Digital Commons Network^™

Transgenic Control Of Aflatoxin Contamination In Maize Through Host-Induced Gene Silencing Targeting Aspergillus Flavus Genes Encoding Polygalacturonase (P2c) And Versicolorin Dehydrogenase (Aflm), Yenjit Raruang

LSU Doctoral Dissertations

Maize (Zea mays L.) is susceptible to Aspergillus flavus infection and subsequent contamination with aflatoxins, the most potent naturally produced carcinogenic secondary metabolites. Here, the A. flavus gene aflM encoding the versicolorin dehydrogenase in aflatoxin biosynthesis and the p2c gene encoding the polygalacturonase that is involved in infection were selected as targets for suppression through host induced gene silencing (HIGS). A HIGS vector targeting these genes was constructed and introduced into immature B104 maize embryos. Thirteen out of fifteen p2c transformation events and six out of seven aflM events were confirmed positive by PCR. Kernels containing the p2c gene …

Shortest Path Calculation Using Contraction Hierarchy Graph Algorithms On Nvidia Gpus, Roozbeh Karimi

LSU Doctoral Dissertations

PHAST is to date one of the fastest algorithms for performing single source shortest path (SSSP) queries on road-network graphs. PHAST operates on graphs produced in part using Geisberger's contraction hierarchy (CH) algorithm. Producing these graphs is time consuming, limiting PHAST's usefulness when graphs are not available in advance. CH iteratively assigns scores to nodes, contracts (removes) the highest-scoring node, and adds shortcut edges to preserve distances. Iteration stops when only one node remains. Scoring and contraction rely on a witness path search (WPS) of nearby nodes. Little work has been reported on parallel and especially GPU CH algorithms. This …

Casimir Effect In Free Fall Towards A Schwarzschild Black Hole, Francesco Sorge, Justin H. Wilson

Faculty Publications

In this paper we discuss the Casimir effect in a small cavity, freely falling from spatial infinity in spacetime geometry outside of a Schwarzschild black hole. Our main goal is to search for possible changes in the vacuum energy, as well as particle creation inside the falling cavity, with respect to a comoving observer. Working in the Lemaître chart and assuming a cavity size L much smaller than the Schwarzschild radius (L/rg1), we solve the Klein-Gordon equation for a massless scalar field confined within the cavity in the reference frame of the comoving observer. We follow Schwinger's proper time approach, …

Consequences Of Magnetic Ordering In Chiral M N1/3nb S2, Sunil K. Karna, F. N. Womack, R. Chapai, D. P. Young, M. Marshall, Weiwei Xie, D. Graf, Yan Wu, Huibo Cao, L. Debeer-Schmitt, P. W. Adams, R. Jin, J. F. Ditusa

Faculty Publications

We have investigated the structural, magnetic, thermodynamic, and charge-transport properties of Mn1/3NbS2 single crystals through x-ray and neutron diffraction, magnetization, specific heat, magnetoresistance, and Hall-effect measurements. Mn1/3NbS2 displays a magnetic transition at TC∼45K with highly anisotropic behavior expected for a hexagonal-structured material. Below TC, neutron diffraction reveals increased scattering near the structural Bragg peaks having a wider Q dependence along the c axis than the nuclear Bragg peaks. This indicates either a short-range ferromagnetic (FM) order with a domain size of ∼250 nm along the c axis or a possible magnetic modulation with a large pitch length. The expectation of …

Characterisation Of Ashes From Waste Biomass Power Plants And Phosphorus Recovery, Lijian Leng, Anna A. Bogush, Amitava Roy, Julia A. Stegemann

Faculty Publications

Biowastes, such as meat and bone meal (MBM), and poultry litter (PL), are used as energy sources for industrial combustion in the UK. However, the biomass ashes remaining after combustion, which contain nutrients such as phosphorus, are landfilled rather than utilised. To promote their utilisation, biomass ashes from industries were characterised in terms of their elemental and mineral compositions, phosphorus extractability, and pH-dependent leachability. These ashes were highly alkaline (pH as high as 13), and rich in calcium and phosphorus. The P bio-availabilities in the ash evaluated by Olsen's extraction were low. Hydroxyapatite and potassium sodium calcium phosphate were identified …

