Chemistry Commons^™

Laser Ablation Icp-Ms Of Actinide Oxides As Simulated Used Nuclear Fuels, Keri Campbell

UNLV Theses, Dissertations, Professional Papers, and Capstones

The ability to examine elemental and isotopic ratios of fuels, waste forms, and other solids by direct analysis using laser ablation techniques can greatly reduce analysis costs and time. This is particularly true for actinide elements, as they contain useful information of the fuel cycle and nuclear forensics. Current methods to evaluate the composition of used fuel include a lengthy process of digestion, separations and often require multiple techniques and sample preparations to determine the elemental and isotopic composition. Furthermore all spatial information is lost during the digestion process, eliminating potentially useful data for detailed analysis. The goal of this …

Versatile Synthetic Methods For Photoluminescent Pyrylium Tosylates, Jung Jae Koh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pyrylium salts are an important class of cationic organic molecules that exhibit good absorption, fluorescence, and photo-induced electron transfer properties. They can also function as precursors for synthesis of different heterocyclic organic molecules such as furan, pyridine, pyridinium salt, and betaine dyes. This thesis describes versatile methods of synthesis for a series of 2,4,6-triarylsubstitued pyrylium tosylates with different substituents by using p-toluenesulfonic acid monohydrate instead of conventional acid catalysts including perchloric acid or boron trifluoride diethyl etherate that accompany explosion danger and difficult storage problem, respectively. The chemical structures were established by ¹H and ¹³C NMR spectroscopic techniques …

Studies Of Flerovium And Element 115 Homologs With Macrocyclic Extractants, John Dustin Despotopulos

UNLV Theses, Dissertations, Professional Papers, and Capstones

Study of the chemistry of the heaviest elements, Z ≥ 104, poses a unique challenge due to their low production cross-sections and short half-lives. Chemistry also must be studied on the one-atom-at-a-time scale, requiring automated, fast, and very efficient chemical schemes. Recent studies of the chemical behavior of copernicium (Cn, element 112) and flerovium (Fl, element 114) together with the discovery of isotopes of these elements with half-lives suitable for chemical studies have spurred a renewed interest in the development of rapid systems designed to study the chemical properties of elements with Z ≥ 114. This dissertation explores both extraction …

Beryllium Is A Potent And Unique Gsk-3Β Inhibitor With Potential To Differentially Regulate Glycogen Synthase And Β-Catenin, Ata Ur Rahman Mohammed Abdul

UNLV Theses, Dissertations, Professional Papers, and Capstones

Glycogen Synthase Kinase-3β (GSK-3β) is an important serine/threonine kinase that phosphorylates/regulates diverse and metabolically important proteins. Some of the important substrates of GSK-3β are glycogen synthase, tau, β-catenin, cyclin D1, axin, c-jun, c-myc, Heat Shock Factor–1, BCL-3, CREB, Histone H1.5, mdm2, p21 (CIP1), pyruvate dehydrogenase and many more. De-regulation of GSK-3β has been implicated in diseases like cancer, Alzheimer’s disease, bipolar disorder and type 2 diabetes mellitus. Currently, GSK-3β is one of the most widely studied proteins and there is a great interest in developing potent and efficient GSK-3β-inhibitors for research as well as therapeutic purposes. We demonstrate that beryllium …

Mcnair Research Journal - Summer 2015, Kelly Abuali, Starr Bailey, Krystal Courtney D. Belmonte, Brittaney Benson-Townsend, Jennifer Bolick, Mihaela A. Ciulei, Ashley Crisp, Daniel N. Erosa, Richard V. Foster, Gisele Braga Goertz, Michael A. Langhardt, Kara Osborne, Julienne Jochel Paraiso, Shawn M. Rosen, Bella V. Smith, Jeevake Attapattu, Ernesto H. Bedoy, Michael G. Curtis, Wanda Inthavong, Marielle Leo, Primrose Martin, Tamieka Meadows, Rosa Perez, Jessica Recarey, Shea Silver, Linda Tompkins

McNair Journal

Journal articles based on research conducted by undergraduate students in the McNair Scholars Program

Table of Contents

Biography of Dr. Ronald E. McNair

Statements:

Dr. Neal J. Smatresk, UNLV President

Dr. Juanita P. Fain, Vice President of Student Affairs

Dr. William W. Sullivan, Associate Vice President for Retention and Outreach

Mr. Keith Rogers, Deputy Executive Director of the Center for Academic Enrichment and Outreach

