Digital Commons Network^™

Derivation Of Tropospheric Methane From Tccon Ch4 And Hf Total Column Observations, K. M. Saad, D. Wunch, P. Bernath, C. Boone, B. Connor, N. M. Deutscher, D.W.T. Griffith, R. Kivi, J. Notholt, C. Roehl, M. Schneider, V. Sherlock, P. O. Wennberg

Chemistry & Biochemistry Faculty Publications

The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CH₄). Temporal variability in the total column of CH₄ due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local surface fluxes that are critical for understanding CH₄ sources and sinks. We reduce the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CH₄ derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for …

Bubbles: A Review Of Their Relationship To The Formation Of Thin Films And Porous Materials, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Fluorescence Off-On Sensors For F-, K+, Fe3+, And Ca2+ Ions, Binglin Sui

Electronic Theses and Dissertations

Fluorescence spectroscopy has been considered to be one of the most important research techniques in modern analytical chemistry, biochemistry, and biophysics. At present, fluorescence is a dominant methodology widely used in a great number of research domains, including biotechnology, medical diagnostics, genetic analysis, DNA sequencing, flow cytometry, and forensic analysis, to name just a few. In the past decade, with the rapid development of fluorescence microscopy, there has been a considerable growth in applying fluorescence technique to cellular imaging. The distinguished merits of fluorescence techniques, such as high sensitivity, non-invasiveness, low cytotoxicity, low cost, and convenience, make it a promising …

Synthesis And Study Of Chemo-Hydrothermally Derived Water-Soluble Chitosan And Chiosan-Metal Oxide Composites, Srijita Basumallick

Electronic Theses and Dissertations

Chitosan (CS) is a man-made sugar based biopolymer derived from chitin, the second most abundant natural polymer after cellulose. Chitin is sourced from crustacean species such as shrimps and crabs. The chemical structure of chitin contains N-Acetyl D-glucosamine monomer units which forms CS upon deacetylation. In CS, ?-(1-4) linked D-glucosamine units are randomly distributed. Approximately 75% - 80% sugar units contains primary amine groups in commercially available low molecular weight CS. Biodegradability, low toxicity, mucoadhesive and transfecting properties of CS polymer are attractive for applications as oral and nasal drug delivery systems. Chitosan polymer is water insoluble at neutral pH. …

Art Or Science?, Allison Marsh

Section 3: Imaging the Fast Moving

No abstract provided.

Vanadium Complexes Are In Vitro Inhibitors Of Leishmania Secreted Acid Phosphatases, Richard Mendez, Benjamin M. Dorsey, Craig C. Mclauchlan, Matt Beio, Timothy L. Turner, Victoria H. Nguyen, Alexander Su, William Beynon, Jon A. Friesen, Marjorie A. Jones

Faculty Publications – Chemistry

Leishmaniasis is a parasitic disease caused by the protozoa Leishmania. These organisms secrete acid phosphatases during their growth cycle as an important part of cell targeting to host macrophage cells thus allowing for a successful infection. Secreted acid phosphatases (SAP) are reported to play a significant role in the survival of Leishmania cells, thus evaluation of these enzymes is of interest. The inhibition of SAP can be the focus of a new drug therapy. We tested for SAP activity from Leishmania tarentolae following the addition of a series of vanadium complexes including decavanadate. Cell cultures at different stages in their …

Novel Tuberculostatic Agents Suitable For Treatment Of Mycobacterium Tuberculosis Infections Of The Central Nervous System, Ronald Bartzatt, Preeti Sule, Suat L.G. Cirillo, Jeffrey D. Cirillo

Chemistry Faculty Publications

Aims: To demonstrate the efficacy of five small molecule compounds for inhibiting the growth of Mycobacterium tuberculosis. To present evidence that these compounds will penetrate into the central nervous system.

Study Design: Five small molecule compounds bearing a hydrazide group were synthesized utilizing microwave excitation. These compounds were then placed into tissue culture with Mycobacterium tuberculosis at various concentrations for evaluation of bacterial growth inhibition.

