Physical Sciences and Mathematics Commons^™

Reduction In Salt Deposition On Carbon Nano-Tube Immobilized Membrane During Desalination Via Membrane Distillation, Madihah Saud Humoud

Dissertations

As water scarcity increases globally under the stresses of increasing demand, aquifer depletion, and climate change, the market for efficient desalination technologies has grown rapidly to fill the void. One such developing technology, membrane distillation (MD), has found much interest in the scientific community. MD has also been powered by solar energy and waste heat resources because it can be operated at relatively low temperatures. Recent studies indicate that MD could potentially achieve the efficiencies of state-of-the-art mature thermal desalination technologies, although additional engineering and scientific challenges must first be overcome.

MD can be used to treat high salinity water …

Mitochondria Imaging And Targeted Cancer Treatment, Tinghan Zhao

Dissertations

Mitochondria are essential organelles as the site of respiration in eukaryotic cells and are involved in many crucial functions in cell life. Dysfunction of mitochondrial metabolism and irregular morphology have been frequently found in human cancers. The capability of imaging mitochondria as well as regulating their microenvironment is important both scientifically and clinically. Mitochondria penetrating peptides (MPPs), certain peptides that are composed of cationic and hydrophobic amino acids, are good candidates for mitochondria targeting. Herein, a novel MPP, D-argine-phenylalanine-D-argine-phenylalanine-D-argine-phenylalanine-NH₂ (rFrFrF), is conjugated with a rhodamine-based fluorescent chromophore (TAMRA). The TAMRA-rFrFrF probe exhibits advantageous properties for long-term mitochondria tracking of …

Hypervalent Iodine Compounds With Carboxylate And Tetrazolate Ligands, Avichal Vaish

Chemistry Theses and Dissertations

In modern organic chemistry, hypervalent (HV) iodine(III) compounds are frequently used as oxidizing agents but application of λ³-iodanes in polymer and material chemistry is still underexplored. This dissertation describes the preparation of dynamic and self-healing materials by employing ligand exchange reactions involving HV iodine(III) compounds of the type ArIL₂ (Ar = Aryl, L = ligand, e.g., carboxylate or (pseudo)halide). These compounds can undergo ligand exchange reactions in presence of nucleophiles (Nu^-) to form ArINu₂. Diacetoxyiodo benzene was successfully employed as a crosslinker to prepare dynamic and self-healing gels derived from carboxylate-containing polymers. Furthermore, …

Cell-Trappable Chemiluminescent Probes For Monitoring Hydrogen Sulfide In Living Cells, Briley Bezner

Chemistry Theses and Dissertations

Hydrogen sulfide (H2S) is an important biological signaling molecule that has been recognized alongside nitric oxide and carbon monoxide as being a small gasotransmitter that is enzymatically produced and impacts multiple physiological functions. To detect hydrogen sulfide, there has been a focus on developing fluorescent probes to target particular analytes; however, fluorescent probes lack sensitivity and depth penetration due to background autofluorescence and light scattering. Chemiluminescence does not require light excitation, which greatly reduces the amount of autofluorescence and photoactivation.

In order to detect hydrogen sulfide in living systems with high sensitivity, a series of sterically stabilized 1,2-dioxetane chemiluminescent reduction-reaction …

Evaluation Of The Mechanisms And Effectiveness Of Nano-Hydroxides, Wood And Dairy Manure-Derived Biochars To Remove Fluoride And Heavy Metals From Water, Anna Rose Wallace, Wenjie Sun Dr, Chunming Su Dr

Civil and Environmental Engineering Theses and Dissertations

The development of effective treatment processes for the removal contaminants, such as fluoride and heavy metals, from polluted water have been urgently needed due to serious environmental health and safety concerns. In this dissertation, a variety of materials including various (hydro)oxide nanomaterials, biochars and surface modified biochar were studied to evaluate their effectiveness and mechanism on removing fluoride or mixed heavy metals from water.