McNair Scholars Institute Staff

Keeping In Touch: Exchange As An Adaptive Strategy In Southern Nevada, Timothy Joshua Ferguson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Archaeologists have always wondered about the extent of vessel movement in the American Southwest. Identifying vessel movement allows for the study of social interactions across a region and the role of ceramics in the adaptive processes of agriculturalists living in marginal, highly variable environments. In many instances, exchange may act as a way to reduce the risk of resource shortfalls by creating social ties in other areas. This research investigated the changing risk reduction strategies of households in the lowland Virgin region of southern Nevada by using geochemical methods to trace the exchange of locally produced pottery. It was hypothesized …

Speciation Of Pentavalent Technetium Complexes With Aniline And Thiobenzene Derivatives, Kyle E. Childs

UNLV Theses, Dissertations, Professional Papers, and Capstones

The reaction of bidentate aniline oligomers with pentavalent technetium has been investigated previously through the reaction of (n-Bu4N)TcOCl4 with o-phenylenediamine (PDA). The initial studies found that PDA reacted in a 1 to 2 molar ratio with pentavalent technetium in in ethanol. This study was expanded by the examination of a second aniline derivatives, 2-aminophenol (AMP)) and two thiobenzene derivatives (2-mercaptophenol (MP) and thiosalicylic acid (TSA)) to evaluate the kinetic formation of these complexes with pentavalent technetium. The pentavalent technetium complexes all showed reactivity with technetium having a coordination numbers of 5 with all ligands reacting in a 1 to 2 …

Simultaneous Determination Of Multiple Actinide Elements In A Variety Of Soils Utilizing A Standardized Sequential Extraction Protocol, Sherry Alina Faye

UNLV Theses, Dissertations, Professional Papers, and Capstones

To obtain a better understanding of the mobility of actinide element contaminants in the environment, the association of the contaminants with specific host phases of soils and sediments must be investigated. This investigation is most commonly conducted using sequential extraction techniques that employ the selective dissolution of soil phases with increasingly aggressive chemical treatment. Though several sequential extraction studies exist in literature, conclusions cannot be made by direct comparison of data due to the lack of uniformity in the protocols used. This work aims to continue development of a standard sequential extraction protocol and expanding its capabilities to include the …

Technetium Sulfide: Fundamental Chemistry For Waste Storage Form's Application, Maryline Ghislaine Ferrier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Technetium is the lightest radioelement. The isotope ⁹⁹Tc has around a 6% yield from ²³⁵U with a half-life of 2.13 x 10⁵ years. The high mobility of TcO₄^-, the common chemical form of technetium in the environment makes ⁹⁹Tc an isotope of concern in nuclear waste management. Despite its important role in radiopharmaceuticals and in the nuclear fuel cycle, the fundamental chemistry of technetium is not as well developed as that of the neighboring transition metals; one of the most striking examples being its sulfide chemistry.

Only two technetium binary sulfide compounds had …

Spectroscopic Investigation Of The Chemical And Electronic Properties Of Chalcogenide Materials For Thin-Film Optoelectronic Devices, Kimberly Horsley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chalcogen-based materials are at the forefront of technologies for sustainable energy production. This progress has come only from decades of research, and further investigation is needed to continue improvement of these materials.

For this dissertation, a number of chalcogenide systems were studied, which have applications in optoelectronic devices, such as LEDs and Photovoltaics. The systems studied include Cu(In,Ga)Se2 (CIGSe) and CuInSe2 (CISe) thin-film absorbers, CdTe-based photovoltaic structures, and CdTe-ZnO nanocomposite materials. For each project, a sample set was prepared through collaboration with outside institutions, and a suite of spectroscopy techniques was employed to answer specific questions about the system. These …

Synthesis And Characterization Of Novel Platinum(Ii) And Platinum(Iv) Complexes Containing 4,4′--Disubstituted--2,2′--Bipyridine Ligands For The Treatment Of Cancer, Van Vo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Three series of platinum(II) and platinum(IV) complexes containing 4,4′-disubstituted-2,2′-bipyridine ligands have been synthesized and characterized by 1H NMR, 13C NMR spectroscopy, elemental analysis, mass spectroscopy, and differential scanning calorimetry measurements. The MTS cell proliferation assay was used to examine the in vitro anti-proliferative activities of these complexes in various human breast, lung, and prostate cancer cells. The cell's response to the complexes varies between different cell lines; however, the low EC₅₀ values determined from the MTS data indicate that several of the complexes are much more potent than cisplatin.