Place and Duration of Study: The compounds to be tested were prepared at the University of Nebraska Chemistry Department August 2013. The evaluation of antibacterial activity was determined at the Texas A&M Health Science …

Position Of Premature Termination Codons Determines Susceptibility Of Herg Mutations To Nonsense-Mediated Mrna Decay In Long Qt Syndrome, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

The degradation of human ether-a-go-go-related gene (hERG, KCNH2) transcripts containing premature termination codon (PTC)mutations by nonsense-mediatedmRNA decay (NMD) is an importantmechanismof long QT syndrome type 2 (LQT2). The mechanisms governing the recognition of PTC-containing hERG transcripts asNMD substrates have not been established. We used a minigene system to study two frameshift mutations, R1032Gfs*25 and D1037Rfs*82. R1032Gfs*25 introduces a PTC in exon 14, whereas D1037Rfs*82 causes a PTC in the last exon (exon 15). We showed that R1032Gfs*25, but not D1037Rfs*82, reduced the level of mutant mRNA compared to thewild-type minigene in an NMD-dependent manner. The deletion of intron 14 prevented …

Quantification Of Factors Governing Drug Release Kinetics From Nanoparticles: A Combined Experimental And Mechanistic Modeling Approach, Kyle Daniel Fugit

Theses and Dissertations--Pharmacy

Advancements in nanoparticle drug delivery of anticancer agents require mathematical models capable of predicting in vivo formulation performance from in vitro characterization studies. Such models must identify and incorporate the physicochemical properties of the therapeutic agent and nanoparticle driving in vivo drug release. This work identifies these factors for two nanoparticle formulations of anticancer agents using an approach which develops mechanistic mathematical models in conjunction with experimental studies.

A non-sink ultrafiltration method was developed to monitor liposomal release kinetics of the anticancer agent topotecan. Mathematical modeling allowed simultaneous determination of drug permeability and interfacial binding to the bilayer from release …

Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson

Theses and Dissertations--Forestry and Natural Resources

Combustion of fossil fuels has contributed to many environmental problems including acid deposition. The Clean Air Act (CAA) was created to reduce ecological problems by cutting emissions of sulfur and nitrogen. Reduced emissions and rainfall concentrations of acidic ions have been observed since the enactment of the CAA, but soils continue to receive some acid inputs. Soils sensitive to acid deposition have been found to have low pH, a loss of base cations and a shift in the mineral phase controlling the activity of Al³⁺ and/or SO₄^2-. If inputs continue, soil may be depleted of base …

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.

Basic Features Of A Cell Electroporation Model: Illustrative Behavior For Two Very Different Pulses, Reuben S. Son, Kyle C. Smith, Thiruvallur R. Gowrishankar, P. Thomas Vernier, James C. Weaver

Bioelectrics Publications

Science increasingly involves complex modeling. Here we describe a model for cell electroporation in which membrane properties are dynamically modified by poration. Spatial scales range from cell membrane thickness (5 nm) to a typical mammalian cell radius (10 μm), and can be used with idealized and experimental pulse waveforms. The model consists of traditional passive components and additional active components representing nonequilibrium processes. Model responses include measurable quantities: transmembrane voltage, membrane electrical conductance, and solute transport rates and amounts for the representative "long" and "short" pulses. The long pulse-1.5 kV/cm, 100 μs-evolves two pore subpopulations with a valley at ~5 …

Isomerase Activity Of Candida Rugosa Lipase In Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, Saideh Sadat Mortazavi

Open Access Theses & Dissertations

The Candida rugosa lipase-catalyzed Dynamic Kinetic Resolution of racemic ibuprofen methyl ester was optimal at pH 7.6 to produce (S)-ibuprofen in 72 hours. The concentration of various buffers for these reactions ranged from 0.2 to 0.5 M. The commercial lipase was found to be acidic altering the final pH of the reaction mixtures. Dimethylformamide co-solvent maintained the reaction pH better than dimethylsulfoxide, with evidence of the latter functioning as an oxidizing agent. Lower concentrations of ibuprofen methyl ester and higher stirring rates led to faster conversions. The minimal amount of lipase needed was 20 mg/mL buffer. Reaction of (R)-ibuprofen methyl …

Environmental Assessment Of Used Motor Oil In The Ciudad Juarez-El Paso Area, Alma Leticia Figueroa

Open Access Theses & Dissertations

As a hazardous waste generated in large amounts worldwide, used motor oil (UMO) is an important issue for environmental science. UMO contains the carcinogenic and mutagenic compounds Polycyclic Aromatic Hydrocarbons (PAHs). Unless properly managed and disposed of PAHs remain in the environment, principally in sediments and soil. From such environmental sinks, PAHs can migrate to watersheds contaminate drinking water, and damage ecosystems and human health.

