Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Retrospective Theses and Dissertations

Discipline
Institution
Keyword
Publication Year

Articles 1 - 30 of 4948

Full-Text Articles in Physical Sciences and Mathematics

Polymer Chemistry Effects On Protein Release And Immune Activation, Senja Katarina Lopac Jan 2008

Polymer Chemistry Effects On Protein Release And Immune Activation, Senja Katarina Lopac

Retrospective Theses and Dissertations

The objective was to study the chemistry effect on protein release and stabilization and on immune cell activation using polyanhydrides. The two goals were to: (1) Determine how polyanhydride chemistry and fabrication methods affect the release kinetics of proteins from microspheres and the stability of the released protein. Microspheres were fabricated using two non-aqueous methods: solid/oil/oil and cryogenic atomization. Studies found no significant difference in release kinetics of ovalbumin. The more hydrophilic polyanhydrides showed more favorable protein stability, preserving both the immunological epitopes and the primary structure. (2) Investigate the surface marker expression of CD86, CD40, DC SIGN ...


The State, Resilience, And Potential Future Of Oak-Dominated Forests In The Driftless Area Of The Midwestern U.S., Tricia Gorby Knoot Jan 2008

The State, Resilience, And Potential Future Of Oak-Dominated Forests In The Driftless Area Of The Midwestern U.S., Tricia Gorby Knoot

Retrospective Theses and Dissertations

Forest surveys over the last several decades indicate a decline in oak regeneration in the midwestern United States with a high potential for future replacement by later successional forest types. The current state of oak systems may be nearing critical thresholds, which, if reached, their restoration could become markedly more challenging, if not impossible. Through a combination of qualitative and quantitative research methods, I evaluated the state, resilience, and potential future of oak forest ecosystems within the Driftless Area of the midwestern U.S., with the intention of providing information that can inform the design of timely and targeted oak-specific ...


Asymptotic Behavior Of The Solutions To A Family Of Pde's Arising From The Chemotaxis Equations Of Keller And Segal, Matthew Alan Halverson Jan 2008

Asymptotic Behavior Of The Solutions To A Family Of Pde's Arising From The Chemotaxis Equations Of Keller And Segal, Matthew Alan Halverson

Retrospective Theses and Dissertations

The system ut = uxx - (uvx)x, vt = u - Av is considered where A is a non-negative, self-adjoint operator which commutes with the Laplacian. The operator is considered to have eigenvalues lambda n = nrholambda1, and the system is considered on [0,1] x [0,T] with homogeneous Neumann boundary conditions. The operators which lead to global solutions and those that lead to solutions which blow up in finite time are considered as a function of rho, using an application of the methods of Hillen and Potapov [Math. Methods Appl. Sci., 27 (2004), pp. 1783-1801] to analyze the global case and those ...


Inductively Coupled Plasma: Fundamental Particle Investigations With Laser Ablation And Applications In Magnetic Sector Mass Spectrometry, Nathan Joe Saetveit Jan 2008

Inductively Coupled Plasma: Fundamental Particle Investigations With Laser Ablation And Applications In Magnetic Sector Mass Spectrometry, Nathan Joe Saetveit

Retrospective Theses and Dissertations

Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of ...


Nmr Studies Of Complex Carbon-Containing Materials: Maillard Reaction Products, Soil, Nanodiamond, And Carbon Modified Tio₂, Xiaowen Fang Jan 2008

Nmr Studies Of Complex Carbon-Containing Materials: Maillard Reaction Products, Soil, Nanodiamond, And Carbon Modified Tio₂, Xiaowen Fang

Retrospective Theses and Dissertations

Advanced solid-state magic angle spinning NMR (SS-MAS NMR) techniques have been applied to study the structures of carbon-containing complex materials, including 13C/15N labeled Maillard reaction products (melanoidins), soil and plant materials, detonation nanodiamond, and glucose-13C modified TiO2 photocatalyst.;Melanoidins, complex high molecular weight mixtures, are formed via the Maillard reactions between sugars and amino acids during heating. Due to their tremendous heterogeneity, the structure of melanoidins has remained poorly characterized. 13C and 15N labeling of the reactants has been combined with various solid-state NMR techniques to elucidate the structures of Maillard reaction products.;(i) The fate of glycine in ...