Characterisation Of Ashes From Waste Biomass Power Plants And Phosphorus Recovery, Lijian Leng, Anna A. Bogush, Amitava Roy, Julia A. Stegemann

Faculty Publications

Biowastes, such as meat and bone meal (MBM), and poultry litter (PL), are used as energy sources for industrial combustion in the UK. However, the biomass ashes remaining after combustion, which contain nutrients such as phosphorus, are landfilled rather than utilised. To promote their utilisation, biomass ashes from industries were characterised in terms of their elemental and mineral compositions, phosphorus extractability, and pH-dependent leachability. These ashes were highly alkaline (pH as high as 13), and rich in calcium and phosphorus. The P bio-availabilities in the ash evaluated by Olsen's extraction were low. Hydroxyapatite and potassium sodium calcium phosphate were identified …

Evaluation Of The Rheological Behaviors And Molecular Composition Properties Of Crumb Rubber Modified Emulsion For Chip Seal, Md Tanvir Ahmed Sarkar

LSU Master's Theses

An experimental study was conducted to characterize the chemical, molecular, and rheological properties of different asphalt emulsions including a newly introduced tire rubber modified asphalt emulsion. One tire rubber modified asphalt emulsion (CRS-2TR), two conventional emulsions (CRS-2 and CRS-2P), and one asphalt rubber binder (AC20-5TR) were evaluated. The differences in functional groups, chemical composition, and molecular weight distribution of the asphalt binder and emulsions under different aging conditions (Original, RTFO-aged, and PAV-aged) were evaluated by the Saturates, Aromatics, Resins and Asphaltenes (SARA) fractionation test, High-Pressure Gel Permeation Chromatography (HP-GPC), and Fourier Transform Infrared Spectroscopy (FTIR) test, respectively. Superpave Performance Grade …

Combined Molecular Dynamics And Phase Field Simulation Of Crystal Melt Interfacial Properties And Microstructure Evolution During Rapid Solidification Of Ti-Ni Alloys, Sepideh Kavousi

LSU Doctoral Dissertations

Phase field method has become a popular tool to investigate the microstructure evolution during the solidification. Quantitative predictions using this method is still limited, and in this dissertation, we try to study this problem from different perspectives.

Most of the phase field models consider the solid-liquid interface to be in local equilibrium. Solidification during some manufacturing processes like selective laser melting, and electron beam additive manufacturing is rapid and far from equilibrium which can result in supersaturated solid solutions, segregation-free crystals, or metastable phases. Before obtaining any conclusions from the phase field simulations, we must know the answer for “which …

Searching For Galveztown: Employing Multiple Methodologies To Identify Features Of The Galveztown Settlement, Ashlee Taylor

LSU Master's Theses

Galveztown (1778-1806) was a Spanish fort and settlement located in southeastern Louisiana. This site was historically important as it provided protection for the city of New Orleans during a time of constantly shifting geopolitical environment. Today, this site is among the most important historical archaeological sites in Louisiana. Culturally, this site is significant as the descendants of the settlers still live within the Baton Rouge metropolitan area. Archaeologically, the site is significant due to the limited disturbance and lack of urban development at the location which has protected the archaeological record.

