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Polymer Based Microfabrication And Its Applications In Optical Mems And Biomems, Guocheng Shao Jan 2011

Polymer Based Microfabrication And Its Applications In Optical Mems And Biomems, Guocheng Shao

LSU Doctoral Dissertations

Due to its ease of fabrication, low cost and great variety of functionalities, polymer has become an important material in microfabrication. MEMS devices with polymer as the structure material have found applications in various fields, especially in BioMEMS and optical MEMS. In this dissertation, three polymer based microfabricated devices/components have been developed and tested. Various polymer based fabrication techniques, such as high aspect ratio SU-8 photolithography, three dimensional polydimethylsiloxane (PDMS) soft lithography, multi-layer soft lithography and PDMS double casting technique have been developed/studied and employed in the device fabrication process. The main contribution of this dissertation includes: (1) Developed two …

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Characterization Of Photon Counting Czt Detectors For Medical X-Ray Imaging And Spectroscopy, Shannon Fritz Jan 2011

Characterization Of Photon Counting Czt Detectors For Medical X-Ray Imaging And Spectroscopy, Shannon Fritz

LSU Doctoral Dissertations

Purpose: The purpose of this research was to characterize a photon counting cadmium zinc telluride (CZT) detector for medical x-ray imaging and spectroscopy purposes. The overall aim was to characterize CZT detector properties and to develop modifications and correction methods to address the limiting factors, making the detector clinically viable. Methods: Hole trapping issues were investigated through simulation and experiments with a large area single pixel CZT detector under three different irradiation geometries: edge-on, surface-on, and tilted angle irradiation. Characteristic x-ray escape was simulated using Monte Carlo methods and compared to measurements with a small pixel CZT imaging detector. Monoenergetic …

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Smoking Topography And Smoking-Related Outcome Expectancies In Smokers With Schizotypy, Diana Williams Stewart Jan 2011

Smoking Topography And Smoking-Related Outcome Expectancies In Smokers With Schizotypy, Diana Williams Stewart

LSU Doctoral Dissertations

Individuals with schizophrenia have extremely high smoking rates (70-88%). Compared to smokers in the general population, smokers with schizophrenia have more intense smoking patterns (e.g., more cigarettes per day; smoke stronger cigarettes; higher nicotine dependence, carbon monoxide (CO) boosts, cotinine, and nicotine levels; more extreme smoking topography) and more positive smoking outcome expectancies. However, the relationship between smoking and symptomatology is quite complex. Insight might be gleaned by studying the relationship between smoking and schizotypy, or the putative genetic vulnerability to developing schizophrenia, as it avoids many confounds associated with schizophrenia. This study investigated schizotypy symptoms, smoking characteristics and behaviors, …

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Thermodynamics Of Dna Binding And Break Repair By The Pol I Dna Polymerases From Escherichia Coli And Thermus Aquaticus, Yanling Yang Jan 2011

Thermodynamics Of Dna Binding And Break Repair By The Pol I Dna Polymerases From Escherichia Coli And Thermus Aquaticus, Yanling Yang

LSU Doctoral Dissertations

Klenow and Klentaq are the “large fragments” of the Pol I DNA polymerases from Escherichia coli and Thermus aquaticus. Examination of the DNA binding thermodynamics of both polymerases to replication versus repair substrates shows that Klenow binds primed-template DNA with up to 50X higher affinity than it binds to a nicked DNA, gapped DNAs, DNA with blunt-end or a 3’ overhang, while Klentaq binds all of these DNAs similarly. The presence of 5’ or 3’ phosphates has slightly different effects on DNA binding by both polymerases. In contrast, both polymerases bind mismatched DNA tighter than matched DNA, suggesting that they …

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Inhibition And Nucleic Acid Binding Studies Of The Carboxyltransferase Component Of Bacterial Acetyl-Coa Carboxylase, Brian Benson Jan 2011

Inhibition And Nucleic Acid Binding Studies Of The Carboxyltransferase Component Of Bacterial Acetyl-Coa Carboxylase, Brian Benson

