Chemistry Commons^™

Highly Swelling Ph-Responsive Microgels For Dual Mode Near Infra-Red Fluorescence Reporting And Imaging, Mingning Zhu, Dongdong Lu, Qing Lian, Shanglin Wu, Wenkai Wang, L. Andrew Lyon, Weiguang Wan, Paulo Bártolo, Mark Dickinson, Brian R. Saunders

Engineering Faculty Articles and Research

Near infra-red (NIR) fluorescence is a desirable property for probe particles because such deeply penetrating light enables remote reporting of the local environment in complex surroundings and imaging. Here, two NIR non-radiative energy transfer (NRET) fluorophores (Cy5 and Cy5.5) are coupled to preformed pH-responsive poly(ethylacrylate-methacrylic acid-divinylbenzene) microgel particles (PEA-MAA-5/5.5 MGs) to obtain new NIR fluorescent probes that are cytocompatible and swell strongly. NIR ratiometric photoluminescence (PL) intensity analysis enables reporting of pH-triggered PEA-MAA-5/5.5 MG particle swelling ratios over a very wide range (from 1–90). The dispersions have greatly improved colloidal stability compared to a reference temperature-responsive NIR MG based on …

Multicourse Comparative Study Of The Core Aspects For Flipped Learning: Investigating In-Class Structure And Student Use Of Video Resources, Nicole Naibert, Emryse Geye, Michael M. Phillips, Jack Barbera

Chemistry Faculty Publications and Presentations

Since 2013, the number of publications on flipped learning within chemistry have steadily increased. However, most of these studies focus on flipped course reforms within individual institutions, while the outcomes of any learning environment are dependent on how the environment is structured and the degree to which students interact with its elements. In this study, we apply a coordinated set of assessment practices to investigate similarities among flipped chemistry courses at five institutions in the United States. All courses in the study followed the two basic tenets of flipped learning: (1) foundational information was delivered through preclass materials (PCMs), and …

Erratum: Basis Set Dependence Of Higher-Order Correlation Effects In Π -Type Interactions (J. Chem. Phys. (2012) 136 (014103) Doi: 10.1155/2019/4057848), Emily J. Carrell, Cara M. Thorne, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

For a sequence of three correlation consistent basis sets,1 an algebraic expression can be obtained from Feller's three-parameter exponential function for the complete basis set (CBS) limit of the Hartree–Fock (HF) energy.2 During the derivation of a general three-point algebraic expression for the HF CBS limit,3 it was recognized that Eq. (2) in our original paper4 had the wrong sign in the last term in the denominator. The correct equation is as follows: (Formula Presented). (Table Presented).

Second Harmonic Generation Spectroscopy And Microscopy Of Liposomes, Nanoparticles, And Cells, Prakash Hamal

LSU Doctoral Dissertations

Second harmonic generation (SHG) is used to investigate the factors that impact nanoparticle-based drug-delivery applications. In the first study, molecular adsorption and transport kinetics of a positively-charged dye, malachite green isothiocyanate (MGITC), is characterized at the surface of different colloidal liposomes in water using SHG spectroscopy. The molecular interactions of MGITC is compared to our previous investigations with malachite green (MG). In comparison to MG, MGITC demonstrates stronger adsorption and faster transport through lipid membranes. Correspondingly, the SHG experimental results are in excellent agreement with the molecular dynamics (MD) simulations results. A key finding illustrates the importance of functional groups, …

Near Simultaneous Laser Scanning Confocal And Atomic Force Microscopy (Conpokal) On Live Cells, Joree N. Sandin, Surya P. Aryal, Thomas E. Wilkop, Christopher I. Richards, Martha E. Grady

Physiology Faculty Publications

Techniques available for micro- and nano-scale mechanical characterization have exploded in the last few decades. From further development of the scanning and transmission electron microscope, to the invention of atomic force microscopy, and advances in fluorescent imaging, there have been substantial gains in technologies that enable the study of small materials. Conpokal is a portmanteau that combines confocal microscopy with atomic force microscopy (AFM), where a probe "pokes" the surface. Although each technique is extremely effective for the qualitative and/or quantitative image collection on their own, Conpokal provides the capability to test with blended fluorescence imaging and mechanical characterization. Designed …

H-Atom Ladder Operator Revisited, Carl W. David

Chemistry Education Materials

An error laden note (Am. J. Phys., 34, 984,(1966)) concerning the ladder operator solution to the hydrogen atom electronic energy levels is corrected.

