Biomedical Engineering and Bioengineering Commons^™

Aerodynamic Performance And Particle Image Velocimetery Of Piezo Actuated Biomimetic Manduca Sexta Engineered Wings Towards The Design And Application Of A Flapping Wing Flight Vehicle, Anthony M. Deluca

Theses and Dissertations

Considerable research and investigation has been conducted on the aerodynamic performance, and the predominate flow physics of the Manduca sexta size of biomimetically designed and fabricated wings as part of the AFIT FWMAV design project. Despite a burgeoning interest and research into the diverse field of flapping wing flight and biomimicry, the aerodynamics of flapping wing flight remains a nebulous field of science with considerable variance into the theoretical abstractions surrounding aerodynamic mechanisms responsible for aerial performance. Traditional FWMAV flight models assume a form of a quasi-steady approximation of wing aerodynamics based on an infinite wing element model (BEM). An …

Spectral Analysis Of Nonstationary Heart Rate Of Neonates Receiving Therapeutic Hypothermia Treatment, Tareq Al-Shargabi

Theses and Dissertations

We studied Heart Rate Variability (HRV) evolution during therapeutic hypothermia in newborns with hypoxic ischemic encephalopathy (HIE) using spectral analysis. We hypothesized that HRV measures are predictive of neurological outcome in babies with HIE. Non-stationarity in the data causes inaccurate quantification of the spectral power. A modification was proposed to power spectral analysis approach to mitigate the effect of non-stationarity. The modified and the standard approaches were applied to cardiac beat-to-beat intervals of newborns receiving hypothermia treatment. The performance of the approaches in distinguishing the RRi dynamics of two groups of newborns was assessed using area under the receiver operating …

Synthetic Polymeric Carbohydrates Recognized Toxoplasma Gondii Tachyzoites And Induced Early Phagocytosis By Macrophages, Souzan Hussain Eassa

Theses and Dissertations

Toxoplasmosis is a parasitic disease caused by the intracellular protozoan Toxoplasma gondii your words (T. gondii your words) that affects most types of warm-blooded vertebrate cells. Up to one third of the humans population in the world is chronically infected by this parasite. Human and animals at risk for toxoplasmosis include fetuses, newborns, and immunologically impaired patients. To date, there is no vaccine available and no drug has a successful effective against chronic form of toxoplasmosis. Recent Toxoplasma your words diagnostic methods showed high false positive results and cannot detect the parasite in the early infection stage. Early diagnosis of …

The Design And Development Of A Perceptual-Based Haptic Display Device, Sohaib Akhter

Theses and Dissertations

Graphical information presented as pictures, graphs, maps, and the like are an important media for relaying knowledge and are a fundamental means of education rarely experienced by people who are blind or have a severe visual impairment. This thesis presents the design, development and testing of a multiple finger, haptic matrix dynamic display device capable of relaying graphical information through simulated textures. The design is based on user perception studies that determined which hand constraints provided the best tradeoff between simplicity of design, accuracy and time to answer. The best design was one that incorporated multiple fingers in close proximity …

Semi-Interpenetrating Network Gelatin Fiber Sca Old For Oral Mucosal Delivery Of Insulin, Leyuan Xu

Theses and Dissertations

Common therapy for diabetes mellitus is subcutaneous administration of insulin that is subject to serious disadvantages, such as patient noncompliance and occasional hypoglycemia. Hence, oral administration of insulin could be more convenient and serve as a desired route. However, oral administration of insulin is severely limited by the low bioavailability of insulin through the gastrointestinal tract. In this study, a semi-interpenetrating network gelatin fiber scaffold (sIPN GF) was fabricated for oral mucosal delivery of insulin as an alternative route. This sIPN GF was engineered from an electrospun gelatin fiber scaffold (GF), which was further crosslinked with polyethylene glycol diacrylate (PEG-DA) …

The Effect Of Concurrent Cognitive-Visuomotor Multitasking And Task Difficulty On Dynamic Functional Connectivity In The Brain, Plamen Nikolov

