Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xxx, 268 p.: ill. Includes abstract and vita. Advisor: Robert Lee, Dept. of Electrical Engineering. Includes bibliographical references (p. 256-268).

Fibronectin (Fn) is an adhesive extracellular matrix protein assembled by fibroblasts into fibrils within ECMs of developing and remodeling tissues. Fn is sensitive to mechanical forces exerted by contractile cells, and can alter its structural conformations in response to mechanical strain within Fn fibrils. We developed probes (both peptide and antibody) to Fn to detect mechano-sensitive perturbations of Fn conformation. Probes were characterized for their binding characteristics (affinity, epitope, mechano-sensitivity) and validated on multiple in vitro and in vivo ECM models. Furthermore, we showed that the mechano-sensitive H5 antibody that we have developed have utility in detection of early molecular signatures of fibrosis in vivo in a mouse model of pulmonary fibrosis. Using the H5 antibody, we also report detection of a conformational switch within the integrin binding FnIII9-10 region. Modulation of Fn’s integrin switching behavior may help in the development of controllable “smart” biomaterials, as well as to the development of conformation-specific imaging probes to detect early molecular signatures of tumor and fibrotic ECMs.

Electrosorption involves the application of an electrical potential between carbon electrode pairs submerged in brackish water, effectively “trapping” the ions in an electrical double layer at the solid-liquid interface. Electrosorption has significant applications in environmental engineering, including desalination of water by capacitive deionization (CDI), and in energy storage by supercapacitors. This work combines experimental and modeling studies to investigate the transport and sorption mechanisms of ions in the pores of mesoporous carbon materials that were synthesized at the Oak Ridge National Laboratory (ORNL). The main contribution of this research is examining the effects of operational parameters such as applied potential, solution temperature, ionic concentration, and valence of ions, on the electrosorption behavior of mesoporous carbon materials with the aim to improve the desalination efficiency in the CDI process. It was found that the rates of sorption by mesoporous carbon electrodes and their regeneration increased at a higher temperature and on application of a high-frequency, low-amplitude AC signal. Neutron imaging has been employed as a tool to visually observe and quantify the transport and distribution of ions within the carbon electrodes. The neutron images revealed interesting ion transport phenomena that can aid in the optimization of the CDI process. From the ion concentration profiles inside the electrodes, the effective diffusivities of gadolinium and lithium ions were obtained under various conditions of applied potential. Information on the diffusivity of ions can aid in theoretical modeling of the CDI process as well as guide strategies for the design of advanced electrode materials. In the final part of the study, the extraction of salinity gradient energy or ‘blue energy’ by mixing fluids of different salinities was assessed based on the principle of capacitive double layer expansion. Neutron imaging of blue energy recovery cycles was conducted to observe the ion transport behavior during the various steps of the cycle. The results obtained provide insights into the fundamental ion transport mechanisms during electrosorption by mesoporous carbon materials. This research has important implications for developing advanced system designs for desalination of saline water and energy storage devices.

Accurate insertion and monitoring of metal implants in-vivo is essential for clinical diagnosis and therapy of various diseases. Clinical studies and examples have demonstrated that the misplacement errors of these metal devices can have dramatic consequences. This thesis focuses on three main metal devices that are in widespread use today: needles, coronary stents and brachytherapy seeds. Each application requires proper image-guidance for correct usage. For needles, image guidance is required to ensure correct local injection delivery or needle aspiration biopsy. Fine needle aspiration biopsies are performed in order to avoid major surgical excisions when obtaining tissue biopsy procedures. However, because of the small biopsy sample, the risk is that the sample is collected outside of the tumorigenic region, resulting in a false negative result. Implantation of stents requires that confirmation that proper stent apposition has been achieved due to balloon inflation. Furthermore, it is important to guide the stent to shield the vulnerable region of an atherosclerotic plaque. With prostate brachytherapy seeds, the ability to monitor seed placement is crucial because needle deflections or tissue deformation can result in seed misplacement errors, decreasing the efficacy of the pre-established treatment plan. For the described applications and other possible clinical practices involving the use of metallic implants, an imaging technology that can accurately depict the location of the metal objects, relative to their respective backgrounds, in real-time, is necessary to improve the safety and the efficacy of these procedures. Currently, ultrasound is used because of its real-time capabilities, non-ionizing radiation, and soft tissue contrast. However, due to high acoustic scattering from tissue, the contrast of metal implants can be low. Photoacoustic imaging can be used as an alternative, or complementary, imaging method to ultrasound for imaging metal. This thesis focuses on the benefits and the pitfalls of using photoacoustic imaging for detecting three different metal implants, each having unique requirements. Overall, the goal of this work is to develop a framework for clinical applications using combined ultrasound and photoacoustic imaging to help guide, detect and follow-up on clinical metal implants introduced in-vivo. / text