Galveztown is also one of the best documented Canary …

Effect Of Storage Temperature On The Survival Or Growth Of Listeria Monocytogenes On Whole And Fresh-Cut Produce, Juan F. Moreira Calix

LSU Master's Theses

Whole and fresh-cut produce are minimally processed and, therefore susceptible to microbial contamination. This study examined the survival or growth of Listeria monocytogenes on whole, and fresh-cut produce at different storage temperatures. Fresh fruits (cantaloupes, pears, pineapples, papayas, and watermelon) and vegetables (broccoli, cauliflower, lettuce, kale, and green bell peppers) were cut into 25 g pieces and were spot inoculated with 0.5 mL (8 Log CFU/mL) of Listeria monocytogenes. Inoculated fresh-cut samples were stored at 4°C or 13°C for 6 days. To represent the outer surface of the produce, cantaloupes and green bell pepper disks (20 cm2) were cut with …

Critical Field Behavior Of A Multiply Connected Superconductor In A Tilted Magnetic Field, F. N. Womack, P. W. Adams, J. M. Valles, G. Catelani

Faculty Publications

We report magnetotransport measurements of the critical field behavior of thin Al films deposited onto multiply connected substrates. The substrates were fabricated via a standard electrochemical process that produced a triangular array of 66-nm-diameter holes having a lattice constant of 100 nm. The critical field transition of the Al films was measured near Tc as a function of field orientation relative to the substrate normal. With the field oriented along the normal (θ=0), we observe reentrant superconductivity at a characteristic matching field Hm=0.22 T, corresponding to one flux quantum per hole. In tilted fields, the position H∗ of the reentrance …

Habitat Associations And Reproduction Of Fishes On The Northwestern Gulf Of Mexico Shelf Edge, Elizabeth Marie Keller

LSU Doctoral Dissertations

Several of the northwestern Gulf of Mexico (GOM) shelf-edge banks provide critical hard bottom habitat for coral and fish communities, supporting a wide diversity of ecologically and economically important species. These sites may be fish aggregation and spawning sites and provide important habitat for fish growth and reproduction. Already designated as habitat areas of particular concern, many of these banks are also under consideration for inclusion in the expansion of the Flower Garden Banks National Marine Sanctuary. This project aimed to gain a more comprehensive understanding of the communities and fish species on shelf-edge banks by way of gonad histology, …

An Investigation Of High-Speed Consolidation And Repair Of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding, David A. Hoskins

LSU Master's Theses

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming.

In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using …

Effect Of Biosurfactant And Biochar On Ecosystem Functions And Oil Remediation In Crude Oil Contaminated Wetland Soils, Zhuo Wei

LSU Doctoral Dissertations

Decontamination of oil spill from coastal wetland soils requires a delicate approach. Remediation strategies using biochar, biosurfactant, and nutrient additions have been proposed. However, there is little information on application of these with combination for treatment of crude oil-contaminated wetland soil. Therefore, incubation studies were carried out to investigate the impact of biochar and rhamnolipid (RL) biosurfactant along with nitrogen (N) application on petroleum hydrocarbon degradation in a Louisiana coastal saline marsh and their impacts on greenhouse gas (GHG) emission. Additionally, the toxicity of crude oil as well as remediation materials on coastal wetland ecosystem were assessed at three levels: …

Evaluation Of Metsulfuron-Methyl For Giant Salvinia (Salvinia Molesta) Control And Non-Target Species Sensitivity, William Prevost

LSU Master's Theses

The invasive aquatic fern giant salvinia (Salvinia molesta D.S. Mitchell) has been invading waterbodies across Louisiana and Texas since 1998. Recently, the non-aquatic herbicide metsulfuron-methyl was found to be highly efficacious against giant salvinia, but limited information is available on application techniques, use rates and concentrations, as well as its impact on non-target species. Therefore, a series of mesocosm experiments were conducted to further evaluate foliar and subsurface applications of metsulfuron against giant salvinia, as well as foliar applications of metsulfuron in combination with aquatic herbicides commonly used for giant salvinia control. When applied to the foliage of giant …

Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero

LSU Master's Theses

A provenance study of quartz arenites that stratigraphically are closely associated with major Ordovician K-bentonites has been conducted in order to further our understanding of the tectonic setting of eastern Laurentia during the Late Ordovician. Using laser ablation ICP-MS, detrital zircons separated from Ordovician sandstone samples in the southeastern Appalachian Mountains (Virginia to Alabama) were dated using U-Pb geochronology. Analytical results show three dominate age ranges for the zircons from these sandstones: ~440-490 Ma, ~900-1300 Ma, and ~1300-1500 Ma. In addition, some zircon ages grouped into older ranges of ~1600-1800 Ma, ~1800-1900 Ma, and ~2600-2800 Ma. Zircon ages from ~900-2800 …

