Physical Sciences and Mathematics Commons^™

Liquid Chromatography Mass Spectrometry Method Development For The Determination Of Β–Defensins In Bovine Milk, Elisha Ogbebor

Masters Theses & Specialist Projects

Bovine mastitis is caused by a wide range of pathogens which results in a substantial economic loss for the dairy cattle livestock industry. β-defensins are a part of the innate immune system and act as the first line of defense against mastitis in bovine. β-defensins (~6- 10kDa) are antimicrobial peptides that contain about 28 to 67 amino acids, the presence of six cysteine residues results in their three disulfide bonds and a β-sheet structure. A few β- defensins have been identified in cows based on the site of occurrence and time of expression in tissue, but not in milk. A …

Studies On Electrochemical Hydrogen Isotope Separation, Liyanage Mayura Sankalpa Silva

All Dissertations

Graphene-integrated Proton Exchange Membrane (PEM) electrochemical cells have emerged as a novel area of scientific investigation in the realm of hydrogen isotope separation. Chemical Vapor Deposited (CVD) graphene has been especially useful due to its large-scale production capability for scaling-up purposes. The research described in this dissertation explores the role that inadvertent introduction of cations, notably ammonium and copper, during the CVD graphene transfer onto PEM substrates, such as Nafion, might play in affecting hydrogen ion transport and isotope separation in PEM electrochemical cells. An extensive review of existing literature exposed a gap concerning unintentional cation introductions during graphene transfer, …

Aspects Of Stochastic Geometric Mechanics In Molecular Biophysics, David Frost

All Dissertations

In confocal single-molecule FRET experiments, the joint distribution of FRET efficiency and donor lifetime distribution can reveal underlying molecular conformational dynamics via deviation from their theoretical Forster relationship. This shift is referred to as a dynamic shift. In this study, we investigate the influence of the free energy landscape in protein conformational dynamics on the dynamic shift by simulation of the associated continuum reaction coordinate Langevin dynamics, yielding a deeper understanding of the dynamic and structural information in the joint FRET efficiency and donor lifetime distribution. We develop novel Langevin models for the dye linker dynamics, including rotational dynamics, based …

Godel, Escherian Staircase And Possibility Of Quantum Wormhole With Liquid Crystalline Phase Of Iced-Water - Part I: Theoretical Underpinning, Victor Christianto, T. Daniel Chandra, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

As a senior physicist colleague and our friend, Robert N. Boyd, wrote in a journal (JCFA, Vol. 1,. 2, 2022), Our universe is but one page in a large book [4]. For example, things and Beings can travel between Universes, intentionally or unintentionally. In this short remark, we revisit and offer short remark to Neil’s ideas and trying to connect them with geometrization of musical chords as presented by D. Tymoczko and others, then to Escher staircase and then to Jacob’s ladder which seems to point to possibility to interpret Jacob’s vision as described in the ancient book of Genesis …

The Influence Of Ion-Ion Correlations On Conductivity In Concentrated Ionic Systems, Md Dipu Ahmed

Masters Theses

This study delves into the fascinating realm of concentrated ionic systems, such as ionic liquids, superionic materials, organic ionic plastic crystals, and polyelectrolytes, which hold immense potential for energy storage applications. The focus is on understanding the intricate role of ionic correlations in shaping their ionic conductivity behavior. These correlations can either boost or impede conductivity, yet their underlying mechanisms remain elusive. Through extensive investigation of various materials, including ionic liquids with differing anionic masses, pure organic ionic plastic crystals, and doped systems, this research employs advanced techniques like dielectric spectroscopy and innovative momentum conservation models to quantify these correlations. …

Investigation Of The Chemical And Electronic Structure Of A 2h Phase Mos2 Single Crystal, Mary Blankenship

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molybdenum disulfide has a wide range of applications in energy conversion devices, like thin-film solar cells, batteries, bio sensors, and more. Although the properties of MoS2 and other transition metal dichalcogenides (TMDC) have been widely studied, disagreements and discrepancies regarding its electronic structure remain.