Isolation, Structure Elucidation, And Synthesis Of Natural Products From Marine Cyanobacteria, Keren Solomon

Electronic Theses and Dissertations

This thesis describes the isolation, structure elucidation, and synthesis of natural products from marine cyanobacteria. A crude extract from a cyanobacterium collected in Curacao showed selective affinity for the dopamine D₅ receptor in a screen against a panel of CNS receptors. Due to the high similarity of the D₅ and D₁ receptor, to date there are no known ligands that differentiate them. Attempts to purify the compound responsible for this affinity led to the isolation of the known compound caylobolide A. A second extract from a cyanobacterium collected in Panama underwent bioassay-guided fractionation and yielded the novel …

Advanced Solid-State Lithium Batteries For Electric Vehicles, Yelsin Mendez Camacho

International Programs

Solid-state lithium batteries (SSLBs) may have the potential to safe and long-distance driving in electric-vehicles (EV). […] However, manufacturing processes and new materials need to be developed to make these batteries commercially available.

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 …

Electroactive Anion Receptor With High Affinity For Arsenate, Samuel I. Etkind, Douglas A. Vander Griend, Timothy M. Swager

University Faculty Publications and Creative Works

Herein, we present the synthesis and characterization of a macrocyclic polyamide cage that incorporates redox-active 1,4-dithiin units. UV/vis titration experiments with eight anions in acetonitrile revealed high affinity for H2AsO4− (log β2 = 10.4−+0.40.4) and HCO3− (log β2 = 8.3−+0.30.4) over other common anionic guests, such as Cl− (log K1:1 = 3.20−+0.030.02), HSO4− (log K1:1 = 3.57−+0.020.03), and H2PO4− (log K1:1 = 4.24−+0.050.04), by the selective formation of HG2 complexes. The recognition of arsenate over phosphate is rare among both proteins and synthetic receptors, and though the origin of selectivity is not known, exploiting the difference in the binding stoichiometry …

Structure And Function Of A Flavin-Dependent S-Monooxygenase From Garlic (Allium Sativum), Hannah Valentino, Ashley C. Campbell, Jonathan P. Schuermann, Nazneen Sultana, Han G. Nam, Sophie Leblanc, John J. Tanner, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Allicin is a component of the characteristic smell and flavor of garlic (Allium sativum). A flavin-containing monooxygenase (FMO) produced by A. sativum (AsFMO) was previously proposed to oxidize S-allyl-L-cysteine (SAC) to alliin, an allicin precursor. Here, we present a kinetic and structural characterization of AsFMO that suggests a possible contradiction to this proposal. Results of steady-state kinetic analyses revealed that AsFMO exhibited negligible activity with SAC; however, the enzyme was highly active with L-cysteine, N-acetyl-L-cysteine, and allyl mercaptan. We found that allyl mercaptan with NADPH was the preferred substrate-cofactor combination. Rapid-reaction kinetic analyses showed that NADPH binds tightly (KD of …

University Of Kentucky Measurements Of Wind, Temperature, Pressure And Humidity In Support Of Lapse-Rate Using Multisite Fixed-Wing And Rotorcraft Unmanned Aerial Systems, Sean C. C. Bailey, Michael P. Sama, Caleb A. Canter, Luis Felipe Pampolini, Zachary S. Lippay, Travis J. Schuyler, Jonathan D. Hamilton, Sean B. Macphee, Isaac S. Rowe, Christopher D. Sanders, Virginia G. Smith, Christina N. Vezzi, Harrison M. Wight, Jesse B. Hoagg, Marcelo I. Guzman, Suzanne Weaver Smith

