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Injectable, Magnetic Plum Pudding Hydrogel Composites For Controlled Pulsatile Drug Release, Danielle Maitland 2014 McMaster University

Injectable, Magnetic Plum Pudding Hydrogel Composites For Controlled Pulsatile Drug Release, Danielle Maitland

Open Access Dissertations and Theses

Injectable, in-situ gelling magnetic plum pudding hydrogel composites were fabricated by entrapping superparamagnetic iron oxide nanoparticles (SPIONs) and thermosensitive N-isopropylacrylamide (NIPAM)-co–N-isopropylmethacrylamide (NIPMAM) microgels in a pNIPAM-hydrazide/carbohydrate-aldehyde hydrogel matrix. The resulting composites exhibited significant, repeatable pulsatile release of 4 kDa FITC-dextran upon exposure to an alternating magnetic field. The pulsatile release from the composites could be controlled by altering the volume phase transition temperatures of the microgel particles (with VPTTs over 37°C corresponding to improved pulsatile release) and changing the microgel content of the composite (with higher microgel content corresponding to higher pulsatile release). By changing the ...


A Multi-Well Concentration Gradient Drug Delivery Microfluidic Device For High-Content And High-Throughput Screening, Michael M. Nelson 2014 McMaster University

A Multi-Well Concentration Gradient Drug Delivery Microfluidic Device For High-Content And High-Throughput Screening, Michael M. Nelson

Open Access Dissertations and Theses

A microfluidic device capable of drug delivery to multiple wells in a concentration gradient was designed for automated high content and high throughput screening. The design was proposed to utilize a nanoporous polycarbonate membrane to spatially and temporally control drug dosage from the microchannels below to the wells above. Microchannels were to hold to the drugs or reagents, while wells were to culture cells. An array of 16 wells was to fit in the equivalent area of a single well of a 96 well plate. Two simpler devices were created to validate electrokinetic drug delivery to a single well and ...


Advances In Image Acquisition And Filtering For Mri Neuroimaging At 7 Tesla, Andrew T. Curtis 2014 Western University

Advances In Image Acquisition And Filtering For Mri Neuroimaging At 7 Tesla, Andrew T. Curtis

University of Western Ontario - Electronic Thesis and Dissertation Repository

Performing magnetic resonance imaging at high magnetic field strength promises many improvements over low fields that are of direct benefit in functional neuroimaging. This includes the possibility of improved signal-to-noise levels, and increased BOLD functional contrast and spatial specificity. However, human MRI at 7T and above suffers from unique engineering challenges that limit the achievable gains. In this thesis, three technological developments are introduced, all of which address separate issues associated with functional magnetic resonance neuroimaging at very high magnetic field strengths.

First, the image homogeneity problem is addressed by investigating methods of RF shimming — modifying the excitation portion of ...


Implementation And Validation Of Aortic Remodeling In Hypertensive Rats, Shijia Zhao, Linxia Gu 2014 University of Nebraska - Lincoln

Implementation And Validation Of Aortic Remodeling In Hypertensive Rats, Shijia Zhao, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

A computational framework was implemented and validated to better understand the hypertensive artery remodeling in both geometric dimensions and material properties. Integrating the stress-modulated remodeling equations into commercial finite element codes allows a better control and visualization of local mechanical parameters. Both arterial thickening and stiffening effects were captured and visualized. An adaptive material remodeling strategy combined with the element birth and death techniques for the geometrical growth were implemented. The numerically predicted remodeling results in terms of the wall thickness, inner diameter, and the ratio of elastin to collagen content of the artery were compared with and fine-tuned by ...


Design And Assessment Of An Experimental Test Setup For Use In Studies On The Vibrational Response Of The Head To Impact, Claudia M. Blandford 2014 Western University

Design And Assessment Of An Experimental Test Setup For Use In Studies On The Vibrational Response Of The Head To Impact, Claudia M. Blandford

University of Western Ontario - Electronic Thesis and Dissertation Repository

With the mortality, disability and socioeconomic costs associated with head injury, head impact biomechanics is important to developing injury criterions and safety tolerances. However, the current state of knowledge is contradictory and vague. This thesis will contribute to research done on the vibrational response of the head to impact by discussing two studies. The first will describe the design, implementation and validation of a head impactor setup specific for the study of the frequency response of the skull. An impactor capable of producing sub-5ms duration, sub-fracture impacts was successfully designed. The apparatus was validated by comparing the results of a ...


