Physical Sciences and Mathematics Commons^™

Maximizing And Modeling Malonyl-Coa Production In Escherichia Coli, Tatiana Thompson Silveira Mello

LSU Master's Theses

In E. coli, fatty acid synthesis is catalyzed by the enzyme acetyl-CoA carboxylase (ACC), which converts acetyl-CoA into malonyl-CoA. Malonyl-CoA is a major building block for numerous of bioproducts. Multiple parameters regulate the homeostatic cellular concentration of malonyl-CoA, keeping it at a very low level. Understanding how these parameters affect the bacterial production of malonyl-CoA is fundamental to maximizing it and its bioproducts. To this end, competing pathways consuming malonyl-CoA can be eliminated, and optimal nutritional and environmental conditions can be provided to the fermentation broth. Most previous studies utilized genetic modifications, expensive consumables, and high-cost quantification methods, making …

Reproductive Parameters And Methodologies For The Culture Of Golden Topminnows (Fundulus Chrysotus) And Bluenose Shiners (Pteronotropis Welaka), Jacob A. Fetterman

LSU Master's Theses

The global ornamental fish trade has expanded over the past 20 years, requiring captive rearing methods to be improved or developed for species of interest. Aquaculture of desirable species is preferable over wild harvest to conserve natural habitats and biodiversity. This thesis focused on improving culture methods for Golden Topminnows Fundulus chrysotus and developing culture methods for Bluenose Shiners Pteronotropis welaka, both native fishes of the southeastern United States with ornamental demand. A combination of reproductive metric analyses, examination of historical collections, and captive spawning trials were employed to target specific objectives for each species. In female Golden Topminnows, …

Smoothing Parameters For Recursive Kernel Density Estimators Under Censoring, Yousri Slaoui

Communications on Stochastic Analysis

No abstract provided.

Spectral Theorem Approach To The Characteristic Function Of Quantum Observables, Andreas Boukas, Philip J. Feinsilver

Communications on Stochastic Analysis

No abstract provided.

Strong Convergence Rate In Averaging Principle For The Heat Equation Driven By A General Stochastic Measure, Vadym Radchenko

Communications on Stochastic Analysis

No abstract provided.

A Limiting Process To Invert The Gauss-Radon Transform, Jeremy J. Becnel

Communications on Stochastic Analysis

No abstract provided.

Increasing C-Additive Processes, Nadjib Bouzar

Communications on Stochastic Analysis

No abstract provided.

Long-Term Dust Formation By Core Collapse Supernovae, Kelsie Marie Krafton

LSU Doctoral Dissertations

Studying long-term dust formation by CCSNe is an important step toward understanding the large dust masses found in early galaxies. The amazing new discovery of approximately a solar mass of cold dust in the ejecta of SN 1987A has caused a complete re-evaluation of dust formation in core collapse supernovae (CCSNe). CCSNe form only a small amount of dust after three years, but SN 1987A has a dust mass that is several orders of magnitude larger after 25 years. A recent study of SN 2010jl by Gall et al. (2014) made the fascinating suggestion that dust is continuously forming in …

Determination Of Scatter Fractions, Albedos, And Tenth Value Layers For Shielding Of Synchrotron Beamline Hutches, Bethany Lynn Broekhoven

LSU Master's Theses

Synchrotron facilities require substantial amounts of shielding to protect facility staff and researchers. To meet mandatory exposure limits, the traditional combination of time, distance, and shielding of the radiation source are utilized. Because of continuous 24-7 operation of most synchrotrons, time is the least useful tool. The experimental stations for synchrotron x-ray beamlines, called hutches, enforce a minimum distance from the source, but shielding provided by hutch walls is still the principal tool for a synchrotron facility. Currently there is no single resource for synchrotron beamline hutch shielding design in the literature; most hutch shielding is designed through either over-simplified …

Chemical Approaches For Nanofabrication Based On Colloidal Lithography With Organosilanes, Nanoparticles And Nickel Films: The Role Of Water In Directing Surface Self-Assembly, Neepa Malsi Kumari Kuruppu Arachchige

