Chemistry Commons^™

Differentiation Of Human, Dog, And Cat Hair Fibers Using Dart Tofms And Machine Learning, Laura Ahumada, Erin R. Mcclure-Price, Chad Kwong, Edgard O. Espinoza, John Santerre

SMU Data Science Review

Hair is found in over 90% of crime scenes and has long been analyzed as trace evidence. However, recent reviews of traditional hair fiber analysis techniques, primarily morphological examination, have cast doubt on its reliability. To address these concerns, this study employed machine learning algorithms, specifically Linear Discriminant Analysis (LDA) and Random Forest, on Direct Analysis in Real Time time-of-flight mass spectra collected from human, cat, and dog hair samples. The objective was to develop a chemistry- and statistics-based classification method for unbiased taxonomic identification of hair. The results of the study showed that LDA and Random Forest were highly …

A Computational Study Of Adsorptive Desulfurization In Metal Organic Frameworks, Kyle Concha

Theses

Fossil fuel usage has been related to several concerns about the environment and human health. One of these concerns is related to fuels containing Organic Sulfur Compounds (OSCs) which upon burning produce hazardous compounds such as SO₂ which contributes to acid rain and affects respiratory health. Removal of these OSCs is an important field of study as it can prevent the production of SO_x compounds. One technique to remove OSCs is Adsorptive Desulfurization (ADS) in which Metal Organic Frameworks (MOFs) are potential candidates to be used as adsorbents. Two archetypal MOFs, HKUST-1 and Cu₃HHTP₂, …

Correlation Effects On Intramolecular C-H...Oh And O-H...O Hydrogen Bond Interactions In Azelaic Acid: An Ab Initio Study, Sabina Kalata, Alina Huang, Ruben Parra

DePaul Discoveries

Electron correlation effects on both conventional, O-H…O, and nonconventional, C-H…O, intramolecular hydrogen bonds present in a selected azelaic acid folded conformation were evaluated ab initio using HF and MP2 methodologies. The relative strength of the hydrogen bonds was examined through different indicators derived from geometry, vibrational frequencies, and electron density along the hydrogen bond path. The HF method results in weaker O-H…O and C-H…O hydrogen bonds when compared with the corresponding results using the MP2 method. Additionally, the stability of the folded azelaic conformation is found to depend on the level of theory used. Accordingly, the zero-point corrected energies of …

From Small Molecules To Infinite Crystals: Probing Noncovalent Interactions Through Vibrational Spectroscopy, Sadisha Nanayakkara

Chemistry Theses and Dissertations

During my four years in the CATCO group supervised by Dr. Kraka, I have been exposed to various topics targeted to address a multitude of chemical problems, broadening our knowledge of modern chemistry research as we know it. In undertaking the age-old problem of understanding the nature of chemical bonding, I could modestly contribute with my work, using in-house tools based on vibrational spectroscopy.

First part of my dissertation is focused on inventing new methods and tools to efficiently investigate chemical bonding, followed by the study of some non-covalent interactions, imperative in catalysis and solid-state chemistry. This includes analysis of …

Iron Speciation In Pm2.5 From Urban, Agriculture, And Mixed Environments In Colorado, Usa, Joseph R. Salazar, David J. Pfotenhauer, Frank Leresche, Fernando L. Rosario-Ortiz, Michael P. Hannigan, Sirine C. Fakra, Brian Majestic

Chemistry and Biochemistry: Faculty Scholarship

Atmospheric iron solubility varies depending on whether the particles are collected in rural or urban areas, with urban areas showing increased iron solubility. In this study, we investigate if the iron species present in different environments affects its ultimate solubility. Field data are presented from the Platte River Air Pollution and Photochemistry Experiment (PRAPPE), aimed at understanding the interactions between organic carbon and trace elements in atmospheric particulate matter (PM). 24-hr PM2.5 samples were collected during the summer and winter (2016–2017), at three different sites on the Eastern Colorado plains: an urban, agricultural, and a mixed site. Downtown Denver had …

Electrostatic Denaturation Of Dna-Cisplatin Adducts, Eddie Madrigal

Master's Theses

In this thesis, electrochemical approaches are used to determine the properties of deoxyribonucleic acid (DNA) by electrostatic denaturation. The electrochemical routine involves an application of a destabilization potential, an equilibration potential, and a square wave voltammogram (SWV) to monitor the extent of melting. Our method uses a monolayer consisting of thiol modified DNA and mercaptohexanol on a gold electrode. These electrodes are then incubated in a complementary sequence tagged with methylene blue. By using our electrostatic denaturation technique, different parameters are explored, such as surface densities, surface coverages, and ionic strengths. As proof of concept, these techniques were applied toward …

