To see the other types of publications on this topic, follow the link: Biomedical instrumentation.
Dissertations / Theses on the topic 'Biomedical instrumentation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Biomedical instrumentation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Besar, Serry Shehata Ali. "Two new instruments for biomedical applications." Thesis, University of Kent, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236862.
Full text
2
Mancini, Michael C. "Biomedical instrumentation and nanotechnology for image-guided cancer surgery." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43657.
Full textAbstract:
Once diagnosed, cancer is treated by surgical resection, chemotherapy, radiation therapy, or a combination of these therapies. It is intuitive that physically and completely removing a solid tumor would be an effective treatment. A complete resection of the tumor mass, defined by surgical margins that are clear of neoplasia, is prognostic for a decreased chance of cancer recurrence and an increased survival rate. In practice, complete resection is difficult. A surgeon primarily has only their senses of touch and sight to provide "real-time" guidance in the removal of a tumor while in the operating room. Preoperative imaging can guide a surgeon to a tumor but does not give a continuous update of surgical progress. Intraoperative pathology is limited to a few slides worth of samples: a product of its time-consuming nature and the limited time a patient can remain under general anesthesia. Technologies to guide a surgeon in effecting complete resection of a tumor mass during the surgical procedure would greatly increase cancer survival rates by lowering rates of cancer recurrence; such a technology would also reduce the need for follow-up chemotherapy or radiation therapy. Here, we describe a prototype instrumentation system that can provide intraoperative guidance with exogenous optical contrast agents. The instrumentation combines interactive point excitation, local spectroscopy, and widefield fluorescence imaging to enable low-cost surgical guidance using FDA-approved fluorescent dyes, semiconductor quantum dots (QDs), or surface-enhanced Raman scattering (SERS) nanoparticles. The utility of this surgical system is demonstrated in rodent tumor models using an FDA-approved fluorescent dye, indocyanine green (ICG), and is then more extensively demonstrated with a pre-clinical study of spontaneous tumors in companion canines. The pre-clinical studies show a high sensitivity in detecting a variety of canine tumors with a low false positive rate, as verified by pathology.
We also present a fundamental study on the behavior of quantum dots. QDs are a promising fluorophore for biological applications, including as a surgical contrast agent. To use QDs for in vivo human imaging, toxicity concerns must be addressed first. Although it is suspected that QDs may be toxic to an organism based on the heavy-metal elemental composition of QDs, overt organism toxicity is not seen in long-term animal model studies. We have found that some reactive oxygen species (ROS) generated by the host inflammatory response can rapidly degrade QDs; in the case of hypochlorous acid, optical changes to the QDs are suggestive of degradation occurring within seconds. It is well-known that QDs are sequestered by the immune system when used in vivo---we therefore believe that QD degradation through an inflammatory response may represent a realizable in vivo mechanism for QD degradation. We demonstrate in an in vitro cell culture model that immune cells can degrade QDs through ROS exposure. Knowledge of the degradative processes that QDs would be subject to when used in vivo informs on adaptations that can be made to the QDs to resist degradation. Such adaptations will be important in developing QD-based contrast agents for image guided surgery.
3
De, Beule Pieter Albert Arthuur. "Development of multi-dimensional fluorescence instrumentation for biomedical applications." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500313.
Full text
4
Barnett, Nicholas James. "The development of biomedical instrumentation using backscattered laser light." Thesis, Oxford Brookes University, 1990. https://radar.brookes.ac.uk/radar/items/854b71a4-e72a-4396-bac2-df2608345d2d/1.
Full textAbstract:
This thesis is concerned with the measurement of blood flow and oxygen saturation in the microcirculation using the techniques of laser Doppler flowmetry and pulse oximetry. An investigation of the responses of Doppler flowmeters using different signal processing bandwidths and laser sources revealed two major findings. Firstly, that careful choice of processing bandwidth is required in order to sample the whole range of possible Doppler frequencies present in the backscattered light. Secondly, that the choice of laser source is important in governing the output stability of a flowmeter. Another investigation focused on the evaluation of a dual channel laser Doppler flowmeter using both in vitro and in vivo models. It was demonstrated that the instrument permitted a useful method of obtaining flow information by comparing simultaneous responses at experimental and control sites. The choice of laser wavelength was investigated in a study to determine whether blood flow measurements are obtained from different depths within the skin tissue. The results indicate that some depth discrimination is obtainable using instruments operating at different wavelengths, however it is difficult to demonstrate the effect in vivo. In a separate study it was shown that pressure applied to the skin surface greatly affects the underlying blood flow. It is recommended that care has to be taken when positioning Doppler probes on the skin. A reflection pulse oximeter was developed using laser light backscattered from the skin. The instrument was evaluated in vitro and in vivo by comparing desaturation responses with a commercial transmission pulse oximeter. The reflection oximeter was demonstrated to reliably follow trends in oxygen saturation but several problems prevented instrument calibration. Finally, a device combining laser Doppler flowmetry with reflection pulse oximetry was developed and used in vivo to follow trends in blood flow and oxygen saturation from the same tissue sample.
5
Ahmed, Mohamed E. "PORTABLE MEDICAL INSTRUMENT FOR OBJECTIVELY DIAGNOSING HUMAN TINNITUS." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/165.
Full textAbstract:
This thesis presents designs of portable medical instruments to diagnose human tinnitus. At the present time, portable medical instruments are used everywhere for almost all kinds of daily health needs. Those high-performance instruments are used in medical facilities, hospitals, and clinics, and on the personal use level, as patients need them. Nowadays the digital means to design those instruments have become very important, and it's our goal to make use of the technology to upgrade and make those designs fast, accurate, easy to use, and inexpensive, so all people with need of those devices will be able to obtain them. At this time, there are many questions regarding tinnitus, but few definitive answers. Since it is still not fully understood, many comprehensive studies and analysis were carried out to present a complete model for the instruments.
6
Leahy, Martin J. "Biomedical instrumentation for monitoring micro-vascular blood perfusion and oxygen saturation." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249227.
Full text
7
McLean, Calum Conner. "Instrumentation for the multiparameter assessment of speech defects." Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362183.
Full text
8
Davis, James. "A study of mediated electron transfer in potential biosensors." Thesis, University of the West of Scotland, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307785.
Full text
9
Aamoth, Kelsey. "Instrumentation and Control System to Quantify Colonic Activity." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459190138.
Full text
10
Mares, David M. "Developmental laboratories for biomedical instrumentation and digital signal processing with virtual instrument technology and diverse software techniques." Laramie, Wyo. : University of Wyoming, 2006. http://proquest.umi.com/pqdweb?did=1292461511&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full text
11
Patterson, Laura. "A COMPUTATIONAL STUDY OF CURVATURE IN THE OUTFLOW GRAFT OF A CONTINUOUS FLOW LEFT VENTRICULAR ASSIST DEVICE." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4615.
Full textAbstract:
Left ventricular assist devices (LVADs) are an increasingly utilized therapy for end-stage heart failure. Thrombosis within the graft from the pump to the aorta has been documented, but is poorly researched. This study examines the effect of graft geometry, as measured by radius of curvature, bend angle, and diameter, on thrombogenic flow patterns within the graft for a range of flow conditions. It also examines the effect blood properties, including viscosity and density, on these flow patterns. The results indicated that radius of curvature had a powerful effect on thrombogenic flow patterns. Flowrate and bend angle were also influential. The results of this study offer insight on how graft geometry may interact with flow conditions and blood properties to produce regions of stagnation or recirculation within the outflow graft, which may precipitate thrombogenesis and pose a risk to patients.
12
Engman, Zoie. "Design and Validation of a Wearable, Continuous, and Non-Invasive Hydration Monitor that uses Ultrasonic Pulses to Detect Changes in Tissue Hydration Status." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1218.