In the Chapter 2, this study investigated the adsorptive removal of fluoride from water using various (hydro)oxide nanomaterials, focusing on ferrihydrite, hydroxyapatite (HAP) and brucite, which have the potential to be used as sorbents for surface …

Polyarylenes: Synthesis And Characterization Towards Advanced Applications, Stephen Budy

Chemistry Theses and Dissertations

A series of semi-fluorinated and non-fluorinated Diels−Alder step-growth polyarylene polymers and co-polymers were synthesized via typical oil bath heating (days/weeks) and more rapid microwave-assisted polymerization (hours). The polymers were characterized by multi-nuclear (¹H, ¹³C, and ¹⁹F) NMR and ATR−FTIR spectroscopy, thermal analysis (TGA, DSC, and DMA), GPC, XRD, water contact analysis (WCA), and refractive index (RI) measurements. The NMR spectra indicated a mixture of para and meta conformations through the polymer backbone increasing to more para with greater fluorine content. Thermal gravimetric analysis revealed the fluorine-containing polyarylenes possessed the highest char yields at almost 80% at …

Greening Of Catalytic Processes Using First-Row Transition Metals For Atom Transfer Radical Addition And Transfer Hydrogenation, Gabrielle Pros

Electronic Theses and Dissertations

This work focused on “greening” catalytic processes, atom transfer radical addition (ATRA), which adds an alkyl halide across and alkene, and transfer hydrogenation/dehydrogenation, which reduces a carbonyl without needing direct H₂ gas. Part of “greening” of these processes is through using abundant first row metals, Cu and Ni for catalysis. One aim was to design new ligands which would be more active in these systems; the second was investigation of additives for catalyst regeneration to reduce the catalyst loading necessary for high yields.

The TPMA^* family was investigated in ATRA. Rate constants followed the expected trend, which increased …

C-Metalated Nitriles: Diastereoselective Alkylations And Arylations, Robert John Mycka

Electronic Theses and Dissertations

Development of an sp³ hybridized halogen-magnesium exchange route to Grignard reagents, chelation-controlled asymmetric induction of γ- and δ-hydroxynitriles as well as a diastereoselective arylation procedure for C-zincated nitriles have been explored. Sequential addition of i-PrMgCl and n-BuLi to 3- and 4-carbon iodoalcohols triggers a facile halogen-metal exchange to generate cyclic magnesium alkoxides capable of intercepting electrophiles to produce a diverse range of substituted alcohols. This work advances progress toward the synthesis of highly desirable chiral Grignard reagents.

Double deprotonation of γ- and δ-acyclic hydroxynitriles with i-PrMgCl effects highly diastereoselective alkylations via a singly-chelated magnesiated nitriles. …

Computational Studies And Design Of Pparγ And Glut1 Inhibitors, Suliman Almahmoud

Theses & Dissertations

The peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-dependent transcription factor of the nuclear receptor superfamily that controls the expression of a variety of genes involved in fatty acid metabolism, adipogenesis, and insulin sensitivity. PPARγ is a target for insulin-sensitizing drugs, and it plays a significant function in prostate cancer. PPARγ antagonists have anti-proliferative effects in a broad range of hematopoietic and epithelial cell lines. The ligand binding domain (LBD) of PPARγ is large and has orthosteric and allosteric binding sites. Several PPARγ-ligand co-crystal structures show two bound molecules, one to the orthosteric pocket and a second to the allosteric …

Performance Of Nitrogen As A Carrier Gas In Capillary Gas Chromatography Using A Thin Film Column, Brittany A. Handzo

Seton Hall University Dissertations and Theses (ETDs)

Gas chromatography (GC) is one of the most widely used analytical techniques for the separation and analysis of volatile compounds. Solids, liquids, and gases, organic and inorganic materials, and large molecular weight compounds can all be analyzed via this technique. Gas chromatographic separations are fast, accurate, and reliable. One of the reasons why these separations are so efficient is because of the carrier gas. The purpose of the carrier gas is to carry the injected sample through the column. It is known as the mobile phase and does not interact chemically with the sample. Common carrier gases include helium, hydrogen, …

High-Pressure Studies On The Transition From Red Phosphorus To Black Phosphorus, Heng Xiang

Electronic Thesis and Dissertation Repository

Black phosphorus (BP) is a promising material in many research fields. However, the transition process from amorphous red phosphorus (ARP) is elusive and hence hinders large scale synthesis and applications. This work describes the application of the high-pressure method to study the transition process from ARP to BP.

In this thesis, the following three objectives were achieved: (1) to understand the mechanism of the transition, (2) to facilitate the synthesis of BP by taking the advantage of less pure ARP, (3) to propose new methods of synthesizing BP-based materials, such as the moderately oxidized BP and the black phosphorus/ amorphous …

Devising A Scalable Synthesis To Probe The G-Protein Cell Receptor Signaling Pathway, Matthew Robert Medcalf