Rice Response To Nitrogen Fertilization And Comparison Of Unmanned Aerial Systems And Active Crop Canopy Sensors Vegetative Index To Estimate Rice Yield Potential, Anna Coker

LSU Master's Theses

Nitrogen (N) fertilization is a key component in producing profitable, maximized rice grain yields because yield is directly affected by N fertilizer applications. Economical optimum N rate (EONR) is used to estimate where the N fertilization rate impacts rice grain yield but is still economically efficient. Three common response models, linear-plateau, quadratic-plateau, and quadratic models were used to determine the response of rice to N fertilizer to determine the optimum N fertilization rate. The objective of the first part of this study was to evaluate the models by assessing the coefficients of determination (R²), maximum rice grain yields …

Assessment Of Off-Bottom Oyster (Crassostrea Virginica) Aquaculture Techniques On Biofouling In The Northern Gulf Of Mexico, Ellis Chapman

LSU Master's Theses

Although off-bottom oyster aquaculture is a rising industry in the northern Gulf of Mexico, it is susceptible to biofouling, the accumulation of organisms on industry surfaces. Biofouling creates problems for commercial growers by increasing the costs of labor associated with biofouling management. The most used off-bottom production techniques involve aerial exposure. OysterGro™ 6-slot off-bottom oyster cages were used in this project to test aerial exposure frequency, antifouling coatings and bag position on mortality, growth rates, shell ratios and condition indices on four sites in the northern Gulf of Mexico. Aerial exposure of floating cages was performed in increments of once …

Thermal-Kinect Fusion Scanning System For Bodyshape Inpainting And Estimation Under Clothing, Sirazum Munira Tisha

LSU Master's Theses

In today's interactive world 3D body scanning is necessary in the field of making virtual avatar, apparel industry, physical health assessment and so on. 3D scanners that are used in this process are very costly and also requires subject to be nearly naked or wear a special tight fitting cloths. A cost effective 3D body scanning system which can estimate body parameters under clothing will be the best solution in this regard. In our experiment we build such a body scanning system by fusing Kinect depth sensor and a Thermal camera. Kinect can sense the depth of the subject and …

Sandy Dredge Pit Sedimentation – Characteristics And Processes In Caminada Borrow Area, Ship Shoal, Louisiana Shelf, Usa, Zehao Xue

LSU Master's Theses

Mississippi River Deltaic Plain’s barrier islands are undergoing rapid disintegration due to high rates of subsidence and a deficit in coastal sediment supply. To mitigate for barrier island land loss, Louisiana has implemented a restoration program that supplements coastal sediment deficits by introducing sand from outside of the active coastal system. Ship Shoal is an inner-shelf submarine shoal with large amounts of restoration quality sand that was dredged in 2013-2016 for the Caminada Headland Restoration Project in central Louisiana, USA.

Vibracore samples (1.5 - 3.5 m deep) collected in 2017 and 2018 in Caminada Borrow Area revealed new silts and …

Andrew T. Hatcher: Press, Public Information & Perception For A Nation In Transition Historical Content Analysis On The First African American To Serve As A White House Associate Press Secretary, Nayita Wilson

LSU Master's Theses

Andrew T. Hatcher rose to one of the highest positions in U.S. government when he became the first African American to serve as associate White House press secretary in 1960 under the administration of President John F. Kennedy and during the peak of the Civil Rights Movement. This is a historical content analysis that analyzes Hatcher’s role through primary sources, presidential archives, and select national, local, and minority newspapers.