Mesoporous Silica Nanoparticles As Vehicles For Intracellular Trafficking And Controlled Release, Igor Iván Slowing Jan 2008

Mesoporous Silica Nanoparticles As Vehicles For Intracellular Trafficking And Controlled Release, Igor Iván Slowing

Retrospective Theses and Dissertations

Mesoporous silica nanoparticles (MSN) are introduced as vehicles for the intracellular delivery of a variety of molecular cargoes into living cells. The general synthesis of the material, the dependence of its uptake upon surface functionalization as well as its toxicity are investigated in the work.


Lie Algebra Decompositions With Applications To Quantum Dynamics, Mehmet DaǧLı Jan 2008

Lie Algebra Decompositions With Applications To Quantum Dynamics, Mehmet DaǧLı

Retrospective Theses and Dissertations

Lie group decompositions are useful tools in the analysis and control of quantum systems. Several decompositions proposed in the literature are based on a recursive procedure that systematically uses the Cartan decomposition theorem. In this dissertation, we establish a link between Lie algebra gradings and recursive Lie algebra decompositions, and then we formulate a general scheme to generate Lie group decompositions. This scheme contains some procedures previously proposed as special cases and gives a virtually unbounded number of alternatives to factor elements of a Lie group.


Intercept System To Edit, Control, And Analyze Packets (Isecap), Grant Rogers Brinkmeyer Jan 2008

Intercept System To Edit, Control, And Analyze Packets (Isecap), Grant Rogers Brinkmeyer

Retrospective Theses and Dissertations

ISECAP is an advanced packet filtering framework designed for use with the Internet Scale Event and Attack Generation Environment (ISEAGE) at Iowa State University. ISEAGE is a network security test bed where cyber attacks can be carried out for security research. ISECAP functions as a FreeBSD-based general purpose packet control system designed to alter ISEAGE network data as it is being transmitted. Scripts are interpreted by ISECAP to modify network data in real-time, assisting in the simulation and obfuscation of various network attacks tested at the ISEAGE facility. The ISECAP system is developed as a flexible tool with a forward ...


Structural And Electronic Investigations Of Complex Intermetallic Compounds, Hyunjin Ko Jan 2008

Structural And Electronic Investigations Of Complex Intermetallic Compounds, Hyunjin Ko

Retrospective Theses and Dissertations

Structure-composition-property relationships of complex intermetallic compounds are investigated.


Implementing The Science Writing Heuristic Laboratory Report Format In The Undergraduate Organic Chemistry Laboratory, Jacob Daniel Schroeder Jan 2008

Implementing The Science Writing Heuristic Laboratory Report Format In The Undergraduate Organic Chemistry Laboratory, Jacob Daniel Schroeder

Retrospective Theses and Dissertations

This dissertation describes how a traditional organic chemistry laboratory was reformed into a guided inquiry laboratory. Data presented illustrate the lack of correlation between the traditional laboratory and the corresponding lecture. After reforming the laboratory, student scores on lecture exams increased, specifically on exam questions directly related to concepts introduced in the laboratory. This dissertation covers work completed over the course of four years and includes the new laboratory manual, instructor notes for each new experiment, as well as a laboratory practical exam.


Palladium-Catalyzed And Electrophilic Cyclization Approaches To Carbocycles And Heterocycles, Shilpa Arvind Worlikar Jan 2008

Palladium-Catalyzed And Electrophilic Cyclization Approaches To Carbocycles And Heterocycles, Shilpa Arvind Worlikar

Retrospective Theses and Dissertations

Palladium-catalyzed and electrophilic cyclization reactions are among the most studied in synthetic organic chemistry. However, these methodologies cannot always be generally applied to obtain good yields of a desired class of compounds. Many factors, including the reaction conditions, the nature of the ligands, and the reactivity of the involved species determine the product and the yield. This thesis describes several useful and novel palladium-catalyzed and electrophilic cyclization methodologies that have been optimized to obtain biologically and industrially useful carbocycles and heterocycles in good to excellent yields. These methods are tolerant of a number of functional groups including, a halogen moiety ...