Arts & Sciences Electronic Theses and Dissertations

The G-protein coupled cell receptor signaling pathway is amongst the largest and most diverse class of cell-surface receptors in the body. Nearly 800 different genes encode for these cell membrane receptors which are responsible for mediating a variety of hormones, neurotransmitters, and sensory stimuli through the activation of intracellular G proteins. To date, roughly 34% of pharmaceuticals on the market target GPCR’s, but despite this fact, there are still many difficulties associated with targeting this family of receptors. The vast number of GPCR’s, disease states resulting from a dysregulation of multiple GPCR signaling pathways, and difficulties crystalizing and purifying the …

Sideromycin Pathway Elucidation: Insights Into Salmycin Biosynthesis, Transport Paradigms, And Drug Release, Gerry Sann Macaraeg Rivera

Arts & Sciences Electronic Theses and Dissertations

Antibiotic resistance is an increasing threat in today’s society. In order to overcome resistant bacteria, it is necessary to discover new drugs with novel mechanisms of action. This work focuses on the sideromycin pathway, encompassing the biosynthetic production, mechanism of entry and hydrolysis-mediated drug release. Sideromycins are an interesting approach to combat the rise of antibiotic resistance since they provide a different avenue that overcomes problems that arise when entering the cell. The dissertation is separated into distinct sections dealing with the various areas of interest in the sideromycin pathway, particularly for the sideromycin, salmycin, produced by Streptomyces violaceus. The …

Instrumentation For Dynamic Nuclear Polarization And Application Of Electron Decoupling For Electron Relaxation Measurement, Nicholas Howard Alaniva

Arts & Sciences Electronic Theses and Dissertations

Dynamic nuclear polarization nuclear magnetic resonance (DNP NMR) exploits internal electron spin and nuclear spin interactions to increase sensitivity and uncover valuable information regarding structure and dynamics of a system. To manipulate these interactions, instrumentation is developed to combine high-power microwave and radiofrequency irradiation with the ability to spin samples at the magic angle (MAS) at temperatures from 90 K to 4.2 K. Electron decoupling uses frequency-modulated microwaves to mitigate the electron-nuclear dipolar interaction, improving signal intensity and resolution in DNP NMR experiments. Electron decoupling is combined with short DNP periods to encode electron spin information in polarized nuclear signal. …

Zirconium Tetrachloride, Fundamental Chemistry And Nuclear Fuel Cycle, Rosendo Borjas Nevarez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zirconium alloys are used in the United States as cladding materials in nuclear reactors. The purification of Zr is of relevance due to the large amount of spent nuclear fuel produced every year (2,000 metric tons per year and rising), of which 25% corresponds to radioactive zirconium cladding. Through the recovery and reuse of Zr, estimated savings of $40 million per year are estimated due to the high cost of hafnium-free nuclear grade zirconium, and also due to the minimization of nuclear waste disposal requirements.

Several chemical approaches have been proposed for the recovery and purification of Zr. Historically, a …

The Retrospective Analysis Of Radionuclides In Banded Coral From The Bikini Atoll, Athena Marie Gallardo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nuclear weapons testing conducted within the Bikini Atoll in the Marshall Islands resulted in local fallout contamination, including long lived isotopes of plutonium (Pu) and uranium (U), within the surrounding environment. The Bikini lagoon provides a continuous source of Pu (239+240Pu) and U (236U) to the Pacific Basin. The rate at which these isotopes are flushed from the lagoon to the ocean is balanced by inputs from remobilization of lagoon sediments. This research will provide a basis for predicting future change in the solubility and export potential of Pu and U in lagoon sediments. This is important to better understand …

Development And Application Of Mass Spectrometry-Based Protein Footprinting In Structural Proteomics, Ming Cheng

Arts & Sciences Electronic Theses and Dissertations

Integral mass spectrometry (MS) has emerged as an important tool for protein structural characterization. It readouts are a broad range of structural information, including stoichiometry, interactions, conformations and conformation change, and dynamics. Protein footprinting is a pivotal component in the intergral MS toolkit.My dissertation centers around the development and application of protein footprinting to characterize protein structure. It is divided into seven chapters.Chapter 1 serves as the introduction for integral mass spectrometry in structural proteomic.In Chapter 2, we extended the fast-photochemical oxidation of proteins (FPOP) platform by adding the trifluoromethyl radical (•CF3) as a new reagent. We discovered that •CF3 …

Influence Of Biosolids Upon The Uptake Of Mn And Cd By Radish (Raphanus Sativus L.), Oluwadamilola O. Fateru