LSU Doctoral Dissertations

Acetyl-CoA carboxylase is an essential enzyme, as it catalyzes the first committed and regulated step in fatty-acid biosynthesis in all organisms excepting few Archaea and Eubacteria. Acetyl-CoA carboxylase from gram-negative and gram-positive bacteria is a multifunctional enzyme composed of three separate proteins. The carboxyltransferase subunit catalyzes the transfer of a carboxyl group from carboxybiotin to acetyl-CoA, forming malonyl-CoA. The crystal structure of the Escherichia coli (E. coli) carboxyltransferase component of acetyl-CoA carboxylase revealed a unique Zn-domain, presumed to mediate nucleic acid binding, that is absent in the eukaryotic enzyme. Notably, the Zn-domain, adjacent to the active site of carboxyltransferase, makes …

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Production And Processing Of A Functional Yogurt Fortified With Microencapsulated Omega-3 And Vitamin E, Jose Daniel Estrada Andino Jan 2011

Production And Processing Of A Functional Yogurt Fortified With Microencapsulated Omega-3 And Vitamin E, Jose Daniel Estrada Andino

LSU Master's Theses

Market and nutritional values of fermented milks can be enhanced by adding microencapsulated polyunsaturated fish oil and vitamin E. Polyunsaturated fatty acids (PUFAs) lower the risk of heart disease and vitamin E is an important lipophilic antioxidant that protects cell membranes from oxidation. This study aimed to develop functional yogurts YMSO and YMMO fortified with á-tocopherol and microencapsulated salmon oil (MSO) or microencapsulated menhaden oil (MMO), respectively and to evaluate their physicochemical properties during 1-mo of storage. Stable emulsions were prepared with 7% red salmon oil (SO) or menhaden oil (MO), 22% arabic gum, 11% maltodextrin, 0.83% á-tocopherol and 59.17% …

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Simplicillium Lanosoniveum, A Mycoparasite Of Phakopsora Pachyrhizi And Its Use As A Biological Control Agent, Nicole A. Ward Jan 2011

Simplicillium Lanosoniveum, A Mycoparasite Of Phakopsora Pachyrhizi And Its Use As A Biological Control Agent, Nicole A. Ward

LSU Doctoral Dissertations

In 2007, a filamentous fungus was recovered from sori of soybean rust (SBR), caused by Phakopsora pachyrhizi, collected from Louisiana and Florida. This fungus was identified as Simplicillium lanosoniveum on the basis of ITS sequence data and morphological traits. Simplicillium lanosoniveum was found coiling within sori and around urediniospores and showed a trophic attraction to rust sori, extending from sorus to sorus. In co-inoculated soybean leaves, the fungus did not grow or establish on leaf surfaces until sori erupted. Similarly, S. lanosoniveum colonized within 3 days and sporulated within 4 days on leaves showing disease symptoms. In field studies, when …

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Effects Of Granivores And Herbivores On Pine Savanna Groundcover Vegetation, Ellen Ruth Leichty Jan 2011

Effects Of Granivores And Herbivores On Pine Savanna Groundcover Vegetation, Ellen Ruth Leichty

LSU Doctoral Dissertations

Pine savannas are an endangered ecosystem and cover <2% of their former range. Although often characterized by the presence of a single tree, P. palustris, the groundcover vegetation is extremely species rich. Thus, the groundcover vegetation is the focus of conservation efforts in pine savannas. This dissertation describes how fire, patches of shrubs, winter avian granivores, winter mammalian herbivores, and an introduced climbing fern (Lygodium japonicum) affect pine savanna groundcover. The fieldwork for this dissertation was done at Camp Whispering Pines, a pine savanna that has been undergoing restoration since 1990. Biennial, prescribed fires at the beginning of the growing season are a part of the habitat restoration. Although stem production of all groups of plants except bunchgrasses was stimulated by fire, annuals were found to respond most strongly to fire. Thus frequent fires appear to increase the presence of annuals in the groundcover of pine savannas. Pine savanna vegetation is interspersed with patches of shrubs. Along the margins of shrub patches there were more annual stems and fewer bunchgrass stems. Thus, shrubs appear to increase the heterogeneity of the groundcover. Pine savannas have a diverse group of avian granivores including some rare and endemic species. Avian granivores are probably selective in the seeds that they remove. Thus, they probably change the composition of the pool of seeds available to germinate. By removal of common species or large-seeded competitive dominants, avian granivores were predicted to increase the species richness of pine savanna groundcover vegetation. The White-tailed Deer (Odocoileus virginianus) and the Eastern Cottontail (Sylvilagus virginianus) are mammalian herbivores present at the study site. Mammalian herbivores often affect plant communities by removal of competitive dominants or selective removal of woody species. Mammalian herbivory was found to decrease the numbers of bunchgrasses, but did not affect other components of the plant community. In addition, bunchgrasses showed a large increase through the five seasons of data. There were, however, no subsequent changes as a result of this increase in stem numbers. Thus, bunchgrasses do not appear to competitively exclude other members of the species-rich groundcover community. Lygodium japonicum potentially threatens pine savanna groundcover. I evaluated how shrubs and fire affect its ability to invade pine savannas. Lygodium japonicum was found to occur in many more of the experimental plots along the margins of shrubs, and fire did not decrease its biomass. Presence of shrubs appears to facilitate invasion of pine savannas by L. japonicum, and fire is not an effective method of control.