The overarching purpose of this study was to ascertain Hatcher’s role as associate White House press secretary during civil rights. This study provides further insight into: 1) to what extent did …

The Effects Of Photographic Representations On Scores Of The Stroke And Aphasia Quality Of Life Scale-39 For People With Aphasia, Taylor Glorioso

LSU Master's Theses

Background: The Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) survey was designed explicitly for people with aphasia (PWA). Aphasia is an acquired language disorder that may affect comprehension, expression, reading, and writing deficits. Those with severe aphasia may not be able to read the questionnaire. The literature shows that high-context color photographs accompanying text may assist PWA improve their comprehension of questions. A previous study provided face validity for a set of high-context color photographic representations of the SAQOL-39 items. The present study aimed to determine whether these photographs would aid PWA to rate the SAQOL-39 with more …

Immune Gene Diversity And Populations Structure Of Reticulated Flatwoods Salamander (Ambystoma Bishopi), Steven Tyler Williams

LSU Master's Theses

Reticulated flatwoods salamander (Ambystoma bishopi) populations began decreasing dramatically in the late 1900s. Contemporary populations are small, isolated, and may be susceptible to inbreeding and reduced adaptive potential because of low genetic variation. Genetic variation at immune genes is especially important as it influences disease susceptibility and adaptation to emerging infectious pathogens, a central conservation concern for declining amphibians. Connectivity between isolated populations is also vital to maintain genetic diversity and avoid inbreeding. I collected tissue samples from across the extant range of this salamander to examine genetic variation and population structure in: immune genes broadly (immunome), the …

The Ties That Bind: The Meaning Of Attachment In State Constitutional Revision, 1820-1845, Allison J. Morvant

LSU Master's Theses

This thesis examines the changing conception of attachment in state constitutional conventions from 1820 – 1845. During the colonial and early national periods, attachment was defined primarily through property ownership. Accordingly, early state constitutions limited the rights of citizenship, namely suffrage, to free white men who possessed a freehold. Over time, in response to pressure from upwardly mobile white males, state constitutional conventions began to create a new political order based on an expanded definition of attachment: non-propertied white males could exhibit attachment and be granted citizenship through affection, civic virtue, and public duty.

Dynamics Of Trophoblast Differentiation In Peri-Implantation–Stage Human Embryos, Rachel C. West, Hao Ming, Deirdre M. Logsdon, Jiangwen Sun, Sandeep K. Rajput, Rebecca A. Kile, William B. Schoolcraft, R. Michael Roberts, Rebecca L. Krisher, Zongliang Jiang, Ye Yuan

Faculty Publications

© 2019 National Academy of Sciences. All rights reserved. Single-cell RNA sequencing of cells from cultured human blastocysts has enabled us to define the transcriptomic landscape of placental trophoblast (TB) that surrounds the epiblast and associated embryonic tissues during the enigmatic day 8 (D8) to D12 peri-implantation period before the villous placenta forms. We analyzed the transcriptomes of 3 early placental cell types, cytoTB (CTB), syncytioTB (STB), and migratoryTB (MTB), picked manually from cultured embryos dissociated with trypsin and were able to follow sublineages that emerged from proliferating CTB at the periphery of the conceptus. A unique form of CTB …

A Deda Family Membrane Protein Is Required For Burkholderia Thailandensis Colistin Resistance, Pradip R. Panta, Sujeet Kumar, Caroline F. Stafford, Caitlin E. Billiot, Martin V. Douglass, Carmen M. Herrera, M. Stephen Trent, William T. Doerrler

Faculty Publications

© Copyright © 2019 Panta, Kumar, Stafford, Billiot, Douglass, Herrera, Trent and Doerrler. Colistin is a “last resort” antibiotic for treatment of infections caused by some multidrug resistant Gram-negative bacterial pathogens. Resistance to colistin varies between bacterial species. Some Gram-negative bacteria such as Burkholderia spp. are intrinsically resistant to very high levels of colistin with minimal inhibitory concentrations (MIC) often above 0.5 mg/ml. We have previously shown DedA family proteins YqjA and YghB are conserved membrane transporters required for alkaline tolerance and resistance to several classes of dyes and antibiotics in Escherichia coli. Here, we show that a DedA family …