LSU Doctoral Dissertations

The capabilities for accomplishing fundamental surface studies with molecular systems are demonstrated in this dissertation using measurement and imaging modes of scanning probe microscopy. Model systems were chosen for investigations of surface self-assembly mechanisms, with an emphasis on understanding the role of interfacial water in surface reactivity. A key strategy for molecular level studies was to prepare nanostructures using protocols with colloidal lithography and scanning probe-based lithography (SPL). Nanofabricated samples were characterized ex situ with contact and tapping-mode atomic force microscopy (AFM) after key reaction steps, providing direct views of changes in surface morphology at the nanoscale. Magnetic sample modulation …

Mobile Music Development Tools For Creative Coders, Daniel Stuart Holmes

LSU Doctoral Dissertations

This project is a body of work that facilitates the creation of musical mobile artworks. The project includes a code toolkit that enhances and simplifies the development of mobile music iOS applications, a flexible notation system designed for mobile musical interactions, and example apps and scored compositions to demonstrate the toolkit and notation system.

The code library is designed to simplify the technical aspect of user-centered design and development with a more direct connection between concept and deliverable. This sim- plification addresses learning problems (such as motivation, self-efficacy, and self-perceived understanding) by bridging the gap between idea and functional prototype …

A New Magnetic Topological Quantum Material Candidate By Design, Weiwei Xie, Xin Gui

Faculty Publications

Magnetism, when combined with an unconventional electronic band structure, can give rise to forefront electronic properties such as the quantum anomalous Hall effect, axion electrodynamics, and Majorana fermions. Here we report the characterization of high-quality crystals of EuSn2P2, a new quantum material specifically designed to engender unconventional electronic states plus magnetism. EuSn2P2 has a layered, Bi2Te3-type structure. Ferromagnetic interactions dominate the Curie-Weiss susceptibility, but a transition to antiferromagnetic ordering occurs near 30 K. Neutron diffraction reveals that this is due to two-dimensional ferromagnetic spin alignment within individual Eu layers and antiferromagnetic alignment between layers-this magnetic state surrounds the Sn-P layers …

Geometric Problems In Robot Exploration, Wyatt Preston Clements

LSU Doctoral Dissertations

Robots are increasingly utilized to perform tasks in today's world. This has varied from vacuuming to building advanced structures. With robots being used for tasks such as these, new challenges are introduced. Problems that have been previously researched to be performed, either theoretically or implemented, need to be redesigned to be able to better handle these challenges. In this thesis, I will discuss multiple problems that have previously been researched and I have redesigned to be possible to be implemented by robots or that I have developed a new way for the robots to solve the problem. I focus on …

Nonlinear Optical Studies Of Bulk And Thin Film Complex Materials, Joel E. Taylor

LSU Doctoral Dissertations

Nonlinear optical studies of bulk and thin film materials provide a vast playground for physical and dynamical characterization. In this thesis, we have implemented experimental methods to probe novel phase transitions in single crystals using rotational anisotropic second harmonic generation (RASHG) and carrier dynamics in thin films with time-resolved pump-probe reflectivity. Furthermore, a novel low temperature ultra-high vacuum system coupled to nonlinear optics has been developed to extend lab capabilities. Doping (Bi_1-xSb_x)₂Se₃ with antimony, the surface electronic reconstruction near x=80% was identified with RASHG by deviations in the six-fold and three-fold polarization anisotropic …

Numerical Modeling Of Wave Dynamics And Sediment Transport Near The Mississippi Birdfoot Delta And Barataria Estuary, Soroush Sorourian

LSU Doctoral Dissertations

The Barataria Basin is a large estuarine system in Southeastern Louisiana, connected to the Gulf of Mexico through a number of inlets, the most important of which is the Barataria Pass. This research examines, during April-June 2010 including both cold front passage and calm summer-time wind regimes, the wave dynamics in this basin and in its major inlets, morphological evolution near the Barataria Pass, and the budgeting and dispersal of the Mississippi River sediment in the birdfoot delta region. An unstructured grid, terrain following, high resolution coupled FVCOM-SWAVE-SED model is employed and validated in this study. The numerical model results …

Photo-Physical Properties Of Novel Gumbos For Optoelectronic Applications, Thenahandi Prasanthi Deepthika De Silva

LSU Doctoral Dissertations

Organic Light Emitting Diodes (OLEDs) are predicted to revolutionize next generation consumer electronics by offering many advantageous device characteristics, including low power consumption, low heat dissipation, a tunable and wider color gamut, high resolution and contrast, light weight, flexibility, and semi-transparency. However, a major limiting factor for OLEDs to reach their full potential is that only a few known blue OLED emitters with substantial spectral purity and longevity are available to date. Therefore, focus of this research is on understanding and addressing limitations of OLED emitters, with an emphasis on improving the characteristics of blue emitters.