Full textAbstract:
Chronic dehydration is an endemic problem for many population groups. Current methods of monitoring hydration status are invasive, time consuming, cannot be performed while exercising, and require lab resources. A proposed solution is a wearable, continuous, and non-invasive device that uses harm-free ultrasonic pulses to detect changes in tissue hydration status over time. Customer and engineering requirements were defined and used to guide the design process. Literature reviews were performed to identify essential information on dehydration, assess current methods, discover state of the art devices, and describe ultrasonic theory. Market research was performed to identify athletes as the target population group. An adjustable elastic nylon bicep band prototype was manufactured and the integration of more advanced components was proposed. The theoretical signal processing method used to detect hydration status was validated through initial tests with a prototype electrical system composed of a Teensy 3.1 board, two 18 kHz piezoceramic disc elements, and an Arduino/LabVIEW interface. Tests with aluminum, rubber, and sponge materials were performed to compare the signal response to propagation through materials with different acoustic properties and water contents. Finally, tests performed with dehydrated bovine muscle tissue revealed a statistically significant difference between hydrated and dehydrated tissue, a promising indication for future device refinement.
13
Mosley, Connor Lewis. "Design and Validation of a Fall Detection Application for iOS." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1554.
Full textAbstract:
Despite significant preventative efforts, falls continue to be a major source of morbidity and mortality among the elderly. Additionally, the fear of falling can be a major obstacle to independent living for otherwise self-sufficient individuals. This fear is significantly heightened in individuals who have sustained a fall and often results in self-imposed restrictions on mobility and exercise, causing weakening in these individuals and further exacerbating the danger. Much time has been spent developing alert systems in an attempt to mitigate these problems. Unfortunately these systems typically involve dedicated monitoring centers and therefore often come with substantial upfront and recurring costs. This thesis proposes a solution to these problems by implementing fall detection and alert capabilities on a smartphone, devices that are quickly becoming ubiquitous in today’s society. This solution has the potential to quell the fears of many elderly people and their families, while allowing them to maintain their independence at little expense. Detailed herein is the process of designing, developing, and validating this fall detection application. The final application was written in Objective-C for iOS and tested on an iPhone.
14
Weiss, Martin. "Computer assisted audiometric evaluation system." Master's thesis, University of Cape Town, 1991. http://hdl.handle.net/11427/25671.
Full textAbstract:
A computer-based audiometric evaluation system has been developed. The system makes use of an IBM PC/XT/AT compatible personal computer to perform pure tone and speech tests and · comprises a plug-in card and custom software. The card contains pure tone and masking noise generators, together with amplifiers for a. set of headphones .and bone conduction transducer, patient and audiologist microphone amplifiers and a hand-held infra-red remote-control unit. A voice-operated gain-adjusting device on the audiologist's microphone eliminates the need for a sound pressure level meter during speech tests. The software-based user-interface makes use.of overlaid pop-up menus, context sensitive assistance.and a text editor on a graphics screen. Pure tone and speech data are acquired and displayed on a dynamic audiogram and speech discrimination gram respectively. This data may be stored and later retrieved from a patient data base. Further audiometric tests may be incorporated at a later stage.
15
Soski, Daniel Aaron. "Extended-Use ECG Monitor." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1875.
Full textAbstract:
In this thesis, a prototype ECG monitor was developed that is integrated into an elastic shirt and takes a 3-lead ECG for over 5 days. The high-quality measurements can be used to identify markers indicative of various detrimental heart conditions. Measurements recorded by the device are encrypted and stored onto a micro-SD card. Current Holter monitors are expensive and have functional lives less than 48 hours; however, extended duration monitoring has been proven more useful in diagnosis. The device designed demonstrates that ECG measurements can be taken over longer durations without sacrificing quality, comfort, or device cost.
16
Cronjé, Thomas Frederick. "A plethysmographic device for determining human body volume and body density." Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/27150.
Full textAbstract:
The measurement of total body volume (V) (excluding lung volume) together with total body mass (m) is required in order to determine body density (d = m/V). From this, and using certain simplifying assumptions, it is possible to derive body composition in terms of fat mass (FM) and fat free mass (FFM) for the two-compartment model. The standard method for determining body volume (and hence body composition) is the densitometric (underwater weighing) technique based on Archimedes' principle. Three variables, notably residual lung volume (RV), total body mass (m) and submerged body mass are measured. RV is normally determined using a gas dilution technique while total body mass is simply measured using an accurate weighing scale. The submerged body mass is measured while the subject is totally submerged in a tank of water. This method, although relatively accurate, requires substantial apparatus and is time consuming. An alternative method, based on a polytropic thermodynamic process, is described for body volume measurement and thereby for body composition assessment. Previous use of this method by Taylor, et al. (1985) and Gundlach and Visscher (1986) were successful, but complex in terms of operating system. The described system comprises of a Perspex, sealed chamber. A cycling piston communicates with the chamber and imposes a minute sinusoidal pressure variation which is then measured. With a subject situated inside the chamber an increased pressure variation, caused by the decreased chamber volume, is then measured and processed to yield the displaced, or body volume. Subject comfort, above all, is greatly enhanced, in comparison to the underwater weighing method. A substantial advantage of the method appears to be that RV need no longer be measured. Variables such as a rise of temperature and humidity caused by the subject, as well as pressure variations due to respiration, were expected and found. These were analyzed both theoretically and experimentally and where necessary the data were modified to account for these variables using a personal computer. Calibration and preliminary validation of the instrument has been carried out using underwater weighing, bioimpedance and skinfold analyses and the error of measurement assessed. It appears that the described plethysmographic method is capable of measuring body volume and thus compares favourably to the underwater weighing method. Even though other groups have succeeded in employing similar principles, a substantially simpler mechanism has been used here.
17
Martel, Sylvain. "A predictable real-time system for control and instrumentation /." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=42092.
Full textAbstract:
Many research and commercial environments need to measure fast time varying signals and need to control subsystems, e.g. actuators, also in real-time with high bandwidth and minimum latency. Existing commercial systems for data acquisition and control have many shortcomings and behave in a non-deterministic manner. Determinism or predictability is a key element of high performance real-time systems which must always meet specific deadlines under tight synchronizations. In this thesis, a new approach to very high-performance predictable real-time acquisition and control is proposed, theoretically analyzed, implemented in hardware, and experimentally tested. The resulting system is highly adaptable and reconfigurable, and has been applied to a number of problem areas including micro-robot control via a high performance parallel computer architecture, and cardiac electropotential mapping. Indeed, the resulting cardiac mapping system is so far as we know, the highest resolution produced to date.
18
Shet, Keerthi Vishnudas. "Development Of Instrumentation And Techniques To Adapt Proton Electron Double Resonance Imaging For Biomedical Imaging." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1227731151.
Full text
19
Seoane, Martínez Fernando. "Electrical bioimpedance cerebral monitoring." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3421.
Full textAbstract:
Neurologically related injuries cause a similar number of deaths ascancer, and brain damage is the second commonest cause of death in theworld and probably the leading cause of permanent disability. Thedevastating effects of most cases of brain damage could be avoided if itwere detected and medical treatment initiated in time. The passiveelectrical properties of biological tissue have been investigated for almost acentury and electrical bioimpedance studies in neurology have beenperformed for more than 50 years. Even considering the extensive effortsdedicated to investigating potential applications of electrical bioimpedancefor brain monitoring, especially in the last 20 years, and the specificallyacute need for such non-invasive and efficient diagnosis support tools,Electrical Bioimpedance technology has not made the expectedbreakthrough into clinical application yet. In order to reach this stage inthe age of evidence-based medicine, the first essential step is todemonstrate the biophysical basis of the method under study. The presentresearch work confirms that the cell swelling accompanying thehypoxic/ischemic injury mechanism modifies the electrical properties ofbrain tissue, and shows that by measuring the complex electricalbioimpedance it is possible to detect the changes resulting from braindamage. For the development of a successful monitoring method, after thevital biophysical validation it is critical to have available the properelectrical bioimpedance technology and to implement an efficient protocolof use. Electronic instrumentation is needed for broadband spectroscopymeasurements of complex electrical bioimpedance; the selection of theelectrode setup is crucial to obtain clinically relevant measurements, andthe proper biosignal analysis and processing is the core of the diagnosissupport system. This work has focused on all these aspects since they arefundamental for providing the solid medico-technological backgroundnecessary to enable the clinical usage of Electrical Bioimpedance forcerebral monitoring.
20
De, Jesus Reis Lagarto Joao. "Development of instrumentation for autofluorescence spectroscopy and its application to tissue autofluorescence studies and biomedical research." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/30817.