Estimating The Distance Distribution Of Subpopulations And Testing Observation Outlyingness For A Large-Scale Complex Survey, Jianqiang Wang Jan 2008

Estimating The Distance Distribution Of Subpopulations And Testing Observation Outlyingness For A Large-Scale Complex Survey, Jianqiang Wang

Retrospective Theses and Dissertations

Many finite populations targeted by sample surveys comprise a relatively small number of homogeneous subpopulations. In on-going survey operations, it is often of interest to be able to assess whether a new observation belongs to one of those subpopulations or should be flagged as not belonging to any of them. Because the homogeneity of the subpopulations depends on potentially large numbers of survey variables interacting in complex ways, we define a distance measure in the space induced by the survey variables, and consider the distribution of these distances within the subpopulation as a summary of the distributional characteristics of the ...


Studies In Electrophilic Cyclization, Palladium Migration And Cationic Polymerization, Tanay Kesharwani Jan 2008

Studies In Electrophilic Cyclization, Palladium Migration And Cationic Polymerization, Tanay Kesharwani

Retrospective Theses and Dissertations

2,3-Disubstituted benzo[b]selenophenes have been prepared by the electrophilic cyclization of various 1-(1-alkynyl)-2-(methylseleno)arenes by Br2, NBS, I2, ICl, PhSeCl, PhSeBr and Hg(OAc) 2. This method tolerates a wide variety of functional groups, including alcohol, ester, nitrile, nitro and silyl groups, and proceeds under exceptionally mild reaction conditions. A cationic intermediate in the cyclization with Br2 has been isolated and studied, providing evidence for a stepwise cyclization process.


A Concept Virtual Harp With Physical String Vibrations Using Augmented Reality For Therapy, Tanasha A. Taylor Jan 2008

A Concept Virtual Harp With Physical String Vibrations Using Augmented Reality For Therapy, Tanasha A. Taylor

Retrospective Theses and Dissertations

This thesis presents a multimodal three-dimensional harp for interactive musical experiences for use in therapy for individuals with disabilities. A preliminary harp model in OpenGL with user interaction being a mouse and keyboard tested on special education children lead the Virtual Harp program on a new design approach to provide more interaction and stimuli. This system provides individuals with three forms of feedback visual, audio, and haptic during interaction using a Sensable Phantom Omni haptic device and immersion in a portable augmented reality-based system using a video see-through head mounted display. Modeled as a realistic harp, the virtual harp uses ...


Design And Evaluation Of Auditory Spatial Cues For Decision Making Within A Game Environment For Persons With Visual Impairments, Michael Anthony Oren Jan 2008

Design And Evaluation Of Auditory Spatial Cues For Decision Making Within A Game Environment For Persons With Visual Impairments, Michael Anthony Oren

Retrospective Theses and Dissertations

An audio platform game was created and evaluated in order to answer the question of whether or not an audio game could be designed that effectively conveys the spatial information necessary for persons with visual impairments to successfully navigate the game levels and respond to audio cues in time to avoid obstacles. The game used several types of audio cues (sounds and speech) to convey the spatial setup (map) of the game world. Most audio-only players seemed to be able to create a workable mental map from the game's sound cues alone, pointing to potential for the further development ...