Theses and Dissertations

This thesis investigated the effect of visuomotor and working memory 1) task difficulty and 2) multitasking on dynamic functional connectivity in the brain. Studies have only recently begun to investigate functional connectivity within the scope of concurrent dual task or varying task difficulty conditions (Cocchi, Zalesky, et al. 2011; Rietschel et al. 2012). A series of EEG recordings were conducted during execution of visuomotor or working memory tasks within a novel paradigm using BCI2VR custom MATLAB toolbox. Functional connectivity was correlated with task-related coherence (TRCoh) analysis between two task conditions involving either variation in task difficulty or concurrent execution during …

Modernization Of The Mock Circulatory Loop: Advanced Physical Modeling, High Performance Hardware, And Incorporation Of Anatomical Models, Charles Taylor

Theses and Dissertations

A systemic mock circulatory loop plays a pivotal role as the in vitro assessment tool for left heart medical devices. The standard design employed by many research groups dates to the early 1970's, and lacks the acuity needed for the advanced device designs currently being explored. The necessity to update the architecture of this in vitro tool has become apparent as the historical design fails to deliver the performance needed to simulate conditions and events that have been clinically identified as challenges for future device designs. In order to appropriately deliver the testing solution needed, a comprehensive evaluation of the …

Automatic Segmentation Of Pressure Images Acquired In A Clinical Setting, Anathea Pepperl

Theses and Dissertations

One of the major obstacles to pressure ulcer research is the difficulty in accurately measuring mechanical loading of specific anatomical sites. A human motion analysis system capable of automatically segmenting a patient's body into high-risk areas can greatly improve the ability of researchers and clinicians to understand how pressure ulcers develop in a hospital environment. This project has developed automated computational methods and algorithms to analyze pressure images acquired in a hospital setting. The algorithm achieved 99% overall accuracy for the classification of pressure images into three pose classes (left lateral, supine, and right lateral). An applied kinematic model estimated …

The Design And Validation Of A Computational Model Of The Human Wrist Joint, Afsarul Mir

Theses and Dissertations

Advancements in computational capabilities have allowed researchers to turn towards modeling as an efficient tool to replicate and predict outcomes of complex systems. Computational models of the musculoskeletal system have gone through various iterations with early versions employing dramatic simplifications. In this work, a three-dimensional computational model of the wrist joint was developed. It accurately recreated the skeletal structures of the hand and wrist and represented the constraints imposed by soft tissue structures like ligaments, tendons, and other surrounding tissues. It was developed to function as a tool to investigate the biomechanical contributions of structures and the kinematic response of …

Tissue Engineering Composite Biomimetic Gelatin Sponges For Bone Regeneration, Isaac Rodriguez

Theses and Dissertations

The field of tissue engineering aims to develop viable substitutes with the ability to repair and regenerate the functions of damaged tissue. Common practices to supplement bone regeneration in larger defects include bone graft biomaterials such as autografts, allografts, xenografts, and synthetic biomaterials. Autologous bone grafting is the current gold-standard procedure used to replace missing or damaged bone. However, these grafts have disadvantages such as donor site morbidity, limited availability, and the need for a secondary surgery. The focus of this study is to tissue engineer a lyophilized gelatin composite sponge composed of hydroxyapatite (HA), chitin whiskers (CW), and preparations …

The Mechanotransduction Of Primary Cilia In Tumor Progression Of Lung Adenocarcinoma, Sagar Patel

Theses and Dissertations

The objective of this study was to investigate primary cilia and their mechanotransduction role in lung adenocarcinoma tumor progression. The main focus investigated the effect of primary cilia on cell cycle progression, survival, adhesion and migration analysis of these cells and the role of sonic hedgehog signaling pathway in mechanotransduction. Human Non-Small Cell Lung Cancer (NSCLC) adenocarcinoma biopsies contain more primary cilia than non-tumor lung sections. To observe the effects of primary cilia presence in lung cancer cells in-vitro, formation of primary cilia is inhibited using small interfering RNA. A549 cells with intact primary cilia observe less cell cycle progression …

Computer Based Behavioral Biometric Authentication Via Multi-Modal Fusion, Kyle O. Bailey

