Persistent Dopants And Phase Segregation In Organolead Mixed-Halide Perovskites, 2019 Iowa State University
Persistent Dopants And Phase Segregation In Organolead Mixed-Halide Perovskites, Bryan A. Rosales, Long Men, Sarah D. Cady, Michael P. Hanrahan, Aaron J. Rossini, Javier Vela
Organolead mixed-halide perovskites such as CH3NH3PbX3–aX′a (X, X′ = I, Br, Cl) are interesting semiconductors because of their low cost, high photovoltaic power conversion efficiencies, enhanced moisture stability, and band gap tunability. Using a combination of optical absorption spectroscopy, powder X-ray diffraction (XRD), and, for the first time, 207Pb solid state nuclear magnetic resonance (ssNMR), we probe the extent of alloying and phase segregation in these materials. Because 207Pb ssNMR chemical shifts are highly sensitive to local coordination and electronic structure, and vary linearly with halogen electronegativity and band gap, this technique can provide the true chemical speciation and ...
Cu2znsns4 Nanorods Doped With Tetrahedral, High Spin Transition Metal Ions: Mn2+, Co2+, And Ni2+, 2019 Iowa State University
Cu2znsns4 Nanorods Doped With Tetrahedral, High Spin Transition Metal Ions: Mn2+, Co2+, And Ni2+, Michelle J. Thompson, Kyle J. Blakeney, Sarah D. Cady, Malinda D. Reichert, Joselyn Del Pilar-Albaladejo, Seth T. White, Javier Vela
Because of its useful optoelectronic properties and the relative abundance of its elements, the quaternary semiconductor Cu2ZnSnS4 (CZTS) has garnered considerable interest in recent years. In this work, we dope divalent, high spin transition metal ions (M2+ = Mn2+, Co2+, Ni2+) into the tetrahedral Zn2+ sites of wurtzite CZTS nanorods. The resulting Cu2MxZn1–xSnS4 (CMTS) nanocrystals retain the hexagonal crystalline structure, elongated morphology, and broad visible light absorption profile of the undoped CZTS nanorods. Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and infrared (IR) spectroscopy help corroborate the composition and local ion environment of the doped nanocrystals ...
The Roundtable Of Scientific Communication: From Classroom To Course Creation, Back To Classroom And Beyond, 2019 University of New Orleans
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 ...
Development Of A Screening Method For Drugs Of Abuse By Direct Analysis Of Dried Urine Spots Coupled To Mass Spectrometry, 2019 John Jay College of Criminal Justice
Development Of A Screening Method For Drugs Of Abuse By Direct Analysis Of Dried Urine Spots Coupled To Mass Spectrometry, Melanie Goldstein
Fast and easy screening procedures are essential in any forensic toxicology laboratory to differentiate negative samples from presumptive positive cases. Immunoassay techniques, such as enzyme multiplied immunoassay technique (EMIT), are routinely employed as screening procedures. However, these techniques lack specificity (only differentiate group of drugs and not individual compounds) and it is difficult to add new compounds to the panel. Direct analysis of dried urine spots (DUS) by mass spectrometry (MS) offers a novel strategy to overcome these issues. DUS offer an improved storage alternative for biological samples, reducing costs and space requirements. In this work, an original method to ...
Toward Mass Spectrometry Imaging In The Metabolomics Scale: Increasing Metabolic Coverage Through Multiple On-Tissue Chemical Modifications, Maria Emilia Dueñas, Evan A. Larson, Young Jin Lee
Exploring the metabolic differences directly on tissues is essential for the comprehensive understanding of how multicellular organisms function. Mass spectrometry imaging (MSI) is an attractive technique toward this goal; however, MSI in metabolomics scale has been hindered by multiple limitations. This is most notable for single cell level high-spatial resolution imaging because of the limited number of molecules in small sampling size and the low ionization yields of many metabolites. Several on-tissue chemical derivatization approaches have been reported to increase MSI signals of targeted compounds, especially in matrix-assisted laser desorption/ionization (MALDI)- MSI. Herein, we adopt a combination of chemical ...
Using Molecular Dynamics To Study Qs21 Interactions And Penetration Of Lipid-Cholesterol Bilayers, 2019 The University of Western Ontario
Using Molecular Dynamics To Study Qs21 Interactions And Penetration Of Lipid-Cholesterol Bilayers, Sarai Guerrero, Mikko Karttunen
Western Research Forum
Saponins have been used as adjuvant agents for decades in vaccines and therapies, but none are as well studied or heavily used as QS-21. This achievement is notwithstanding the fact that QS-21 usage is limited by its stability, toxicity, and scarcity. These shortcomings have only pushed researchers to develop and experiment with artificial recreations of the saponin to harness its unique benefits. A considerable number of research hours have been poured into this topic, but like QS-21 there is a shortcoming here as well. The number of articles that look at QS-21 interactions with the bilayer or the conditions under ...