Interactive Graphics, Graphical User Interfaces And Software Interfaces For The Analysis Of Biological Experimental Data And Networks, Michael Lawrence Jan 2008

Interactive Graphics, Graphical User Interfaces And Software Interfaces For The Analysis Of Biological Experimental Data And Networks, Michael Lawrence

Retrospective Theses and Dissertations

Biologists need to analyze and comprehend increasingly large and more complex multivariate experimental data. Biological experiments often produce multiple data sets, each describing one aspect of the system, such as the transcriptome recorded by a microarray or metabolome recorded using gas chromatography mass spectrometry (GC-MS). A biochemical network model provides a conceptual system-level framework for integrating data from different sources.;Effective use of graphics enhances the comprehension of data, and interactive graphics permit the analyst to actively explore data, check its integrity, satiate curiosities and reveal the unexpected. Interactive graphics have not been widely applied as a means for understanding ...


Cooking Up Quantum Chemistry, Bosiljka Njegic Jan 2008

Cooking Up Quantum Chemistry, Bosiljka Njegic

Retrospective Theses and Dissertations

Accurate vibrational frequencies were calculated using the vibrational self-consistent field method (VSCF). The effect of anharmonicity of calculated frequencies on thermodynamic properties, such as entropy, was explored. The developments of the VSCF method were introduced in the manner in which potential energy surface (PES) is being generated. The comparison of harmonic, scaled harmonic and anharmonic frequencies, was made. Furthermore, the computing of a PES within the VSCF method was coarse-grain parallelized in order to enable calculations on bigger molecules. Finally, the work conducted on the reaction mechanism of the industrially important process of production of H2O2 catalyzed by gold nanoparticles ...


Understanding Protein Motions By Computational Modeling And Statistical Approaches, Lei Yang Jan 2008

Understanding Protein Motions By Computational Modeling And Statistical Approaches, Lei Yang

Retrospective Theses and Dissertations

Because of its appealing simplicity, the elastic network model (ENM) has been widely accepted and applied to study many molecular motion problems, such as the molecular mechanisms of chaperonin GroEL-GroES function, allosteric changes in hemoglobin, ribosome motions, motor-protein motions, and conformational changes in general. In this dissertation, the ENM is employed to study various protein dynamics problems, and its validity is also examined by comparing with experimental data. First, we apply principal component analysis (PCA) to identify the essential protein motions from multiple structures (X-ray, NMR and MD) of the HIV-1 protease. We find significant similarities between the first few ...


Analysis On Protein Structures Using Statistical And Bioinformatical Methods, Aimin Yan Jan 2008

Analysis On Protein Structures Using Statistical And Bioinformatical Methods, Aimin Yan

Retrospective Theses and Dissertations

This PhD dissertation mainly focuses on the statistical analysis for the protein structure data. The first research project focuses on data mining and prediction for side chain orientation in protein structure. Through this study, we find that the general side chain orientation can be viewed as a manifestation of hydrophobic force. Along with this study, we also developed the software for visualizing the general side chain vector and applied statistical machine learning methods to fit several models for predicting general side chain orientation. In the second project, we studied the motion of partially assembled ribosome 30S subunit using the coarse-grained ...


Kinetic Study Of Copper Chemistry In Chemical Mechanical Polishing (Cmp) By An In-Situ Real Time Measurement Technique, Changhoon Choi Jan 2008

Kinetic Study Of Copper Chemistry In Chemical Mechanical Polishing (Cmp) By An In-Situ Real Time Measurement Technique, Changhoon Choi

Retrospective Theses and Dissertations

This work describes a systematic approach to study chemical reactions of copper in contact with various chemical agents and to construct a coherent etching rate model based on the fundamental chemistry. Reactions of copper with chemical agents were investigated by in-situ real time technique, quartz crystal microgravimetry (QCM). Kinetic processes were followed by QCM measurement and analyzed. A coherent etching rate formula was built based on the kinetic analysis of fundamental reactions. The requirement of repeated experiments for studying copper chemistry motivated us to develop a high throughput measurement system. We utilized surface plasmon resonance (SPR) imaging combined with multi ...