Theses and Dissertations

Biometric computer authentication has an advantage over password and access card authentication in that it is based on something you are, which is not easily copied or stolen. One way of performing biometric computer authentication is to use behavioral tendencies associated with how a user interacts with the computer. However, behavioral biometric authentication accuracy rates are much larger then more traditional authentication methods. This thesis presents a behavioral biometric system that fuses user data from keyboard, mouse, and Graphical User Interface (GUI) interactions. Combining the modalities results in a more accurate authentication decision based on a broader view of the …

An Investigation And Analysis Of The Vestibulo-Ocular Reflex In A Vibration Environment, Daniel J. Uribe

Theses and Dissertations

Forty years of innovations have greatly improved Helmet-Mounted Displays (HMDs) and their integration into military systems. However, a significant issue with HMDs is the effect of vibration and the associated Vestibulo-Ocular Reflex (VOR). When a human’s head is subject to low-frequency vibration, the VOR stabilizes the eye with respect to objects in the external environment. However, this response is inappropriate in HMDs as the display moves with the user’s head and the VOR blurs the image as it is projected on the human retina. Current compensation techniques suggest increasing the size of displayed graphics or text to compensate for the …

Biomechanics Of Porcine Renal Artery And The Development Of A Replacment Vessel, Mohamed Gabr

Theses and Dissertations

Mechanical characterization of biological soft tissues is essential in the field of biomedical engineering. In this study several loading experiments have been performed to efficiently characterize the passive mechanical response of both native porcine renal arteries and newly developed tissue constructs. The first aim of these studies is to determine whether there is a difference in mechanical response between the main renal artery and its first branch. After fitting the bi-axial data to a Holzapfel-type constitutive model, the results show that there is no statistical difference between the model parameters for renal artery and the first branch. The only significant …

Toward Directing Cell Fate: Carbon Nanotubes As Modulators Of Extracellular And Transporters Of Intracellular Cues, Qingsu Cheng

Theses and Dissertations

The unique properties of CNTs lead CNTs attractive in biological engineering applications. It is expected to use CNT based biomaterials for clinic use in the near future. CNTs can be used to tune cellular fate through bother extracellular pathway and intracellular pathway. CNT based biomaterials has been applied into bone, nerves, and cardiovascular system. There has also been progress in the use of CNTs in controlling cellular alignment, to enhance tissue regeneration, growth factor delivery and gene delivery.

Pluripotent stem cells (hPSCs) offer a promising tool in tissue engineering strategies, as their differentiated derivatives can be used to reconstruct most …

Automated Detection Of Incomplete Exhalation As An Indirect Detection Of Auto-Peep On Mechanically Ventilated Adults, Nyimas Arief

Theses and Dissertations

Auto-PEEP is auto positive end-expiratory pressure due to excessive amounts of alveolar gas produced by sustained recurrent incomplete exhalation. Incomplete exhalation occurs when the exhaled breath never reaches a flow rate of 0 L/min. The objective of this dissertation is to develop an automated detection system of auto-PEEP through incomplete exhalation as revealed by ventilator graphics for mechanically ventilated adults. Auto-PEEP can cause adverse effects if allowed to linger and if not quickly identified. An automated detection system will be instrumental in helping to quickly identify auto-PEEP. A computerized algorithm was developed to detect incomplete exhalation based on the following …

Plantar Measurements To Determine Success Of Surgical Correction Of Stage Iib Adult Acquired Flatfoot Deformity, Erika Matheis

Theses and Dissertations

Adult Acquired Flatfoot Deformity (AAFD) is a progressive disease characterized by mechanical degeneration of the soft tissue structure in the arch of the foot that leads to changes in joint alignment. Surgical intervention commonly via tendon transfer and bony osteotomy is used to restore arch architecture, however there is a lack of quantitative assessments that measure the success of the surgical correction in vivo. Using plantar pressures via Tekscan® HR Mat and surveys (SF-36, FAOS), pre-operative and post-operative measures for six participants were defined, analyzed and compared. A paired t-test showed significant lateral shift for percent body weight during walking …

Development Of A Closed-Loop Force Reduction Mechanism In A Gait Rehabilitation Device, Jeffrey Frankart

Theses and Dissertations

Elliptical trainers are prescribed in rehabilitative exercise but difficult to implement in populations with significant functional gait deficits. Typical elliptical machines do not mimic normal gait and therefore require modifications for clinical rehabilitation. This research builds on previous modifications of an elliptical trainer designed to simulate level-surface walking. This design differed from a commercial version. It included articulated footplates and an electromechanically-driven virtual-cam to control footplate position. Ankle dorsiflexion elicited lower-extremity muscle spasticity which produced an unwanted gait variant during stroke patient testing. Spasticity is a hyperexcitable stretch reflex causing inefficient gait. This project’s purpose was to develop an autonomous …

A Study Towards Development Of An Automated Haptic User Interface (Ahui) For Individuals Who Are Blind Or Visually Impaired, Ravi Rastogi

Theses and Dissertations

An increasing amount of information content used in schools, work and everyday living is being presented in graphical form, creating accessibility challenges for individuals who are blind or visually impaired, especially in dynamic environments, such as over the internet. Refreshable haptic displays that can interact with computers can be used to access such information tactually. Main focus of this study was the development of specialized computer applications allowing users to actively compensate for the inherent issues of haptics when exploring visual diagrams as compared to vision, which we hypothesized, would improve the usability of such devices. An intuitive zooming algorithm …

Piezoelectric Probes And Their Capacity To Monitor Time Varying Viscosity, Eman Ahmed

Theses and Dissertations

Real-time, bedside observation of patient clotting is essential in various surgeries in the operating room (OR), but specifically during cardiac surgeries. The objective of this thesis is to design and test a new piezoelectric device that can be used for viscoelasticity measurement with time as a Point of Care (POC) test. Slow turnaround times (TAT) of current methods to monitor blood viscoelastic changes in patients have led to excessive bleeding and the need for blood transfusions in many situations (Despotis et al, 1997). This study shows that the phase shift produced by a resonator sensor can be related to the …

Integrated Fiber Electrospinning: Creating Spatially Complex Electrospun Scaffolds With Minimal Delamination, Casey Grey

Theses and Dissertations

Tissue engineering scaffolds come in many shapes and sizes, however, due to difficulty manufacturing the microstructure architecture required in tissue engineering, most scaffolds are architecturally non-dynamic in nature. Because the microstructural architecture of all biological tissues is inherently complicated, non-dynamic tissue engineering scaffolds tend to be a poor platform for tissue regeneration. The current method for manufacturing dynamic tissue engineering scaffolds involves electrospinning successive layers of different fibers, an approach that exhibits no fiber transition between layers and subsequent delamination problems. In this study we aim to address the design challenges of tissue engineering scaffolds through our novel integrated fiber …

Preparation And Characterization Of A Self-Crimp Side-By-Side Bicomponent Electrospun Material, Yang Han

Theses and Dissertations

Bicomponent composite fibers have been widely used in the textile industry and are gaining increasing attention on biomedical applications. In this research, polycaprolactone/poly (lactic acid) side-by-side bicomponent fibers were created for the application of a biodegradable scaffold. The side-by-side structure endowed the fiber with self-crimps when it was processed under certain conditions. This material was produced by electrospinning and collected on a high speed rotating mandrel to get highly oriented fibers. A mechanical stretch at the same direction was done followed by a wet heat treatment for polymer retraction. Crimped fibers were demonstrated by scanning electron microscopy. The quantitative porosity …

A Novel Method For Determining Acetabular Orientation, Sean Higgins

Theses and Dissertations

Enhanced knowledge of the acetabulum is of paramount importance in the diagnostic, planning, and execution stages of procedures and treatments targeting the hip joint. The convoluted and highly variable morphology of the structures comprising the bony pelvis make ascertaining measures of the acetabulum challenging. Furthermore, current methods for determining acetabular orientation assume symmetry between the separate halves of the pelvis by utilizing a coordinate system based on bilateral landmarks. The purpose of this study was to determine the three-dimensional orientation of the entire acetabulum. For this research, an improved programmatic method was developed for determining acetabular orientation using three-dimensional data. …

The Effect Of A Navigational Aid On Training Of A Minimally Invasive Surgery Camera Task, Ketan Vidwans

Theses and Dissertations

Minimally Invasive Surgery (MIS) differs from Open Surgery as surgeons view the surgical site indirectly on a monitor. The view shown is typically from an angled endoscope off to one side of the surgery (i.e., uncollocated with the view of the hands). This makes camera navigation a challenging ability to learn. MIS thus requires longer training periods, more practice and mental effort to achieve proficiency. Current training setups and Operating Room (OR) environments lack appropriate real-time visual cues for navigation and other perception related information that could help with learning and performance in the OR. The purpose of this research …

Evaluation Of A Novel Myoelectric Training Device, Ryan Clingman

Theses and Dissertations

While research shows that a patient’s success in using a myoelectric prosthetic arm is dependent on receiving effective training, current methods of training are not designed to effectively hold attention long enough for optimal training. This study focused on evaluating a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the arm. Subjects’ performance with the trainer was evaluated to determine its ability to provide experience with EMG controls. Eight healthy adult subjects were taken through typical initial stages of myoelectric training, then asked to drive the car through a slalom course while the time, …

Life History Switch Point Plasticy In Response To Pond Drying Alyers Metamorph Allometry And Jumping Performance, Julie Charbonnier

Theses and Dissertations

Animals with complex life cycles can cope with environmental uncertainty by altering life history switch points through developmental plasticity. Pond drying is an important factor which may alter life history switch points in aquatic organisms. Many amphibians can plastically respond to changes in pond drying by emerging earlier, but few studies have examined the post-metamorphic consequences for performance. To investigate the potential carry-over effects of plasticity to pond drying, we studied the túngara frog, Physalaemus pustulosus, a tropical anuran that breeds in highly ephemeral habitats. We conducted a field study with three different water depth treatments in 60 L mesocosms …

Development Of A Multiple Contact Haptic Display With Texture-Enhanced Graphics, David Burch

Theses and Dissertations

This dissertation presents work towards the development of a multiple finger, worn, dynamic display device, which utilizes a method of texture encoded information to haptically render graphical images for individuals who are blind or visually impaired. The device interacts directly with the computer screen, using the colors and patterns displayed by the image as a means to encode complex patterns of vibrotactile output, generating the texture feedback to render the image. In turn, the texture feedback was methodically designed to enable parallel processing of certain coarse information, speeding up the exploration of the diagram and improving user performance. The design …

Optimization Of Feature Selection In A Brain-Computer Interface Switch Based On Event-Related Desynchronization And Synchronization Detected By Eeg, Mason Montgomery

Theses and Dissertations

There are hundreds of thousands of people who could benefit from a Brain-Computer Interface. However, not all are willing to undergo surgery, so an EEG is the prime candidate for use as a BCI. The features of Event-Related Desynchronization and Synchronization could be used for a switch and have been in the past. A new method of feature selection was proposed to optimize classification of active motor movement vs a non-active idle state. The previous method had pre-selected which frequency and electrode to use as electrode C3 at the 20Hz bin. The new method used SPSS statistical software to determine …

Finite Element Analysis Of Transverse Medial Malleolar Fracture Fixation, Ruchi Chande

Theses and Dissertations

Injury to the medial malleolus, the distal end of the tibia and one of the bones comprising the ankle joint, can occur in various loading scenarios. Open reduction/internal fixation (ORIF) to reattach the malleolar fragment to the proximal tibia can be achieved via various devices, however small fragments are particularly challenging to treat. In this study, computational finite element analysis (FEA) was utilized to investigate the fixation of transverse medial malleolar fractures by two cancellous screws or by a new fixation device, the Medial Malleolar Sled™. Cadaveric testing assessed the performance of the two constructs in both tension and torsion. …

Brain Controlled Switch, Dimple Bhuta

Theses and Dissertations

This study aims at designing and implementing a single channel stand-alone Brain-Controlled Switch (BCS) device, which records the electroencephalography (EEG) signals from the scalp using electrodes, amplifies it, eliminates interferences (associated with the EEG signals) and processes the EEG signals to extract and decode temporal signal features to determine user’s intention of regulating an external switch. The design of our “brain-controlled switch” device is implemented using a bio-potential amplifier and a microcontroller. The bio-potential amplifier amplifies the EEG signals to a level sufficient for processing, eliminates interferences and ensures patient safety. The microcontroller (dsPIC30F4013) digitizes the amplified and conditioned analog …