Generators of used oil include "businesses that handle used oil through commercial or industrial operations or from the maintenance of vehicles and equipment," (United States Environmental Protection Agency (USEPA), 2013). An example of such a …

Structural Investigation Of The Molecular Chaperonin Tf55 From Thermophilic Archaeon Sulfolobus Solfataricus, Sanjay Kumar Molugu

Open Access Theses & Dissertations

Chaperonins are ubiquitous multi-subunit macromolecules that mediate the folding and assembly of certain proteins that cannot fold properly in vivo. The Archaea bacterium Sulfolobus solfataricus encodes for three chaperonin complexes formed from three different, but closely related subunits named alpha,betaand Gamma. These subunits form a homo-18mer composed of all beta subunits at temperatures ranging between 80oC-85oC, a hetero-16mer composed of alpha and beta subunits at temperatures ranging between 70oC-75oC and a hetero 18mer composed of alpha, beta and gamma subunits at temperatures of 60oC. Structures exist for the chaperonin TF55 all-beta complex and for the TF55 alpha-beta complex but not …

Synthesis Of Peptide-Α-Phenylthioesters Using A Solid Support With A Photoreactive Nitroindoline Moiety, Andrew Pardo

Open Access Theses & Dissertations

Peptide-alpha-phenylthioesters are particularly reactive starting materials for Native Chemical Ligation. Here we present a new photochemical method for the synThesis of peptide-alpha-phenylthioesters under neutral reaction conditions with various C-terminal amino acids. The peptides were synthesized by Fmoc strategy on Sieber amide resin with a photoreactive nitroindoline linker. After cleavage of the photoreactive and fully protected peptide from the beads with dilute trifluoroacetic acid an auxiliary nucleophile such as N-hydroxybenzotriazole or N-hydroxysuccinimide is used to photochemically generate the activated peptide ester in situ. Then thiophenol is introduced in the dark. This new method enabled us to synthesize peptide-alpha-phenylthioesters up to 21 …

Effects Of Cerium Oxide Nanoparticles In Cereals: Insights Into The Toxicity Mechanisms And Macromolecular Modifications, Cyren Mendoza Rico

Open Access Theses & Dissertations

Despite the inundation of studies on the interaction of engineered nanomaterials (ENMs) with plants, investigations involving complete life cycle (i.e from seedling establishment to full maturity) are still lacking. Assessments on the nutritional value of plants cultivated to full maturity in ENMs-treated soil are also missing. Cerium oxide nanoparticles (nCeO2) have significant interactions with plants; however, there are no life cycle studies yet on their implications in cereals like rice (Oryza sativa L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.). These cereals are globally important crops that support the economic activity, and nutritional and health needs of billions …

Spectroscopic Characterization Of Dissolved Organic Matter: Insights Into The Linkage Between Sources And Chemical Composition, Xiaoyan Cao

Chemistry & Biochemistry Theses & Dissertations

This dissertation investigated the chemical structure of DOM by advanced solid-state nuclear magnetic resonance (NMR) spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) techniques, as well as isotopic measurements and UV-visible spectroscopy, to shed light on the linkages between DOM sources and DOM composition. Unique and extensive sets of DOM samples studied here were isolated from various aquatic systems, covering end-member environments in which DOM is considered either microbially derived or terrestrially derived, and areas in which DOM has characteristics intermediate between the two end members. Important insights into specific site-related questions were also gained such as …

Spectroscopic Investigation And Oxidation Of The Anticholinergic Drug Atropine Sulfate Monohydrate By Hexacyanoferrate(Iii) In Aqueous Alkaline Media: A Mechanistic Approach, Manjunath Meti, Sharanappa Nandibewoor, Shivamurti Chimatadar

Turkish Journal of Chemistry

The oxidation of the anticholinergic drug atropine sulfate monohydrate by hexacyanoferrate(III) in aqueous alkaline media was investigated spectrophotometrically by monitoring the decrease in absorbance of hexacyanoferrate(III) (HCF(III)). Oxidation products were identified. The oxidation mechanism was proposed from kinetic studies. The reaction constants involved in the different steps of the mechanism were calculated. The effects of added products, ionic strength, and dielectric constant of the reaction were investigated. The polymerization test revealed that oxidation occurred with intervention of free radicals. The activation parameters were evaluated.