Isotopically-Resolved Neutron Cross Sections As Probe Of The Nuclear Optical Potential, 2019 Washington University in St. Louis
Isotopically-Resolved Neutron Cross Sections As Probe Of The Nuclear Optical Potential, Cole Davis Pruitt
Arts & Sciences Electronic Theses and Dissertations
Neutron scattering experiments provide direct access to the forces experienced by nucleons in the nuclear environment. Due to the experimental difficulty of cross section measurements with neutrons, isotopically-resolved neutron scattering cross sections are sorely needed as inputs for many nuclear models. This dissertation presents the results from a campaign of isotope-specific neutron total cross section measurements on 16,18O, 58,64Ni, 112,124Sn, and 103Rh from 3-450 MeV and elastic scattering differential cross section measurements on 112,nat,124Sn at 11 and 17 MeV. Equipped with these new data and with computational improvements to the Dispersive Optical Model (DOM), we ...
Obscurin Is A Semi-Flexible Molecule In Solution, 2019 James Madison University
Obscurin Is A Semi-Flexible Molecule In Solution, Jacob Whitley
Senior Honors Projects, 2010-current
Obscurin, a giant modular cytoskeletal protein, is comprised mostly of tandem immunoglobulin-like (Ig-like) domains. This architecture allows obscurin to connect distal targets within the cell. The linkers connecting the Ig domains are usually short (3-4 residues). The physical effect arising from these short linkers is not known; such linkers may lead to a stiff elongated molecule or, conversely, may lead to a more compact and dynamic structure. In an effort to better understand how linkers affect obscurin flexibility, and to better understand the physical underpinnings of this flexibility, here we study the structure and dynamics of four representative sets of ...
Computational Studies Of Small Molecule Activation In Catylsis And Green Chemistry, 2019 University of Tennessee, Knoxville
Computational Studies Of Small Molecule Activation In Catylsis And Green Chemistry, Alexa N. Griffith Ms.
Chancellor’s Honors Program Projects
No abstract provided.
Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, 2019 The Graduate Center, City University of New York
Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, Glenn O. Ralph
All Dissertations, Theses, and Capstone Projects
Organometallic reagents containing the tin-carbon bond are used extensively in modern synthetic chemistry for the formation of new bonds to carbon. Over recent decades, transition metal catalyzed cross coupling reactions between two C(sp2) centers have been widely developed. However, the introduction of a C(sp3) center complicates the catalytic cycle, and opens unproductive chemical pathways which lead to isomerization, elimination, and racemization. Our lab has developed a modified-Stille reaction to combat the deleterious effects of β-hydride elimination. Our protocol enables unactivated 2° alkyl organotin nucleophiles to undergo efficient cross coupling reactions with C(sp2) electrophiles, avoiding ...
The Effects Of Ph On The Kinetics Of The Follow-Up Reaction Of Dopamine O-Quinone, 2019 University of San Francisco
The Effects Of Ph On The Kinetics Of The Follow-Up Reaction Of Dopamine O-Quinone, Cyril Fong, Ziming Dong
Creative Activity and Research Day - CARD
The electrochemical studies of dopamine have been conducted for many years due to dopamine’s importance as a neurotransmitter and its function in daily life for individuals. Dopamine undergoes electrochemical redox reactions in which the different products can be detected by cyclic voltammetry.3 The focus of the experiments was to determine the pH range at which dopamine o-quinone would undergo cyclization as well as the relationship between the rate of cyclization as pH in the physiological range. The measurements were taken using a gold working electrode vs. a Ag/AgCl (1 M KCl) reference electrode. It was observed that ...
A Comparative Study Of Cryoballoon, Radiofrequency, And Laser Ablations For The Treatment Of Atrial Fibrillation, 2019 Western Michigan University
A Comparative Study Of Cryoballoon, Radiofrequency, And Laser Ablations For The Treatment Of Atrial Fibrillation, Amanda Croft
Atrial fibrillation (AF) is both a prevalent and life debilitating arrhythmia. It presents in the form of chronic fatigue, strokes, palpitations, and tachycardia. There is currently a wide variety of treatment options including antiarrhythmic drugs and procedures such as cardioversions. Unfortunately, the medical field offers few long-term solutions. Catheter ablations, however, are promising technology whose technological advancement is shedding light on a real AF solution. This study explores the safety and efficacy of three major ablation techniques: cryoballoon, radiofrequency, and laser ablation. This comparative study investigates the occurrence rates of complications such as groin hematomas, thromboembolic events, and phrenic nerve ...
