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Articles 1 - 30 of 46
Full-Text Articles in Physical Sciences and Mathematics
Real Time Monitoring Of Surface Chemical Events By Streaming Potentials In Microfluidic Channels, Kenji Nokura
Real Time Monitoring Of Surface Chemical Events By Streaming Potentials In Microfluidic Channels, Kenji Nokura
Theses and Dissertations
Zeta potential is one of the tools to measure the surface charge of materials, and Alvarez et al. have developed a microchannel device to measure zeta potentials in real time for label-free sensing using immobilized receptors on microchannel surfaces. However, the challenge has been the charge interference of surface modifiers on analyte detection. Therefore, it was necessary to find the best strategy to regenerate minimal surface charge after modifying the channel with polymer films that would anchor the affinity groups for the analyte. It was demonstrated that adsorption of positively and negatively charged analytes were monitored via real time zeta …
Accelerating Computational Algorithms, Michael Risley
Accelerating Computational Algorithms, Michael Risley
Theses and Dissertations
Mathematicians and computational scientists are often limited in their ability to model complex phenomena by the time it takes to run simulations. This thesis will inform interested researchers on how the development of highly parallel computer graphics hardware and the compiler frameworks to exploit it are expanding the range of algorithms that can be explored on affordable commodity hardware. We will discuss the complexities that have prevented researchers from exploiting advanced hardware as well as the obstacles that remain for the non-computer scientist.
Synthesis, Characterization, And Functionalization Of Magnetic Iron Nanoparticles For Enhanced Biological Applications, Christopher Warren
Synthesis, Characterization, And Functionalization Of Magnetic Iron Nanoparticles For Enhanced Biological Applications, Christopher Warren
Theses and Dissertations
The transition metal ferrites of composition MFe2O4 where M is Fe, Co, or Ni are well established materials for various biological applications due to their interesting magnetic properties. Their elemental and stochiometric composition can be easily manipulated which allows further tuning of their ferrimagnetic properties. By changing the identity of M and by changing the crystallite size of the ferrites, nanocrystals with diverse magnetic properties can be systematically produced. Furthermore, ferrites are more stable in diverse chemical environments, as compared to metallic nanoparticles, which make ferrites particularly useful for a broad range of biomedical applications, especially in the field of …
Analysis Of Mathematical Models Of The Human Lung, Cooper Racheal
Analysis Of Mathematical Models Of The Human Lung, Cooper Racheal
Theses and Dissertations
The processes of lung ventilation and perfusion, diffusion, and gas transport make up the system of breathing and tissue oxygenation. Here, we present several mathematical formulations of the essential processes that contribute to breathing. These models aid in our understanding and analysis of this complex system and can be used to form treatments for patients on ventilators. With the right analysis and treatment options, patients can be helped and money can be saved. We conclude with the formulation of a mathematical model for the exchange of gasses in the body based on basic reaction kinetics.
Multi-Column Multi-Layer Computational Model Of Neocortex, Beata Strack
Multi-Column Multi-Layer Computational Model Of Neocortex, Beata Strack
Theses and Dissertations
We present a multi-layer multi-column computational model of neocortex that is built based on the activity and connections of known neuronal cell types and includes activity-dependent short term plasticity. This model, a network of spiking neurons, is validated by showing that it exhibits activity close to biology in terms of several characteristics: (1) proper laminar flow of activity; (2) columnar organization with focality of inputs; (3) low-threshold-spiking (LTS) and fast-spiking (FS) neurons function as observed in normal cortical circuits; and (4) different stages of epileptiform activity can be obtained with either increasing the level of inhibitory blockade, or simulation of …
Optimization And Spatial Queueing Models To Support Multi-Server Dispatching Policies With Multiple Servers Per Station, Sardar Ansari
Optimization And Spatial Queueing Models To Support Multi-Server Dispatching Policies With Multiple Servers Per Station, Sardar Ansari
Theses and Dissertations
In this thesis, we propose novel optimization and spatial queueing models that expand the currently existing methods by allowing multiple servers to be located at the same station and multiple servers to be dispatched to a single call. In particular, a mixed integer linear programming (MILP) model is introduced that determines how to locate and dispatch ambulances such that the coverage level is maximized. The model allows multiple servers to be located at the same station and balances the workload among them while maintaining contiguous first priority response districts. We also propose an extension to the approximate Hypercube queueing model …
The Design And Synthesis Of Magnetic Nanocomposites, Daniel Hudgins
The Design And Synthesis Of Magnetic Nanocomposites, Daniel Hudgins
Theses and Dissertations
Magnetism lies at the core of modern technology and can be found in industries such as oil refining, automotive, telecommunications, personal electronics, and power generation that are integral to our day to day lives. This permeation into everyday life has been enhanced in the past several decades with improvements in material design based upon the principles of nanotechnology leading to smaller, faster, and more efficient devices. The presented research will discuss the synthesis and processing of multiple magnetic nanoparticle structures designed for the enhancement of various, application specific, properties. In the first experiments a tunable core/shell structure was developed with …