Mechanical Engineering Faculty Publications

In July 2018, unmanned aerial systems (UASs) were deployed to measure the properties of the lower atmosphere within the San Luis Valley, an elevated valley in Colorado, USA, as part of the Lower Atmospheric Profiling Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE). Measurement objectives included detailing boundary layer transition, canyon cold-air drainage and convection initiation within the valley. Details of the contribution to LAPSE-RATE made by the University of Kentucky are provided here, which include measurements by seven different fixed-wing and rotorcraft UASs totaling over 178 flights with validated data. The data from these coordinated UAS flights …

Formation Of Gaseous Proteins Via The Ion Evaporation Model (Iem) In Electrospray Mass Spectrometry., Elnaz Aliyari, Lars Konermann

Chemistry Publications

The mechanisms whereby protein ions are released into the gas phase from charged droplets during electrospray ionization (ESI) continue to be controversial. Several pathways have been proposed. For native ESI the charged residue model (CRM) is favored; it entails the liberation of proteins via solvent evaporation to dryness. Unfolded proteins likely follow the chain ejection model (CEM), which involves the gradual expulsion of stretched-out chains from the droplet. According to the ion evaporation model (IEM) ions undergo electrostatically driven desorption from the droplet surface. The IEM is well supported for small precharged species such as Na⁺. However, it …

Building An Ins-1 Cdna Library For A Genome-Wide Crispr-Cas9 Screen, Idongesit Ekpo

Undergraduate Honors Theses

By the year 2040, an estimated 642 million people are expected to have diabetes globally. Diabetes results from an elevation of metabolic stressors, such as glucotoxicity, lipotoxicity, oxidative stress and apoptosis. In type 2 diabetes, these stressful conditions contribute to the malfunction and loss of functional insulin-producing β-cells. Current treatment methods for diabetes include insulin therapy, islet transplant and anti-diabetes medication. These treatments are not curative and ignore other factors that contribute to the pathogenesis of diabetes beyond insulin resistance and islet β-cell failure. Previous research on β-cells has focused on ways to replace functional β-cell mass, trigger β-cell proliferation, …

Structure And Unprecedented Reactivity Of A Mononuclear Nonheme Cobalt(Iii) Iodosylbenzene Complex, J. Yang, M. S. Seo, K. H. Kim, Y. M. Lee, S. Fukuzumi, Jason M. Shearer, W. Nam

Chemistry Faculty Research

A mononuclear nonheme cobalt(III) iodosylbenzene complex, [Co^III(TQA)(OIPh)(OH)]²⁺ (1), is synthesized and characterized structurally and spectroscopically. While 1 is a sluggish oxidant in oxidation reactions, it becomes a competent oxidant in oxygen atom transfer reactions, such as olefin epoxidation, in the presence of a small amount of proton. More interestingly, 1 shows a nucleophilic reactivity in aldehyde deformylation reaction, demonstrating that 1 has an amphoteric reactivity. Another interesting observation is that 1 can be used as an oxygen atom donor in the generation of high-valent metal-oxo complexes. To our knowledge, we present the first crystal structure …

Nowotny Chimney Ladder Phases With Group 5 Metals: Crystal And Electronic Structure And Relations To The Crsi2 Structure Type, Evgney V. Dikarev, Zheng Wei, Maxim S. Likhanov, Nikita V. Sytov, Andrei V. Shevelkov

Chemistry Department Faculty Scholarship

Nowotny chimney ladder (NCL) phases are intermetallic compounds formed by transition metals and metals of groups 13 and 14. This family can be expanded by combining two p-elements from different groups with those transition metals, for which the corresponding binary NCL phases are unknown. In this paper, we present three new compounds in the V-Al-Ge, Nb-Al-Ge, and Nb-Ga-Ge systems related to the TiSi₂ structure type (Sp. Gr. Fddd) obtained with the standard ampule technique. The crystal structures of the new compounds were determined using synchrotron powder X-ray diffraction data. A transition to the CrSi₂ structure type was detected …

Response Of Photoluminescence Of H-Terminated And Hydrosilylated Porous Si Powders To Rinsing And Temperature, Kurt W. Kolasinski, Joseph D. Swanson, Benjamin Roe, Teresa Lee