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Role Of Substrate Moisture, Relative Humidity And Temperature On Survival And Foraging Behavior Of Formosan Subterranean Termites, Bal Krishna Gautam Jan 2011

Role Of Substrate Moisture, Relative Humidity And Temperature On Survival And Foraging Behavior Of Formosan Subterranean Termites, Bal Krishna Gautam

LSU Doctoral Dissertations

The Formosan subterranean termite is an important structural pest in the southern United States, especially Louisiana. Baiting systems and spot treatment with non-repellent delayed action termiticides are among the most eco-friendly control approaches. However, to achieve a desired success from these approaches requires a sophisticated knowledge of foraging behavior and food transfer system of these social insects. Moisture and temperature play a vital role in influencing the foraging behavior of these desiccation prone insects. A series of laboratory experiments were conducted to understand the subtleties of foraging behavior of Coptotermes formosanus Shiraki in relation to moisture, relative humidity and temperature. …

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Amino Acid-Supplemented Diets And Amino Acid Requirements In Corn And Soybean Meal Diets For Broilers And Pigs, April Marie Waguespack Jan 2011

Amino Acid-Supplemented Diets And Amino Acid Requirements In Corn And Soybean Meal Diets For Broilers And Pigs, April Marie Waguespack

LSU Doctoral Dissertations

The objectives of this research were to: 1) evaluate the role of Gly in low CP, AA supplemented diets for broilers, 2) determine subsequent effects of supplementing Gly in broiler diets, and 3) determine the Val and Ile requirement in an AA supplemented, C-SBM diet for 20- to 45-kg pigs. Three experiments were conducted to evaluate supplementation of Gly, creatine, GAA, and fishmeal in C-SBM diets on growth performance of broiler chicks and to determine if Gly, creatine, or GAA could be added to a C-SBM diet in place of fishmeal to produce similar growth performance. The results from these …

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Synthesis, Biological And Photophysical Studies Of Novel Compounds For Cancer Therapy, Edith Khavwajira Amuhaya Jan 2011

Synthesis, Biological And Photophysical Studies Of Novel Compounds For Cancer Therapy, Edith Khavwajira Amuhaya

LSU Doctoral Dissertations

Cancer remains the second most common cause of death in the United States. It is therefore imperative that a lot of effort be put into finding a cure for this dreadful disease that shows no discrimination, and virtually anybody is at risk of developing the disease. Chapter 1 introduces basic facts about cancer and the available treatments, including PDT and BNCT. Our focus will be on these two bimodal therapies, which form the basis of my research work, which involves the synthesis of potential sensitizers to be used either in PDT or BNCT or both. In Chapter 2, I discuss …

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Characterization Of Novel Akermanite:Poly-E-Caprolactone Scaffolds For Bone Tissue Engineering Aapplications Combined With Human Adipose-Derived Stem Cells, Andre S. Zanetti Jan 2011

Characterization Of Novel Akermanite:Poly-E-Caprolactone Scaffolds For Bone Tissue Engineering Aapplications Combined With Human Adipose-Derived Stem Cells, Andre S. Zanetti

LSU Doctoral Dissertations

The development of porous materials useful as scaffolds for the sustained three-dimensional (3D) growth of human adipose-derived stem cells (hASC) is of particular interest to facilitate healing after musculoskeletal injuries. In this study, a composite porous material obtained by blending akermanite with poly-e-caprolactone (PCL) is proposed as novel alternative to bone tissue regeneration. The objectives of this study are (1) to characterize the akermanite:PCL scaffold properties; (2) to investigate the in vitro osteogenic potential of hASC loaded to optimal akermanite:PCL scaffolds; (3) to assess the metabolic activity and osteogenesis of hASC loaded to optimal akermanite:PCL scaffolds post-thawing using optimal cryopreservation …