Full textAbstract:
Autofluorescence spectroscopy is a promising non-invasive label-free approach to characterise biological samples and has shown potential to report structural and biochemical changes occurring in tissue owing to pathological transformations. This thesis discusses the development of compact and portable single point fibre-optic probe-based instrumentation for time-resolved spectrofluorometry, utilising spectrally resolved time-correlated single photon counting (TCSPC) detection and white light reflectometry. Following characterisation and validation, two of these instruments were deployed in clinical settings and their potential to report structural and metabolic alterations in tissue associated with osteoarthritis and heart disease was investigated. Osteoarthritis is a chronic and progressive disease of the joint characterised by irreversible destruction of articular cartilage for which there is no effective treatment. Working with the Kennedy Institute of Rheumatology, we investigated the potential of time-resolved autofluorescence spectroscopy as a diagnostic tool for early detection and monitoring of the progression of osteoarthritis. Our studies in enzymatically degenerated porcine and murine cartilage, which serve as models for osteoarthritis, suggest that autofluorescence lifetime is sensitive to disruption of the two major extracellular matrix components, aggrecan and collagen. Preliminary autofluorescence lifetime data were also obtained from ex vivo human tissue presenting naturally occurring osteoarthritis. Overall, our studies indicate that autofluorescence lifetime may offer a non-invasive readout to monitor cartilage matrix integrity that could contribute to future diagnosis of early cartilage defects as well as monitoring the efficacy of therapeutic agents. This thesis also explored the potential of time-resolved autofluorescence spectroscopy and steady-state white-light reflectometry of tissue to report structural and metabolic changes associated with cardiac disease, both ex vivo and in vivo, in collaboration with clinical colleagues from the National Heart and Lung Institute. Using a Langendorff rat model, the autofluorescence signature of cardiac tissue was investigated following different insults to the heart. We were able to correlate and translate results obtained from ex vivo Langendorff data to an in vivo myocardial infarction model in rats, where we report structural and functional alterations in the infarcted and remote myocardium at different stages following infarction. This investigation stimulated the development of a clinically viable instrument to be used in open-chest surgical procedures in humans, of which progress to date is described. 4 The impact of time-resolved autofluorescence spectroscopy for label-free diagnosis of diseased would be significantly enhanced if the cost of the instrumentation could be reduced below what is achievable with commercial TCSPC-based technology. The last part of this thesis concerns the development of compact and portable instrumentation utilising low-cost FPGA-based circuitry that can be used with laser diodes and photon-counting photomultipliers. A comprehensive description of this instrument is presented together with data from its application to both fluorescence lifetime standards and biological tissue. The lower potential cost of this instrument could enhance the potential of autofluorescence lifetime metrology for commercial development and clinical deployment.
21
Klein, Justin Shaun. "Cerenkov Luminescence for Imaging and Therapy| Quantitative Investigation of Clinical Applications and New Instrumentation." Thesis, University of California, Davis, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10606959.
Full textAbstract:
Cerenkov luminescence (CL) is optical radiation induced by fast, charged, particles. In the biomedical setting, it is produced by all PET radionuclides and by radiotherapy beams.
The work presented in this dissertation, spanning some five years, has sought to both investigate the utility of Cerenkov luminescence imaging (CLI) in the biomedical setting and to push the boundaries by inventing ultrasound-modulated Cerenkov luminescence imaging (USCLI), a modality that potentially mitigates the scattering limit of resolution for CLI.
Clinical applications of CLI have focused on evaluating the potential of Cerenkov luminescence as a tool for guidance during brain tumor resection. Monte Carlo simulations of a brain phantom, along with an experimental analysis scheme, were developed to recapitulate a tumor margin assessment task. The brain phantom has optical properties derived from real brain tissues, and the simulation accounts for all physics of nuclear decay, charged particles, and optical photon propagation. The relative merits of the Cerenkov luminescence signal have been compared with other decay signals in the context of an intraoperative detection task. Considering two surgically-feasible implementations, imaging with a sensitive camera or intraoperative probe, CL objectively provides the most sensitive signal when the tumor remnant resides at superficial (<2 mm) depths.
CL-activated photodynamic therapy (PDT) was quantitatively explored, and progress was made toward resolving the quantitative dissonance between extraordinary published results and expected required dosimetry. Published in vivo results, which purport to positively demonstrate CL-activated PDT, are at least six orders of magnitude below the therapeutic threshold for PDT dosimetry. The results herein suggest that CL is unlikely to be the driver of the observed therapeutic results, and the mechanism behind these surprising results merits further investigation.
Finally, both the theory and instrumentation for USCLI, a new, high resolution imaging modality, were developed. USCLI uses ultrasound to modulate the CL signal and thereby shift the resolution-dependence from tissue optical properties to those of the ultrasound beam. Monte Carlo simulations were performed and positively demonstrate higher resolution CLI in a scattering media. Instrumentation to experimentally demonstrate and quantify ultrasound modulation of Cerenkov luminescence imaging were developed and characterized.
22
Popp, Matthias H. "Design and construction of a laboratory system for neuromuscular stimulation of the lower extremities during cycling." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/27211.
Full textAbstract:
Functional Neuromuscular Stimulation (FNS) is a method by which paralyzed muscles are stimulated electrically in order to produce a useful movement. The design and testing of a laboratory system for the modulated control of the lower extremities during FNS-induced cycling on an exercising device (Paracycle) is described. The system hardware, which is designed around a standard IBM compatible Personal Computer, features six independent stimulation channels. Waveform characteristics such as pulse frequency, width and amplitude are defined as a function of the crank position of the Paracycle for each channel. An extensive software package allows programmability of the waveform parameters and supports the user in the definition of stimulation sequences. The effective performance of the complete FNS-controller/ Paracycle system has been demonstrated during a controlled case study with two paraplegic subjects.
23
Chen, Chang Hao. "Instrumentation amplifier and filter design for biopotential acquisition system." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2182898.
Full text
24
Garrett, Scott James. "Development of an Open Source Prosthetic Hand Platform." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/573.
Full textAbstract:
Development of an Open Source Prosthetic Hand Platform
Scott Garrett
In the field of upper extremity prosthetic devices, advancements in technology drive the design of products which are becoming capable of restoring the lost functions of the native hand. While several dexterous devices have been developed to serve this purpose, they remain prohibitively expensive and thus are not a viable option for many upper extremity amputees. To address this problem a prosthetic hand platform was developed utilizing the open source Arduino microcontroller and off-the-shelf electrical components. Using these resources, a novel finger actuation mechanism was developed to show how a prosthetic hand platform could be developed which is capable of individual finger actuation, multiple actuation modes, sensing of forces at the individual fingers, providing force feedback to the user, and control of finger actuation through a variety of control inputs.
After going through several iterations of hand’s mechanical components, electronics, and firmware a final prototype was built to showcase the possible capabilities of the open source prosthetic hand platform. This prototype consisted of several groups of subcomponents including an auto-flexing / extending finger design, a modular palm/ servo attachment base, and a wrist section which housed the hand’s electronic components, power supplies, force feedback system.
The open source prosthetic hand platform was then verified using a series of tests to quantify several performance characteristics of the final prototype. Battery life and grip strength during continuous use were evaluated and demonstrated that the hand could provide consistent grip force during up two hours of initial continuous use. Also, the grip performance of the hand was assessed through the grasping of spherical objects with varying surface textures, diameter, and weight. Furthermore the hand was tested in various “real life” applications including manipulating and sorting small objects, opening doors, grasping moderately heavy objects such as water bottles, and sensitive objects such as an egg. Lastly, the platform was connected to a myoelectric input circuit to demonstrate compatibility with advanced electro-physical inputs. These tests demonstrated that the platform was capable of performing some of the dexterous tasks performed by prohibitively expensive available robotic upper extremity prosthetic devices.
Further developments could be made to the open source prosthetic hand platform including enhancements to the platform’s finger force sensing and feedback mechanisms, consolidation of the electronics, refinement of the auto-flexing / extending fingers, and integration with a silicone covering and patients residual limb socket. These future iterations of this platform could help provide a dexterous prosthetic hand platform at lower cost to a wider patient base.