The work presented in …

Floodwater Impact On Galveston Bay Phytoplankton Taxonomy, Pigment Composition And Photo-Physiological State Following Hurricane Harvey From Field And Ocean Color (Sentinel-3a Olci) Observations, Eurico D'Sa

Faculty Publications

Phytoplankton taxonomy, pigment composition and photo-physiological state were studied in Galveston Bay (GB), Texas (USA), following the extreme flooding associated with Hurricane Harvey (25-29 August 2017) using field and satellite ocean color observations. The percentage of chlorophyll a (Chl a) in different phytoplankton groups was determined from a semi-analytical IOP (inherent optical property) inversion algorithm. The IOP inversion algorithm revealed the dominance of freshwater species (diatom, cyanobacteria and green algae) in the bay following the hurricane passage (29 September 2017) under low salinity conditions associated with the discharge of floodwaters into GB. Two months after the hurricane (29-30 October 2017), …

Application Of X-Ray Grating Interferometry To Polymer/Flame Retardant Blends In Additive Manufacturing, Omoefe Joy Kio

LSU Doctoral Dissertations

X-ray grating interferometry is a nondestructive tool for visualizing the internal structures of samples. Image contrast can be generated from the absorption of X-rays, the change in phase of the beam and small-angle X-ray scattering (dark-field). The attenuation and differential phase data obtained complement each other to give the internal composition of a material and large-scale structural information. The dark-field signal reveals sub-pixel structural detail usually invisible to the attenuation and phase probe, with the potential to highlight size distribution detail in a fashion faster than conventional small-angle scattering techniques. This work applies X-ray grating interferometry to the study of …

Framework For Algorithmically Optimizing Longitudinal Health Outcomes: Examples In Cancer Radiotherapy And Occupational Radiation Protection, Lydia Joyce Wilson

LSU Doctoral Dissertations

Background: Advancements in the treatment of non-infectious disease have enabled survival rates to steadily increase in recent decades (e.g., diabetes, heart disease, and cancer). Epidemiological studies have revealed that the treatments for these diseases can have life-threatening and/or life–altering effects. Thus, realizing the full beneficial potential of advanced treatments necessitates new tools to algorithmically consider all major components of the health outcome, including benefit and detriment. The goal of this dissertation was to develop a framework for improving projected health outcomes following planned radiation exposures in consideration of all beneficial and detrimental, early and late, and fatal and non-fatal …

Spatial Variations In Chlorophyll A, C, N, And P In A Louisiana Estuary From 1994 To 2016, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee

Faculty Publications

Intense sampling of an estuary can reveal relative spatial changes that are significant irrespective of whether or not the estuary is eutrophic, micro- or meso-tidal, disturbed, or restored. This waterscape' perspective is analogous to a landscape perspective. We collected monthly water samples in the Barataria Basin watershed from 1994 to 2016 at 37 stations along a 129km transect from 1km offshore to a freshwater stream. The average Chlorophyll a (Chl) concentration from 267 trips was supported from both nitrogen-fixing cyanobacteria in a freshwater lake and partially from nutrients in seaward sources. Estuarine salinity was correlated with the discharge of the …

An Objective Procedure For Delineating The Circumpolar Vortex, Nazla Bushra, Robert V. Rohli

Faculty Publications

The broad-scale, steering atmospheric circulation in the Northern Hemisphere, represented by the tropospheric circumpolar vortex (CPV), is an important driver of environmental processes. The area and circularity of the CPV are analyzed hereby delineating the leading edge of the CPV at the steepest 500-hPa geopotential height gradient globally. The daily CPV area and circularity were aggregated to monthly averages for contrast with measurements identified in previous research for the overlapping period of record (1979-2001). Accuracy of representation of the CPV is assessed through correlations to air-sea teleconnections known to be associated with broad-scale, extratropical steering circulation. Correlation to monthly teleconnection …

Plant-Based Crosslinked Polymers, Jackie Davies

Honors Theses

No abstract provided.