Electronic Theses and Dissertations

The influence of biosolids upon the uptake of Mn and Cd by radish (Raphanus sativus L.) was investigated through the characterization of biosolids, sequential extraction of the biosolids, and the determination of the metal content in the root, shoot and leaves of radish (Raphanus sativus L.).The biosolid samples from Nacogdoches Wastewater Sludge (NWWS), Lufkin Wastewater Sludge (LWWS), Soil Therapy Compost (STC) had pHs between 5.33 – 6.74. The elemental compositions of the biosolid samples were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES) and SEM/EDX. Major elements (K, Mg, Mn, P) needed for plant growth …

X-Ray Absorption Spectroscopy, X-Ray Diffraction And Optical Luminescence Studies Of Phase Transition Of Titania Nanotubes, Lu Yao

Electronic Thesis and Dissertation Repository

The one-dimensional (1D) TiO₂ nanotubes (NTs) and their derivatives have been extensively studied due to their wide applications, such as photocatalysts, solar cell, paints and so on. Since TiO₂ has a wide band gap (~3.0 eV), its photo-absorption as the photocatalyst only occurs in the UV region that wastes mostly solar energy. Therefore, the solution to higher photocatalytic efficiency has been sought for some time. This thesis presents a study of the size-dependent phase transitions of TiO₂ NTs using synchrotron-based X-ray techniques. The chemical environment including local symmetry and the luminescence origin of the TiO₂ NTs …

Influencing Factors On The Velocity And Temperature Of Propagating Fronts In Acrylate Composites, Samuel Morris Bynum

LSU Doctoral Dissertations

Thermal frontal polymerization is a type of polymerization in which a localized reaction zone propagates through an unstirred system. It is incumbent upon the production and transport of heat produced as a result of the exothermic reaction associated with free-radical polymerization. First discovered in the 1970s, frontal polymerization has been since utilized to produce a variety of different materials, utilizing a variety of different chemistries. The temperature of the propagating front and the velocity at which it propagates can be influenced via chemical or physical means. We show that through careful selection of monomers and control of the concentration of …

Electrochemical Investigation Into The External Failure Modes Of Oil And Gas Pipelines, Maxwell Goldman

Electronic Thesis and Dissertation Repository

Carbon steel is the material of choice for transmission pipelines for the oil and gas industry across the globe due to its mechanical properties, and low cost. Carbon steel is only resistffxidant, and the types of anions present in the exposure environment. Transmission pipelines are coated with non-conductive polymeric coatings and can be protected by cathodic protection in order to mitigate exterior corrosion. The primary goals of this thesis were to determine the role of anions, cathodic charging with hydrogen, and steel microstructure on different failure modes of carbon steel.

The corrosion mechanism of carbon steel in the presence of …

Analysis Of E-Cigarette Liquids And Aerosols By Nmr Spectroscopy: Compositions, Boiling Points, And Degradation Profiles, Anna Katherine Duell

Dissertations and Theses

Electronic cigarettes (e-cigarettes) are an increasingly popular tobacco product used by ~3% of adults and 21% of 12th grade students (as reported for the prior 30-days in surveys) in the United States in 2018. As of 2019, this number went up to ~25% for 12th grade students. Due to how quickly e-cigarettes gained popularity and the rapid design changes that have ensued, there has not been enough time to accurately assess the effects of e-cigarettes, particularly for long-term use. The liquids used in e-cigarettes (e-liquids) can degrade when vaped in an e-cigarette, so understanding the variables that can modulate degradation …

The Process Of Establishing Theoretically Grounded Measures Of Science And Chemistry Identity For Use In Undergraduate Chemistry Courses, Kathryn Nicole Hosbein

Dissertations and Theses

Identity has been theorized to aid in student persistence toward science, engineering, technology, and math (STEM) degrees. However, before we can explore the impacts of learning environments on identity, and subsequently persistence, robust measures that can aid in understanding how identity is fostered need to be available. This research study aims to create measures of identity by expanding an existing physics identity framework and contextualizing it to science and chemistry identities. Development of the measures was carried out through two distinct phases that provided evidence for reliability and multiple aspects of validity.

The first phase of the study used qualitative …

Characterization Of The Dimerization Domains On The Mannose-6-Phosphate/Insulin-Like Growth Factor Ii Receptor, Tyler Degener

Theses/Capstones/Creative Projects

The mannose-6-phosphate/insulin-like growth factor II (M6P/IGF2) receptor is a transmembrane protein known to sequester growth factors from the extracellular matrix. This behavior suggests a mechanism of tumor suppression. Structurally, the receptor’s extracellular region is segmented into 15 homologous repeats, which are divided further into 5 triplet domains, labelled 1-3, 4-6, 7-9, 10-12, and 13-15. What is notable about the triplets is their propensity to form dimers with triplets on a second M6P/IGF2 receptor. In fact, previous studies indicate that this protein functions optimally when dimerized. Thus, the purpose of this experiment is to characterize these domain interactions. Using a urea …