Parameter Estimation And Bias Correction For Diffusion Processes And A Nonparametric Approach To Census Population Size Estimation, Chengyong Tang Jan 2008

Parameter Estimation And Bias Correction For Diffusion Processes And A Nonparametric Approach To Census Population Size Estimation, Chengyong Tang

Retrospective Theses and Dissertations

The first part of the dissertation considers parameter estimation for continuous-time diffusion processes which are commonly used to model dynamics of financial securities including interest rates. To understand why the drift parameters are more difficult to estimate than the diffusion parameter as observed in many empirical studies, we develop expansions for the bias and variance of parameter estimators for two mostly employed interest rate processes. A parametric bootstrap procedure is proposed to correct bias in parameter estimation of general diffusion processes with a theoretical justification. Simulation studies confirm the theoretical findings and show that the bootstrap proposal can effectively reduce ...


Developments In Icp-Ms: Electrochemically Modulated Liquid Chromatography For The Clean-Up Of Icp-Ms Blanks And Reduction Of Matrix Effects By Flow Injection Icp-Ms, Cory Thomas Gross Jan 2008

Developments In Icp-Ms: Electrochemically Modulated Liquid Chromatography For The Clean-Up Of Icp-Ms Blanks And Reduction Of Matrix Effects By Flow Injection Icp-Ms, Cory Thomas Gross

Retrospective Theses and Dissertations

The focus of this dissertation is the development of techniques with which to enhance the existing abilities of inductively coupled plasma mass spectrometry (ICP-MS). ICP-MS is a powerful technique for trace metal analysis in samples of many types, but like any technique has certain strengths and weakness. Attempts are made to improve upon those strengths and to overcome certain weaknesses.;One standout figure of merit for ICP-MS is limit of detection. With today's advances in instrumental hardware the limit of detection is often limited by the purity of the blank. While the limit of detection itself is not evaluated ...


Iodine And Palladium Approaches To Medicinally Interesting Heterocycles And Carbocycles, Jesse Page Waldo Jan 2008

Iodine And Palladium Approaches To Medicinally Interesting Heterocycles And Carbocycles, Jesse Page Waldo

Retrospective Theses and Dissertations

Chapter 1. A large number of functionally-substituted 2-alkyn-1-one O-methyl oximes have been cyclized under mild reaction conditions in the presence of ICl to give the corresponding 4-iodoisoxazoles in moderate to excellent yields. The resulting 4-iodoisoxazoles undergo various palladium-catalyzed reactions to yield 3,4,5-trisubstituted isoxazoles, including valdecoxib.;Chapter 2. The iodocyclization of O-methyloximes of 2-alkyn-1-ones affords 4-iodoisoxazoles, which undergo various palladium-catalyzed reactions to yield 3,4,5-trisubstituted isoxazoles. The palladium-catalyzed processes have been adapted to parallel synthesis utilizing commercially available boronic acid, acetylene, styrene and amine sublibraries. Accordingly, a diverse 51-member library of 3,4,5-trisubstituted isoxazoles has been generated ...


Ultrafast Fluorescence Spectroscopy Used As A Probe To Explore Excited State Photophysics Of Biologically And Environmentally Relevant Systems, Prasun Mukherjee Jan 2008

Ultrafast Fluorescence Spectroscopy Used As A Probe To Explore Excited State Photophysics Of Biologically And Environmentally Relevant Systems, Prasun Mukherjee

Retrospective Theses and Dissertations

No abstract provided.


Development And Application Of A Hybrid Femtosecond/Picosecond Coherent Raman Probe Designed For Study Of Excited State Systems, Benjamin Douglas Prince Jan 2008

Development And Application Of A Hybrid Femtosecond/Picosecond Coherent Raman Probe Designed For Study Of Excited State Systems, Benjamin Douglas Prince

Retrospective Theses and Dissertations

The conversion from purely femtosecond coherent anti-Stokes Raman spectroscopy (CARS) to a more advantageous hybrid femtosecond/picosecond CARS (fs/ps CARS) probe for time-resolved vibrational dynamics studies is detailed. This probe provides a number of benefits for the use of studying the evolution of electronically excited states, including rapid data acquisition speeds, increased spectral resolution, and discrimination against competing background signals. The high time resolution is shown to depend on the cross correlation of the excitation pulse and initial CARS pulses while the high frequency resolution is shown to depend on the final CARS electric field. The pump-fs/ps CARS ...