Zinc Environment In Proteins: The Flexible And Reactive Core Of Hiv-1 Ncp7 And The Inhibitory Site Of Caspase-3, A. Gerard Daniel
Zinc Environment In Proteins: The Flexible And Reactive Core Of Hiv-1 Ncp7 And The Inhibitory Site Of Caspase-3, A. Gerard Daniel
Theses and Dissertations
Zinc is an essential cofactor of several proteins. The roles of zinc in these proteins are classified as catalytic, structural or regulatory. Zinc present in structural sites is considered to be a chemically inert, static structural element. On the contrary, previous studies on a C2H2 type zinc finger model compound and the C3H type HIV-1 NCp7 C-terminal zinc knuckle have shown that zinc at these sites can undergo coordination sphere expansion under the influence of a Pt based electrophile. The pentacoordination observed around zinc in these experiments raises an important question: are the structural zinc motifs found in the proteins …
A Novel Spam Campaign In Online Social Networks, Yufeng Zhen
A Novel Spam Campaign In Online Social Networks, Yufeng Zhen
Theses and Dissertations
The increasing popularity of the Online Social Networks (OSNs)\nomenclature{$OSNs$}{Online Social Networks} has made the OSNs major targets of spammers. They aim to illegally gather private information from users and spread spam to them. In this paper, we propose a new spam campaign that includes following key steps: creating fake accounts, picking legitimate accounts, forming friendships, earning trust, and spreading spam. The unique part in our spam campaign is the process of earning trust. By using social bots, we significantly lower the cost of earning trust and make it feasible in the real world. By spreading spam at a relatively low …
Regularization Methods For Predicting An Ordinal Response Using Longitudinal High-Dimensional Genomic Data, Jiayi Hou
Theses and Dissertations
Ordinal scales are commonly used to measure health status and disease related outcomes in hospital settings as well as in translational medical research. Notable examples include cancer staging, which is a five-category ordinal scale indicating tumor size, node involvement, and likelihood of metastasizing. Glasgow Coma Scale (GCS), which gives a reliable and objective assessment of conscious status of a patient, is an ordinal scaled measure. In addition, repeated measurements are common in clinical practice for tracking and monitoring the progression of complex diseases. Classical ordinal modeling methods based on the likelihood approach have contributed to the analysis of data in …
Review And Extension For The O’Brien Fleming Multiple Testing Procedure, Hanan Hammouri
Review And Extension For The O’Brien Fleming Multiple Testing Procedure, Hanan Hammouri
Theses and Dissertations
O'Brien and Fleming (1979) proposed a straightforward and useful multiple testing procedure (group sequential testing procedure) for comparing two treatments in clinical trials where subject responses are dichotomous (e.g. success and failure). O'Brien and Fleming stated that their group sequential testing procedure has the same Type I error rate and power as that of a fixed one-stage chi-square test, but gives the opportunity to terminate the trial early when one treatment is clearly performing better than the other. We studied and tested the O'Brien and Fleming procedure specifically by correcting the originally proposed critical values. Furthermore, we updated the O’Brien …
Response Adaptive Design Using Auxiliary And Primary Outcomes, Shuxian Sinks
Response Adaptive Design Using Auxiliary And Primary Outcomes, Shuxian Sinks
Theses and Dissertations
Response adaptive designs intend to allocate more patients to better treatments without undermining the validity and the integrity of the trial. The immediacy of the primary response (e.g. deaths, remission) determines the efficiency of the response adaptive design, which often requires outcomes to be quickly or immediately observed. This presents difficulties for survival studies, which may require long durations to observe the primary endpoint. Therefore, we introduce auxiliary endpoints to assist the adaptation with the primary endpoint, where an auxiliary endpoint is generally defined as any measurement that is positively associated with the primary endpoint. Our proposed design (referred to …
Laser Vaporization Methods For The Synthesis Of Metal And Semiconductor Nanoparticles; Graphene, Doped Graphene And Nanoparticles Supported On Graphene, Parichehr Afshani
Laser Vaporization Methods For The Synthesis Of Metal And Semiconductor Nanoparticles; Graphene, Doped Graphene And Nanoparticles Supported On Graphene, Parichehr Afshani
Theses and Dissertations
The major objective of the research described in this dissertation is the development of new laser vaporization methods for the synthesis of metal and semiconductor nanoparticles, graphene, B- and N-doped graphene, and metal and semiconductor nanoparticles supported on graphene. These methods include the Laser Vaporization Controlled Condensation (LVCC) approach, which has been used in this work for the synthesis of: (1) gold nanoparticles supported on ceria and zirconia nanoparticles for the low temperature oxidation of carbon monoxide, and (2) graphene, boron- and nitrogen-doped graphene, hydrogen-terminated graphene (HTG), metal nanoparticles supported on graphene, and graphene quantum dots. The gold nanoparticles supported …
Modular Forms And Vertex Operator Algebras, Patrick Gaskill
Modular Forms And Vertex Operator Algebras, Patrick Gaskill
Theses and Dissertations
In this thesis we present the connection between vertex operator algebras and modular forms which lies at the heart of Borcherds’ proof of the Monstrous Moonshine conjecture. In order to do so we introduce modular forms, vertex algebras, vertex operator algebras and their partition functions. Each notion is illustrated with examples.