Flow cytometric analysis of selected compounds revealed induction of apoptosis …

Speciation Behavior Of Americium Higher Oxidation States For The Separation Of Americium From Curium, Catherine Lynn Riddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several countries are currently expanding the use of nuclear energy as a method for the safe generation of carbon free energy and a number are evaluating starting up a nuclear power program. Closed fuel cycle technologies may be key to waste reduction and a sustainable nuclear energy future and to support the development of more efficient fuel cycles, the investigation of the chemical properties of key actinides is at the forefront of separations research. In this work the characterization of higher oxidation states of americium (Am) has been performed using spectroscopic methods. Americium in the formal oxidation state of Am(V) …

Mobilization Of Toxic Elements From An Abandoned Manganese Mine In The Arid Metropolitan Las Vegas (Nv, Usa) Area, Ji Hye Park, Vernon Hodge, Shawn Gerstenberger, Krystyna Stave

Chemistry and Biochemistry Faculty Research

Active and abandoned mines may present health risks, especially to children, from environmental exposure to airborne chemical elements, such as Pb, As, and Mn. X-ray fluorescence analysis of tailings at the Three Kids Mine show they contain high levels of: Pb (15,300 mg/kg), As (3690 mg/kg), and Mn (153,000 mg/kg). Soil was sampled along eight transects, radiating from the dried tailings ponds. Concentrations of Mn and Pb to the NE are at background concentrations at 4.8 km, and, As and Sr at 3.2 km from the mine. Going SW to the City of Henderson, all elements are at background at …

Characterization And Optimization Of Extraction Chromatography Resins For Rapid Separations For Safeguard And Nuclear Forensics Purposes, Audrey Roman

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, extraction chromatography resins, DGA and UTEVA, were characterized under various conditions in order to identify novel rapid separations for safeguards and nuclear forensic purposes. For safeguards purposes, mixed matrices containing some of the largest components found in used fuel and either Am, Pu, or U were characterized on DGA and UTEVA resins in order to determine any effects from the addition of these constituents. Results indicated that 5 M HNO₃ would be an optimal loading condition due to the consistent actinide adsorption in the presence of the additional used fuel components. Investigations of varying the anion …

Initial Characterization Of A Conserved Active Site Residue For The Cdc34 Ubiquitin Conjugating Enzyme, Arvin Akoopie

Honors College Theses

Ubiquitin-conjugating enzymes (E2s) covalently modify protein substrates with ubiquitins. The active site cysteine residues on E2s are essential for catalyzing the transfer of ubiquitin from the E2 active site onto the protein substrate, however there is a limited amount of information available concerning additional active site residues for E2s that may also participate in catalysis. Cdc34 is an essential E2 that has merited the lion’s share of attention for biochemical analysis of the E2 family. Previous phylogenetic analysis of Cdc34 amino acid sequences has identified an invariably conserved histidine residue close to the active site cysteine in the primary structure, …

Binary Technetium Halides, Erik Vaughan Johnstone

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, the synthetic and coordination chemistry as well as the physico-chemical properties of binary technetium (Tc) chlorides, bromides, and iodides were investigated. Resulting from these studies was the discovery of five new binary Tc halide phases: α/β-TcCl₃, α/β-TcCl₂, and TcI₃, and the reinvestigation of the chemistries of TcBr₃ and TcX₄ (X = Cl, Br). Prior to 2009, the chemistry of binary Tc halides was poorly studied and defined by only three compounds, i.e., TcF₆, TcF₅, and TcCl₄. Today, ten phases are known (i.e., TcF …

Assessing Different Zeolitic Adsorbents For Their Potential Use In Kr And Xe Separation, Breetha Alagappan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Separation of Kr from Xe is an important problem in spent nuclear fuel fission gas management. The energy intensive and expensive cryogenic distillation method is currently used to separate these gases. In this thesis, we have carried out the research into appropriate sorbents for the separation of Kr and Xe using pressure swing adsorption. We have examined zeolites using gas adsorption studies as they have the potential to be more cost effective than other sorbents. Zeolites are microporous aluminosilicates and have ordered pore structures. The pores in zeolites have extra-framework cations are substantially free to move. The mobility of cations …

