Chemistry Commons^™

Global And Long-Term Comparison Of Sciamachy Limb Ozone Profiles With Correlative Satellite Data (2002-2008), S. Mieruch, M. Weber, C. Von Savigny, A. Rozanov, H. Bovensmann, J. P. Burrows, P. F. Bernath, C. D. Boone, L. Froidevaux, L. L. Gordley, M. G. Mlynczak, J. M. Russell Iii, L. W. Thomason, K. A. Walker, J. M. Zawodny

Chemistry & Biochemistry Faculty Publications

SCIAMACHY limb scatter ozone profiles from 2002 to 2008 have been compared with MLS (2005–2008), SABER (2002–2008), SAGE II (2002–2005), HALOE (2002–2005) and ACE-FTS (2004–2008) measurements. The comparison is performed for global zonal averages and heights from 10 to 50 km in one km steps. The validation was performed by comparing monthly mean zonal means and by comparing averages over collocated profiles within a zonal band and month. Both approaches yield similar results. For most of the stratosphere SCIAMACHY agrees to within 10% or better with other correlative data. A systematic bias of SCIAMACHY ozone of up to 100% between …

In Vivo Quantitative Study Of Sized-Dependent Transport And Toxicity Of Single Silver Nanoparticles Using Zebrafish Embryos, Kerry J. Lee, Lauren M. Browning, Prakash D. Nallathamby, Tanvi Desai, Pavan K. Cherukui, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Nanomaterials possess distinctive physicochemical properties (e.g., small sizes and high surface area-to-volume ratios) and promise a wide variety of applications, ranging from the design of high quality consumer products to effective disease diagnosis and therapy. These properties can lead to toxic effects, potentially hindering advances in nanotechnology. In this study, we have synthesized and characterized purified and stable (nonaggregation) silver nanoparticles (Ag NPs, 41.6 ± 9.1 nm in average diameter) and utilized early developing (cleavage-stage) zebrafish embryos (critical aquatic and eco- species) as in vivo model organisms to probe the diffusion and toxicity of Ag NPs. We found that single …

Isotopic Characterization Of Aerosol Organic Carbon Components Over The Eastern United States, Andrew S. Wozniak, James E. Bauer, Rebecca M. Dickhut, Xu Li, Ann P. Mcnichol

Chemistry & Biochemistry Faculty Publications

Carbon isotopic signatures (δ¹³C, Δ¹⁴C) of aerosol particulate matter total organic carbon (TOC) and operationally defined organic carbon (OC) components were measured in samples from two background sites in the eastern U.S. TOC and water-soluble OC (WSOC)δ¹³C values (−27 to −24‰) indicated predominantly terrestrial C₃ plant and fossil derived sources. Total solvent extracts (TSE) and their aliphatic, aromatic, and polar OC components were depleted in δ¹³C (−30 to −26‰) relative to TOC and WSOC. Δ¹⁴C signatures of aerosol TOC and TSE (−476 to +25‰) suggest variable fossil contributions (∼5–50%) …

Compositional Features Of Japanese Humic Substances Society Standard Soil Humic And Fulvic Acids By Fourier Transform Ion Cyclotron Resonance Mass Spectrometry And X-Ray Diffraction Profile Analysis, Kosuke Ikeya, Rachel L. Sleighter, Patrick G. Hatcher, Akira Watanabe

Chemistry & Biochemistry Faculty Publications

The composition of humic acids (HAs) and Fulvic Acids (FAs) from Inogashira (Umbric Andosol) and Dando (Dystric Cambisol) soils authorized as standard samples by the Japanese Humic Substances Society was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and X-ray diffraction (XRD) 11 band profile analysis. In FTICR-MS, the number of peaks that molecular formulas were assigned to was 2549-2913 for the FAs and 1943-2457 for the HAs. Molecular formulas with H/C and O/C ratios similar to condensed hydrocarbons were dominant in both the HAs, while those with H/C and O/C ratios similar to lignin were more abundant …

Observation Of Sulfate Aerosols And So₂ From The Sarychev Volcanic Eruption Using Data From The Atmospheric Chemistry Experiment (Ace), D. Doeringer, A. Eldering, C. D. Boone, G. González Abad, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

