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- All Subjects: Sickle Cell Disease
- All Subjects: Aortic Flow
- Creators: Caplan, Michael
- Creators: Shawver, Jamie Christine
- Resource Type: Text
Description
Sickle cell disease is a genetic disorder that can cause substantial helath problems. It is the result of a mutation in the DNA coding for hemoglobin. As a result of changes in two important amino acids, a person suffering from sickle cell disease will have erythrocytes that do not maintain the typical biconcave shape and instead for a crescent shape. Individuals with sickle cell disease may have many health problems tied to their irregular hemoglobin. The unusual shape of the erythrocytes leads to a much shorter cell life, which means that even though bone marrow remains active long past childhood to try to keep up with the loss of erythrocytes, the body is still unable to accommodate the rapid death of erythrocytes. The malformed erythrocytes can also cause vascular occlusion, blocking blood vessels and slowing blood flow. While sickle cell disease has the potential to spread worldwide, it is particularly common in Africa. This may be because people with the sickle cell trait have a high resistance to malaria, making them more likely to survive that ubiquitous disease and pass on their traits to their offspring. However, the mortality rate in young children with sickle cell disease is very high, in part because the spleen, already stressed by filtering out dead erythrocytes, has difficulties filtering out bacteria. One of the keys to stopping the spread of the disease is neonatal screening, but this requires specialized equipment that is fairly uncommon in rural areas, as can be seen in Kenya. Therefore, it would be highly beneficial to develop a more cost-effective and widely available method for testing for sickle cell disease.
ContributorsWold, John (Author) / Caplan, Michael (Thesis director) / LaBelle, Jeffrey (Committee member) / Snyder, Jan (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
Sickle Cell Disease (SCD) is a prevalent genetic disease in Africa, and specifically in Kenya. The lack of available relevant disease education and screening mean that most don't understand the importance of getting testing and many children die before they can get prophylactic care. This project was designed to address the lack of knowledge with supplemental educational materials to be partnered with an engineering capstone project that provides a low cost diagnostic test.
ContributorsShawver, Jamie Christine (Author) / Caplan, Michael (Thesis director) / Snyder, Jan (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Aortic pathologies such as coarctation, dissection, and aneurysm represent a
particularly emergent class of cardiovascular diseases and account for significant cardiovascular morbidity and mortality worldwide. Computational simulations of aortic flows are growing increasingly important as tools for gaining understanding of these pathologies and for planning their surgical repair. In vitro experiments are required to validate these simulations against real world data, and a pulsatile flow pump system can provide physiologic flow conditions characteristic of the aorta.
This dissertation presents improved experimental techniques for in vitro aortic blood flow and the increasingly larger parts of the human cardiovascular system. Specifically, this work develops new flow management and measurement techniques for cardiovascular flow experiments with the aim to improve clinical evaluation and treatment planning of aortic diseases.
The hypothesis of this research is that transient flow driven by a step change in volume flux in a piston-based pulsatile flow pump system behaves differently from transient flow driven by a step change in pressure gradient, the development time being substantially reduced in the former. Due to this difference in behavior, the response to a piston-driven pump can be predicted in order to establish inlet velocity and flow waveforms at a downstream phantom model.
The main objectives of this dissertation were: 1) to design, construct, and validate a piston-based flow pump system for aortic flow experiments, 2) to characterize temporal and spatial development of start-up flows driven by a piston pump that produces a step change from zero flow to a constant volume flux in realistic (finite) tube geometries for physiologic Reynolds numbers, and 3) to develop a method to predict downstream velocity and flow waveforms at the inlet of an aortic phantom model and determine the input waveform needed to achieve the intended waveform at the test section. Application of these newly improved flow management tools and measurement techniques were then demonstrated through in vitro experiments in patient-specific coarctation of aorta flow phantom models manufactured in-house and compared to computational simulations to inform and execute future experiments and simulations.
particularly emergent class of cardiovascular diseases and account for significant cardiovascular morbidity and mortality worldwide. Computational simulations of aortic flows are growing increasingly important as tools for gaining understanding of these pathologies and for planning their surgical repair. In vitro experiments are required to validate these simulations against real world data, and a pulsatile flow pump system can provide physiologic flow conditions characteristic of the aorta.
This dissertation presents improved experimental techniques for in vitro aortic blood flow and the increasingly larger parts of the human cardiovascular system. Specifically, this work develops new flow management and measurement techniques for cardiovascular flow experiments with the aim to improve clinical evaluation and treatment planning of aortic diseases.
The hypothesis of this research is that transient flow driven by a step change in volume flux in a piston-based pulsatile flow pump system behaves differently from transient flow driven by a step change in pressure gradient, the development time being substantially reduced in the former. Due to this difference in behavior, the response to a piston-driven pump can be predicted in order to establish inlet velocity and flow waveforms at a downstream phantom model.
The main objectives of this dissertation were: 1) to design, construct, and validate a piston-based flow pump system for aortic flow experiments, 2) to characterize temporal and spatial development of start-up flows driven by a piston pump that produces a step change from zero flow to a constant volume flux in realistic (finite) tube geometries for physiologic Reynolds numbers, and 3) to develop a method to predict downstream velocity and flow waveforms at the inlet of an aortic phantom model and determine the input waveform needed to achieve the intended waveform at the test section. Application of these newly improved flow management tools and measurement techniques were then demonstrated through in vitro experiments in patient-specific coarctation of aorta flow phantom models manufactured in-house and compared to computational simulations to inform and execute future experiments and simulations.
ContributorsChaudhury, Rafeed Ahmed (Author) / Frakes, David (Thesis advisor) / Adrian, Ronald J (Thesis advisor) / Vernon, Brent (Committee member) / Pizziconi, Vincent (Committee member) / Caplan, Michael (Committee member) / Arizona State University (Publisher)
Created2015