A Mathematical System For Human Implantable Wound Model Studies, Salomonsky Paul-Michael
A Mathematical System For Human Implantable Wound Model Studies, Salomonsky Paul-Michael
Theses and Dissertations
Dermal wound healing involves a myriad of highly regulated and sophisticated mechanisms, which are coordinated and carried out via several specialized cell types. The dominant players involved in this process include platelets, neutrophils, macrophages and fibroblasts. These cells play a vital role in the repair of the wound by orchestrating tasks such as forming a fibrin clot to stanch blood flow, removing foreign organisms and cellular debris, depositing new collagen matrix and establishing the contractile forces which eventually bridge the void caused by the initial infraction.\\[5pt] \indent Our current understanding of these mechanisms has been primarily based upon animal models. …
Fabrication Of Surface Amine Gradients By Controlled-Rate Infusion For Chromatographic Applications, Balamurali Kannan
Fabrication Of Surface Amine Gradients By Controlled-Rate Infusion For Chromatographic Applications, Balamurali Kannan
Theses and Dissertations
Surface gradients are materials that exhibit a variation in properties such as chemical composition, topography etc., in a continuous and/or discrete fashion. They are broadly classified as chemical and physical gradients depending upon the properties that gradient exhibits. Among those, chemical gradients on various surfaces have been a great interest in materials research for the last two decades. This is due to the applications of gradients in various fields such as biological sciences, separation science, etc. There have been several different approaches developed for the preparation of chemical gradients. Silane-based approaches are among those that are widely used because of …
The Estimation And Evaluation Of Optimal Thresholds For Two Sequential Testing Strategies, Amber R. Wilk
The Estimation And Evaluation Of Optimal Thresholds For Two Sequential Testing Strategies, Amber R. Wilk
Theses and Dissertations
Many continuous medical tests often rely on a threshold for diagnosis. There are two sequential testing strategies of interest: Believe the Positive (BP) and Believe the Negative (BN). BP classifies a patient positive if either the first test is greater than a threshold θ1 or negative on the first test and greater than θ2 on the second test. BN classifies a patient positive if the first test is greater than a threshold θ3 and greater than θ4 on the second test. Threshold pairs θ = (θ1, θ2) or (θ3, θ4), depending on strategy, are defined as optimal if they maximized …
Assessment And Prediction Of Cardiovascular Status During Cardiac Arrest Through Machine Learning And Dynamical Time-Series Analysis, Sharad Shandilya
Assessment And Prediction Of Cardiovascular Status During Cardiac Arrest Through Machine Learning And Dynamical Time-Series Analysis, Sharad Shandilya
Theses and Dissertations
In this work, new methods of feature extraction, feature selection, stochastic data characterization/modeling, variance reduction and measures for parametric discrimination are proposed. These methods have implications for data mining, machine learning, and information theory. A novel decision-support system is developed in order to guide intervention during cardiac arrest. The models are built upon knowledge extracted with signal-processing, non-linear dynamic and machine-learning methods. The proposed ECG characterization, combined with information extracted from PetCO2 signals, shows viability for decision-support in clinical settings. The approach, which focuses on integration of multiple features through machine learning techniques, suits well to inclusion of multiple physiologic …
Motion Artifact Reduction In Impedance Plethysmography Signal, Sardar Ansari
Motion Artifact Reduction In Impedance Plethysmography Signal, Sardar Ansari
Theses and Dissertations
The research related to designing portable monitoring devices for physiological signals has been at its peak in the last decade or two. One of the main obstacles in building such devices is the effect of the subject's movements on the quality of the signal. There have been numerous studies addressing the problem of removing motion artifact from the electrocardiogram (ECG) and photoplethysmography (PPG) signals in the past few years. However, no such study exists for the Impedance Plethysmography (IP) signal. The IP signal can be used to monitor respiration in mobile devices. However, it is very susceptible to motion artifact. …
A Systems Biology Approach For Understanding Inflammation In The Gastrointestinal Tract Of A Crohn’S Patient, Gigi Meyer
A Systems Biology Approach For Understanding Inflammation In The Gastrointestinal Tract Of A Crohn’S Patient, Gigi Meyer