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Development And Application Of Serogroup-Independent And Serogroup-Specific Loop-Mediated Isothermal Amplification Assays For Detecting Shiga Toxin-Producing Escherichia Coli, Fei Wang Jan 2011

Development And Application Of Serogroup-Independent And Serogroup-Specific Loop-Mediated Isothermal Amplification Assays For Detecting Shiga Toxin-Producing Escherichia Coli, Fei Wang

LSU Doctoral Dissertations

Shiga toxin-producing Escherichia coli (STEC), encompassing E. coli O157:H7 and non-O157 STEC, is a significant cause of foodborne illnesses and deaths in the United States and worldwide. Shiga toxins (encoded by stx) and intimin (encoded by eae) are important virulence factors for STEC strains causing infection. Although E. coli O157:H7 remains to be the single most common STEC causing disease, the clinical importance of non-O157 STEC is on the rise worldwide. And six major serogroups (O26, O45, O103, O111, O121, and O145) accounted for over 70% of non-O157 STEC infections in the United States. Loop-mediated isothermal amplification (LAMP) is a …

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Arginine Metabolism In The Edwardsiella Ictaluri- Channel Catfish Macrophage Dynamic, Wes Arend Baumgartner Jan 2011

Arginine Metabolism In The Edwardsiella Ictaluri- Channel Catfish Macrophage Dynamic, Wes Arend Baumgartner

LSU Doctoral Dissertations

Edwardsiella ictaluri encodes a urease operon and an arginine decarboxylase (AdiA) that are required for virulence in head kidney derived macrophages (HKDM). The urease produces ammonia in amounts sufficient to alter environmental pH from acid to neutral. A hypothetical model was proposed, involving arginine metabolism in E. ictaluri infected HKDM, focusing on bacterial urease, AdiA, a second arginine decarboxylase (SpeA), and agmatinase (SpeB). Using fluorescence based ratiometric pH determination of E. ictaluri in live HKDM, it was shown that E. ictaluri modulates HKDM phagosome pH to above six. Urease and AdiA mutants failed to up-regulate vacuole pH, while vacuole pH …

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Crisis Management In Organizations: An Exploratory Study Of Factors That Affect Strategy Formation And Selection, Tulika Sinha Jan 2011

Crisis Management In Organizations: An Exploratory Study Of Factors That Affect Strategy Formation And Selection, Tulika Sinha

LSU Doctoral Dissertations

ABSTRACT This study investigated factors that influence the strategic decision-making process, specifically, strategy formation and selection during a crisis. It accomplished this by integrating theoretical concepts from both strategic management and crisis communication literature. Key organizational, environmental, and management factors--comprehensiveness, formalization, uncertainty, politicization, external corporate environment, crisis responsibility, impact of the crisis, stakeholder interests, and top management characteristics --were tested for their role in the strategy formation and selection process using regression analysis. This study used both quantitative and qualitative research methods. The quantitative aspect of the research involved conducting online surveys of senior management within the chemical industry and …

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Symptom Profiles And Rates Of Diagnosis In Autistic And Other Atypically Developing Infants And Toddlers, Timothy Michael Dempsey Jan 2011

Symptom Profiles And Rates Of Diagnosis In Autistic And Other Atypically Developing Infants And Toddlers, Timothy Michael Dempsey

LSU Doctoral Dissertations

Although there are many assessment scales that aid in the diagnosis of Autism Spectrum Disorders (ASD), very few instruments are designed specifically to identify the condition in the population of infants and toddlers. The primary purpose of this study is to systematically examine the differences between scores on the Baby and Infant Screen for Children with aUtIsm Traits (BISCUIT)-Part 1 in a sample of at risk atypically developing children. Participants are children enrolled in Louisiana’s EarlySteps Program, which provides support services (e.g., speech therapy, occupational therapy, physical therapy, behavior psychology) to infants/toddlers and their families from birth to 36 months …

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Comparative Proteome And Qpcr Analysis Of The Sugarcane Reaction To Leaf Scald Caused By Xanthomonas Albilineans, Freddy Fernando Garces-Obando Jan 2011

Comparative Proteome And Qpcr Analysis Of The Sugarcane Reaction To Leaf Scald Caused By Xanthomonas Albilineans, Freddy Fernando Garces-Obando