I. Non-Degradable Polysiloxane Networks For Controlled Release Applications, And Ii. Additive Free, Degradable Silyl-Ether Furyl-Maleimide Networks, Caleb M. Bunton

Chemistry Theses and Dissertations

I. Two different series of non–degradable polysiloxane networks were prepared for the encapsulation and controlled release of a small molecule agent. For the first series, hydrosilylation was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and silylhydride functional poly(dimethyl)siloxanes. For the second series, the thiol-ene reaction was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and mercaptopropyl functional poly(dimethyl)siloxanes. Nile red dye was used as an encapsulated agent and dye release from each series of networks was measured using UV–vis spectroscopy to determine controllability …

Chemistry In Art: The Science Of Dye, Madeleine Gray Burland

Honors Projects

Fabric arts, and the practice of dyeing fabric using various resist techniques, is a tradition that goes back centuries, and is unique among art mediums in its relation to science, as the innovations in dye production have directly affected the art form. The development of synthetic dyes in the 1800’s greatly affected the way fabric is dyed, and subsequently the way clothes were made and consumed. As opposed to dyes made of natural materials, synthetic dyes cam in more colors, were brighter, easier to make in large quantities, and lasted longer since they didn’t fade with repeated washings. The practice …

Synthesis And Evaluation Of Nebraska Red Derivatives For Protein Labeling Studies, Lauren Lesiak

Honors Theses

G protein-coupled receptors (GPCRs) play a vital role in cell signaling, and imaging the internalization of these proteins will allow for better understand of protein trafficking within the cell, as well as identification of potential drug targets. However, there is a need for further development of fluorescent protein labels that are able to effectively monitor GPCR internalization in the near-infrared (NIR) range. We recently described a series of NIR fluorophores in which a phosphinate functionality is inserted at the bridging position of the xanthene scaffold, called the Nebraska Red (NR) dye series. These dyes are attractive reagents for the imaging …

The Roundtable Of Scientific Communication: From Classroom To Course Creation, Back To Classroom And Beyond, Sean P. Hickey

University of New Orleans Theses and Dissertations

This research encompasses many aspects of chemical education research including curriculum and pedagogical changes to the freshman and sophomore courses. Curriculum changes included the addition of recitations to the general chemistry and organic chemistry lectures and the creation of four new classes, CHEM 1001, 1002, 3091, and 3092. The addition of recitations was not limited to but was focused on improving DFW rates for these courses.

CHEM 3091 and 3092 are chemistry internship and undergraduate teaching assistant classes. These courses were necessary to offer outside internship opportunities and training for undergraduate teaching assistants, respectively. CHEM 1001 and 1002 are chemistry …

Unravel Allostery Mechanism Through Molecular Dynamic Simulations With Machine Learning Approaches, Hongyu Zhou

Chemistry Theses and Dissertations

Allostery is referred to as protein function changes due to external perturbations, and ubiquitous in the living cells. Investigation of the allosteric mechanism is essential for developing drugs or assisting protein engineering. Recently, the population shift model has been proposed to explain the allosteric mechanism. This model emphasizes the importance of conformational distribution in the allostery. In the past several years, I have been continuously working on developing computational methods to explore and quantify protein allostery mechanism. By fully utilizing protein simulation results, several machine learning related methods have been applied to protein systems to investigate the underlying conformational changes …

Feco2o4 As An Anode Material For Lithium Ion Batteries, Chelsea Wong

The International Student Science Fair 2018

Lithium ion batteries (LIBs) are commonly found in many portable electronic appliances due to their ability to be rechargeable. Currently, commercial anodes in Li-ion batteries (graphite) have a theoretical capacity of around 372 mAh/g, while FeCo2O4 that will be investigated as the anode material has a theoretical capacity of 901.985mAh/g, more than double of the current commercial anode’s capacity. Earlier work done by Sharma et al also showed that FeCo2O4 has a very promising initial capacity of 827mAh/g. As such, the engineering goal is to produce a battery that will have a higher capacity than the current commercial Li-ion batteries …

Experiential Learning Activity: Biodiesel Inquiry Project, Ji Kim

Open Educational Resources

The activity described herein can be implemented in introductory chemistry and high school chemistry courses. The main goal of the project is to integrate a ubiquitous biodiesel production with experiential learning by providing a community-based project. The students work in groups, research the benefits of using biodiesel over petroleum-based diesel, collect waste cooking oil from home or restaurants, develop simple and cost-effective methods to produce biodiesel.

Quantitative Analysis Of Bleomycin In Rat Plasma By Lc-Ms/Ms, Huawen Li

ETD Archive

Bleomycin is the most commonly used compound in its group of antineoplastic drugs. It works on tumor cells by single and double stranded DNA cleavage after its activation, in which it blocks tumor cells’ DNA replication or transcription activities to inhibit tumor cells’ growth. Bleomycin sulfate (Blenoxane) is the most popular preparation used in clinical research, and contains Bleomycin fractions of A2 and B2, which causes difficulties in quantitative analysis. This work uses the metal chelating property of Bleomycin as an advantage to simplify and improve sensitivity of existing quantitative methods. Copper was spiked in excess to plasma samples, followed …

Tying The Knot: Applications Of Topology To Chemistry, Tarini S. Hardikar

Honors Theses

Chirality (or handedness) is the property that a structure is “different” from its mirror image. Topology can be used to provide a rigorous framework for the notion of chirality. This project examines various types of chirality and discusses tools to detect chirality in graphs and knots. Notable theorems that are discussed in this work include ones that identify chirality using properties of link polynomials (HOMFLY polynomials), rigid vertex graphs, and knot linking numbers. Various other issues of chirality are explored, and some specially unique structures are discussed. This paper is borne out of reading Dr. Erica Flapan’s book, When Topology …

Supplemental Materials For Building Data And Information Literacy In The Undergraduate Chemistry Curriculum, Yasmeen Shorish, Barbara A. Reisner

Yasmeen Shorish

Course syllabus from Chem 481, Fall 2015, to supplement the chapter "Building Data and Information Literacy in the Undergraduate Chemistry Curriculum" in the monograph Integrating Library and Information Literacy Into Chemistry Curricula - ACS Symposium Series, ACS Publications.

Forensic Chemical Analysis Of Synthetic Cathinones Using Portable Mass Spectrometric Instrumentation, Caitlin N. Cain

Undergraduate Research Posters

Forensic laboratories face issues with large backlogs on evidence needing to be analyzed is due to two reasons: budgeting issues and the emergence of designer drugs. Currently, forensic laboratory directors cite that there are a shortage of scientists to deal with the yearly increase in caseloads. Additionally, designer drugs like synthetic cathinones, commonly known as “bath salts,” have increased the backlog due to the changing chemical compositions and misidentification as other compounds. Therefore, the use of a portable mass spectrometer for on-site forensic chemical analysis of synthetic cathinones would reduce the backlog of suspected controlled substances in forensic chemistry laboratories. …

Supplemental Materials For Building Data And Information Literacy In The Undergraduate Chemistry Curriculum, Yasmeen Shorish, Barbara A. Reisner

Department of Chemistry and Biochemistry - Faculty Scholarship

Course syllabus from Chem 481, Fall 2015, to supplement the chapter "Building Data and Information Literacy in the Undergraduate Chemistry Curriculum" in the monograph Integrating Library and Information Literacy Into Chemistry Curricula - ACS Symposium Series, ACS Publications.

Science Classics, Mark Masthay

Mark Masthay

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

The Importance Of Context: An Exploration Of Factors Influencing The Adoption Of Student-Centered Teaching Among Chemistry, Biology, And Physics Faculty, Travis J. Lund, Marilyne Stains

Chemistry Department: Faculty Publications

Background: Research at the secondary and postsecondary levels has clearly demonstrated the critical role that individual and contextual characteristics play in instructors’ decision to adopt educational innovations. Although recent research has shed light on factors influencing the teaching practices of science, technology, engineering, and mathematics (STEM) faculty, it is still not well understood how unique departmental environments impact faculty adoption of evidence-based instructional practices (EBIPs) within the context of a single institution. In this study, we sought to characterize the communication channels utilized by STEM faculty, as well as the contextual and individual factors that influence the teaching practices …

Icp-Oes Analysis Of The Chemical Composition Of Hypergolic Mixtures, Monique Jones

Undergraduate Research Posters

Hypergolic mixtures involve a chemical reaction between an oxidant and a fuel source. These reactions are self-igniting and can be performed using common household materials. The ease of access to the reactants, and delayed ignition have increased the occurrence of hypergolic mixtures in arson-related crimes and incendiary devices. Currently, few chemical signatures exist to link hypergolic residues to a perpetrator. This makes it difficult to obtain forensically relevant information from evidence during an investigation. A hypergolic reaction of interest to forensic laboratories involves combustion between a glycol-based fuel source and potassium permanganate. Past studies have determined that one can distinguish …

Development Of Presumptive And Confirmatory Analytical Methods For The Simultaneous Detection Of Multiple Improvised Explosives, Kelley L. Peters

FIU Electronic Theses and Dissertations

In recent years, there has been a dramatic increase in the use of improvised explosive devices (IEDs) due to ease of synthesis and improved controls placed on commercial/military explosives. Commonly used materials for IED preparations include fertilizers and industrial chemicals containing oxidizers such as ClO₃^-, ClO₄^-, and NO₃^-, as well as other less stable compounds, such as peroxides. Due to these materials having a wide range of volatility, polarity, and composition, detection can be challenging, increasing the amount of time before any analytical information on the identity of the explosive can …