25
Samples, Matthew W. "Micro Electrostatic Actuation of a Silicon Diaphragm." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1432.
Full textAbstract:
There are a number of applications, from hearing aids to microfluidic pumps, which utilize micro-scale actuating diaphragms. These MEMS (micro-electromechanical system) devices can be actuated by electrostatic forces, which utilize an induced electric field to pull two charged plates towards one another. Such devices were fabricated and electrostatic actuation of the diaphragms was performed to analyze its viability as a micro-speaker. The long-term performance of such products requires adequate diaphragm deflection to create audible pressure waves with relatively low maximum stresses to ensure a high cycle fatigue life. With these requirements, initial calculations and FEA (finite element analysis) were performed to establish the optimal square diaphragm side length combined with an attainable gap between electrodes to achieve an audible response. Optical and acoustic testing was then performed on 4, 5, and 7 mm side length square diaphragms with 10 μm thickness and a 70 μm electrode gap. For the 5 mm device and a 300 V applied potential, deflection was calculated to be 4.12 μm theoretically and 3.82 μm using FEA, although deflections based on optical test data averaged 30.53μm under DC conditions. The DAQ used for optical testing was extremely limiting due to its fastest sampling interval of 89 milliseconds, so this testing was performed at 2 and 5 Hz. Although the 7 mm device generated audible noise at 300 V and 2 kHz when the observer was within approximately 6 inches of the device, acoustic testing with a microphone placed 1 inch from the device did not yield any definitive results.
26
Parker, David. "Assessment of Access Methods for Mobile Maps for Individuals Who are Blind or Visually Impaired." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6097.
Full textAbstract:
When people go to a mall, museums, or other such locations they tend to rely on maps to find their way around. However, for people who are blind or visually impaired (BVI) maps are not easily accessible and they depend on other means, such as a guide, to get around. Research has only just begun to investigate providing maps for people who are BVI on touch screen devices. Many different types of feedback have been used: audio (sound), tactile (touch), audio-tactile, and multitouch. Some research has been conducted on the benefit of using multiple fingers (multitouch) and has found conflicting results. Yet, no known research has been conducted on the comparison of using audio feedback to that of tactile feedback.
In this study, we look to try and answer two questions. 1.) Is audio equal to or better than tactile? As well as: 2.) Does multiple fingers help? Participants were asked to use seven different methods (4 audio, 3 tactile) to explore an overview map and an individual map and answer questions about them. Results showed that overall, audio cues are similar or better than tactile cues which is beneficial since it requires less battery to generate audio cues than tactile cues. It was also shown that the use of multiple fingers was more beneficial in tasks that are spatially demanding. While those who have tactile experience benefited when using two fingers with each finger represented by a different instrument played to separated ears.
27
Varma, Avinash Ramesh. "Tracking points on a pacing lead in a beating heart." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1031.
Full textAbstract:
Heart failure is a common condition during which the pumping action of the heart is affected because the heart does not contract or relax properly. Heart failure affects about 5 million Americans, with 550,000 new cases diagnosed each year. Cardiac resynchronization therapy (CRT) is used to treat symptoms and other complications associated with a heart failure. While performing CRT, Implantation of a pacing lead in the left ventricle of the heart is a very challenging surgical procedure performed with fluoroscopy. The target location is often difficult to reach through the tortuous coronary venous anatomy, which varies greatly among individuals. Placement of the pacing lead is an important research topic because the ideal pacing location for some patients with heart disease may be the site of latest contraction in the left ventricle.
The purpose of this project is to develop an algorithm to locate and track points on a lead in a sequence of images. The algorithm will track the motion of the points over time and generate displacement plots over time.
28
Jin, Xiaoxia. "Investigation of Intrinsic Cell Magnetophoresis for Label-Less Cell Separation and Analysis and the Optimization of the CTV Instrumentation for Such Studies." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1268002273.
Full text
29
Selvganesan, Padmini. "Smart Statistics, Signal Processing and Instrumentation for Improved Diagnosis of Pediatric Sleep Apnea." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron159550472185963.
Full text
30
Zimmerman, Robert A. "On-demand Label Production." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2001.
Full textAbstract:
The production and approval process for the various labels used in clinical trials wastes significant time and resources through the need to outsource label production or rely on large reams of pre-cut label stock for each revision throughout the process. An in-house, on-demand label printing and cutting system is a potential remedy to this waste. Previous work by Cheadle et al. resulted in a functional electomechanical prototype of the label cutting aspect of this research, capable of rudimentary linear cuts. In this continued research, emphasis was placed on improved label cutting capabilities and creating PC control software for label design. Cutting operations were enhanced through the development of an algorithm for circular cuts, proportional motor control, and a prototype graphical user interface (GUI) for simple user control. The changes to cutting methods have improved linear cutting precision to an average of 0.00402-in (s = 0.00602-in, n=26) at minimum. The new method for circular cuts has an average precision of 0.04384-in (s = 0.01471-in, n=26). The target precision for cuts is 0.040-in, suggesting that linear cuts are satisfactory, but circular cuts must still be refined. The prototype user interface developed for this research is capable of driving the label cutting system through RS232 communication and exposes all functionality of the system to date. Overall, this research has enhanced the capabilities of the label cutting system significantly, but further work is required to realize a complete label production solution.
31
Morgan, Jones Molly. "Governing the constructs of life : what constitutes ‘good’ governance?" Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6972/.
Full textAbstract:
This thesis explores contrasting perspectives on what constitutes 'good governance' for human embryonic stem cell (hESC) research. It asks whether there are systematic differences between perspectives of UK and US policy actors and what kinds of patterns are discernible. Biomedical technologies like hESCs generate complex interactions between public values, institutional interests, societal expectations and technological uncertainties. These pose serious governance challenges. Under such conditions, diverse aspects and implications of risk, ambiguity and uncertainty come into focus. We need appraisal processes that address these issues by combining quantitative and qualitative dimensions to 'open up' divergent governance framings. The research framework employed here uses and further develops one such elicitation and analysis process called Multicriteria Mapping (MCM). MCM combines qualitative sensitivity with quantitative precision, while also aiding transparency and reflexivity in documenting and understanding diverse stakeholder perspectives. We therefore address 'good' governance both as an analytical subject and as a rationale for testing a novel form of appraisal. The analysis discerns systematic patterns in perspectives on good governance across national contexts and between stakeholders, identifying several points of convergence and divergence. We examine underlying rationales behind individual perspectives, obtaining empirical support for recent theoretical arguments concerning technology appraisal and democratic deliberation. We find national policy literatures make greater use of moral and ethical language to frame governance challenges, by comparison with stakeholders' emphasis on institutional and socio-political factors. This suggests a more critical and cautious stance is needed towards the legitimatory language of 'bioethics' in policy making. Finally, we explore some of the normative implications for governance of culturally sensitive and scientifically uncertain issues. By providing reflexive explanations of factors influencing perspectives of policy actors, this thesis makes a number of interlinked theoretical, methodological, empirical and normative contributions to understanding of how good governance of biomedical technologies is and should be conducted.
32
Boudlali, Hana. "Analysis of Electroanatomic Mapping System Accuracy Using X-Ray Reconstruction of Electrode Locations in a Porcine Animal Model." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2237.
Full textAbstract:
Fluoroscopy is considered the gold standard for locating catheters during cardiac electrophysiology (EP) procedures. However, fluoroscopy emits ionizing radiation which can lead to adverse health effects when exposed to in high doses (World Health Organization, 2016). Electroanatomic mapping (EAM) systems display the three-dimensional location of EP catheters and measure the local electrical activity of the heart. They can minimize a physician’s reliance on fluoroscopy and can help reduce radiation exposure during a case (Casella, 2011).
EAM systems are diagnostic medical devices that inform the placement of ablation therapy and must accurately locate catheters to be deemed safe. Test methods to determine EAM system accuracy should be compared back to a gold standard, such as fluoroscopy. Fluoroscopy only provides a two-dimensional image of the catheter location, which is not a suitable ground truth for measuring the three-dimensional accuracy of EAM systems. X-Ray Reconstruction of Electrode Locations (XRROEL) calculates the true three-dimensional catheter location by performing a coordinate transform on two-dimensional fluoroscopy images. This thesis outlines the development and validation of the XRROEL method in a porcine animal model, and describes how XRROEL can be applied to optimize the location accuracy of electroanatomic mapping system algorithms.