Theses and Dissertations
A system of ordinary differential equations is developed to model the effect of fatty acids on chronic intestinal inflammation that is typical of a Crohn’s patient. Several murine studies have shown an anti-inflammatory response when specific polyunsaturated fatty acids are included regularly in the diet. It is believed that the fatty acids serve as a specific ligand that activates the Peroxisome Proliferator Activated Receptor (PPAR) which is located on multiple cell types that are active in the inflammatory response. The binding of the PPAR results in a suppression of the inflammatory pathway. Results of the model indicate a muted inflammatory …
Effective Network Partitioning To Find Mip Solutions To The Train Dispatching Problem, Christopher Snellings
Effective Network Partitioning To Find Mip Solutions To The Train Dispatching Problem, Christopher Snellings
Theses and Dissertations
Each year the Railway Applications Section (RAS) of the Institution for Operations Research and the Management Sciences (INFORMS) posits a research problem to the world in the form of a competition. For 2012, the contest involved solving the Train Dispatching Problem (TDP) on a realistic 85 edge network for three different sets of input data. This work is an independent attempt to match or improve upon the results of the top three finishers in the contest using mixed integer programming (MIP) techniques while minimizing the use of heuristics. The primary focus is to partition the network in a manner that …
Complex Network Growing Model Using Downlink Motifs, Ahmad Al-Musawi Jr.
Complex Network Growing Model Using Downlink Motifs, Ahmad Al-Musawi Jr.
Theses and Dissertations
Understanding the underlying architecture of gene regulatory networks (GRNs) has been one of the major goals in systems biology and bioinformatics as it can provide insights in disease dynamics and drug development. Such GRNs are characterized by their scale-free degree distributions and existence of network motifs, which are small subgraphs of specific types and appear more abundantly in GRNs than in other randomized networks. In fact, such motifs are considered to be the building blocks of GRNs (and other complex networks) and they help achieve the underlying robustness demonstrated by most biological networks. The goal of this thesis is to …
The Use Of Relation Valued Attributes In Support Of Fuzzy Data, Larry Ritchie Williams Jr.
The Use Of Relation Valued Attributes In Support Of Fuzzy Data, Larry Ritchie Williams Jr.
Theses and Dissertations
In his paper introducing fuzzy sets, L.A. Zadeh describes the difficulty of assigning some real-world objects to a particular class when the notion of class membership is ambiguous. If exact classification is not obvious, most people approximate using intuition and may reach agreement by placing an object in more than one class. Numbers or ‘degrees of membership’ within these classes are used to provide an approximation that supports this intuitive process. This results in a ‘fuzzy set’. This fuzzy set consists any number of ordered pairs to represent both the class and the class’s degree of membership to provide a …
Binding Energies And Solvation Of Organic Molecular Ions, Reactions Of Transition Metal Ions With, And Plasma Discharge Ionization Of Molecular Clusters, Isaac Kwame Attah
Binding Energies And Solvation Of Organic Molecular Ions, Reactions Of Transition Metal Ions With, And Plasma Discharge Ionization Of Molecular Clusters, Isaac Kwame Attah
Theses and Dissertations
In this dissertation, different approaches have been employed to address the quest of understanding the formation and growth mechanisms of carbon-containing molecular ions with relevance to astrochemistry. Ion mobility mass spectrometry and DFT computations were used to investigate how a second nitrogen in the pyrimidine ring will affect the formation of a covalent bond between the benzene radical cation and the neutral pyrimidine molecule, after it was shown that a stable covalent adduct can be formed between benzene radical cation and the neutral pyridine. Evidence for the formation of a more stable covalent adduct between the benzene radical cation and …
Regularities In The Augmentation Of Fractional Factorial Designs, Lisa Kessel
Regularities In The Augmentation Of Fractional Factorial Designs, Lisa Kessel
Theses and Dissertations
Two-level factorial experiments are widely used in experimental design because they are simple to construct and interpret while also being efficient. However, full factorial designs for many factors can quickly become inefficient, time consuming, or expensive and therefore fractional factorial designs are sometimes preferable since they provide information on effects of interest and can be performed in fewer experimental runs. The disadvantage of using these designs is that when using fewer experimental runs, information about effects of interest is sometimes lost. Although there are methods for selecting fractional designs so that the number of runs is minimized while the amount …