Organophilic, Superparamagnetic, And Reversibly Thermoresponsive Silica-Polypeptide Core-Shell Particles, Sibel Turksen-Selcuk, Cornelia Rosu, Alyssa Blake, Erick Soto-Cantu, Jianhong Qiu, Yan Wu, J. F. Ditusa, Amanda Steffens, Paul S. Russo

Faculty Publications

Particles with a superparamagnetic cobalt inner core, silica outer core, and covalently bound homopolypeptide shell were investigated under thermal and magnetic stimuli. The homopolypeptide was poly(ϵ-carbobenzyloxy-l-lysine), PCBL, which is known to exhibit a thermoreversible coil → helix transition when dissolved as a pure polymer in m-cresol. Tethering to a core particle did not prevent PCBL from undergoing this conformational transition, as confirmed by dynamic light scattering and optical rotation, but the transition was broadened compared to that of the untethered polymer. The Co@SiO2-PCBL hybrid particles retained the superparamagnetic properties of the cobalt inner nougat. Indeed, some response remains even after …

Influence Of Magnetism On Dirac Semimetallic Behavior In Nonstoichiometric Sr1-Ymn1-Zsb2 (Y∼0.07,Z∼0.02), Qiang Zhang, Satoshi Okamoto, Matthew B. Stone, Jinyu Liu, Yanglin Zhu, John Ditusa, Zhiqiang Mao, David Alan Tennant

Faculty Publications

Nonstoichiometric Sr1-yMn1-zSb2(y,z<0.1) is known to exhibit a coexistence of magnetic order and the nontrivial semimetallic behavior. In this paper, we report the magnetism and its strong coupling to the semimetallic behavior, by a combined use of inelastic neutron scattering (INS) and density functional theory (DFT). A phase separation consisting of a majority antiferromagentic phase and a minority ferromagnetic phase is proposed. We found a relatively large spin excitation gap ≈8.5meV at 5 K, and the interlayer magnetic exchange constant only 2.8% of the dominant intralayer magnetic interaction, evidencing a quasi-2D magnetism in Sr1-yMn1-zSb2. Using DFT, we find a strong influence of magnetic orders on the electronic band structure and the Dirac dispersions near the Fermi level along the Y-S direction in the presence of a ferromagnetic order. Furthermore, we demonstrate that the size of the ferromagnetic ordered moment is an effective strategy to tune Dirac/Weyl dispersions near the Fermi level. Our study unveils novel interplay between the magnetic order, ordered moment, and electronic band topology in Sr1-yMn1-zSb2 and opens pathways to control the relativistic band structure.

The Impact Of Experimentally-Induced Perceived Discrimination On Substance Use, Kimberlye Elise Dean

LSU Doctoral Dissertations

Substance use disorders (SUDs) are among the most debilitating psychiatric disorders. Although prevalence rates of SUDs are similar between White and Black adults, these groups experience differential treatment outcomes (e.g., Black adults with SUDs are more likely to report greater pre- and post-treatment substance use). Examining culture-specific correlates of racial differences in substance use is vital to improve understanding of the etiological and maintaining mechanisms of SUDs among Black adults. Perceived racial discrimination (PRD) is prospectively related to various substance use-related outcomes. Thus, some may use substances to alleviate psychological distress (e.g., anxiety) associated with PRD, which may over time …

Making Decision Adaptive To Price Uncertainty And Risk Preference: A New Decision-Making Model For Forest Management, Fan Zhang

LSU Doctoral Dissertations

While the forest grows, the price of timber fluctuates. Price uncertainty plays a key role in forestry due to the extended rotation length of growing trees. Like double sides of the same coin, risk preference and uncertainties should be considered together. This is because risk preference represents people’s attitude toward that uncertainty when making management decisions. Risk preference is especially an important issue for forest management because forests are exposed to substantial uncertainties during their long growing period. However, most existing relevant studies either simply overlook the risk preference issue or fail to consider it together with a practical forest …