In this thesis, a highly-oriented synthetic 2H phase MoS₂ single crystal is investigated using a toolchest of spectroscopic techniques to uncover its chemical and electronic properties. Lab-based x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and low energy electron diffraction (LEED) were performed at UNLV and combined with resonant inelastic soft …

Interaction Of Technetium (Iv) With Dibutyl Phosphate In N-Dodecane, Jonathan George

UNLV Theses, Dissertations, Professional Papers, and Capstones

During the reprocessing of nuclear fuel, the degradation of tributylphosphate (TBP) occurs as a result of radiolytic and thermal processes. These processes lead to the formation of minor amounts of dibutyl phosphate (HDBP). However, the presence of DBP poses a challenge in the partitioning of uranium (U), plutonium (Pu), and technetium (Tc) due to its chelating effects. The chelation of these elements by HDBP can interfere with their intended separation and purification, thereby impacting the efficiency and effectiveness of the reprocessing process. In this study, X-ray Absorption Fine Structure (XAFS) spectroscopy is employed to investigate the speciation of Tc following …

The Room Temperature Electrolysis Of F-Elements In Aqueous And Ionic Liquid Media: Synthesis, Dissolution, And Reduction, Phillip George Hammer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Procuring F-element metals is no simple task and often requires the use of caustic and hazardous materials at high temperatures. These materials are invaluable for a variety of scientific missions ranging from the elucidation of fundamental properties, as fast spectrum nuclear fuel forms, to pit production modernizing our nuclear stockpiles. Metallic actinide materials are essential to strategic and critical materials recovery, the nuclear energy sector, and weapons production. Room temperature electrolysis is envisioned as a process to recover laboratory scale (milligram to gram) quantities of actinide metals. This process closes the uranium chemical loop allowing the reclamation of materials for …

Actinide Behavior In Soft Ligand Environments And Higher Oxidation States Of Neptunium In Aqueous Media With Solid-State Synthesis Of Np(Vii) Compounds, Kelly Floyd Seeley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The fundamental properties of Uranium and Neptunium were investigated with Powder X-Ray Diffraction (PXRD) to study the behavior or 5f electrons with chalcogen, alkali metals, and alkaline earth metals. Two novel compounds were generated: NaCuUS₃ and NaCuNpS₃. There are several crystal structures that form in the family of AMM’Q (A = s-block, M = d-block, M’ = d-block or f-block, and Q = chalcogen), with oxidation states of A¹⁺, M¹⁺, M’⁴⁺, and Q^2- ions from the family of type I compounds. Work was continued to …

Ionically Crosslinked Cellulose Nanocrystals By Metal Nitrates For The Preparation Of Stable Emulsions With Tunable Interface Properties, Joseph Batta-Mpouma, Gurshagan Kandhola, Jin-Woo Kim

Materials Science and Engineering Faculty Publications and Presentations

Biologically extracted cellulose nanocrystals (CNCs) are rod-like and amphiphilic materials with surface-exposed (hydrophilic sites) and hidden (hydrophobic sites) hydroxyl groups. These physicochemical characteristics make CNCs suitable for use as emulsifying agents to stabilize emulsions. Stable oil-in-water emulsions, using sulfated (i.e., – SO₃−) CNCs that were ionically crosslinked with alkaline-earth (i.e., Mg ²⁺) or transition-d-block (i.e., Zn ²⁺) metal cations, were developed without the use of any synthetic surfactants or prior functionalization of pure CNCs with hydrophobic molecules. Various emulsion surface properties such as interfacial tension, surface charge, surface chemistry, as well as rheology were characterized. Ionically …

Synthesis And Characterization Of Colorimetric And Flurometric Chemosensor For Trivalent Metal Ions, Fazila Haque