33
Smith, Heather D. "Designing an Instrument Based nn Native Fluorescence to Determine Soil Microbial Content at a Mars Analog Site." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/614.
Full textAbstract:
For this research project we designed an instrument to detect bacteria via biomolecular fluorescence. We introduce the current understanding of astrobiology, our knowledge of life beyond Earth, and the commonality of Earth life as it pertains to the search for life on Mars. We proposed a novel technique for searching for direct evidence of life on the surface of Mars using fluorescence. We use the arid region of the Mojave Desert as an analog of Mars. Results indicate the fluorescence of the biotic component of desert soils is approximately as strong as the fluorescence of the mineral component. Fluorescence laboratory measurements using the portable instrument reveal microbial concentration in the Mojave Desert soil is 107 bacteria per gram of soil. Soil microbial concentrations over a 50 meter area in the Mojave Desert, determined in situ via fluorescence, show that the number varies from 104 to 107 cells per gram of soil. We then designed an instrument for detection of biomolecular fluorescence, and considered also fluorescence from polycyclic aromatic hydrocarbons and minerals on the Martian surface. The majority of the instrument is designed from Mars surface operation flight qualified components, drastically reducing development costs. The basic design adapts the ChemCam instrument package on-board Mars Science Laboratory rover Curiosity to detect organics via fluorescence. By placing frequency multipliers in front of the 1064 nm laser, wavelengths suitable for fluorescence excitation (266 nm, 355 nm, and 532 nm) will be achieved. The emission system is modified by the addition of band pass filters in front of the existing spectrometers to block out the excitation energy. Biomolecules and polycyclic aromatic hydrocarbons are highly fluorescent at wavelengths in the ultra violet (266 nm, 355 nm), but not as much in the visible 532 nm range. Preliminary results show minerals discovered, such as perchlorate, fluoresce highest when excited by 355 nm. Overall, we conclude the fluorescent instrument described is suitable to detect soil microbes, organics, biomolecules, and some minerals via fluorescence, offering a high scientific return for minimal cost with non-contact applications in extreme environments on Earth and on future missions to Mars.
34
Hawit, Ramzi P. Mr. "Development of a Standardized Method for Comparing Biomechanical Properties of Various Sternal Closure Techniques." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/707.
Full textAbstract:
Background:
33.6% of all deaths in America are caused by cardiovascular disease. An estimated 82.6 million adults (>1 in 3) in America have some form of cardiovascular disease. There were over 400,000 bypass surgeries requiring open-heart surgery. Sternal dehiscence is associated with a morbidity rate of over 47% if mediastinitis supervenes. A rigid closure is required to avoid healing complications, and wire, plates, and bands are all used in an attempt to make a better closure. The purpose of this study it to compare multiple closures and validate a new testing method.
Methods:
Polyurethane foam blocks will be used, as an alternative to cadavers, to provide homogeneous samples to test and compare multiple closure techniques. Each closure was performed by an engineer after instruction from a cardiothoracic surgeon and the SternaLock plate manufacturers. Seven different closure techniques (single suture, double suture, figure-eight suture, Robicsek weave, Sternalock Silver, Sternalock Blu, and Sternalock Wide Ladder) were compared in both lateral distraction and longitudinal shear. Statistical analysis was used to show the differences in stiffness, yield force, failure force, and yield displacement of each closure method.
Results:
Under lateral distraction, double wire closure showed the greatest stiffness followed by the Sternalock plates. The Sternalock plates had the greatest failure and yield forces, whereas the double wire performed significantly poorer. The longitudinal testing revealed that the wires provide no resistance to the shearing forces on the sternum, but the screws for plates can allow for multidirectional loading.
Conclusions:
Overall Sternalock plates are less likely to fail in all directions compared to wired closures. Even though double wire closures displayed a higher average lateral stiffness, the high stress concentrations created by wires allowed for easy foam cutting and much lower yield force and failure force. Testing using foam blocks as sternal analogues produces highly reproducible results, with less variance than cadaveric tests.
35
Song, Yinchen. "Intraoperative Guidance for Pediatric Brain Surgery based on Optical Techniques." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2207.
Full textAbstract:
For most of the patients with brain tumors and/or epilepsy, surgical resection of brain lesions, when applicable, remains one of the optimal treatment options. The success of the surgery hinges on accurate demarcation of neoplastic and epileptogenic brain tissue. The primary goal of this PhD dissertation is to demonstrate the feasibility of using various optical techniques in conjunction with sophisticated signal processing algorithms to differentiate brain tumor and epileptogenic cortex from normal brain tissue intraoperatively.
In this dissertation, a new tissue differentiation algorithm was developed to detect brain tumors in vivo using a probe-based diffuse reflectance spectroscopy system. The system as well as the algorithm were validated experimentally on 20 pediatric patients undergoing brain tumor surgery at Nicklaus Children’s Hospital. Based on the three indicative parameters, which reflect hemodynamic and structural characteristics, the new algorithm was able to differentiate brain tumors from the normal brain with a very high accuracy.
The main drawbacks of the probe-based system were its high susceptibility to artifacts induced by hand motion and its interference to the surgical procedure. Therefore, a new optical measurement scheme and its companion spectral interpretation algorithm were devised. The new measurement scheme was evaluated both theoretically with Monte Carlo simulation and experimentally using optical phantoms, which confirms the system is capable of consistently acquiring total diffuse reflectance spectra and accurately converting them to the ratio of reduced scattering coefficient to absorption coefficient (µs’(λ)/µa(λ)). The spectral interpretation algorithm for µs’(λ)/µa(λ) was also validated based on Monte Carlo simulation. In addition, it has been demonstrated that the new measurement scheme and the spectral interpretation algorithm together are capable of detecting significant hemodynamic and scattering variations from the Wistar rats’ somatosensory cortex under forepaw stimulation.
Finally, the feasibility of using dynamic intrinsic optical imaging to distinguish epileptogenic and normal cortex was validated in an in vivo study involving 11 pediatric patients with intractable epilepsy. Novel data analysis methods were devised and applied to the data from the study; identification of the epileptogenic cortex was achieved with a high accuracy.
36
Aziz, Ayesha. "A service oriented architecture to implement clinical guidelines for evidence-based medical practice." Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/53223/.
Full textAbstract:
Health information technology (HIT) has been identified as the fundamental driver to streamline the healthcare delivery processes to improve care quality and reduce operational costs. Of the many facets of HIT is Clinical Decision Support (CDS) which provides the physician with patient-specific inferences, intelligently filtered and organized, at appropriate times. This research has been conducted to develop an agile solution to Clinical Decision Support at the point of care in a healthcare setting as a potential solution to the challenges of interoperability and the complexity of possible solutions. The capabilities of Business Process Management (BPM) and Workflow Management systems are leveraged to support a Service Oriented Architecture development approach for ensuring evidence based medical practice. The aim of this study is to present an architecture solution that is based on SOA principles and embeds clinical guidelines within a healthcare setting. Since the solution is designed to implement real life healthcare scenarios, it essentially supports evidence-based clinical guidelines that are liable to change over a period of time. The thesis is divided into four parts. The first part consists of an Introduction to the study and a background to existing approaches for development and integration of Clinical Decision Support Systems. The second part focuses on the development of a Clinical Decision Support Framework based on Service Oriented Architecture. The CDS Framework is composed of standards based open source technologies including JBoss SwitchYard (enterprise service bus), rule-based CDS enabled by JBoss Drools, process modelling using Business Process Modelling and Notation. To ensure interoperability among various components, healthcare standards by HL7 and OMG are implemented. The third part provides implementation of this CDS Framework in healthcare scenarios. Two scenarios are concerned with the medical practice for diagnosis and early intervention (Chronic Obstructive Pulmonary Disease and Lung Cancer), one case study for Genetic data enablement of CDS systems (New born screening for Cystic Fibrosis) and the last case study is about using BPM techniques for managing healthcare organizational perspectives including human interaction with automated clinical workflows. The last part concludes the research with contributions in design and architecture of CDS systems. This thesis has primarily adopted the Design Science Research Methodology for Information Systems. Additionally, Business Process Management Life Cycle, Agile Business Rules Development methodology and Pattern-Based Cycle for E-Workflow Design for individual case studies are used. Using evidence-based clinical guidelines published by UK's National Institute of Health and Care Excellence, the integration of latest research in clinical practice has been employed in the automated workflows. The case studies implemented using the CDS Framework are evaluated against implementation requirements, conformance to SOA principles and response time using load testing strategy. For a healthcare organization to achieve its strategic goals in administrative and clinical practice, this research has provided a standards based integration solution in the field of clinical decision support. A SOA based CDS can serve as a potential solution to complexities in IT interventions as the core data and business logic functions are loosely coupled from the presentation. Additionally, the results of this this research can serve as an exemplar for other industrial domains requiring rapid response to evolving business processes.