Qsar Study Of Chalcone Derivatives As Anti-Leishmania Agents, Maryam Iman, Asghar Davood, Nasim Banarouei

Turkish Journal of Chemistry

Quantitative structure activity relationship analyses were used to identify the ideal physicochemical characteristics of potential chalcone derivatives as anti-Leishmania agents. The HyperChem program was used to build chalcone structures and to perform conformational analyses through the semiempirical method followed by the PM3 force field. Dragon calculated a large number of molecular descriptors. Multilinear regression was used for quantitative structure activity relationship modeling. Based on our computational studies, 4 descriptors, SEigv, RDF125v, RDF055u, and O-058, can affect the activity of chalcone derivatives.

Graphite Oxide As An Efficient Solid Reagent For Esterification Reactions, Maryam Mirzaaghayan, Rabah Boukherroub, Mahshid Rahimifard

Turkish Journal of Chemistry

Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.

Comparison Of Life Experiences Of Men And Women In The Sciences, Tori Nicole Quist

Honors Program Theses

A lack of sense of belonging and stereotype threat have been shown to contribute to women leaving the sciences (Seymour, 1997; Beasley & Fischer, 2012; Deemer et al., 2013). Contributing to this is the fact that most women find affirmation externally (through friends, family and professors) for their life decisions (Seymour, 1997; Zeldin, 2000). A set of comparative studies in 2000 and 2008 were done examining factors affecting women’s and men’s choices of majors and careers (Zeldin, 2000 and Zeldin, 2008). These studies concluded that men relied on achievements in science as the source of their career decisions to enter …

Development Of Visible Light-Promoted Photocatalytic O-Glycosylation, C-H Activation Of Alkanes And Deoxygenation Of N-(Mesyloxy) Amides, Xiaoping Wang

LSU Master's Theses

This thesis is divided into four chapters reporting various aspects of the background of studies and the preliminary results I obtained in three projects. Chapter 1 gives a brief introduction to the concepts of photoredox catalysis, O-glycosylation, C-H functionalization and amidyl radicals. Chapter 2 describes the development of a visible light-promoted O-glycosylation catalyzed by Ru(bpy)3(PF6)2 or diphenyldiselenide under mild conditions. The glycosylation of primary and secondary alcohols with selenoglycosides was demonstrated with good yields, and disaccharides were constructed by coupling of the selenoglycosides in acetonitrile or dichloromethane with a glucosyl acceptor in moderate yields. The reactions catalyzed by Ru(bpy)3(PF6)2 were …

Using Structure-Based Organic Chemistry Online Tutorials With 2 Automated Correction For Student Practice And Review, Timothy O'Sullivan, Gráinne Hargaden

Articles

This article describes the development and implementation of an open-access organic chemistry question bank for online tutorials and assessments at University College Cork and Technological University Dublin. SOCOT (structure-based organic chemistry online tutorials) may be used to supplement traditional small-group tutorials, thereby allowing students to develop essential problem-solving skills in organic chemistry. This online approach may be used for both formative and summative assessment. Students complete one problem set weekly or fortnightly, which consists of a number of questions of varying difficulty. A wide range of question types is possible; for example, prediction of reaction products, identification of reaction intermediates …

In Vitro Oxygen Availability Modulates The Effect Of Artesunate On Hela Cells, James Murray, Sandra Gannan, Sarah Rawe, James Murphy

Articles

Background/Aim: Hypoxia can affect chemo - therapeutic drug efficacy in cancer patients, yet related in vitro assays in oxygen-rich environment remain the norm. Such levels are well beyond normoxic/hypoxic levels typically experienced by normal tissues/tumor masses. The present study evaluated how artesunate anti-tumor efficacy is modulated by oxygen availability in HeLa cells and its implications for future in vitro analyses. Materials and Methods: Real-time cell analysis was employed to evaluate HeLa cell toxicity to artesunate at 21%, 4% or 1% oxygen. Cell count analysis was performed to validate real-time data. Results: An increase in artesunate efficacy was observed when oxygen …