Science Classics, Mark Masthay

Chemistry Faculty Publications

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

Stop Rotating! One Substitution Halts The B19- Motor, Francisco Cervantes-Navarro, Gerarso Martínez-Guajardo, Edison Osorio, Diego Moreno, William Tiznado, Rafael Islas, Kelling J. Donald, Gabriel Merino

Chemistry Faculty Publications

The B₁₉^- anion and other boron species have been dubbed ‘Wankel motors’ for the almost barrierless rotation of inner and outer concentric rings relative to each other in these compounds. A single substitution in B₁₉^- is shown to shut down the well-established fluxionality in the anion. A carbon atom substituted in the structure to give a neutral CB₁₈ species is shown computationally to enforce bond localization.

Acquisition Of An Electrochemical System Instrument For The Development Of Sensors, Elmer-Rico E. Mojico

Cornerstone 1 Reports : Expansion and Enhancements of the Thinkfinity Platform

No abstract provided.

Organic Thin-Film Transistors And Tips-Pentacene, Zachary Stewart

Lewis Honors College Capstone Collection

TIPS-Pentacene, an organic semiconductor characterized by its good electronic properties, solubility, and stability, is used primarily in organic thin-film transistors (OTFT). This research seeks to create an OTFT by crafting a stencil, depositing the source and drain onto a substrate’s surface, and processing TIPS-Pentacene onto the channel between them. In addition, if time permits, the electronic properties of several OTFTs will be compared to determine how to optimize their production.

Theoretical Design Of Stable Small Aluminium-Magnesium Binary Clusters, Edison Osorio, Alejandro Vasquez, Elizabeth Florez, Fanor Mondragon, Kelling J. Donald, William Tiznado

Chemistry Faculty Publications

We explore in detail the potential energy surfaces of the Al_xMg_y (x, y = 1–4) systems as case studies to test the utility and limitations of simple rules based on electron counts and the phenomenological shell model (PSM) for bimetallic clusters. We find that it is feasible to design stable structures that are members of this set of small Al–Mg binary clusters, using simple electron count rules, including the classical 4n + 2 Hückel model, and the most recently proposed PSM. The thermodynamic stability of the title compounds has been evaluated using several different descriptors, including …

Plane And Simple: Planar Tetracoordinate Carbon Centers In Small Moleculesw, Chad Crigger, Bernard K. Wittmaack, Marina Tawfik, Gabriel Merino, Kelling J. Donald

Chemistry Faculty Publications

A class of neutral 18-electron molecules with planar tetracoordinate carbon (ptC) centers is introduced. We show computationally that when n = 3 the neutral singlet molecule C(BeH)_n(BH₂)_4-n and other isoelectronic (18-valence electron) molecules of main group elements collapse from locally tetrahedral arrangements at the C-center to (near) planar tetracoordinate structures. For C(BeH)₃BH₂ and C(CH₃)(BH₂)Li₂, for example, the tetrahedral type conformation is not even a minimum on the potential energy surface at the B3PW91, MP2(full), or CCSD levels of theory. The Mg analogue C(MgH)₃BH_{2 …}

Cbe5e− (E = Al, Ga, In, Tl): Planar Pentacoordinate Carbon In Heptaatomic Clusters, Abril C. Castro, Gerarso Martinez-Guajardo, Thomas Johnson, Jesus M. Ugalde, Yan-Bo Wu, Jose M. Mercero, Thomas Heine, Kelling J. Donald, Gabriel Merino

Chemistry Faculty Publications

A series of clusters with the general formula CBe₅E^- (E = Al, Ga, In, Tl) are theoretically shown to have a planar pentacoordinate carbon atom. The structures show a simple and rigid topological framework—a planar EBe4 ring surrounding a C center, with one of the ring Be–Be bonds capped in-plane by a fifth Be atom. The system is stabilized by a network of multicenter σ bonds in which the central C atom is the acceptor, and π systems as well by which the C atom donates charge to the Be and E atoms that encircle it.

The Development Of An Effective Water-Soluble Receptor For Pyrene Derivative Dyes, Ashley Longstreet

Undergraduate Theses and Capstone Projects

A receptor with enhanced water solubility was synthesized from an existing receptor to be used as a pyranine fluorescence quencher in endovesiculation detection assays. The existing receptor consisted of a cyclen core with four protruding arms containing an aryl nitro group at each end. Its poor water solubility limited the accuracy and precision of the endovesiculation assay because the low concentration of receptor did not match the concentration of pyranine. To increase the water solubility, ethoxy groups were attached to the ends of each arm by first selectively reducing the nitro group to an amine with NaBHU4, H2, and a …