[1] Infrared spectra measured by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on the SCISAT satellite were used to analyze the Sarychev volcanic aerosol after the eruption in June 2009. Evidence of the Sarychev eruptions was first detected in July 2009 from enhanced SO₂ concentrations and atmospheric extinction. By February 2010, the atmosphere had returned to pre-Sarychev conditions. In July 2009, the volcanic plume was found between 8.5 km and 17.5 km in altitude at mid- and high latitudes (55°N–70°N). The first SO₂ and sulfate aerosol retrievals carried out using the infrared solar occultation spectra recorded with …

Process-Evaluation Of Tropospheric Humidity Simulated By General Circulation Models Using Water Vapor Isotopologues: 1. Comparison Between Models And Observations, Camille Risi, David Noone, John Worden, Christian Frankenberg, Gabriele Stiller, Michael Kiefer, Bernd Funke, Kaley Walker, Peter Bernath, Matthias Schneider, Debra Wunch, Vanessa Sherlock, Nicholas Deutscher, David Griffith, Paul O. Wennberg, Kimberly Strong, Dan Smale, Emmanuel Mahieu, Sabine Barthlott, Frank Hase, Omaira García, Justus Notholt, Thorsten Warneke, Geoffrey Toon, David Sayres, Sandrine Bony, Jeonghoon Lee, Derek Brown, Ryu Uemura, Christophe Sturm

Chemistry & Biochemistry Faculty Publications

The goal of this study is to determine how H₂O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in atmospheric general circulation models (GCMs). We analyze a large number of isotopic data sets (four satellite, sixteen ground-based remote-sensing, five surface in situ and three aircraft data sets) that are sensitive to different altitudes throughout the free troposphere. Despite significant differences between data sets, we identify some observed HDO/H₂O characteristics that are robust across data sets and that can be used to evaluate …

Validation Of Ace And Osiris Ozone And No2 Measurements Using Ground Based Instruments At 80° N, C. Adams, K. Strong, R. L. Batchelor, Peter F. Bernath, S. Brohede, C. Boone, D. Degenstein, W. H. Daffer, J. R. Drummund, P. F. Fogal

Chemistry & Biochemistry Faculty Publications

The Optical Spectrograph and Infra-Red Imager System (OSIRIS) and the Atmospheric Chemistry Experiment (ACE) have been taking measurements from space since 2001 and 2003, respectively. This paper presents intercomparisons between ozone and NO2 measured by the ACE and OSIRIS satellite instruments and by ground-based instruments at the Polar Environment Atmospheric Research Laboratory (PEARL), which is located at Eureka, Canada (80◦ N, 86◦ W) and is operated by the Canadian Network for the Detection of Atmospheric Change (CANDAC). The ground-based instruments included in this study are four zenith-sky differential optical absorption spectroscopy (DOAS) instruments, one Bruker Fourier transform infrared spectrometer (FTIR) …

Atmospheric Effects Of Energetic Particle Precipitation In The Arctic Winter 1978-1979 Revisted, L. A. Holt, C. E. Randall, V. L. Harvey, E. E. Remsberg, G. P. Stiller, B. Funke, P. F. Bernath, K. A. Walker

Chemistry & Biochemistry Faculty Publications

[1] The Limb Infrared Monitor of the Stratosphere (LIMS) measured polar stratospheric enhancements of NO₂ mixing ratios due to energetic particle precipitation (EPP) in the Arctic winter of 1978–1979. Recently reprocessed LIMS data are compared to more recent measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) to place the LIMS measurements in the context of current observations. The amount of NO_x (NO + NO₂) entering the stratosphere that has been created by EPP in the mesosphere and lower thermosphere (EPP-NO_x) has been quantified …

Studies On A Dirhodium Tetraphosphine Hydroformylation Catalyst, Darina Polakova

LSU Doctoral Dissertations

The dirhodium tetraphosphine catalyst [Rh2(nbd)2(rac-et,ph-P4)](BF4)2 was investigated in acetone and water/acetone in order to explain better hydroformylation results in the latter solvent. In-situ NMR spectroscopy showed slower degradation in water/acetone. Less tendency to form penta/hexacarbonyl complexes in water/acetone was shown by 31P{1H} NMR and FT-IR. A pH decrease and hydroformylation studies in presence of a base indicated formation of a monocationic monohydride species. A new reaction mechanism was suggested that takes into account the observed differences from the acetone solvent system. The presence of water enabled production of hydride species when the dirhodium catalyst was exposed to CO gas. We …