37
Wyatt, Barry Neil. "A multi-channel system for use in cardiac electrophysiologic studies." Master's thesis, University of Cape Town, 1991. http://hdl.handle.net/11427/27151.
Full textAbstract:
The location of accessory pathways in Wolff-Parkinson-White syndrome patients is performed manually during open heart surgery at Groote Schuur Hospital, using a hand-held roving electrode. This manual procedure is slow and tedious, prolonging the operation and the time for which the patient remains on cardiac bypass. A multichannel electrogram acquisition and display system with a storage facility would significantly reduce the time taken and improve the reliability of locating the accessory pathways. Having considered a number of currently available cardiac mapping systems it was decided that a new system be developed for specific application within Groote Schuur Hospital. The main design goals of this system are to improve accuracy, increase reliability and enhance the speed of the entire mapping procedure with direct benefit to staff and patients. The system is based on an IBM compatible computer and allows for the acquisition of a maximum of thirty-two electrogram inputs. A typical configuration would acquire twenty epicardial, two references (one each from atrium and ventricle), one roving electrode and two surface lead signals. The epicardial signals are obtained from a custom-built electrode belt which is placed around the heart over the atrioventricular groove. The project includes the development of front-end hardware and software for processing, display and storage of electrogram signals. The relative activation times of the signals are displayed under software control in order to facilitate the location of any accessory pathway(s).
38
Smith, Leonard. "A system for the acquisition and digital analysis of lower limb flow waveforms." Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/27049.
Full textAbstract:
A PC based waveform acquisition and analysis system has been developed for use in aorta-iliac arterial assessment. A Motorola DSP56001 based system containing dual Analog to Digital converters is used to sample phase quadrature demodulated signals from a commercially available continuous wave Doppler unit. The Power Spectral Density is calculated using an autoregressive model from which the mean velocity waveform is calculated. This waveform is used to calculate the damping factor, vessel compliance and runoff resistance of a simple electrical model of the lower limb arterial circulation using a non-linear regression technique of curve fitting in the time domain. A pilot study using the system shows a significant separation (p < 0.001 Mann Whitney U-test) between the damping factors of a normal control group (quartile range = 0. 15 - 0.25 ; median = 0. 19) and a patient group with angiographically determined aorta-iliac arterial disease (quartile range = 0.45 - 0.89 ; median= 0.49).
39
Okarski, Kevin Mark Mr. "IMPLEMENTATION OF PHYSIOLOGIC PRESSURE CONDITIONS IN A BLOOD VESSEL MIMIC BIOREACTOR SYSTEM." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/356.
Full textAbstract:
ABSTRACT
Implementation of Physiologic Pressure Conditions in a Blood Vessel Mimic Bioreactor System
Kevin Mark Okarski
Tissue engineering has traditionally been pursued as a therapeutic science intended for restoring or replacing diseased or damaged biologic tissues or organs. Cal Poly’s Blood Vessel Mimic Laboratory is developing a novel application of tissue engineering as a tool for the preclinical evaluation of intravascular devices. The blood vessel mimic (BVM) system has been previously used to assess the tissue response to deployed stents, but under non-physiologic conditions. Since then, efforts have been made to improve the vessel and bioreactor’s ability to emulate in vivo conditions. The ability to tissue engineer constructs similar to their native tissue counterparts is heavily reliant upon controlling the environment and mechanical stimuli the construct is exposed to. Mimicking physiologic conditions influences cellular growth, proliferation, and differentiation. Two important mechanical stimuli are cyclic strain and wall shear stress. Previous work sought to improve these factors within the BVM bioreactor and resulted in the implementation of pulsatile perfusion and increased fluid viscosity. These previous bioreactor design modifications generated pulsatile pressures of approximately 80 mmHg and a wall shear stress of 6.4 dynes/cm2. However, physiologic pressure waveforms were not achieved.
Studies in this thesis were carried out to implement an effective means of establishing a more physiologic pressure wave within the bioreactor that is accurate, consistent, and easily adjustable. As a result of conducting the present studies, modifications to the bioreactor system were made that uphold the overall goals of efficacy and efficiency. The desired pressure wave was created by setting the degree of pump tubing occlusion on the 3-roller peristaltic pump head and using a water column to backpressure the bioreactor chamber. Maintaining a desired backpressure within the system necessitated the development of a new bioreactor chamber with increased extraluminal leak pressure resistance. The opportunity was also used to further improve upon the bioreactor chamber design to allow for 360° rotation to reduce cell sedimentation. Modifications to the bioreactor system required quantitative evaluation to assess their impact upon local flow dynamics to the tissue construct. A system model was created and evaluated using computational modeling.
Through the work performed in this thesis, pulsatile pressure waves of approximately 120/80 mmHg were successfully established within the bioreactor. The ability to accurately model physiologic pressures will ultimately help yield tissue constructs more similar to native tissues – both healthy and pathological. The newly designed bioreactor chamber and computational model for the system will be helpful tools for implementing or evaluating future bioreactor developments or improvements. While the main objective of the thesis has been completed by creating a system capable of emulating physiologic pressure fluctuations, there still remains room for further improvements in back-pressuring and scaling the system, refining the rotational bioreactor chamber design, and building upon the complexity and accuracy of the computational model.
40
Patel, Chirag Mukesh. "SAR MAP OF GEL PHANTOM IN A 64MHz MRI BIRDCAGE BY FIBER-OPTIC THERMOMETRY AND FDTD SIMULATION." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/472.
Full textAbstract:
As implantable medical devices are being used more often to treat medical problems for which pharmaceuticals don’t suffice, it is important to understand their interactions with commonly used medical modalities. The interactions between medical implants and Magnetic Resonance Imaging machines have proven to be a risk for patients with implants.
Implanted medical devices with elongated metallic components can create harmful levels of local heating in a Magnetic Resonance Imaging (MRI) environment [1]. The heating of a biological medium under MRI is monitored via the Specific Absorption Rate (SAR). SAR, defined as power absorbed per unit mass (W/kg), can be calculated as , where σ is electrical conductivity of the medium in units of , |E| is the magnitude of the applied electric field in units of , and ρ is the density of the medium in units of . For continuous, uniform power deposition this can be measured experimentally as a rise in temperature over time (∆T/t), where c is the specific heat capacity of the medium in units of. To understand the SAR induced in-vivo, a phantom (Figure 2.10) is used to conduct in-vitro experiments, as it provides a controllable and repeatable experimental setup.
In order to experiment in the phantom, an understanding of the background SAR distribution and in turn the exposure field distribution of the phantom is required as per the ASTMF2182-09 standard [2]. In this work, the background SAR distribution of an ASTM standard torso phantom is measured and studied via fiber optic thermometry. The measurements are compared with an electromagnetic model simulated via FDTD, demonstrating agreement between 10-25%. A custom exposure and data collection setup (including oscilloscope, function generator, RF amplifier, directional coupler, and Neoptix Omniflex Fiber Optic Thermometry system) was integrated and automated using NI LabView.
The purpose of this thesis is to map the field distribution in a torso phantom under RF exposure from a 64 MHz MRI RF Birdcage, compare the results to an electromagnetic simulation, and finally conclude the accuracy of this method for field measurements in a standard torso phantom. Understanding the capabilities and accuracy of the fiber optic thermometry method will ultimately allow researchers to successfully apply this method to monitor background fields in their respective experimental setups (related to MRI implant heating) and understand its limitations.