Fabric defects inspection is a vital step for fabric quality assessment. Many vision-based automatic fabric defect detection methods have been proposed to detect fabric flaws efficiently and accurately. Because the inspection methods are vision-based, image quality is of great importance to the accuracy of detection result. To our knowledge, most of camera lenses have radial distortion. So our goal in this project is to remove the radial distortion and achieve undistorted images. Much research work has been done for 2-D image correction, but the study for 1-D line scan camera image correction is rarely done, although line scan cameras are gaining more and wider applications due to the high resolution and efficiency on 1-D data processing. A novel line scan camera correction method is proposed in this project. We first propose a pattern object with mutually parallel lines and oblique lines to each pair of parallel ones. The purpose of the pattern design is based upon the fact that line scan camera acquires image one line at a time and it's difficult for one scan line to match the "0-D" marked points on pattern. We detect the intersection points between pattern lines and one scan line and calculate their position according to the pattern geometry. As calibrations for 2-D cameras have been greatly achieved, we propose a method to calibrate 1-D camera. A least-square method is applied to solve the pinhole projection equation and estimate the values of camera parameter matrix. Finally we refine the data with maximum-likelihood estimation and get the camera lens distortion coefficients. We re-project the data from the image coordinate to the world coordinate, using the obtained camera matrix and the re-projection error is 0.68 pixel. With the distortion coefficients ready, we correct captured images with an undistortion equation. We introduce a term of unit distance in the discussion part to better assess the proposed method. When testifying the undistortion results, we observe corrected image has almost identical unit distance with standard deviation of 0.29 pixels. Compared to the ideal distortion-free unit distance, the corrected image has only 0.09 pixel off the average, which proves the validity of the proposed method. / text

An intense laser or charged particle pulse propagating through matter excites light-speed refractive index structures in its wake via Kerr effect, ionization, or displacement of electrons from background ions. Examples include plasma wakes used to accelerate charged particles and self-guided filaments used for atmospheric analysis and micromachining. Such applications constrain the shape, size and evolution of the index structure, yet often these are known in detail only through intensive computer simulations based on estimated initial conditions. Here we develop and demonstrate three methods for visualizing evolving light-speed structures directly in the laboratory in a single shot : (1) frequency-domain streak camera, (2) frequency-domain tomography, and (3) multi-object-plane phase-contrast imaging. All three methods are based on analyzing phase perturbations that an evolving object imprints on one or more probe laser pulses that cross its path obliquely. The methods are tailored to different propagation lengths, material densities, and dimensionality of imaging. Using these techniques, evolving laser-driven filaments in glass and air and plasma wakes in helium gas driven by laser pulses up to petawatt peak power are visualized in one shot, revealing underlying nonlinear laser-plasma interaction physics that is compared in detail to computer simulations. / text

Non-melanoma skin cancer is the most prevalent malignancy in the world, with over a million annual positive diagnoses in the United States. If left untreated, these cancers cause morbidity and in rare cases, can become life threatening. The key to identifying and characterizing these tumors in the earliest stages, where they are most treatable lie in margin delineation in order to prevent recurrence. The visual obscurity of tumor morphology and physiology can make early detection a difficult task for dermatologists, particularly in the initial stages of cancer development. Tumor resection is a common course of action once they are discovered; however, there is a high recurrence rate due to incomplete removal of the malignant tissue. This dissertation presents an imaging system that can capture the spectral signatures correlating with morphological and physiological changes that accompany skin dysplasia. With this system, we may improve tumor margin delineation, reducing the number of incomplete tumor biopsies and false negative screenings. As an initial step of this process, we begin with a non-contact point sampling diffuse reflectance probe that mitigates the adverse effects of traditional contact probing. Validation of this probe is performed using tissue simulating phantoms spanning a biologically relevant range of optical and physiological properties to ensure that the non-contact format will not hinder performance relative to the contact probe. Cross polarization and auto-focus mechanisms were included in the design to reduce specular reflections and movement artifacts from in vivo measurements. This non-contact design was further developed into a platform for investigating the role of sampling geometry on diffuse reflectance measurements with the addition of a DMD spatial filter. Finally, we developed a hyperspectral DRSi system for the acquisition of wide-field maps of optical and physiological properties that is currently being tested on patients undergoing skin cancer screenings. The spectral output of this system has been validated for scattering and absorption across biologically relevant ranges using tissue simulating phantoms. The DRSi system was optimized for portability, ergonomics and resolution. / text

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy