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Articles 1 - 17 of 17
Full-Text Articles in Physical Sciences and Mathematics
Feature Selection From Clinical Surveys Using Semantic Textual Similarity, Benjamin Warner
Feature Selection From Clinical Surveys Using Semantic Textual Similarity, Benjamin Warner
McKelvey School of Engineering Theses & Dissertations
Survey data collected from human subjects can contain a high number of features while having a comparatively low quantity of examples. Machine learning models that attempt to predict outcomes from survey data under these conditions can overfit and result in poor generalizability. One remedy to this issue is feature selection, which attempts to select an optimal subset of features to learn upon. A relatively unexplored source of information in the feature selection process is the usage of textual names of features, which may be semantically indicative of which features are relevant to a target outcome. The relationships between feature names …
Synthesis, Radiolabeling And Evaluation Of A Suite Of Tracers With 44Sc For Detecting Extracellular Dna, Zhiyao Li
McKelvey School of Engineering Theses & Dissertations
Neutrophil extracellular traps involve the rapid translocation of DNA to the outside of the cell under certain stimuli. This structure forms a fibrous network that is able to limit the spread of pathogens and to kill microorganisms. It has also been shown to be present in various pathological processes such as inflammation, autoimmune diseases, and cancer metastasis. Currently, the formation process of NETs in vivo is being extensively studied. However noninvasive detection and quantitation has yet to be achieved. A class of PET tracers are described here that consists of a DNA dye as the backbone that is labeled with …
Evaluation And Clinical Implementation Of A Dual-Energy Ct Stopping-Power Ratio Mapping Technique For Proton-Therapy Treatment Planning, Maria Jose Medrano Matamoros
Evaluation And Clinical Implementation Of A Dual-Energy Ct Stopping-Power Ratio Mapping Technique For Proton-Therapy Treatment Planning, Maria Jose Medrano Matamoros
McKelvey School of Engineering Theses & Dissertations
Proton radiotherapy has the potential to treat tumors with better conformal dose distribution than competing modalities when the rapid dose falloff at the end of the proton-beam range is correctly aligned to the edge of the clinical target volume (CTV). However, its clinical potential is dependent on the accurate localization of the Bragg-peak position from predicted stopping-power ratio maps. The method that is most commonly used in today’s clinical practice for predicting stopping-power ratio (SPR) consists of a stoichiometric calibrationtechnique based on single-energy CT (SECT) for direct estimation of patient-specific SPR distribution from vendor-reconstructed Hounsfield Unit (HU) images. Unfortunately, this …
Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew
Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew
Electrical & Systems Engineering Publications and Presentations
In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm−2) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve …
Phantoms To Placentas: Mr Methods For Oxygen Quantification, Kelsey Meinerz
Phantoms To Placentas: Mr Methods For Oxygen Quantification, Kelsey Meinerz
Arts & Sciences Electronic Theses and Dissertations
Molecular oxygen (O2) is vital for efficient energy production and improper oxygenation is a hallmark of disease or metabolic dysfunction. In many pathologies, knowledge of tissue oxygen levels (pO2) could aid in diagnosis and treatment planning. The gold standard for pO2 measures in tissue are implantable probes, which are invasive, require surgery for placement, and are inaccessible to certain regions of the body. Methods for determining pO2 both non-invasively and quantitatively are lacking. The slight paramagnetic nature of O2 provides opportunities to non-invasively characterize pO2 in tissue via magnetic resonance (MR) techniques. As such, O2 can be treated as a …
Predicting Disease Progression Using Deep Recurrent Neural Networks And Longitudinal Electronic Health Record Data, Seunghwan Kim
Predicting Disease Progression Using Deep Recurrent Neural Networks And Longitudinal Electronic Health Record Data, Seunghwan Kim
McKelvey School of Engineering Theses & Dissertations
Electronic Health Records (EHR) are widely adopted and used throughout healthcare systems and are able to collect and store longitudinal information data that can be used to describe patient phenotypes. From the underlying data structures used in the EHR, discrete data can be extracted and analyzed to improve patient care and outcomes via tasks such as risk stratification and prospective disease management. Temporality in EHR is innately present given the nature of these data, however, and traditional classification models are limited in this context by the cross- sectional nature of training and prediction processes. Finding temporal patterns in EHR is …
Predicting Disease Progression Using Deep Recurrent Neural Networks And Longitudinal Electronic Health Record Data, Seunghwan Kim
Predicting Disease Progression Using Deep Recurrent Neural Networks And Longitudinal Electronic Health Record Data, Seunghwan Kim
McKelvey School of Engineering Theses & Dissertations
Electronic Health Records (EHR) are widely adopted and used throughout healthcare systems and are able to collect and store longitudinal information data that can be used to describe patient phenotypes. From the underlying data structures used in the EHR, discrete data can be extracted and analyzed to improve patient care and outcomes via tasks such as risk stratification and prospective disease management. Temporality in EHR is innately present given the nature of these data, however, and traditional classification models are limited in this context by the cross-sectional nature of training and prediction processes. Finding temporal patterns in EHR is especially …
Differential Estimation Of Audiograms Using Gaussian Process Active Model Selection, Trevor Larsen
Differential Estimation Of Audiograms Using Gaussian Process Active Model Selection, Trevor Larsen
McKelvey School of Engineering Theses & Dissertations
Classical methods for psychometric function estimation either require excessive resources to perform, as in the method of constants, or produce only a low resolution approximation of the target psychometric function, as in adaptive staircase or up-down procedures. This thesis makes two primary contributions to the estimation of the audiogram, a clinically relevant psychometric function estimated by querying a patient’s for audibility of a collection of tones. First, it covers the implementation of a Gaussian process model for learning an audiogram using another audiogram as a prior belief to speed up the learning procedure. Second, it implements a use case of …
Super‐Resolution Imaging Of Amyloid Structures Over Extended Times By Using Transient Binding Of Single Thioflavin T Molecules, Kevin Spehar, Tianben Ding, Yuanzi Sun, Niraja Kedia, Jin Lu, George R. Nahass, Matthew D. Lew, Jan Bieschke
Super‐Resolution Imaging Of Amyloid Structures Over Extended Times By Using Transient Binding Of Single Thioflavin T Molecules, Kevin Spehar, Tianben Ding, Yuanzi Sun, Niraja Kedia, Jin Lu, George R. Nahass, Matthew D. Lew, Jan Bieschke
Electrical & Systems Engineering Publications and Presentations
Oligomeric amyloid structures are crucial therapeutic targets in Alzheimer's and other amyloid diseases. However, these oligomers are too small to be resolved by standard light microscopy. We have developed a simple and versatile tool to image amyloid structures by using thioflavin T without the need for covalent labeling or immunostaining. The dynamic binding of single dye molecules generates photon bursts that are used for fluorophore localization on a nanometer scale. Thus, photobleaching cannot degrade image quality, allowing for extended observation times. Super‐resolution transient amyloid binding microscopy promises to directly image native amyloid by using standard probes and record amyloid dynamics …
Can Prescribed Fire Reduce Tick Parasitism Of Birds?, Leslie A. Sterling, Kim Medley, Katie Westby, Solný Adalsteinsson
Can Prescribed Fire Reduce Tick Parasitism Of Birds?, Leslie A. Sterling, Kim Medley, Katie Westby, Solný Adalsteinsson
Undergraduate Research Symposium Posters
Tick-borne diseases spread through enzootic transmission cycles that often involve ticks parasitizing bird hosts. Some avian species are competent reservoirs, amplifying the pathogens that cause tick-borne illnesses in humans. Prescribed burns in forests have the potential to reduce tick-borne disease risk if they limit interactions between ticks and infectious wildlife hosts. Although prescribed burns are increasingly being used for a variety of habitat management purposes, little is known about how they affect tick-host interactions. We hypothesize that if prescribed fires reduce tick abundance, then birds in burned forest plots will host fewer ticks than birds in unburned forest plots. Experimental …
Two-Component Hydrogel As Biomimetic Vitreous Substitutes, Sruthi Santhanam
Two-Component Hydrogel As Biomimetic Vitreous Substitutes, Sruthi Santhanam
McKelvey School of Engineering Theses & Dissertations
The vitreous humor of the eye is a biological hydrogel principally composed of fibrillary collagen interspersed with semi-flexible polyelectrolyte, hyaluronic acid (HA). Certain pathological conditions necessitate its removal and replacement. Current vitreous substitutes, such as silicone oils and perfluorocarbons, are hydrophobic, do not resemble the properties of the vitreous, and have known complications. An ideal vitreous substitute should have properties of the natural vitreous, perform its functions, and be biocompatible in the eye. Inspired by the structure and composition of the natural vitreous, we used bio-mimicry to develop an injectable two-component hydrogel. The hydrogel is composed of a fibrillary gellan, …
Participation In Governance And Well-Being In The Yukon Flats, Jessica Charlene Black
Participation In Governance And Well-Being In The Yukon Flats, Jessica Charlene Black
Arts & Sciences Electronic Theses and Dissertations
This dissertation explains the relationship between participation in governance and well-being in the Yukon Flats. To garner a deeper understanding of this relationship, definitions of governance and well-being are sought from the participants, thus providing holistic, Indigenous definitions of these concepts. Both formal and informal governance are also explored to understand the important institutions that underpin these larger relationships. Lastly, this dissertation investigates the relationship between participation in traditional hunting, fishing, and gathering and well-being in the Yukon Flats. Qualitative methods, including semi-structured interviews, observations, and photographs are all used to document these relationships. Applied thematic analysis is used due …