Design And Development Of A Miniature In Vivo Surgical Robot With Distributed Motor Control For Laparoendoscopic Single-Site Surgery, Eric J. Markvicka 2014 University of Nebraska - Lincoln

Design And Development Of A Miniature In Vivo Surgical Robot With Distributed Motor Control For Laparoendoscopic Single-Site Surgery, Eric J. Markvicka

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Paradigm shifts in invasiveness, recovery time, cosmesis, and cost have been seen within the field of general surgery through major advances in surgical technology. Some of the most advanced types of general surgery now include Minimally Invasive Surgery (MIS), LaparoEndoscopic Single-Site (LESS) surgery, and Natural Orifice Translumenal Endoscopic Surgery (NOTES). One of the newest and rapidly developing catalysts is robotic platforms. Such platforms have improved ergonomics and control, increased workspace and dexterity, and have surpassed the efficacy of many non-robotic platforms such as traditional laparoscopic surgical tools. This thesis presents the design and development of a four-degree-of-freedom (4- DOF) miniature ...


Improvements To Uhmwpe, Brooke McKelvogue 2014 Minnesota State University, Mankato

Improvements To Uhmwpe, Brooke Mckelvogue

Journal of Undergraduate Research at Minnesota State University, Mankato

Ultra high molecular weight polyethylene (UHMWPE) is a material used in artificial implants for articular joint replacements. However, these implants have a limited lifespan in which the patient will be pain-free due to the wear of the UHMWPE components. Recently crosslinking, or exposing the material to radiation, has been used to extend the wear resistance of UHMWPE. Crosslinking introduces another set of drawbacks; mainly the reduction of the fracture toughness of UHMWPE and the generation of free radicals, which leave the polymer vulnerable to damage from oxidation. Currently, research is being conducted on other methods to increase the wear resistance ...


Computational Model Of A Left Ventricle: Showing The Effects Of Inertia On Cardiac Dyssynchrony, Andrew McNally, Matthew Korpela, Erin Lamke, Matthew Hudson 2014 Minnesota State University, Mankato

Computational Model Of A Left Ventricle: Showing The Effects Of Inertia On Cardiac Dyssynchrony, Andrew Mcnally, Matthew Korpela, Erin Lamke, Matthew Hudson

Journal of Undergraduate Research at Minnesota State University, Mankato

In an effort to research heart failure, a leading cause of death in the industrialized world, this research team has developed a segmented lumped parameter model of the left ventricle. The computations model developed focuses on dyssynchrony, a heart condition where some regions of the heart vary significantly in properties like internal muscle resistance, mass, or elastance. Inertial effects are often assumed as negligible by cardiovascular models. One primary function of this model is to investigate inertial effects as they relate to mechanical cardiac dyssynchrony. An added dimension of this analysis is to observe the thermodynamics of the cardiac cycle ...


Rapid Segmentation Techniques For Cardiac And Neuroimage Analysis, Martin Rajchl 2014 Western University

Rapid Segmentation Techniques For Cardiac And Neuroimage Analysis, Martin Rajchl

University of Western Ontario - Electronic Thesis and Dissertation Repository

Recent technological advances in medical imaging have allowed for the quick acquisition of highly resolved data to aid in diagnosis and characterization of diseases or to guide interventions. In order to to be integrated into a clinical work flow, accurate and robust methods of analysis must be developed which manage this increase in data. Recent improvements in in- expensive commercially available graphics hardware and General-Purpose Programming on Graphics Processing Units (GPGPU) have allowed for many large scale data analysis problems to be addressed in meaningful time and will continue to as parallel computing technology improves. In this thesis we propose ...


Laser-Assisted Surface Modification Of Hybrid Hydrogels To Prevent Bacterial Contamination And Protein Fouling, Guobang Huang 2014 Western University

Laser-Assisted Surface Modification Of Hybrid Hydrogels To Prevent Bacterial Contamination And Protein Fouling, Guobang Huang

University of Western Ontario - Electronic Thesis and Dissertation Repository

Silicone hydrogels have been extensively studied in the fields of contact lenses, tissue engineering, and drug delivery due to their good biocompatibility, high oxygen permeability, and proper light transmission. However, their applications in biomedical devices are limited by protein adsorption and bacterial contamination because of the hydrophobic surface of silicone, which will cause more irreversible protein adsorption. Several physical methods can be applied to create a hydrophilic surface on hydrogels, such as spin coating, physical vapor deposition, dip coating, drop casting, etc. Compared to the conventional methods, the matrix assisted pulsed laser evaporation (MAPLE) is suitable to produce biopolymer/polymer ...