LSU Doctoral Dissertations

Leaf scald is an important disease of sugarcane caused by Xanthomonas albilineans (Xa). Leaf scald is controlled by the development and planting of resistant cultivars. However, erratic symptom expression makes conventional screening for resistance difficult. In addition, the mechanisms of resistance to leaf scald are not completely understood. Real-time, quantitative polymerase-chain-reaction (qPCR) assays were developed utilizing SYBR Green for a highly sensitive detection method or a TaqMan probe to quantify Xa populations in infected plants. Xa populations detected by qPCR followed similar trends to disease severity ratings and vascular infection results for two resistant and two susceptible cultivars under greenhouse …

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Fragmentation Sensitivity And Its Consequences On Demography And Host-Ectoparasite Dynamics In Amazonian Birds, Erik I. Johnson Jan 2011

Fragmentation Sensitivity And Its Consequences On Demography And Host-Ectoparasite Dynamics In Amazonian Birds, Erik I. Johnson

LSU Doctoral Dissertations

The Amazon rainforest is experiencing rapid deforestation due to ranching, agriculture, and urban development, which often leads to remnant patches serving as refugia for forest organisms. By mist-netting passerines in 11 forest fragments (1-, 10-, and 100-ha patches) and nearby continuous forest at the Biological Dynamics of Forest Fragmentation Project near Manaus, Brazil, I conducted a series of studies to identify mechanisms that drive population changes in fragmented landscapes. First, I examined the age structure of bird populations from six ecological guilds in fragments and continuous forest. Immatures are the dispersing age group in birds, and their relative abundance in …

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Implementation Of A Wireless Sensor Network With Ez430-Rf2500 Development Tools And Msp430fg4618/F2013 Experimenter Boards From Texas Instruments, Lu De Yang Jan 2011

Implementation Of A Wireless Sensor Network With Ez430-Rf2500 Development Tools And Msp430fg4618/F2013 Experimenter Boards From Texas Instruments, Lu De Yang

LSU Master's Theses

Wireless sensor networks have found a great deal of applications in diverse areas. Recent interest has been focused on low-power feature of the sensor nodes because the power consumption is always an issue for wireless sensor nodes which are supplied from the batteries. The eZ430RF2500 Development Tool and MSP430FG4618/F2013 Experimenter Board from Texas Instruments have integrated MSP430 family of ultralow-power microcontrollers and CC2500 low-power wireless RF transceivers which are suitable for low-power, low-cost wireless applications. In this thesis, the features of these TI devices are explored and a wireless sensor network is implemented with these devices. To implement the routing …

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Structure-Function Relationships In Poly(3-Hexylthiophene)S Formed Via Manipulation Of Oxidative Coupling Routes, Warren James Solfiell Jan 2011

Structure-Function Relationships In Poly(3-Hexylthiophene)S Formed Via Manipulation Of Oxidative Coupling Routes, Warren James Solfiell

LSU Doctoral Dissertations

This investigation focused on the analytical characterization of poly(3-hexylthiophene), a heterocyclic conducting polymer system, with an overall objective of elucidating the effects that the experimental conditions during chemical oxidation using iron(III) chloride as an oxidant impart on the structure of the resulting polymers. Poly(3-alkylthiophene)s are extensively studied materials due to their high electrical conductivities and unique optical properties that make them extremely valuable for use in contemporary technological applications and devices. Specifically, the aim of this research was to determine the dependence of structural characteristics, such as endgroups, molecular weights, and regioregularities, on the solvent employed for the reaction and …

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Quantitative Mapping Of Cyanobacterial Blooms Using Oceansat-1 Ocm Satellite Data, Padmanava Dash Jan 2011

Quantitative Mapping Of Cyanobacterial Blooms Using Oceansat-1 Ocm Satellite Data, Padmanava Dash

LSU Doctoral Dissertations

Cyanobacteria represent a major harmful algal group in fresh to brackish water environments. Lac des Allemands, a freshwater lake of 49 km2 southwest of New Orleans, Louisiana, provides a natural laboratory for remote characterization of cyanobacteria blooms because of their seasonal occurrence. This dissertation makes a contribution to research methodology pertaining to atmospheric correction of satellite data and development of remote sensing algorithms to quantify cyanobacterial pigments. The Ocean Color Monitor (OCM) sensor provides radiance measurements similar to Sea-viewing Wide Field-of-View Sensor (SeaWiFS) but with higher spatial resolution. However, OCM does not have a standard atmospheric correction procedure and …