Geometric Approach To Support Vector Machines Learning For Large Datasets, Robert Strack
Geometric Approach To Support Vector Machines Learning For Large Datasets, Robert Strack
Theses and Dissertations
The dissertation introduces Sphere Support Vector Machines (SphereSVM) and Minimal Norm Support Vector Machines (MNSVM) as the new fast classification algorithms that use geometrical properties of the underlying classification problems to efficiently obtain models describing training data. SphereSVM is based on combining minimal enclosing ball approach, state of the art nearest point problem solvers and probabilistic techniques. The blending of the three speeds up the training phase of SVMs significantly and reaches similar (i.e., practically the same) accuracy as the other classification models over several big and large real data sets within the strict validation frame of a double (nested) …
The Effect Of Temperature On The Electrical And Optical Properties Of P-Type Gan, Joy Mcnamara
The Effect Of Temperature On The Electrical And Optical Properties Of P-Type Gan, Joy Mcnamara
Theses and Dissertations
The development of gallium nitride (GaN) light emitting devices has reached extraordinary echelons. As such, the characterization and analysis of the behavior of GaN materials is essential to the advancement of GaN technology. In this thesis, the effect of temperature on the optical and electrical properties of p-type GaN is investigated. The GaN samples used in this work were grown by various methods and studied by Kelvin probe and photoluminescence (PL) techniques. Specifically, the surface photovoltage (SPV) behavior and PL data were analyzed at different temperatures and illumination intensities. Using the SPV results, we show that p-type GaN exhibits n-type …
Reproduction And Functional Response Of Cornus Florida Across An Urban Landscape Gradient, Angela Redwine
Reproduction And Functional Response Of Cornus Florida Across An Urban Landscape Gradient, Angela Redwine
Theses and Dissertations
Urbanization greatly alters plant and pollinator communities and can affect pollinator movement and subsequent gene flow. Plants persisting in urban areas must adjust to local environmental conditions often different from those in which they naturally evolved, and cultivation techniques for landscaping species have developed traits suitable for existence in urban habitats. Cultivated varieties and native conspecifics often exist in geographic proximity, and if pollinator movement is not blocked by urban structural components, functional differences may negatively impact spatially proximate native populations. I used spatial analysis of successful pollination of Cornus florida to estimate how pollinator movement is affected by urban …
Atomic And Electronic Structure Of A Ligand-Protected Bimetallic Nanocluster, Ag4ni2(Dmsa)4, Anthony F. Pedicini
Atomic And Electronic Structure Of A Ligand-Protected Bimetallic Nanocluster, Ag4ni2(Dmsa)4, Anthony F. Pedicini
Theses and Dissertations
An important direction in nanoscale science is to synthesize materials whereby atomic clusters serve as the building blocks. Properties of these clusters can be controlled through size and composition, and such an approach offers a pathway toward designing larger, customized materials. One way to stabilize such materials is through the use of ligated clusters. Ag4Ni2(DMSA)4 is one such cluster, the first with a bimetallic core, and has been stabilized by the experimental group of A. Sen at The Pennsylvania State University. The theoretical studies undertaken in this thesis were directed toward providing information on the atomic structure, nature of electronic …
Automated Midline Shift Detection On Brain Ct Images For Computer-Aided Clinical Decision Support, Xuguang Qi
Automated Midline Shift Detection On Brain Ct Images For Computer-Aided Clinical Decision Support, Xuguang Qi
Theses and Dissertations
Midline shift (MLS), the amount of displacement of the brain’s midline from its normal symmetric position due to illness or injury, is an important index for clinicians to assess the severity of traumatic brain injury (TBI). In this dissertation, an automated computer-aided midline shift estimation system is proposed. First, a CT slice selection algorithm (SSA) is designed to automatically select a subset of appropriate CT slices from a large number of raw images for MLS detection. Next, ideal midline detection is implemented based on skull bone anatomical features and global rotation assumptions. For the actual midline detection algorithm, a window …