, technologies for flow visualization, MEMS, biochips, and lab-on-a-chip devices and their application to research and industry. We hope to provide an opportunity to the engineering and biomedical community to exchange knowledge and information and to bring together researchers who are interested in the general field of MEMS and micro/nanofluidics and, especially, in its applications to biomedical areas.
Download or read book A Mesoscopic Model for Blood Flow Prediction Based on Experimental Observation of Red Blood Cell Interaction written by Erfan Niazi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In some species, including humans, red blood cells (RBCs) under low shear stress tend to clump together and form into regular stacks called rouleaux. These stacks are not static, and constantly move and break apart. This phenomenon is referred to as red blood cell aggregation and disaggregation. When modelled as a single liquid, blood behaves as a non-Newtonian fluid. Its viscosity varies, mainly due to the aggregation of RBCs. The aim of this research is to develop a mesoscale computational model for the simulation of RBCs in plasma. This model considers RBC interaction and aggregation to predict blood-flow characteristics such as viscosity, rouleaux size and velocity distribution. In this work, the population-balance modelling (PBM) approach is utilized to model the RBC aggregation process. The PBM approach is a known method that is used for modelling agglomeration and breakage in two-phase flow fluid mechanics to find aggregate size. The PBM model is coupled to the incompressible Navier-Stokes equations for the plasma. Both models are numerically solved simultaneously. The population-balance equation has been used previously in a more restricted form, the Smoluchowski equation, to model blood viscosity, but it has never been fully coupled with the Navier-Stokes equation directly for the numerical modelling of blood flow. This approach results in a comprehensive model which aims to predict RBC aggregate size and their velocities for different flow configurations, as well as their effects on the apparent macro-scale viscosity. The PBM approach does not treat the microscopic physics of aggregation directly but rather uses experimental correlations for aggregation and disaggregation rates to account for the effects of aggregation on the bulk. To find the aggregation rate, a series of experiments on RBC sedimentation due to gravity is designed. In these tests, aggregated RBCs (rouleaux) tend to settle faster than single RBCs and, due to low shear stresses, disaggregation is very low and can be neglected. A high-speed camera is used to acquire video-microscopic pictures of the process. The size of the aggregates and their velocities are extracted using image processing techniques. For image processing, a general Matlab program is developed which can analyze all the images and report the velocity and size distribution of rouleaux. An experimental correlation for disaggregation rate is found using results from a previous steady-state Couette flow experiment. Aggregation and disaggregation rates from these experiments are used to complete the PBM model. Pressure-driven channel flow experiments are then used for the final validation of the model. Comparisons of the apparent viscosity of whole blood in previous experiments show reasonable agreement with the developed model. This model fills a gap between micro-scale and macro-scale treatments and should be more accurate than traditional macro-scale models while being cheaper than direct treatment of RBCs at the micro-scale.