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Spray Drying Technology For The Production And Processing Of Microencapsulated Omega-3 Fish Oil With Egg Powder, Kevin Estuardo Mis Solval Jan 2011

Spray Drying Technology For The Production And Processing Of Microencapsulated Omega-3 Fish Oil With Egg Powder, Kevin Estuardo Mis Solval

LSU Master's Theses

Protein with essential amino acids is required for recovering, repairing, and building muscles after intensive exercise. A powder produced with egg white (EW) (high quality protein) and fish oil (menhaden (Brevoortia patronus) (MO) oil or salmon oil (SO)) with high DHA and EPA content should be particularly beneficial for athletes. The objective of this study was to develop microencapsulated omega-3 fatty acids fortified EW powders. Two stable emulsions were prepared with 3.43% (MO) or (SO), 56.21% EW, and 40.36% water (E-MO-EW and E-SO-EW). An EW with water solution (without fish oil) (E-EW) was prepared as a control. Two emulsions (E-MO-EW; …

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Analysis Of Amyloid Beta (A [Beta]) Peptides By Capillary Electrophoresis And Laser-Induced Fluorescence Anisotropy Detection, Ryan Andrew Picou Jan 2011

Analysis Of Amyloid Beta (A [Beta]) Peptides By Capillary Electrophoresis And Laser-Induced Fluorescence Anisotropy Detection, Ryan Andrew Picou

LSU Doctoral Dissertations

The goal of the research presented in this dissertation is to develop laser-induced fluorescence anisotropy (LIFA) detection for detecting and characterizing amyloid beta (Aβ) peptide aggregates separated by capillary electrophoresis (CE). Senile plaques composed primarily of aggregated Aβ (1-40) and Aβ (1-42) peptides have been found in the brains of Alzheimer’s disease patients. These peptides are thought to be responsible for the disease pathology. A CE method using UV absorbance detection was developed for the quantification of Aβ (1-40) monomer and testing of Aβ monomer preparations for undesired aggregates (Chapter 2). Analyses of both Aβ (1-40) and Aβ (1-42) monomer …

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An Historical Study Of Teaching Biology To Science-Illiterate Students In Eighteenth-Century France: Instructional Strategies Employed By Madame Du Coudray - Royal Midwifery Educator, Trudy Lynn Gammill Witt Jan 2011

An Historical Study Of Teaching Biology To Science-Illiterate Students In Eighteenth-Century France: Instructional Strategies Employed By Madame Du Coudray - Royal Midwifery Educator, Trudy Lynn Gammill Witt

LSU Doctoral Dissertations

In August 1767 King Louis XV of France appointed Madame du Coudray, a 52-year-old midwife, to teach midwifery “throughout the whole extent of the Realm.” In so doing he acknowledged the “science and experience” and “high degree of perfection” that she had obtained in midwifery. Over the next 20 years Madame du Coudray traveled throughout France teaching midwifery to illiterate peasant women. It is estimated that she taught over 4,000 students. How did she teach midwifery to these women who had no previous experience with science? Could modern biology educators learn from her methods? This case study addressed these questions …

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La Ola Verde: Female, Hispanic Consumers And The Green Movement, Stefanie Ann Ramirez Jan 2011

La Ola Verde: Female, Hispanic Consumers And The Green Movement, Stefanie Ann Ramirez

LSU Master's Theses

Due to their impact on the environment, apparel companies have gradually begun to change manufacturing and production processes and provide consumers with environmentally responsible apparel product options. Among these consumers are Hispanics, a consumer group which research has shown to have a strong purchasing power and astounding population increase. Between 2000 and 2010, the total population in the United States increased by 23.7million people, with Hispanics accounting for over 50% of that total increase (Humes, Jones, & Ramirez, 2011). It is estimated that by 2125 Hispanics will account for 50% of the total U.S. population (Day, 1996). Additionally, between 1990 …

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Biochemical And Genetic Insights Into Asukamycin Biosynthesis, Zhe Rui Jan 2011