Single-Molecule Detection Of Molecular Beacons Generated From Ldr On Thermoplastic Microfluidic Device For Bioanalysis, Zhiyong Peng

LSU Doctoral Dissertations

Current clinical techniques for nucleic acid detection and analysis often involve PCR, lacking adequate specificity or sensitivity to meet the stringent requirements in certain applications. This research aims to develop an innovative molecular assay and the associated hardware to rapidly signal the presence of certain targets using reporter sequence found in their genome without requiring PCR. This assay coupled the sensitivity of single-pair fluorescence resonance energy transfer (spFRET) with the specificity of ligase detection reaction (LDR) to provide near real-time readout of target biomarkers. Heightened concerns on potential bioterrorism threats, such as rapid dissemination of pathogenic bacteria or viruses into …

Chemical And Biological Evaluation Of Antibiotic-Based Ionic Liquids And Gumbos Against Pathogenic Bacteria, Marsha Rae Cole

LSU Doctoral Dissertations

The research presented in this dissertation explores a novel pragmatic therapeutic approach for control, prevention, and treatment of infectious disease using Active-Pharmaceutical Ingredient-based Ionic Liquids (API-ILs) and Groups of Uniform Materials Based on Organic Salts (GUMBOS). Accordingly, several antiseptic- and antibiotic-based API-ILs and GUMBOS were synthesized and characterized using a combination of analytical and microbiological techniques. Overall, this research presents an advanced alternative to combination antibiotic therapy by using a novel group of ionic antimicrobial materials that have controlled pharmacokinetics, improved bioavailabilities, reduced toxicities, multi-modal properties, and potent antimicrobial spectrum of activity as a viable alternative to combating bacterial infections. …

Geometrical And Electronic Structure Of Metal Oxide Nanoparticles On Silica And Alumina, Udaya Indike Rodrigo

LSU Doctoral Dissertations

Recent studies demonstrated nanometer-scale combustion-generated nanoparticles cause demonstrable health effects. It is essential to understand the chemical characteristics of these nanoparticles. Since combustion-generated nanoparticles arise in complex mixtures, we employed a dendrimeric method to generate simpler, more reproducible nanoparticles, which were tethered to fumed silica and alumina to provide surrogates for fly ash. We collected XANES and EXAFS data, which are useful for characterizing disordered mixtures where the metal is a minor component. The effect of particle size on structural properties was studied with copper oxide nanoparticles on fumed silica. XANES data demonstrated copper atoms in the nanoparticles are present …

Fabrication, Analysis, Application, And Characterization Of Core-Containing Microparticles And Hydrophilic Microfluidic Devices Produced Via The Primary- And In Situ Tertiary-Amine Catalyzed Michael Addition Of Multifunctional Thiols To Multifunctional Acrylates, Christopher O. Bounds

LSU Doctoral Dissertations

The objective of this research was to investigate amine-catalyzed thiol-acrylate chemistry for various novel applications that could fully utilize the untapped potential of this useful and robust chemistry. The use of this chemistry in each application solved a problem, improved on a disadvantage of current technologies, and decreased the level of complexity in association with required time, cost, and/or preparation conditions. The first novel application conceived, applied, and analyzed was in the field of microencapsulation. A novel approach for the preparation of microparticles via a dispersion polymerization using the primary amine-catalyzed addition of a trithiol to a triacrylate was realized …

Synthesis, Cellular Studies, And Computational Analysis Of Porphyrin And Bodipy Conjugates With Affinity For Epidermal Growth Factor Receptor, Alecia Michelle Mccall

LSU Doctoral Dissertations

Chapter 1 is a description of the basic fundamental concepts of porphyrins and BODIPYs, (including synthetic methodologies), a general mechanism of the processes of EGFR, and computational concepts that are elaborated upon in future chapters. Chapter 2 is a discussion solely on the porphyrins that were synthesized to be used as fluorophores for EGFR-targeted conjugates, both peptidic and non-peptidic. The porphyrins were primarily synthesized via the Lindsey method as well as by O-alkylation of tetrahydroxy porphyrins. Synthesis of PEG linkages are discussed as well through three methodologies. Chapter 3 is a presentation of the synthesis, characterization, cellular studies, and computational …