Evaluating Human Performance For Image-Guided Surgical Tasks, Matthew Kenneth Kramers 2014 Western University

Evaluating Human Performance For Image-Guided Surgical Tasks, Matthew Kenneth Kramers

University of Western Ontario - Electronic Thesis and Dissertation Repository

The following work focuses on the objective evaluation of human performance for two different interventional tasks; targeted prostate biopsy tasks using a tracked biopsy device, and external ventricular drain placement tasks using a mobile-based augmented reality device for visualization and guidance. In both tasks, a human performance methodology was utilized which respects the trade-off between speed and accuracy for users conducting a series of targeting tasks using each device. This work outlines the development and application of performance evaluation methods using these devices, as well as details regarding the implementation of the mobile AR application. It was determined that the ...


Fluid Powered Miniature In-Vivo Robots For Minimally Invasive Surgery (Mis), Abolfazl Pourghodrat 2014 University of Nebraska - Lincoln

Fluid Powered Miniature In-Vivo Robots For Minimally Invasive Surgery (Mis), Abolfazl Pourghodrat

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Minimizing the invasiveness of surgery is believed to improve patient outcomes. Bleeding, infection, and pain are major concerns in surgery afflicting patients for decades. Minimally invasive techniques have come into play to reduce these concerns and smooth the evolution of abdominal surgery to a scarless process where nearly all surgeries can be performed without a skin incision. Technology continually advances the frontier of development of novel surgical devices to implement less invasive surgical techniques.

Fusion of robotics and Minimally Invasive Surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems ...


Analysis Study And Imaging On Stepwise Multi-Photon Activation Fluorescence Of Melanin, Zetong Gu 2014 Northeastern University

Analysis Study And Imaging On Stepwise Multi-Photon Activation Fluorescence Of Melanin, Zetong Gu

Electrical and Computer Engineering Master's Theses

In this thesis, the author's work is divided into two aspects: multi-modal microscopy and the stepwise multi-photon activated fluorescence (SMPAF) of melanin.

A multimodal microscope provides a researcher with the ability to capture images with multiple sources of contrast. The Keck 3D fusion multi-modal microscope (3DFM) in the Optical Science Laboratory (OSL) at Northeastern University allows us to image samples with multiple different modalities on the same stage. During the course of this thesis, we upgraded the whole control system and part of the optical layout. Another multimodal microscope (the Target System) is also designed for precise positioning.

The ...


Development And Characterization Of Chick Forebrain Neuron - Based Neurotoxin Biosensor On A Microelectrode Array, Yan Kuang 2014 Clemson University

Development And Characterization Of Chick Forebrain Neuron - Based Neurotoxin Biosensor On A Microelectrode Array, Yan Kuang

All Dissertations

The number and amount of synthetic chemicals in the environment has greatly increased over the past several decades and will continue to do so as thousands of new chemicals and mixtures are developed each year. At the same time, the incidence of neurodevelopmental diseases and disorders has increased tremendously, especially in children. As a result, the long-standing demand for a rapid, economical, large-scale screening-based approach to assessing neurotoxic substances in the environment has become urgent in recent years. So far, only biosensors based on rodent-sourced cells on a microelectrode array (MEA) platform show any promise for fast neurotoxicant screening, but ...


Rhythmic Manipulation Of A Complex Object, Fei Ye 2014 Northeastern University

Rhythmic Manipulation Of A Complex Object, Fei Ye

Electrical and Computer Engineering Master's Theses

Manipulation of complex dynamic objects or tool use is ubiquitous in everyday life. To gain insight into the control of such complex motor skills, the present study examined the strategies that humans choose when manipulating an object with internal dynamics, mimicking a cup of coffee. Using the cart-and-pendulum model implemented in a virtual environment, two experiments examined the continuous rhythmic displacement of this nonlinear system and the execution strategies that humans adopted. In continuous rhythmic movements the nonlinearity of the object's dynamics renders temporal evolutions complex and, technically, chaotic. Interacting with unpredictable dynamics is challenging. Hence, we hypothesized that ...