Biochemical And Genetic Insights Into Asukamycin Biosynthesis, Zhe Rui

LSU Doctoral Dissertations

Asukamycin, a member of the manumycin family metabolites, is an antimicrobial and potential antitumor agent isolated from Streptomyces nodosus subsp. asukaensis. The entire asukamycin biosynthetic gene cluster was cloned, assembled and expressed heterologously in Streptomyces lividans. Bioinformatic analysis and mutagenesis studies elucidated the biosynthetic pathway at the genetic and biochemical level. Four gene sets, asuA-D, govern the formation and assembly of the asukamycin building blocks, a 3-amino-4-hydroxybenzoic acid (3,4-AHBA) core component, a cyclohexane ring, two triene polyketide chains and a 2-amino-3-hydroxycyclopent-2-enone (C5N) moiety to form the intermediate protoasukamycin. AsuE1 and AsuE2 catalyze the conversion of protoasukamycin to 4-hydroxyprotoasukamycin, which is …

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Molecular Dynamics Simulation Studies Of Surface-Stress Effects In Metallic Nanostructures, Jijun Lao Jan 2011

Molecular Dynamics Simulation Studies Of Surface-Stress Effects In Metallic Nanostructures, Jijun Lao

LSU Doctoral Dissertations

Using molecular dynamics (MD) simulations we investigate the surface-stress-induced structural transformations and pseudoelastic behavior in palladium (Pd) crystalline nanowires. For a <100> initial crystal orientation our studies indicate that the surface stress can cause Pd nanowires to spontaneously undergo structural changes with characteristics that are determined by the wire cross-sectional area. Specifically, when the cross-sectional area is below 2.18nm x 2.18nm the wire changes spontaneously its crystal structure from the initial fcc structure to a body-centered-tetragonal (bct) structure. In wires of larger cross-sectional area (i.e., 2.57nm x 2.57nm) the structural transformation is achieved via a spontaneous lattice reorientation leading to an …

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Pharmacological And Non-Pharmacological Approaches To Prevent Hypertension-Induced Renal Disease In The Spontaneously Hypertensive Rate, Carrie Marie Elks Jan 2011

Pharmacological And Non-Pharmacological Approaches To Prevent Hypertension-Induced Renal Disease In The Spontaneously Hypertensive Rate, Carrie Marie Elks

LSU Doctoral Dissertations

Hypertension affects 50 million Americans and remains the second leading cause of renal failure in the United States. Current pharmacological and non-pharmacological approaches to treat hypertension have proven effective, but the complexities of the disease and its renal effects warrant the need for new treatments. The hypothesis of this dissertation was that pharmacological or non-pharmacological approaches to reducing inflammation and oxidative stress would prevent hypertension-induced renal injury in the spontaneously hypertensive rat (SHR). In the first study, we blocked the inflammatory transcription factor, nuclear factor-kappa B (NF-ĸB), with pyrrolidine dithiocarbamate in the SHR kidney. In treated SHR, blood pressure decreased, …

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Ecology And Chemical Ecology Of Plant-Insect Interactions In Rice: Implications For Pest Management, Jason Charles Hamm Jan 2011

Ecology And Chemical Ecology Of Plant-Insect Interactions In Rice: Implications For Pest Management, Jason Charles Hamm

LSU Doctoral Dissertations

Induced resistance to the rice water weevil, Lissorhoptrus oryzophilus, was assessed in greenhouse and field experiments. The fall armyworm,Spodoptera frugiperda, and an elicitor, jasmonic acid, were used to induce resistance. The effect of these treatments on rice resistance to oviposition varied between cultivar used, but significantly fewer larvae were found on plants exposed to S. frugiperda and jasmonic acid on both cultivars tested. Application of jasmonic acid significantly reduced the number of L. oryzophilus larvae per plant, and represents the first example of elicitor-induced resistance in rice in field experiments. Oviposition by the sugarcane borer, Diatraea saccharalis, induced resistance to …

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Hmo2, A Yeast Hmgb Protein That Preferentially Binds To Dna Ends, Sreerupa Ray Jan 2011

Hmo2, A Yeast Hmgb Protein That Preferentially Binds To Dna Ends, Sreerupa Ray

LSU Doctoral Dissertations

DNA damage is a common hazard that all cells have to combat. Saccharomyces cerevisiae HMO2 is a high mobility group protein (HMGB) that is a component of the chromatin remodeling complex INO80, which is involved in double strand break repair. I show here using DNA end-joining and exonuclease protection assays that HMO2 binds preferentially to DNA ends. While HMO2 binds DNA with both blunt and cohesive ends, the sequence of a single stranded overhang significantly affects binding, supporting the conclusion that HMO2 recognizes features at DNA ends. Analysis of the effect of duplex length on the ability of HMO2 to …

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