Alkalinity And Mineral Concentration Estimation In Commercial Drinking Water, Holly Mills

Honor’s College Freeman Research Journal

Several aspects of water and water quality were reviewed and investigated in this study; the effects of dehydration on human health, the role of alkalinity in drinking water, and the actual levels of alkalinity and other minerals in commercial drinking water. Hydration plays a critical role in human physical performance as well as in the prevention of chronic diseases. This experiment was conducted to determine if the level of acidity ( or alkalinity) of commercial alkaline water are truly above the normal ph levels, and to identify the salts in each type of water. Based on researches, a more alkaline …

Exploration Of Nucleic Acid Hydrogran Bonding Using Molecular Mechanics And Dft Calculations, Simi Kaur

Biological Sciences

Many recent theoretical and experimental techniques have been developed to probe the structurefunction relationships of complex biomolecules. The roles of RNAs are dependent upon various intricate structural motifs and interactions, including hairpins, pseudoknots, long range territory contacts, bulges and internal loops, that are not easily captured by these methods. We had previously developed an enhanced replica exchange molecular dynamics method that incorporated secondary structure information in the form of distance restraints in order to effectively overcome kinetic barriers and sample conformational space. In several structures, restrained RNA base pairs near large bulges displayed a preference for stacking over hydrogen bonding …

Synthesis And Study Of Hydroxytyrosol Derivatives, Ebenezer Ametsetor

Electronic Theses and Dissertations

Hydroxytyrosol is one of the most powerful known antioxidants. It is a naturally occurring polyphenol, most commonly produced in olive trees, (Olea europaea). The remarkable antioxidant and pharmacological properties of hydroxytyrosol has made it an outstanding compound in the polyphenol family and of great interest to many researchers. Hydroxytyrosol can scavenge free radicals produced during cellular oxidative stress and helps to protect the integrity of cells in living systems. Despite its numerous biological and pharmacological uses, it is found in very low concentration in olive oil, this limits its availability for biomedical applications. This work reports a novel and effective …

Preparation Of Folic Acid-Carbon Dots-Doxorubicin Nanoparticles As Targeting Tumor Theranostics, Samson Dada

Electronic Theses and Dissertations

Carbon dots (CDs) have attracted much attention as an excellent gene/drug delivery and biological imaging agent for early cancer theranostics. In this study, we prepared two series of nanoparticles (NPs), which are composed of (CDs) with a targeting agent, folic acid (FA), and a chemotherapeutic agent Doxorubicin (Dox). All the NPs and their intermediates were characterized using ultraviolet-visible spectroscopy (UV-vis), fluorescence spectroscopy, and Fourier transform-infrared spectroscopy (FT-IR). The drug loading capacity (DLC) and drug loading efficiency (DLE) of two series of FA-CDs-Dox were assessed using UV-vis absorption spectroscopy at the wavelength of 485 nm. Both showed good DLE and DLC …

The Antimicrobial Activity And Cellular Targets Of Plant Derived Aldehydes And Degradable Pro-Antimicrobial Networks In Pseudomonas Aeruginosa, Yetunde Adewunmi

Dissertations

Essential oils (EOs) are plant-derived products that have been long exploited for their antimicrobial activities in medicine, agriculture, and food preservation. EOs represent a promising alternative to conventional antibiotics due to the broad-range antimicrobial activity, low toxicity to human commensal bacteria, and the capacity to kill microorganisms without promoting resistance. Despite the progress in the understanding of the biological activity of EOs, many aspects of their mode of action remain inconclusive. The overarching aim of this work was to address these gaps by studying molecular interactions between antimicrobial plant aldehydes and the opportunistic human pathogen Pseudomonas aeruginosa. We initiated …

Adsorption Of Polyisobutylene-Based Dispersants Onto Carbon Black, Travis Paul Holbrook

Dissertations

The formation of carbonaceous by-products (e.g. soot) during the operation of an internal combustion engine is unavoidable and the aggregation of this soot leads to deleterious effects including abrasive wear of the engine, increased oil viscosities, and sludge deposition. Dispersants, which are composed of a hydrophobic tail and a polar headgroup, are used as oil additives to aid in the suspension and stabilization of the soot particles. Polyisobutylene succinimide (PIBSI) is the most well-studied class of dispersants and is characterized by a linear architecture and polyamine headgroup that interacts with soot by acid-base and dipole-dipole interactions. As such, there remains …