Honors Program Theses and Research Projects

There are many biological and environmental uses for trivalent metals (like Fe3+, Al3+, and Cr3+) within our daily lives. Whether these trivalent metals are found in deficiency or excess can cause issues within our environment (global warming) or our bodies (can cause problems with our digestive, cardiovascular, and immune systems). Being able to detect them and understanding their importance becomes crucial in our understanding of the world that surrounds us.
One of the ways we can detect these trivalent metals is through the use of chemosensors. Chemosensors are used to sense analyte (trivalent metal) to produce a signal (fluorescence or …

A Bio-Tribocorrosion Comparison Between Additively Manufactured And Forged Ti6al4v Parts, Sina Matin, Sahar Toorandaz, Saman Nikpour, Hamidreza Abdolvand, Eshan Toyserkani, Yolanda S. Hedberg

Chemistry Publications

Ti6Al4V has been used widely as a biomedical alloy and is increasingly manufactured by additive manufacturing due to customized shapes. As implant material, it is frequently exposed to both friction and corrosive environments. This study investigates the effect of the fabrication process (laser powder bed fusion and forging) on the tribocorrosion behavior of Ti6Al4V in various environments including diluted hydrochloric acid to simulate the acidic environment in a crevice (HCl), phosphate-buffered saline (pH 7.3) with 10 g/L bovine serum albumin (PBS+BSA), and PBS+BSA with 30 mM H2O2. While the presence of BSA hindered the repassivation (reforming of the protective passive …

Quantifying The Role Of Water Quality On Nitrogen Cycling In A Trophic Estuary, Kayla Gonzalez-Boy

Symposium of Student Scholars

Jobos Bay Estuary is an intertidal, tropical estuary located in southern Puerto Rico. The estuary covers about 12 km² and has a variety of habitats, such as seagrass beds, mangroves, mud flats, and coral reefs, which play important roles in sediment trapping and water quality maintenance. Seagrasses also serve as nursery and feeding grounds and provide shelter for macrofauna. Currently, the role of seagrasses and water quality on nitrogen (N) cycling in trophic estuaries is not well constrained. Understanding variations in sediment-based effects on N cycling rates and transformations, and how they are associated with water quality, is an …

Preparation And Lithium Storage Properties Of Carbon Confined Li3Vo4 Nano Materials, Jia-Qi Fan, Huan-Qiao Song, Jia-Ying An, Amantai A-Yi-Da-Na, Mo Chen

Journal of Electrochemistry

Li₃VO₄, as a promising anode material for lithium ion batteries, has been widely studied because of its low and safe voltage, and large capacity. However, its poor electronic conductivity impedes the practical application of Li₃VO₄ particularly at high rates. In this paper, carbon confined Li₃VO₄ nano materials (Li₃VO₄/C) were synthesized by hydrothermal and solid-phase method, and for comparison, the Li₃VO₄ (N) nano materials without carbon confinement and Li3VO4 (B) materials were also synthesized by pure solid-phase method. The composition, structure, morphology and specific …

Peg-Water Electrolyte For High-Performance Zinc Iodine Dual-Ion Batteries, Xiao-Feng Qu, Yu-Ting Tang, Xin-Cheng He, Jia-Sheng Zhou, Zi-Heng Tang, Wen-Hua Feng, Jun Liu

Journal of Electrochemistry

Thanks to abundant resource and rapid redox reaction kinetics, iodine is regarded as promising positive materials inthe batteries. However, the shuttling effect due to the high solubility of iodine in the electrolyte makes the performance of battery poor. In this paper, polyethylene glycol (PEG400) and potassium iodide were added into zinc-ion aqueous electrolyte. PEG400 could complex with iodine to reduce the dissolution of iodine, therefore alleviating the formation of soluble triiodide (I₃^–) from iodine and iodide ions. Furthermore, this electrolyte was used in the battery with double carbon cloths as the current collectors, double separators and zinc …

Constructing Carbon-Encapsulated Nifev-Based Electrocatalysts By Alkoxide-Based Self-Template Method For Oxygen Evolution Reaction, En-Hui Ma, Xu-Po Liu, Tao Shen, De-Li Wang