First Remote Sensing Observations Of Trifluoromethane (Hfc-23) In The Upper Troposphere And Lower Stratosphere, Jeremy J. Harrison, Christopher D. Boone, Alexander T. Brown, Nicholas D. C. Allen, Geoffrey C. Toon, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

This work reports the first remote sensing measurements of atmospheric HFC-23 (CHF₃) using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and the Jet Propulsion Laboratory Mark IV (MkIV) balloon interferometer. A total of 8809 ACE occultations measured between 2004 and 2010 have been processed, along with 24 MkIV occultations measured between 1989 and 2007. ACE data (yearly averages over the 10-25 km altitude range) in the tropics/subtropics (40°S-40°N) reveal a trend of 4.0 ± 1.6% per year in the growth of HFC-23 for 2004-2009 (or 3.9 ± 1.2% per year for 2004-2010), …

Analysis Of Iasi Tropospheric O₃ Data Over The Arctic During Polarcat Campaigns In 2008, M. Pommier, C. Clerbaux, K. S. Law, G. Ancellet, P. Bernath, P.-F. Coheur, J. Hadji-Lazaro, D. Hurtmans, P. Nédélec, J.-D. Paris, F. Ravetta, T. B. Ryerson, H. Schlager, A. J. Weinheimer

Chemistry & Biochemistry Faculty Publications

Ozone data retrieved in the Arctic region from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp-A European satellite are presented. They are compared with in situ and lidar observations obtained during a series of aircraft measurement campaigns as part of the International Polar Year POLARCAT activities in spring and summer 2008. Different air masses were sampled during the campaigns including clean air, polluted plumes originating from anthropogenic sources, forest fire plumes from the three northern continents, and stratospheric-influenced air masses. The comparison between IASI O₃ [0–8 km], [0–12 km] partial columns and …

Dna-Carbon Nanotubes Composites As Gene Sensors, Hugo Alarcon

Open Access Theses & Dissertations

Carbon fullerenes are unusually structured molecules with robust mechanical and electronic properties. Their versatility is astounding; envisioned applications range from field emission displays to impregnated metal composites, battery storage media, and nanoelectronic devices. The combination of simple constituency, diverse behavior, and ease of fabrication makes these materials a cornerstone topic in current research.

This work describes experiments conducted on nanotubes using Dynamic light scattering (DLS). The aim is to detect cluster formation from individual carbon nanotube (CNT) solutions using a nanotube DNA binding sequence and a secondary recognizing complementary DNA sequence to bind neighboring CNTs. Dynamic Light Scattering is an …

Applications Of Density Functional Theory In Materials Science And Engineering, Manuel Alvarado

Open Access Theses & Dissertations

Density Functional Theory (DFT) is a powerful tool that can be used to model various systems in materials science. Our research applies DFT to two problems of interest. First, an organic/inorganic complex dye system known as a Mayan pigment is modeled to determine chemical binding sites, verifying each model with physical data such as UV/Vis spectra. Preliminary studies on palygorskite-based mayan pigments (mayacrom blue, mayacrom purple) show excellent agreement with experimental studies when using a dimer dye geometry binding with tetrahedrally-coordinated aluminum impurity sites in palygorksite. This approach is applied to a sepiolite-based organic/inorganic dye system using thioindigo attached to …

Electrical Characterization Of Microcrystalline Lifepo4 For Application In Lithium Ion Batteries, Sukhdeep Amarjeet Labana

Open Access Theses & Dissertations

Electrical Characterization of Microcrystalline LiFePO4 for application in lithium ion batteries. Mainly, to study about the electrical properties of Lithium Iron Phosphate as a cathode material to increase its Electrical consumption.

Progress Towards Heterocycles As Inhibitors Of Plasminogen Activator Inhibitor-1, Gregory Alan Abernathy

Master's Theses and Doctoral Dissertations

No abstract provided.