Investigation Of Storage-Phosphor Autoradiography For The Rapid Quantitative Screening Of Air Filters For Emergency Response Purposes, Athena Marie Gallardo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Past nuclear accidents, such as Chernobyl, resulted in a large release of radionuclides into the atmosphere. Radiological assessment of the vicinity of the site of the incident is vital to assess the exposure levels and dose received by the population and workers. Therefore, it is critical to thoroughly understand the situation and risks associated with a particular event in a timely manner in order to properly manage the event. Current atmospheric radiological assessments of alpha emitting radioisotopes include acquiring large quantities of air samples, chemical separation of radionuclides, sample mounting, counting through alpha spectrometry, and analysis of the data. The …

Separation Of Tc From U And Development Of Metallic Tc Waste Forms, Edward Mausolf

UNLV Theses, Dissertations, Professional Papers, and Capstones

The isotope Technetium-99 (⁹⁹Tc) is a major fission product of the nuclear industry. In the last decade, approximately 20 tons of 99Tc have been produced by the US nuclear industry. Due to its long half-life (t_1/2 = 214,000 yr), beta radiotoxicity, and high mobility as pertechnetate [TcO₄]^-, Tc represents long-term concern to the biosphere. Various options have been considered to manage ⁹⁹Tc. One of them is its separation from spent fuel, conversion to the metal and incorporation into a metallic waste form for long-term disposal. After dissolution of spent fuel in nitric …

Forensic Signatures Of Chemical Process History In Uranium Oxides, Jonathan Plaue

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation comprehensively explores and develops new tools for nuclear forensic science to facilitate the identification of chemical process history in uranium oxides. Nuclear forensics is an emerging discipline motivated by the need to prevent and combat malevolent acts involving nuclear and radiological materials. This dissertation examined process signatures in uranium oxide powders, precursors, and sintered fuel pellets.

Signatures were investigated on set of powder and pellet exemplars synthesized in the laboratory and a set of real‐world samples with process information obtained from the literature or manufacturer. The examined techniques included morphology as revealed by scanning electron microscopy, near‐infrared reflectance …

Strategic Electronic Property Control Of Self-Assembling Pyrazine-Acenes, Lacie Brownell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Control of electronic properties in organic semiconductor materials is essential for electro-optical applications such as field-effect transistors, light-emitting diodes, and photovoltaic devices. This work is focused on two systems that highlight different approaches for the manipulation of electronic properties: (I) the development of electron-deficient (n-type) materials by selective lowering of E_LUMO and (II) low energy gap materials by controlling both E_LUMO and E_HOMO

To specifically lower E_LUMO, a pyrazine-acene π-platform was extended using electron-withdrawing moieties. These include: pyridine, pyrazine, and benzothiadiazole (system I). From the base pyrazine-acene, the most significant change in E_LUMO of …

What Can Biochemistry Students Learn About Protein Translation? Using Variation Theory To Explore The Space Of Learning Created By Some Common External Representations, Thomas J. Bussey

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biochemistry education relies heavily on students' ability to visualize abstract cellular and molecular processes, mechanisms, and components. As such, biochemistry educators often turn to external representations to provide tangible, working models from which students' internal representations (mental models) can be constructed, evaluated, and revised. However, prior research has shown that, while potentially beneficial, external representations can also lead to alternative student conceptions.

Considering the breadth of biochemical phenomena, protein translation has been identified as an essential biochemical process and can subsequently be considered a fundamental concept for biochemistry students to learn. External representations of translation range from static diagrams to …

Anti-Germinants As A New Strategy To Prevent Clostridium Difficile Infections, Amber Janece Howerton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridium difficileinfections (CDI) have emerged as a leading cause of hospital-associated complications. CDI is the major cause of antibiotic-related cases of diarrhea and nearly all cases of pseudomembranous colitis. The infective form of C. difficileis the spore, a dormant and hardy structure that forms under stress. Germination of C. difficile spores into toxin producing bacteria in the GI tract of susceptible patients is the first step in CDI establishment. Patient susceptibility occurs with a disruption of the natural gut microbiota by broad-spectrum antibiotics. Antibiotic treatments usually resolve CDI but refractory cases are on the rise. Of great concern is the …

Elemental Contributions From Minor And Major Constituents Of Bone On The Separation Of Radiostrontium, Ashlee Rae Dailey

UNLV Theses, Dissertations, Professional Papers, and Capstones

While many methods exist to separate and analyze radionuclides from a variety of environmental matrices, the performance of all of these methods is often limited by other interfering constituents that are consistently found in most of these samples. The presence of such constituents can significantly reduce the recovery of the radioisotopes of interests and lead to incomplete separations.