41
Vasudev, Abhay. "Electrochemical Immunosensing of Cortisol in an Automated Microfluidic System Towards Point-of-Care Applications." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/956.
Full textAbstract:
This dissertation describes the development of a label-free, electrochemical immunosensing platform integrated into a low-cost microfluidic system for the sensitive, selective and accurate detection of cortisol, a steroid hormone co-related with many physiological disorders. Abnormal levels of cortisol is indicative of conditions such as Cushing’s syndrome, Addison’s disease, adrenal insufficiencies and more recently post-traumatic stress disorder (PTSD). Electrochemical detection of immuno-complex formation is utilized for the sensitive detection of Cortisol using Anti-Cortisol antibodies immobilized on sensing electrodes. Electrochemical detection techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been utilized for the characterization and sensing of the label-free detection of Cortisol. The utilization of nanomaterial’s as the immobilizing matrix for Anti-cortisol antibodies that leads to improved sensor response has been explored. A hybrid nano-composite of Polyanaline-Ag/AgO film has been fabricated onto Au substrate using electrophoretic deposition for the preparation of electrochemical immunosening of cortisol. Using a conventional 3-electrode electrochemical cell, a linear sensing range of 1pM to 1µM at a sensitivity of 66µA/M and detection limit of 0.64pg/mL has been demonstrated for detection of cortisol. Alternately, a self-assembled monolayer (SAM) of dithiobis(succinimidylpropionte) (DTSP) has been fabricated for the modification of sensing electrode to immobilize with Anti-Cortisol antibodies. To increase the sensitivity at lower detection limit and to develop a point-of-care sensing platform, the DTSP-SAM has been fabricated on micromachined interdigitated microelectrodes (µIDE). Detection of cortisol is demonstrated at a sensitivity of 20.7µA/M and detection limit of 10pg/mL for a linear sensing range of 10pM to 200nM using the µIDE’s.
A simple, low-cost microfluidic system is designed using low-temperature co-fired ceramics (LTCC) technology for the integration of the electrochemical cortisol immunosensor and automation of the immunoassay. For the first time, the non-specific adsorption of analyte on LTCC has been characterized for microfluidic applications. The design, fabrication technique and fluidic characterization of the immunoassay are presented. The DTSP-SAM based electrochemical immunosensor on µIDE is integrated into the LTCC microfluidic system and cortisol detection is achieved in the microfluidic system in a fully automated assay. The fully automated microfluidic immunosensor hold great promise for accurate, sensitive detection of cortisol in point-of-care applications.
42
Dawson, Marc Cody. "IMPLEMENTATION OF PHYSIOLOGIC FLOW CONDITIONS IN A BLOOD VESSEL MIMIC BIOREACTOR SYSTEM FOR THE EVALUATION OF INTRAVASCULAR DEVICES." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/78.
Full textAbstract:
The prevalence and devastating nature of cardiovascular diseases has led to many advancements in the therapies used to treat the millions of patients that suffer as a result of these conditions. As coronary artery disease (CAD) is the most common of these cardiovascular conditions, it is a major focus of research among the medical industry. Although lifestyle changes and drug therapies can treat early CAD, more advanced cases often require more definitive interventions. In conjunction with angioplasty, stenting of an occluded vessel has shown significant success in preventing restenosis. However, as with nearly every therapeutic process in the medical field, several complications have arisen in stented patients that pose a need for further improvement of the devices. As a result, the stent industry is constantly striving towards improving the characteristics and outcome of their product and with these efforts comes the need for extensive testing and research.
Continuous improvement and innovation in the field of tissue engineering has brought about the possibility of creating laboratory grown tissue engineered vascular grafts (TEVGs) for the purpose of replacing and/or bypassing damaged or occluded regions of the vasculature. By employing the techniques used to produce TEVGs, a blood vessel mimic (BVM) bioreactor system has been developed with the intent of using the resulting construct as a model for testing the cellular response of a human blood vessel to an intravascular device such as a stent. This would allow gathering of more significant data in the early stages of device development and may reduce the overall costs and time required to refine a design.
Although the BVM system has previously been used to cultivate viable constructs that were subsequently used to observe the response to a deployed stent, the flow conditions within the original design are not representative of the physiologic conditions in a native vessel. This aspect of the original system presented a need for development in order to be considered by researchers as an accurate in vitro representation of the target vessels in which the stents are used. One of the primary concerns of this environment is creating and maintaining physiologic flow conditions that will represent those present in native vessels in order to facilitate cells sodded on the construct to grow as they would under native conditions. The two key aspects of flow are pulsatility and wall shear stress.
Studies in this thesis were carried out to determine the best and most feasible methods for implementing appropriate levels of pulsation and wall shear stress in the previously established BVM bioreactor system with the intention of maintaining the original system’s simplicity and high throughput potential. Pulsatile flow was created by elevating backpressure in the BVM chamber while using a different pump head and pump tubing. Wall shear stress was adjusted by altering the viscosity of the perfusate and flow rate through the system. Both pulsatile flow and shear stress were established without any major changes to the overall configuration of the system.
Pulsatile pressures of ~80 mmHg and wall shear stress forces of ~6.4 dyn/cm2 were established with minimal alteration to the original system. Pulsatility was created by using a 3-roller peristaltic pump head in place of the originally specified 8-roller head to create pulses that were then regulated with backpressure created by restricting down stream flow. Increasing the viscosity and corresponding flow rate allowed for instigation and control of wall shear stress at the inner wall of the BVM graft. Although the resulting protocols presented here require refinement for ultimately successful implementation, they are important underpinnings that will facilitate the eventual development of an ideal BVM system that is highly suitable for use as a high-throughput intravascular device testing model.
43
Teng, Carolyn. "A 3-Dimensional In Silico Test Bed for Radiofrequency Ablation Catheter Design Evaluation and Optimization." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2076.
Full textAbstract:
Atrial fibrillation (AF) is the disordered activation of the atrial myocardium, which is a major cause of stroke. Currently, the most effective, minimally traumatic treatment for AF is percutaneous catheter ablation to isolate arrhythmogenic areas from the rest of the atrium. The standard in vitro evaluation of ablation catheters through lesion studies is a resource intensive effort due to tissue variability and visual measurement methods, necessitating large sample sizes and multiple prototype builds. A computational test bed for ablation catheter evaluation was built in SolidWorks® using the morphology and dimensions of the left atrium adjacent structures. From this geometry, the physical model was built in COMSOL Multiphysics®, where a combination of the laminar fluid flow, electrical currents, and bioheat transfer was used to simulate radiofrequency (RF) tissue ablation. Simulations in simplified 3D geometries led to lesions sizes within the reported ranges from an in-vivo ablation study. However, though the ellipsoid lesion morphologies in the full atrial model were consistent with past lesion studies, perpendicularly oriented catheter tips were associated with decreases of -91.3% and -70.0% in lesion depth and maximum diameter. On the other hand, tangentially oriented catheter tips produced lesions that were only off by -28.4% and +7.9% for max depth and max diameter. Preliminary investigation into the causes of the discrepancy were performed for fluid velocities, contact area, and other factors. Finally, suggestions for further investigation are provided to aid in determining the root cause of the discrepancy, such that the test bed may be used for other ablation catheter evaluations.
44
Do, Khoa Tat. "Universal Engineering Programmer - An In-house Development Tool For Developing and Testing Implantable Medical Devices In St. Jude Medical." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/488.
Full textAbstract:
During development and testing of the functionality of the pacemaker and defibrillator device, engineers in the St. Jude Medical Cardiac Rhythm Management Division use an in-house development tool called Universal Engineering Programmer (UEP) to ensure the device functions as expected, before it can be used to test on an animal or a human during the implantation process. In addition, some applications of UEP are incorporated into the official releases of the device product. UEP has been developed and used by engineers across departments in the St. Jude Medical Cardiac Rhythm Management Division (CRMD). This thesis covers the flexible and reusable design and implementation of UEP features, to allow engineers to easily and effectively develop and test the devices.
45
Purcell, Cameron Paul. "A PMMA CONDUCTIVITY PRETREATMENT MICROFLUIDICS DEVICE FOR THE OPTIMIZATION OF ELECTROKINETIC MANIPULATIONS." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/538.