Chemistry Faculty Publications

The photoluminescence (PL) response of porous Si has potential applications in a number of sensor and bioimaging techniques. However, many questions still remain regarding how to stabilize and enhance the PL signal, as well as how PL responds to environmental factors. Regenerative electroless etching (ReEtching) was used to produce photoluminescent porous Si directly from Si powder. As etched, the material was H-terminated. The intensity and peak wavelength were greatly aected by the rinsing protocol employed. The highest intensity and bluest PL were obtained when dilute HCl(aq) rinsing was followed by pentane wetting and vacuum oven drying. Roughly half of the …

Synthesis And Assessment Of Radiotherapy-Enhancing Nanoparticles, Hayden Winter

Dissertations and Theses

Radiation Therapy (RT) is a common treatment for cancerous lesions that acts by ionizing matter in the affected tissue, causing cell death. The disadvantage of RT is that it is most often delivered via an external beam of radiation which must pass through healthy tissues to reach the target site, ionizing matter within healthy tissues as well. To address this drawback, techniques are being developed for increasing RT-induced cell death in a target tissue while minimizing cell death in surrounding tissues. This effect is known as radiation dose enhancement or RT enhancement.

The approach to RT enhancement studied in this …

Synthesis Of Alpha-Methylselenocysteine, Its Relevant Analogues, And An Unnatural Glutathione Disulfide Core, Robert J. Wehrle

Dissertations

Selenoproteins, such as glutathione peroxidase, have gained interest for their ability to act as antioxidants, and their potential to act as anti-cancer agents. Synthesizing and studying selenoproteins can be problematic, however, due to their propensity to degrade from over-oxidation. The degradation from over-oxidation can be avoided by the incorporation of the unnatural amino acid, alpha-methylselenocysteine. A synthesis utilizing methyl malonic esters was used to synthesize protected (R)-alpha-methylselenocysteine efficiently (46% over four steps) and in high enantio-purity (88% enantiomeric excess). Using similar procedures, the (S)-enantiomer was also synthesized as well as a beta-analogue.

The use of enzymes …

Machine Learning Approaches For Improving Prediction Performance Of Structure-Activity Relationship Models, Gabriel Idakwo

Dissertations

In silico bioactivity prediction studies are designed to complement in vivo and in vitro efforts to assess the activity and properties of small molecules. In silico methods such as Quantitative Structure-Activity/Property Relationship (QSAR) are used to correlate the structure of a molecule to its biological property in drug design and toxicological studies. In this body of work, I started with two in-depth reviews into the application of machine learning based approaches and feature reduction methods to QSAR, and then investigated solutions to three common challenges faced in machine learning based QSAR studies.

First, to improve the prediction accuracy of learning …

Structures Of Disodium Hydrogen Citrate Monohydrate, Na2hc6h5o7(H2o), And Diammonium Sodium Citrate, (Nh4)2nac6h5o7, From Powder Diffraction Data, Jerry Hong '20, Shivang Bhaskar, Joseph T. Golab, James A. Kaduk

Student Publications & Research

No abstract provided.

California - Peralta Weigh Station, University Of Denver

FEAT Heavy-Duty Vehicle Measurements

Relevant Publications

Environmental Science & Technology Publication (2001)

Environmental Science & Technology Publication (2012)

Environmental Science & Technology Publication (2013)

Environmental Science & Technology Publication (2018)

Air & Waste Management Journal (2021)

2008 Final Report

2009 Final Report

2010 Final Report

2012 Final Report

2017 Final Report

Texas - San Marcos Weigh Station 1998, University Of Denver

FEAT Heavy-Duty Vehicle Measurements

Relevant Publications

Environmental Science & Technology Publication

Final Report

Novel Detection Methods And Gas-Free Hydroxide Eluent Generator For Capillary Liquid/Ion Chromatography, Bikash Chouhan

Chemistry & Biochemistry Dissertations - Archive

The light absorbed by a molecule, except for an efficient fluorophore, is mostly converted into heat, thereby causing a change in temperature. In a liquid flow system, this change in temperature results in changes in the refractive index (RI) and electrical conductivities of the solution. Photothermal measurement of optical absorption (PMOA) most often involves detecting the temperature change indirectly by measuring changes in pressure, RI, or conductivity. In a small-bore capillary, the PMOA detection technique has some distinct advantages: (a) no penalty is paid for smaller path length, (b) there are no stray light issues, and (c) a broadband light …