Nanogels And Microgels: From Model Colloids To Applications, Recent Developments, And Future Trends, 2019 Heinrich-Heine-University
Nanogels And Microgels: From Model Colloids To Applications, Recent Developments, And Future Trends, Mattias Karg, Andrij Pich, Thomas Hellweg, Todd Hoare, L. Andrew Lyon, J. J. Crassous, Daisuke Suzuki, Rustam A. Gumerov, Stefanie Schneider, Igor I. Potemkin, Walter Richtering
Engineering Faculty Articles and Research
Nanogels and microgels are soft, deformable, and penetrable objects with an internal gel-like structure that is swollen by the dispersing solvent. Their softness and the potential to respond to external stimuli like temperature, pressure, pH, ionic strength, and different analytes make them interesting as soft model systems in fundamental research as well as for a broad range of applications, in particular in the field of biological applications. Recent tremendous developments in their synthesis open access to systems with complex architectures and compositions allowing for tailoring microgels with specific properties. At the same time state-of-the-art theoretical and simulation approaches offer deeper ...
Monitoring Transverse Relaxation Times Of Kerosene-Adulterated Diesel Using Low-Field Nuclear Magnetic Resonance Spectroscopy, 2019 Harrisburg University of Science and Technology
Monitoring Transverse Relaxation Times Of Kerosene-Adulterated Diesel Using Low-Field Nuclear Magnetic Resonance Spectroscopy, Tristen Rumbaugh
Experiential Learning Projects
Time-domain nuclear magnetic resonance spectroscopy (TD-NMR) and low-field nuclear magnetic resonance spectroscopy (LF-NMR) are different techniques that vary in the range of magnetic field strengths that they use, which is a determining factor for the type of analysis that can be done. In this study, LF-NMR was used to perform a time-domain analysis of petroleum products, diesel and kerosene. This is a type of analysis which is typically performed using TD-NMR. Diesel and kerosene are two petroleum products that have different characteristics such as viscosity, boiling point, and hydrocarbon length. Diluting, or adulterating, diesel fuels with kerosene is a common ...
Dentin Biomodification Potency Of Proanthocyanidins, 2019 Taylor University
Dentin Biomodification Potency Of Proanthocyanidins, David J. Ryker
Student Scholarship: Chemistry
No abstract provided.
A Chemical Overview Of Opioid Receptors And Their Agonists, 2019 Taylor University
A Chemical Overview Of Opioid Receptors And Their Agonists, Noah Kuszak
Student Scholarship: Chemistry
This work is a brief overview of the three main opioid receptors and some current research of the ways we can change the agonists and how they affect the opioid receptor pathway.
Drug Improvement And Design Involving G-Protein Coupled Receptors, 2019 Taylor University
Drug Improvement And Design Involving G-Protein Coupled Receptors, Gabriel Saliba
Student Scholarship: Chemistry
No abstract provided.
Ligand-Protein Binding Of Cantharidin And Norcantharidin On Hsf1: A Docking Study, 2019 La Salle University
Ligand-Protein Binding Of Cantharidin And Norcantharidin On Hsf1: A Docking Study, Daniel Coyle
Previous research provides experimental evidence that cantharidin acts as an inhibitor of HSF1 in cancer cells whereas the similar norcantharidin exhibits no inhibitory activity on HSF1. This computational study utilized Autodock to suggest both binding site(s) and binding energies of cantharidin and norcantharidin on HSF1. This study found cantharidin to consistently bind stronger than norcantharidin in the same area on HSF1 when assuming a rigid protein structure.
Seasonal Origins Of Soil Water Used By Trees, 2019 ETH Zurich
Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source for ...
An Experimental And Numerical Investigation Of Flow Accelerated Flibe Corrosion, 2019 University of New Mexico
An Experimental And Numerical Investigation Of Flow Accelerated Flibe Corrosion, David B. Weitzel
Nuclear Engineering ETDs
Renewed interest in molten salt reactor technology has brought to light the need for a better understanding of FLiBe corrosion. To this end a flowing FLiBe corrosion test loop was designed to test the flow effects of FLiBe corrosion. The loop consists of a pump, melt tank, and stainless-steel tubing assembly that heats the molten salt to high temperatures and circulates it over test specimens. The experiment has been constructed and has completed initial shakedown testing.
To support the flowing FLiBe experiment, a numerical corrosion model that couples FLiBe electrochemistry, solid metal diffusion, and mass transport was implemented. The model ...