Investigation Of Lung Structure-Function Relationships Using Hyperpolarized Noble Gases, Robert P. Thomen
Investigation Of Lung Structure-Function Relationships Using Hyperpolarized Noble Gases, Robert P. Thomen
Arts & Sciences Electronic Theses and Dissertations
Magnetic Resonance Imaging (MRI) is an application of the nuclear magnetic resonance (NMR) phenomenon to non-invasively generate 3D tomographic images. MRI is an emerging modality for the lung, but it suffers from low sensitivity due to inherent low tissue density and short T2*. Hyperpolarization is a process by which the nuclear contribution to NMR signal is greatly enhanced to more than 100,000 times that of samples in thermal equilibrium. The noble gases 3He and 129Xe are most often hyperpolarized by transfer of light angular momentum through the electron of a vaporized alkali metal to the noble …
Tau And Aβ Imaging, Csf Measures, And Cognition In Alzheimer's Disease, Matthew R. Brier, Brian Gordon, Karl Friedrichsen, John E. Mccarthy, Ari Stern, Jon Christensen, Christopher Owen, Patricia Aldea, Yi Su, Jason Hassenstab, Nigel J. Cairns, David M. Holtzman, Anne M. Fagan, John C. Morris, Tammie L.S. Benzinger, Beau M. Ances
Tau And Aβ Imaging, Csf Measures, And Cognition In Alzheimer's Disease, Matthew R. Brier, Brian Gordon, Karl Friedrichsen, John E. Mccarthy, Ari Stern, Jon Christensen, Christopher Owen, Patricia Aldea, Yi Su, Jason Hassenstab, Nigel J. Cairns, David M. Holtzman, Anne M. Fagan, John C. Morris, Tammie L.S. Benzinger, Beau M. Ances
Mathematics Faculty Publications
Alzheimer’s disease (AD) is characterized by two molecular pathologies: cerebral β-amyloidosis in the form of β-amyloid (Aβ) plaques and tauopathy in the form of neurofibrillary tangles, neuritic plaques, and neuropil threads. Until recently, only Aβ could be studied in humans using positron emission tomography (PET) imaging owing to a lack of tau PET imaging agents. Clinical pathological studies have linked tau pathology closely to the onset and progression of cognitive symptoms in patients with AD. We report PET imaging of tau and Aβ in a cohort of cognitively normal older adults and those with mild AD. Multivariate analyses identified unique …
Partial Covariance Based Functional Connectivity Computation Using Ledoit-Wolf Covariance Regularization, Matthew R. Brier, Anish Mitra, John E. Mccarthy, Beau M. Ances, Abraham Z. Snyder
Partial Covariance Based Functional Connectivity Computation Using Ledoit-Wolf Covariance Regularization, Matthew R. Brier, Anish Mitra, John E. Mccarthy, Beau M. Ances, Abraham Z. Snyder
Mathematics Faculty Publications
Highlights •We use the well characterized matrix regularization technique described by Ledoit and Wolf to calculate high dimensional partial correlations in fMRI data. •Using this approach we demonstrate that partial correlations reveal RSN structure suggesting that RSNs are defined by widely and uniquely shared variance. •Partial correlation functional connectivity is sensitive to changes in brain state indicating that they contain functional information. Functional connectivity refers to shared signals among brain regions and is typically assessed in a task free state. Functional connectivity commonly is quantified between signal pairs using Pearson correlation. However, resting-state fMRI is a multivariate process exhibiting a …
Local And Distributed Pib Accumulation Associated With Development Of Preclinical Alzheimer's Disease, Matthew R. Brier, John E. Mccarthy, Tammie L.S. Benzinger, Ari Stern, Yi Su, Karl A. Friedrichsen, John C. Morris, Beau M. Ances, Andrei G. Vlassenko
Local And Distributed Pib Accumulation Associated With Development Of Preclinical Alzheimer's Disease, Matthew R. Brier, John E. Mccarthy, Tammie L.S. Benzinger, Ari Stern, Yi Su, Karl A. Friedrichsen, John C. Morris, Beau M. Ances, Andrei G. Vlassenko
Mathematics Faculty Publications
Amyloid-beta plaques are a hallmark of Alzheimer's disease (AD) that can be assessed by amyloid imaging (e.g., Pittsburgh B compound [PiB]) and summarized as a scalar value. Summary values may have clinical utility but are an average over many regions of interest, potentially obscuring important topography. This study investigates the longitudinal evolution of amyloid topographies in cognitively normal older adults who had normal (N = 131) or abnormal (N = 26) PiB scans at baseline. At 3 years follow-up, 16 participants with a previously normal PiB scan had conversion to PiB scans consistent with preclinical AD. We investigated the multivariate …
Additional Results For "Joint Entropy Of Continuously Differentiable Ultrasonic Waveforms" [J. Acoust. Soc. Am. 133(1), 283-300 (2013)], M S. Hughes, J N. Marsh, S A. Wickline, John E. Mccarthy
Additional Results For "Joint Entropy Of Continuously Differentiable Ultrasonic Waveforms" [J. Acoust. Soc. Am. 133(1), 283-300 (2013)], M S. Hughes, J N. Marsh, S A. Wickline, John E. Mccarthy
Mathematics Faculty Publications
Previous results on the use of joint entropy for detection of targeted nanoparticles accumulating in the neovasculature of MDA435 tumors [Fig. 7 of M. S. Hughes et al., J. Acoust. Soc. Am. 133, 283–300 (2013)] are extended, with sensitivity improving by nearly another factor of 2. This result is obtained using a “quasi-optimal” reference waveform in the computation of the joint entropy imaging technique used to image the accumulating nanoparticles.