Investigating Hemodynamic Responses To Electrical Neurostimulation, Sean Youra 2014 California Polytechnic State University

Investigating Hemodynamic Responses To Electrical Neurostimulation, Sean Youra

Master's Theses and Project Reports

Since the 1900s, the number of deaths attributable to cardiovascular disease has steadily risen. With the advent of antihypertensive drugs and non-invasive surgical procedures, such as intravascular stenting, these numbers have begun to level off. Despite this trend, the number of patients diagnosed with some form of cardiovascular disease has only increased. By 2030, prevalence of coronary heart disease is expected to increase approximately by 18% in the United States. By 2050, prevalence of peripheral arterial occlusive disease is expected to increase approximately by 98% in the U.S. No single drug or surgical intervention offers a complete solution to ...


Microfluidic Isolation Of Endothelial Progenitor Cells For Vascular Tissue Engineering, Adam Hatch 2014 Northeastern University

Microfluidic Isolation Of Endothelial Progenitor Cells For Vascular Tissue Engineering, Adam Hatch

Chemical Engineering Dissertations

In the last decade, the regenerative ability of stem and progenitor cells has been demonstrated in several types of tissue. Endothelial progenitor cells (EPCs), which are naturally present in circulating blood, are an especially interesting cell type because they have the ability to repair damaged blood vessels. EPCs have been utilized as precursors in the in vitro cultivation of vascular grafts. As tissue engineering and cell-based therapeutics begin the transition from the laboratory to clinical applications, the availability of robust and simple cell isolation techniques becomes significant. The use of antibody coated channels for cell capture in microfluidic devices has ...


A Rubric For Electrochemical Testing Of Metallic Biomaterials, Frederick G. De La Fuente 2014 California Polytechnic State University

A Rubric For Electrochemical Testing Of Metallic Biomaterials, Frederick G. De La Fuente

Master's Theses and Project Reports

Corrosion is a major factor for the failure of metallic medical implants. Testing a metal’s suseptability to corrosion prior to implantation is key to a successful implantation. Electrochemical processes were used in this study to evaluate the characteristics of corrosion of both AISI 316 stainless steel and titanium alloy Ti6Al4V, welded and non-welded. Linear, potentiodynamic, and cyclic polarization curves were produced by the PARC 2273 potentiostat showing the corrosion tendencies of the metals in four unique solutions 3.5% NaCl, 0.35% NaCl, phosphate buffered saline solution (PBS), and Butterfield phosphate buffered solution (BPS). The concentration of chloride ions ...


Potential For Photoacoustic Imaging Of Neonatal Brain, Pantea Tavakolian 2014 Western University

Potential For Photoacoustic Imaging Of Neonatal Brain, Pantea Tavakolian

University of Western Ontario - Electronic Thesis and Dissertation Repository

Photoacoustic imaging is a hybrid imaging technique that combines many of the merits of both optical and ultrasound imaging. Photoacoustic imaging (PAI) has been hypothesized as a technique for imaging neonatal brain. However, PAI of the brain is more challenging than traditional methods (e.g. near infrared spectroscopy) due to the presence of the skull layer. To evaluate the potential limits the skull places on 3D PAI of the neonatal brain, we constructed a neonatal skull phantom (~1.52-mm thick) with a mixture of epoxy and titanium dioxide powder that provided acoustic insertion loss (1-5MHz) similar to human infant skull ...


Curcumin-Loaded Magnetic Nanoaggregates Conjugated With Folic Acid For Targeted Cancer Treatment, Melessa Salem 2014 Western University

Curcumin-Loaded Magnetic Nanoaggregates Conjugated With Folic Acid For Targeted Cancer Treatment, Melessa Salem

University of Western Ontario - Electronic Thesis and Dissertation Repository

Cancer has been, and still remains, one of the most complicated diseases to treat. As a result of the side effects experienced from current cancer treatment methods, there has been a growing interest in the development of targeted drug delivery systems that can destroy cancer cells, but render healthy tissue unharmed. To address this challenge, magnetite nanoaggregates were synthesized through the precipitation of iron oxide in the presence of polymers, conjugated with folic acid for folate targeting, and loaded with curcumin for cancer treatment. The resulting magnetite nanoparticles were 10 – 20 nm in size and the aggregates formed varied in ...


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