Ethnic-Identity Intensity As A Moderator Of The Technology Acceptance Model And Its Antecedents, Marcus Anthony Alexander Jan 2008

Ethnic-Identity Intensity As A Moderator Of The Technology Acceptance Model And Its Antecedents, Marcus Anthony Alexander

Retrospective Theses and Dissertations

The goal of this dissertation is oriented to study the motivation of minorities to adopt and learn new, innovative technologies. The primary research question: is there some reason the African-American experience is driving certain sub-groups of the population to the wrong side of the digital divide? To examine this, I introduce ethnic identity as a moderating variable to a leftward extended technology acceptance model (TAM). Additionally, both components of the classic TAM (ease of use and usefulness) are divided into two antecedents: (1) ease of use - (a) trait efficacy and (b) state efficacy and (2) usefulness (completely replaced by) - (a ...


Integrating Qtl Analysis Into Plant Breeding Practice Using Bayesian Statistics, Shengqiang Zhong Jan 2008

Integrating Qtl Analysis Into Plant Breeding Practice Using Bayesian Statistics, Shengqiang Zhong

Retrospective Theses and Dissertations

Plant breeders face the challenges to incorporate significant developments in Bayesian quantitative trait locus (QTL) analysis into breeding practice. The overall objective of this dissertation is to integrate QTL analysis into marker-assisted selection (MAS) in plant breeding using Bayesian statistics. Three different perspectives were studied: identification of optimal designs to generate multiple families for QTL mapping, cross prediction using QTL analysis results, and genomic selection for cultivated barley. First, the impact of two mating designs was studied on QTL mapping in multiple families generated by crosses between multiple inbred lines, using within-family linkage disequilibrium (LD) with a Bayesian variable selection ...


Lc-Ms Analysis Of Related Peptides And Anions In The Positive Mode, Renee Joy Hein Jan 2008

Lc-Ms Analysis Of Related Peptides And Anions In The Positive Mode, Renee Joy Hein

Retrospective Theses and Dissertations

This dissertation focuses on the use of LC-MS for the analysis of related peptides and anions in the positive mode. Separating closely related peptides (those differing by one or two amino acids or the chirality of a single amino acid) can be challenging using reversed-phase liquid chromatography (LC), ion exchange LC, or using ion-pairing agents. Also, the mobile phases that give the best separations in these modes may not be electrospray ionization mass spectrometry (ESI-MS) compatible. Macrocyclic glycopeptide stationary phases were investigated as an alternative to the standard C18 stationary phase for the separation of related peptides. On the macrocyclic ...


Practical Tools For Exploring Data And Models, Hadley Alexander Wickham Jan 2008

Practical Tools For Exploring Data And Models, Hadley Alexander Wickham

Retrospective Theses and Dissertations

No abstract provided.


An Assessment Of Riparian Land-Use And Channel Condition Impacts On Streambank Eroding Lengths And Recession Rates In Two Third Order Rural Watersheds In Central Iowa, Jason Alan Palmer Jan 2008

An Assessment Of Riparian Land-Use And Channel Condition Impacts On Streambank Eroding Lengths And Recession Rates In Two Third Order Rural Watersheds In Central Iowa, Jason Alan Palmer

Retrospective Theses and Dissertations

Over the 150 year history of major agricultural activity in Iowa nearly all the native prairie (99.9%) and wetlands (95%) were lost as native plant communities were converted to row-crop agriculture. This major change from perennial to annual upland vegetation was accompanied by broad scale installation of tile drainage intended to remove moisture from saturated wetland soils, increasing available crop land. The increased removal of water by tile drainage accompanied by the increase in surface runoff caused by the loss of permanent soil cover and compaction resulted in an increase in the rate and amount of water entering stream ...