Strontium has the same oxidation state and a similar atomic radius as calcium and is therefore readily able to substitute for calcium in lattice sites. This similarity in behavior leads to the preferential accumulation of strontium in newly formed bone. The study …

Synthesis And Characterizations Of Pyridinium Salts Including Poly(Pyridinium Salt)S And Their Applications, Tae Soo Jo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pyridinium salts, both molecular and polymeric, are an interesting class of multifunctional materials that exhibit liquid-crystalline and light-emitting properties. Moreover, their properties can be easily tuned by introducing new types of anions or by modifying their chemical structures. This dissertation describes synthesis and characterization of poly(pyridinium salt)s containing macrocounterions and fluorene moieties in their backbones, synthesis and characterization of nanocomposites of poly(pyridinium salt)s with single-walled carbon nanotubes via non-covalent interactions, and synthesis and characterizations of pyridinium salts having different aliphatic linkages and their application in organic acid sensing.

First, all of these ionic polymers were prepared by either ring-transmutation or …

Molecular Forensic Science Analysis Of Nuclear Materials, Dallas Reilly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Concerns over the proliferation and instances of nuclear material in the environment have increased interest in the expansion of nuclear forensics analysis and attribution programs. A new related field, molecular forensic science (MFS) has helped meet this expansion by applying common scientific analyses to nuclear forensics scenarios. In this work, MFS was applied to three scenarios related to nuclear forensics analysis. In the first, uranium dioxide was synthesized and aged at four sets of static environmental conditions and studied for changes in chemical speciation. The second highlighted the importance of bulk versus particle characterizations by analyzing a heterogeneous industrially prepared …

Molecular Processes In Astrophysics: Calculations Of H + H2 Excitation, De-Excitation, And Cooling, Matthew Kelley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The implications of H+H2 cooling in astrophysics is important to several applications. One of the most significant and pure applications is its role in cooling in the early universe. Other applications would include molecular dynamics in nebulae and their collapse into stars and astrophysical shocks. Shortly after the big bang, the universe was a hot primordial gas of photons, electrons, and nuclei among other ingredients. By far the most dominant nuclei in the early universe was hydrogen. In fact, in the early universe the matter density was 90 percent hydrogen and only 10 percent helium with small amounts of lithium …

Recycling And Reuse Of Radioactive Materials, Thomas Joseph O'Dou

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Radiochemistry Program at the University of Nevada, Las Vegas (UNLV) has a Radiation Protection Program that was designed to provide students with the ability to safely work with radioactive materials in quantities that are not available in other academic environments. Requirements for continuous training and supervision make this unique program capable of turning out graduates that have an understanding of contamination and dose control techniques that complement their knowledge of the elements that they work with. The Program has also adopted a radionuclide recovery and reuse program that has provided materials from other universities, government agencies, and private companies …

Evaluating Actinide Sorption To Graphite With Regards To Triso Repository Performance, Corey Christopher Keith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Graphite has the potential for inclusion in nuclear waste for disposal in waste repository settings. Implementation of High Temperature Gas-cooled Reactors contributes to this potential through use of TRISO fuel, if direct disposal of the graphite matrix surrounding the fuel is employed. The inclusion of the large mass and volume in the TRISO fuel waste form differs significantly from used light water reactor fuel waste forms, requiring new performance models to describe the behavior in a repository setting. The purpose of this study is to evaluate the potential for the graphite to improve actinide, specifically uranium and neptunium, retardation from …

Angular And Dynamical Properties In Resonant Inelastic X-Ray Scattering: Case Study Of Chlorine-Containing Molecules, Renaud Guillemin, Wayne C. Stolte, Loic Journel, Stephane Carniato, Maria Novella Piancastelli, Dennis W. Lindle, Marc Simon

Chemistry and Biochemistry Faculty Research

Polarization-dependent resonant inelastic x-ray scattering (RIXS) has been shown to be a probe of molecular-field effects on the electronic structure of isolated molecules. In this experimental analysis we explain the linear dichroism observed in Cl 2p polarized RIXS following Cl 1s excitation of a series of chlorofluoromethanes (CF3Cl, CF2Cl2, CFCl3, and CCl4) as due to molecular-field effects, including singlet-triplet exchange. We present an approach to extract directly the 2p inner-shell electronic state populations from the experimental measurements. Using the angular properties of the measured KV emission we also are able to determine the value of the polarization anisotropy parameter βp …