New Strategies For Hydrosilylation Of Propargyl Alcohols, Olefin Polymerization And On-Chip Organic Synthesis, Udaya Sree Dakarapu

Chemistry & Biochemistry Dissertations - Archive

The research described in this dissertation is on three different projects namely i) design and synthesis of traceless hydrosilyl acetal-directed, exo-syn hydrosilylation of propargyl alcohols to produce α-hydroxy (E)-vinylsilanes, ii) alkali metal lewis base-catalyzed, complexation-induced hydrogen atom transfer (LBCI-HAT) olefin polymerization and iii) on-chip organic synthesis enabled by engine-and-cargo on an electrowetting-on-dielectric digital microfluidic (EWOD) device. The first chapter is focused on the design and synthesis of traceless hydrosilyl acetal-directed, exo-syn hydrosilylation of propargyl alcohols to produce α-hydroxy (E)-vinylsilanes. Transition metal-catalyzed regioselective intramolecular hydrosilylation of propargylic alcohols utilizing easily accessible, inexpensive, and readily installable hydrosilyl acetals as a directing group …

Synthesis, Study, And Applications Of Highly Fluorinated Copper Pyrazolate Complexes Of Small Alkene, Alkynes And Carbon Monoxide, Devaborniny Parasar

Chemistry & Biochemistry Dissertations - Archive

Trinuclear copper pyrazolate complexes (copper trimers) function as excellent precursors to synthesize multinuclear complexes of copper. Using highly fluorinated pyrazolates as supporting ligands, we have successfully synthesized and isolated several unique complexes of copper with alkene (e.g., ethylene), alkynes (e.g., 3-hexyne, butyne, acetylene, etc.) and carbon monoxide from the copper trimers. Synthetic details, solid-state structures, and physico-chemical properties of a series of multinuclear complexes have been studied. Chapter 2 of this research work focuses on the olefin/paraffin separation technology. For this we have succesfully synthesized a novel, highly fluorinated copper pyrazolate complex, that undergoes remarkable structural rearrangement forming a dinuclear …

Designing A Reactor Chamber For Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn Merrill, Bingjie Zhang, Jerry Larue

SURF Posters and Papers

Catalysis provides pathways for efficient and selective chemical reactions by lowering the energy barriers for desired products. Gold nanoparticles (AuNPs) show excellent promise as plasmonic catalysts. Plasmonic materials have localized surface plasmon resonances, oscillations of the electron bath at the surface of a nanoparticle, that generate energetically intense electric fields which rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize atoms strongly bound to the catalysts through occupation of antibonding orbitals. Tuning the antibonding orbitals to make them accessible for occupancy by electrons is achieved by coating the AuNP in a thin layer of another …

Investigation Of Computational Determination Of Elastic Properties For Silicon Nitride And Silicon Carbonitride Materials, Timothy Aaron West

Chemistry & Biochemistry Theses - Archive

Silicon nitride and silicon carbonitride materials are versatile materials exhibiting useful properties at high temperatures and pressures. This study investigates the use of molecular dynamics simulations to determine the elastic properties of these materials. Elastic constants and moduli are determined for a series of crystalline and amorphous silicon nitride materials and amorphous silicon carbonitride materials employing Tersoff, Garofalini, and Marian-Gastreich two-body empirical potentials. Our results show that the Tersoff empirical potential is best suited of the three under study to elastic property determination. Results also show that the elastic behavior of silicon carbonitride is highly dependent on the morphology of …

California - Port Of Los Angeles, University Of Denver

FEAT Heavy-Duty Vehicle Measurements

Relevant Publications

Environmental Science & Technology Publication (2012)

Environmental Science & Technology Publication (2013)

2008 Final Report

2009 Final Report

2010 Final Report

2012 Final Report

Colorado - Dumont Weigh Station, University Of Denver

FEAT Heavy-Duty Vehicle Measurements

Relevant Publications

Environmental Science & Technology Publication (2001)

Environmental Science & Technology Publication (2006)

Thesis