Synthesis And Characterization Of New (E)-N'-(Substituted Benzylidene)-2-(3-(2-Methyl)-4-Oxo-3,4-Dihydroquinazolin-2-Ylthio)Acetohydrazides, Aamer Saeed, Shams-Ul Mahmood, Ulrich Flörke

Turkish Journal of Chemistry

A small library of new azomethine derivatives of 3-aryl-2-thioxo-2,3-dihydroquinazolin-4(1H)-ones was synthesized. The key intermediates 2-thioxo-quinazolinones (3a--e), obtained in 2 steps from the corresponding anilines, were treated with methyl chloroacetate to afford S-substituted esters (4a,d), which were then converted into corresponding acetohydrazides (5a,d). Further, acetohydrazide (5d) was converted to the azomethines derivatives (6a--k) by reacting with a number of suitably substituted benzaldehydes. FTIR, ^1H NMR, ^{13}C NMR, GC-MS, and elemental analyses were used to confirm the assigned structures of the synthesized compounds. Further, compounds 3a, 5, and 6j were also confirmed by X-ray diffraction data.

Azolylimidazoles: Synthetic Strategies And Medicinal Applications, Bakr Fathy Abdelwahab, Rizk Elsayed Khidre

Turkish Journal of Chemistry

The current review summarizes the known routes to different azoles linked directly to imidazole. This review is divided into classes based on the type of azoles connected to an imidazole ring. Some medical applications are mentioned.

Nh-Acidities And Hammett Correlation Of 3-Para Substituted Phenyl-1,2,4-Oxadiazol-5(4h)-Ones And 1,2 \Lambda^43,5-Oxathiadiazole 2-Oxides In Nonaqueous Media, Nedi̇me Dürüst, Yaşar Dürüst, Emi̇ne Özge Gözlükaya

Turkish Journal of Chemistry

NH acidities of some 3-(p-substitutedphenyl)-1,2,4-oxadiazol-5(4H)-ones and 4-(p-substitutedphenyl)-1,2 \lambda^43,5-oxathiadiazole 2-oxides were determined in methanol by means of potentiometric titration with sodium methoxide. pK_a values of the title compounds calculated from the potentiometric data were interpreted on the basis of structural effects caused by para-substituted groups on the phenyl ring by plotting pK_a values versus Hammett \sigma_p^+ constants, which gave excellent linear correlations.

Self-Condensation Reactions Of Acyl Phosphonates: Synthesis Of Tertiary O-Protected \Alpha-Hydroxyphosphonates, Serkan Eymur, Mehmet Göllü, Ayhan Sitki Demi̇r

Turkish Journal of Chemistry

The self-condensation reaction of benzoyl dialkyl phosphonates was developed using cyanide ion as catalyst, affording versatile tertiary O-protected \alpha-hydroxy phosphonates in moderate yield.

Synthesis Of New Pyrazole And Antibacterial Pyrazolopyrimidine Derivatives, Ameur Rahmouni, Anis Romdhane, Abderrahim Ben Said, Kaouther Majouli, Hichem Ben Jannet

Turkish Journal of Chemistry

3-Substituted-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-amines 2a--c were synthesized by treating 5-aminopyrazole-4-carbonitriles 1a--c with formamide. The reactivity of compounds 1a--c towards some cyclic anhydrides was studied. The condensation of 5-aminopyrazole-4-carbonitrile 1b with triethylorthoformate gives imidate 7b, which reacts with a series of primary amines and leads to pyrazolo[3,4-d]pyrimidine-4-amines 9 and 10. The reaction of imidate 7b with ammonia and hydroxylamine afforded pyrazolopyrimidine 2b and pyrazolo[3,4-d]pyrimidin-5-(4H)-ol 11, respectively. The synthesized compounds were completely characterized by ^1H NMR, ^{13}C NMR, IR, and HRMS. The antibacterial activity of some new synthesized compounds was evaluated and appeared to be significant.