Building A Better Batture: A Regional Recreational Enhancement Around The Morganza To The Gulf Levee, Taylor N. Fehmel

LSU Master's Theses

Twenty-five years ago, the existing flood protection levees along the Louisiana coastline were removed and construction was started by Terrebonne Levee and Conservation District on a new project called ‘Morganza to the Gulf’ or MTG. This project was undertaken to construct a new flood protection levee system around Louisiana in the communities in Terrebonne and Lafourche Parish. The MTG Levee is one of the first coastal projects in Louisiana to incorporate a risk-based analysis for a double levee system containing both local parish drainage levees and future storm surge levees of MTG. It was designed to protect approximately 250,000 people …

Evaluation Of Ventilation Assistance For Improving Respiratory Reproducibility In Radiation Therapy, Cameron J. Sprowls

LSU Master's Theses

Background: Respiratory motion affects all tumor sites in the thorax and abdomen. Variations of the respiratory pattern cause variations of the tumor motion which can result in differences between the planned and delivered dose distributions. Previous breathing guidance techniques have been investigated to improve respiratory reproducibility; however, ventilation assistance has not been investigated. We evaluated using bi-level positive airway pressure (BIPAP) ventilation assistance for improving respiratory reproducibility in patients with tumor sites impacted by respiratory motion.

Methods: Written informed consent was obtained for 10 patients currently undergoing radiation therapy treatment. Patients participated in sessions over their course of treatment, which …

Exploring New Fe-Substituted Rare-Earth-Based High Entropy Alloys, Glendon Rewerts

Honors Theses

No abstract provided.

Accuracy Of Personalized 3-D Printed Phantoms For Radiotherapy Applications, Margaret Carey

Honors Theses

No abstract provided.

Sedimentary Budget Of The Northwest Sub-Basin, South China Sea: Controlling Factors And Geological Implications, Peter D. Clift

Faculty Publications

We calculated the sedimentary budget of the Northwest Sub-basin (NWSB), South China Sea for different geological times based on interpretations of four multichannel seismic profiles across the basin with constraints from International Ocean Discovery Program (IODP) Expeditions 367 and 368 drilling results. Sedimentation was generally dominated by regional tectonic events and climate change, but complicated by local tectonic events and geographic position, which resulted in a specific sedimentary budget in the NWSB compared with other marginal basins and the Southwest Sub-basin. The sedimentation rate was relatively low following the opening of the NWSB but increased gradually during the Middle Miocene, …

Differentiation Of Surface Water And Groundwater In A Karst System Using Anthropogenic Signatures, Joe Honings

Faculty Publications

Surface water-groundwater interaction within a karstic system enhances contaminant transport, making karst aquifers susceptible to anthropogenic practices. Contaminated waters related to agricultural and animal husbandry in northwestern Illinois (USA) prompted this investigation. Six streams and five springs were sampled for 16 parameters to assess anthropogenic influences. Statistical analyses revealed differences in 13 of 16 parameters between the stream and spring waters. Rock-water interaction was identified as the dominant mechanism defining the chemistry for both waters, which were classified as Ca-Mg HCO3. Elevated nitrate as nitrogen (NO3-N), chloride (Cl-), sodium, and potassium concentrations indicate that human activities have influenced the quality …

Salt Marsh Restoration In Louisiana: An Analysis Of Litter Decomposition, Joseph Winston

Honors Theses

No abstract provided.

Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf, Byron Ebner

LSU Master's Theses

Dissolved silica (DSi), plays an important role in regulating primary productivity of silicifying organisms, such as diatoms which precipitate hard parts composed of biogenic silica (bSi) in coastal and shelf ecosystems fed by major rivers. In the Northern Gulf of Mexico (NGOM), loading of nitrogen and phosphorous have increased compared to a decline in DSi in the Mississippi River. Continued decreasing in DSi loading could lead to limited diatom growth and production or shifts in community composition, therefore, it is important understand the role of benthic fluxes in providing silica to the overlying water column as there are few regional …