Journal of Electrochemistry

The development of green and sustainable water-splitting hydrogen production technology is beneficial to reducing the over-reliance on fossil fuels and realizing the strategic goal of "carbon neutral". As one of the half reactions for water splitting, oxygen evolution reaction has suffered the problems of sluggish four-electron transfer process and relatively slow reaction kinetics. Therefore, exploring efficient and stable catalysts for oxygen evolution reaction is of critical importance for water-splitting technology. Metal alkoxides are a series of compounds formed by the coordination function of metal ions with alcohol molecules. Metal alkoxides possess the double advantages of organic materials and inorganic materials, …

Lif-Sn Composite Modification Layer To Modify Garnet/Lithium Metal Interface, Wu Yang, Xue-Fan Zheng, Yu-Qi Wu, Zheng-Liang Gong

Journal of Electrochemistry

The growing demands for electric vehicles and consumer electronics; as well as the expanding renewable energy storage market; have promoted extensive research on energy storage technologies with low costhigh energy density and safety. Lithium (Li) metal and solid-state electrolytes are considered as important components for next-generation batteries because of their great potential for improvements in energy density and safety performance. Inorganic garnet-type solid electrolytes with high Li-ion conductivity (about 10^-3 S·cm^-1) and high shear modulus (55 GPa) are considered to be ideal solid-state electrolytes; however; the issue of Li dendrite growth still obstructs their practical application. Herein; …

Fluorescent Molecular Rotors As Versatile In Situ Sensors For Protein Quantitation, Kevin Daus, Sorachat Tharamak, Wanchai Pluempanupat, Peter Galie, Maria A Theodoraki, Emmanuel A Theodorakis, Mary Alpaugh

College of Science & Mathematics Departmental Research

Accurate protein quantitation is essential for many cellular mechanistic studies. Existing technology relies on extrinsic sample evaluation that requires significant volumes of sample as well as addition of assay-specific reagents and importantly, is a terminal analysis. This study exploits the unique chemical features of a fluorescent molecular rotor that fluctuates between twisted-to-untwisted states, with a subsequent intensity increase in fluorescence depending on environmental conditions (e.g., viscosity). Here we report the development of a rapid, sensitive in situ protein quantitation method using ARCAM-1, a representative fluorescent molecular rotor that can be employed in both non-terminal and terminal assays.

Investigation Of Electron Transfer In The Ksha-Kshb-R286a Protein Complex From Mycobacterium Tuberculosis, Elyse Tavares

Honors Program Theses and Projects

With drug-resistant bacteria such as Mycobacterium tuberculosis being a serious public health problem, infected individuals have minimal treatment options. By investigating the electron transfer within 3-ketosteroid-9��-hydroxylase (KshAB), a protein involved in the energy production pathway of this bacteria, it will allow for potential inhibitors of this enzyme to be designed as antibiotics against tuberculosis. The purpose of this project is to stop the interaction between the KshA and KshB complexes to prevent the bacteria from gaining energy by breaking down steroids like cholesterol. To achieve this goal, an arginine at the 286th position of the KshB protein was mutated to …

Investigating The Diffusion Of Solid Yttria Into Solid Zirconia For The Formation Of Yttria Stabilized Zirconia, Logan Thomas Ockershausen

Seton Hall University Dissertations and Theses (ETDs)

A molecular dynamics simulation of yttria-stabilized zirconia (YSZ) is reported in order to analyze the diffusion of the oxygen atoms from the yttria into the zirconia from an initial structure containing a layer of yttria on zirconia. The simulation was performed starting from a pure zirconia slab which was amorphized at the surface followed by placing a slab of yttria on top and a vacuum layer above that. The yttria/zirconia system was simulated at increasing temperatures to 1500K under canonical (NVT) constraints for 6.98 ns until the yttrium atom diffusion was found to occur. The final run was analyzed for …

New Methods For Stereoselective Glycosylation In Application To Significant Biomedical Targets, Melanie L. Shadrick