Full textAbstract:
This project encompasses the design and development of a pretreatment microfluidic device for samples of physiological conductivity, namely a saline solution. The conductivity was reduced through the combination of dilution and ion removal using electric fields to enable downstream electro kinetic manipulations. The two major parts of this project include (1) designing a pretreatment protocol to reduce the conductivity of the sample solution to an acceptable level and (2) designing /fabricating a microchip that will effectively allow aim (1) to be performed on chip.
This project is one of the first to observe the effects of an electric field, used in the application of ion removal, to reduce the conductivity of a sample. Through the combination of sample and low conductivity buffer, as well as the presence of an electric field, a conductivity pretreatment chip is created. Since biomarkers and analytes of interest are difficult to detect in complex raw samples, such as blood, this chip is a necessary preliminary step that allows for successive separations.
Using previous literature from the field of capillary electrophoresis, a design and pretreatment protocol was developed to pretreat a sample into a target conductivity range. A PMMA device was fabricated using a laser photoablation system located on the Cal Poly campus. Off-chip electrodes were used to induce electrophoretic movement of ions across a membrane and out of the sample. The combination of dilution and electrical fields yielded samples that had their conductivity reduced 80%. Dilution was found to be more effective in a chip designed with a short process time and continuous flow. Ultimately, we wish to incorporate this device with other pre-fabricated pretreatment and electrokinetic devices to optimize certain bioseparations.
46
Cohen, Nathan M. "DC Dielectrophoretic Assisted Anti-Fouling Filtration System." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/694.
Full textAbstract:
Filtration processes, whether on the microfluidic, clinical treatment systems, or industrial scale (e.g., point-of-care diagnostics, dialysis, and biopharmaceutical manufacturing, respectively), are often inseparable from membrane clogging (fouling). As a consequence, most, if not all, filtration systems require frequent maintenance to maintain functionality and efficiency. The thesis of this project hypothesizes that Dielectrophoresis can be combined with standard filtration to reduce filter fouling, extending membrane life, and enabling continuous operation. This project investigates a method to reduce fouling, add specificity and efficiency, and decrease the cost and challenge of filtration based biofluid separations.
To substantiate this thesis, we designed, fabricated, and tested a filtration system to filter micron diameter particles in suspension using Millipore™ membranes together with fabricated electrodes in a cross-flow filtration system. This prototype device elicits a repulsive dielectrophoretic (DEP) force via the application of a direct current (5-20 volts) sourced from a computer controlled voltage sequencer, designed to levitate and remove larger particles (> 6 µm) before particulate-membrane interaction. Analysis of the results shows a sufficient decrease in particles adhered to the filtration membrane, as compared to control, suggesting DC DEP may be a valid effector in this device. We are convinced that further research will augment the results validating the proof-of-concept thesis presented herein.
47
Meckel, Jon-Peter. "Surgical Tooling Designed for the Direct Anterior Approach to Total Hip Arthroplasty." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1061.
Full textAbstract:
Surgical Tooling Designed for the Direct Anterior Approach to Total Hip Arthroplasty Jon-Peter Meckel
Total hip arthroplasty (THA) is becoming more and more common in the US as people continue to live longer and more active lives. The main reason that a THA is required is due to the “wear and tear” affliction of osteoarthritis, which in the year 2000 had at least 3% of the population over 30 showing symptoms. A revitalized approach to THA is the direct anterior approach, or Smith-Petersen approach, which limits the amount of musculature affected by the surgery and creates a very stable joint post-operatively. While this approach is showing great clinical success, it does require slightly unconventional patient positioning. The pioneers of this surgical approach include Dr. Joel Matta, who along with Mizuhosi (Union City, CA, USA) has created an impressive direct anterior approach surgical table to address the problems associated with getting patients in the right position. Unfortunately, this table is very expensive, gives no feedback on force application, and surgeons are being taught that it is required to perform the procedure. This thesis introduces a simple set of surgical tooling that facilitates the direct anterior approach very cost effectively, giving the surgeon the feedback lacking in the expensive Mizuhosi table, and the flexibility to attempt the approach without convincing his or her hospital to make such a large capital investment. A prototype was successfully developed and tested to show that a simple solution exists to make the direct anterior approach more feasible for surgeons to incorporate into their practice.
48
Kanbar, Jad. "HYDRODYNAMIC FOCUSED PASSIVE SEPARATION UNDER CONTINUOUS FLOW IN A MICROFLUIDIC CHIP." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/870.
Full textAbstract:
A continuous flow, passive separation device was designed using an equivalent circuit to create variable flow rates for hydrodynamic focusing to drain channels and collection outlets. By varying the diameter of the sample inlet connection into the reservoir, the particle position was influenced significantly, which enabled desired separations. Additionally it was noted that the relative, horizontal position of the inlet also had a significant influence on particle position within the device. A dimensionless number, the Characteristic Sample Inlet, was developed to relate geometric properties of the inlet reservoir to downstream particle distribution. It was found that a 2:1 ratio between inlet reservoir and sample inlet diameter, and placed at the top of the reservoir yielded the best separation results. Fluid velocity profiles in the reservoir were explored using Comsol Multyphysics. The experimentally observed particle trajectories and COMSOL predictions were in good agreement. Based on Comsol models a dimensionless parameter to relate the unique velocity profiles within the inlet reservoir to downstream separation of particles was also developed. A mixture of 10, 5.5, and 3.0 µm particles were separated to three distinct collection outlets at 73.4%, 64.7%, and 52.8% respectively. Therefore this project shows that passive separations of particles can be achieved simply by alerting the ratio of inlet hole relative to inlet reservoir diameter, and by placing the inlet hole at the top of the reservoir.
49
Young, Mitchell Patrick. "A 3-D Multiplex Paper-microfluidic Platform." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1680.
Full textAbstract:
3-D paper-based microfluidic devices (micoPADs) are small and portable devices made out of paper that offer a promising platform for diagnostic applications outside of a laboratory. These devices are easy to use, low cost, require no power source, and capable of detecting multiple targets simultaneously. The work in this thesis demonstrated the ability of a 3-D paper-microfluidic platform to simultaneously detect 5 targets. Rubber cord stock was used in conjunction with an acrylic housing unit to apply pressure along the edge of the channel. The indirect pressure application was successful in promoting vertical fluid flow between layers. Average channel development times were recorded between 110 seconds and 150 seconds.
The implementation of the 3-D paper-microfluidic platform as a diagnostic device was validated with a colorimetric glucose assay. In a novel application, reagents were deposited onto the 3-D platform via a glucose reagent pencil created by Martinez et al. A visual signal was observed for the successful detection of glucose at a concentration of 1.2 mM. These results offer promise for future work in combing new reagent deposition techniques with a multi-layer paper-microfluidic platform. Overall, this research made advancements in the design of a paper-microfluidic platform capable of the simultaneous detection of 5 targets.
50
Whitman, Matthew A. A. "INSULATIVE (DIRECT CURRENT) DIELECTROPHORETIC FOUL-LESS FILTRATION IN MICROFUIDIC SYSTEMS." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2125.
Full textAbstract:
Filtration is a technology that is used almost ubiquitously in society from uses raging from filtration of macroparticles from water to pharmaceutical grade filtration products to remove anything larger than a protein. However, with such a wide range of uses, most filtration products have the same issue; membrane clogging (fouling) that prevents continuous use and requires frequent maintenance. This thesis hypothesizes that by applying a direct current (DC) to an insulating array of posts, they will create a foul-less insulative dielectrophoretic filter (iDEP) that does not clog since particles will levitate above the insulating array.
This thesis tested an inherited device (legacy device) and found that its design did not perform the desired foul-less filtration operation under the tested conditions. Therefore, using COMSOL simulations, the conditions of testing and improved deign were developed to fruition. These devices were fabricated and tested and found to successfully levitate yeast particles above the foul-less filtration array using a direct current insulative dielectrophoretic (iDEP) filter. Additionally, different post geometries were observed and how they affect the dielectric force on particles. Although a foul-less filter was not successfully developed over the course of this thesis, the groundwork for development of DC iDEP has been set.