Dissertations

Glycosyl halides have been utilized for glycosylation reactions since the early studies by Arthur Michael, nearing the end of the 19^th century. Koenigs and Knorr then utilized silver salts to activate glycosyl bromides and chlorides to create synthetic glycosides. Many efforts to improve the outcome of reactions with glycosyl halides have emerged. The key emphasis has traditionally been placed on reaction rates, product yields, and stereocontrol. Recently, our lab reported that silver(I) oxide-mediated Koenigs-Knorr glycosylation reaction can be dramatically accelerated in the presence of catalytic acid additives. Methods to improve glycosylation was explored using mannosyl and glucosyl bromides. However, …

Cognitive Engagement During Group Learning Activities In Chemistry Courses: An Analysis Of Student Discourse, Safaa Youssef El-Mansy

Dissertations and Theses

As educators, our goal is to help our students be successful, but in order to accomplish this, we need to understand what factors contribute to student success. One factor, small-group active learning, has been correlated to improved academic outcomes; however, the magnitude of this improvement can vary across different courses, different types of group work, and even across courses that use the same group work structure. Therefore, it is important to understand what aspects of group work contribute to its effectiveness. The work presented in this dissertation investigated one specific aspect: students’ cognitive engagement. This was done by analyzing the …

Binding Interactions Of Biologically Relevant Molecules Studied Using Surface-Modified And Nanostructured Surfaces, Palak Sondhi

Dissertations

This research focuses on the field of surface nanobioscience, wherein different nanosurfaces that will be used as working electrodes in the electrochemical cell are manufactured and surface modified to understand the critical binding interactions between biologically significant molecules like proteins, carbohydrates, small drug molecules, and glycoproteins. This research is essential if we are to determine whether a synthetic molecule can serve as a therapeutic candidate or diagnose a disease in its early stages. In order to fully understand the binding interactions, the study begins with defining some of the fundamental concepts, principles, and analytical tools for biosensing.

Afterwards, we addressed …

Impacts Of Hydrophobic Mismatch On Antimicrobial Peptide Efficacy And Bilayer Permeabilization., Steven Meier, Zachary M Ridgway, Angela L Picciano, Gregory A. Caputo

College of Science & Mathematics Departmental Research

Antimicrobial resistance continues to be a major threat to world health, with the continued emergence of resistant bacterial strains. Antimicrobial peptides have emerged as an attractive option for the development of novel antimicrobial compounds in part due to their ubiquity in nature and the general lack of resistance development to this class of molecules. In this work, we analyzed the antimicrobial peptide C18G and several truncated forms for efficacy and the underlying mechanistic effects of the sequence truncation. The peptides were screened for antimicrobial efficacy against several standard laboratory strains, and further analyzed using fluorescence spectroscopy to evaluate binding to …

Functional Aggregation Of Cell-Free Proteins Enables Fungal Ice Nucleation, Ralph Schwidetzky, Ingrid De Almeida Ribeiro, Nadine Bothen, Anna T. Backes, Arthur L. Devries, Mischa Bonn, Janine Fröhlich-Nowoisky, Valeria Molinero, Konrad Meister

Chemistry and Biochemistry Faculty Publications and Presentations

Biological ice nucleation plays a key role in the survival of cold-adapted organisms. Several species of bacteria, fungi, and insects produce ice nucleators (INs) that enable ice formation at temperatures above −10 °C. Bacteria and fungi produce particularly potent INs that can promote water crystallization above −5 °C. Bacterial INs consist of extended protein units that aggregate to achieve superior functionality. Despite decades of research, the nature and identity of fungal INs remain elusive. Here, we combine ice nucleation measurements, physicochemical characterization, numerical modeling, and nucleation theory to shed light on the size and nature of the INs from the …

Evaluation Of Iron Element By New Cpe Method And (Icp-Ms) In The Wastewater Of The Lifting And Treatment Stations, Mohammed Nasser Hussain, Ahmed Fadhil Khudhair, Hussain Jawad Ahmed

Al-Bahir Journal for Engineering and Pure Sciences

A new micell-mediated phase separation technique has been created to preconcentrate levels of iron before measuring it using a UV-Vis spectrophotometer. The method is based on the extraction of iron from the 1-Nitroso-2- naphthol reagent using Triton X-114 in a cloud point extraction procedure, where the method's ideal conditions were attained. 0.2 mL of Triton X-114, 2.887 mmol. L-1 of 1-Nitroso-2-naphthol reagent, pH = 8, 60 ºC. The Iron detection limit for the method is 0.05 µg. mL-1, and the RSD% is 4.728 µg. mL-1. Linearity was maintained in the iron concentration range of 0.25 to 16 µg. mL-1. Furthermore, …

Development Of Antibacterial Neural Stimulation Electrodes Via Hierarchical Surface Restructuring And Atomic Layer Deposition., Henna Khosla, Wesley Seche, Daniel Ammerman, Sahar Elyahoodayan, Gregory A. Caputo, Jeffrey Hettinger, Shahram Amini, Gang Feng

College of Science & Mathematics Departmental Research

Miniaturization and electrochemical performance enhancement of electrodes and microelectrode arrays in emerging long-term implantable neural stimulation devices improves specificity, functionality, and performance of these devices. However, surgical site and post-implantation infections are amongst the most devastating complications after surgical procedures and implantations. Additionally, with the increased use of antibiotics, the threat of antibiotic resistance is significant and is increasingly being recognized as a global problem. Therefore, the need for alternative strategies to eliminate post-implantation infections and reduce antibiotic use has led to the development of medical devices with antibacterial properties. In this work, we report on the development of electrochemically …

Cost Analysis Of Adsorption Based Air Capture Of Co2, Mona Muzammil, Muzammil Arshad, Muazzam Arshad

Chemistry Faculty Publications and Presentations

Carbon dioxide (CO2) capture and conversion to value added products, such as chemicals, polymers, and carbon-based fuels represents a promising approach to transform a potential threat to the environment into a value-added product for long term sustainability. Emerging Carbon Capture Technologies: Towards a Sustainable Future provides a multidisciplinary view of the research that is being carried out in this field, covering materials and processes for CO2 capture and utilization and including a broad discussion of the impact of novel technologies in carbon capture on the energy landscape, society and climate. Of interest to students, researchers and professionals in industries related …

Youth In Danger And Students At Risk Of Dropping Out, Mamoona Muzammil, Muzammil Arshad

Chemistry Faculty Publications and Presentations

Bullying is any unwanted aggressive behavior(s) by another youth or group of youth that involves an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated. Bullying may inflict harm or distress on the targeted youth including physical, psychological, social, or educational harm. Bullying can lead to fear of school, absenteeism, and stunted academic progress, which in turn are precursors to dropping out of school.

• Effects of Bullying on Students Long lasting effects
• School Dropout.
• Lack of Concentration
• Reduced Motivation
• Less Class Participation
• Less Attendance Lower Academic Achievement

Student Dropouts

The increase in …

Inhibition Of Chromium(Iii) Oxidation Through Manganese(Iv) Oxide Passivation And Iron(Ii) Abiotic Reduction, Miranda L. Aiken, Macon J. Abernathy, Michael V. Schaefer, Ilkeun Lee, Samantha C. Ying

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Manganese (Mn) oxides are strong oxidants that are ubiquitous in soils and can oxidize redox-active metals, including chromium (Cr). In soil environments, trivalent chromium (Cr(III)) is a benign, immobile micronutrient, whereas the hexavalent Cr(VI) form is present as a highly mobile, toxic chromate oxyanion. Although many studies have characterized the capacity of Mn(III/IV) oxides to oxidize Cr(III) to toxic Cr(VI), the oxidative capacity of Mn oxides in the presence of potentially passivating soil constituents, specifically reduced soluble iron (Fe(II)aq), remains unresolved. We hypothesized that chemical processes at redox interfaces, such as diffusion-limited environments within soil aggregates, can lead to decreased …