The Synthesis Of Amphiphilic Diblock Copolymers: An Investigation Into The Formation Of Micelles As A Function Of Hydrophobic Block Length, Kevin S. Kawchak

Master's Theses and Doctoral Dissertations

Acrylate-based amphiphilic diblock copolymers show great potential for anti-cancer drug transport due to their ability to aggregate into protective core-shell micelles. Using RAFT polymerization, copolymers containing poly(acrylic acid) and poly(methyl acrylate) blocks were made with high monomer conversion and narrow distributions of molecular weight for eventual use in medicinal applications. Based on previous findings of copolymers with low weight hydrophobic blocks failing to micellize, it was hypothesized that increasing the poly(methyl acrylate) block length would allow for micelle formation. 1H-NMR experiments conducted in the presence of an aqueous solution yielded diminished and broadened resonances of the lengthened hydrophobic block, which …

Synthesis And Purification Of Potential Antimicrobial Peptides, Christopher Ryan Snyder

Master's Theses and Doctoral Dissertations

No abstract provided.

Near Single-Molecule Sers-Based Detection Using Ultrafiltered, Unfunctionalized Silver Nanoparticles, Joshua Dale Baker

Browse all Theses and Dissertations

Silver nanoparticles (AgNPs) are currently widely-used in consumer products, therapeutics, biomedical devices, and electronics. Yet, one application for which AgNPs have been used extensively is surface-enhanced Raman spectroscopy (SERS)-based sensing. However, AgNP size and aggregation state are known to greatly influence these applications. This works aimed 1) to synthesize a large volume of unfunctionalized, Creighton AgNPs, to characterize their chemical and physical properties, 2) then to size-select AgNPs of 1-50 nm and 50-100 nm in diameter and to concentrate them using a three-step, "green" tangential flow ultrafiltration (TFU) process. 3) Finally, to determine and compare the SERS-based sensing capabilities of …

Micro-Raman Imaging And Hyperspectral Analysis Of Tibiotarsi From Chick Embryos Exposed To Sublethal Doses Of Platinum Group Metals, Adam Christopher Stahler

Browse all Theses and Dissertations

Platinum group metals (PGMs), i.e., Pd, Pt and Rh, are found at pollutant levels in the environment. PGMs accumulate in plant and animal tissues, and little is known about their toxicity. Our previous studies have shown that chick embryos exposed to 1.0 mL PGM solutions of 5.0 ppm (LD₅₀) and higher exhibited severe skeletal deformities. This work hypothesized that 1.0 ppm sublethal doses of PGMs would negatively impact the mineralization process in tibiotarsi. One milliliter of 1.0 ppm of Pd(II), Pt(IV), Rh(III) aqueous salt solutions and a PGM-mixture were injected into the air sac of the eggs …

Investigations Of Noncovalent Interactions Using Raman Spectroscopy And Electronic Structure Computations, Ashley Wright

Electronic Theses and Dissertations

This dissertation research focuses on the effects of noncovalent interactions on vibrational energy levels. Vibrational spectroscopy is a powerful tool for the study of the effects of weak intermolecular interactions such as hydrogen bonding and interactions with the environment, including solvation effects. Changes in the vibrational spectra of interacting molecules allow us to ascertain exactly which atoms and bonds are affected and to what extent they are affected. Quantum mechanical methods, ab initio theory and density functional theory, are employed to model molecular geometries, properties, and subtle interactions between molecules. Much of this research centers on the comparison of these …

Techniques For Sensor-Integrated Robotic Systems: Raman Spectra Analysis, Image Guidance, And Kinematic Calibration, Luke Anthony Reisner

Wayne State University Dissertations

Robotics and sensor technology have made impressive advancements over the years. There are now robotic systems that help perform surgeries or explore the surface of Mars, and there are sensors that detect trace amounts of explosives or identify diseased human tissue. The most powerful systems integrate robots and sensors, which are natural complements to each other. Sensors can provide information that might otherwise be unavailable due to indirect robotic manipulation (e.g., images of the target environment), and robots can provide suitably precise positioning of an analytical sensor.

To have an effective sensor-integrated robotic system, multiple capabilities are needed in the …

An Unexpected Stereochemical Insignificance Discovered In Acinetobacter Baumannii Quorum Sensing, Amanda L. Garner, Sook Kyung Kim, Jie Zhu, Anjali Kumari Struss, Richard Watkins, Brent D. Feske, Gunnar F. Kaufmann, Kim D. Janda

Chemistry: Faculty Publications (1990-2023)

Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl)-l-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R)-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S)-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a …

A General Synthesis Of Bis-Indolylpiperazine-2,5-Diones, Stephen N. Crooke, Christine Whitlock

Chemistry: Faculty Publications (1990-2023)

The one-pot synthesis of three dragmacidin derivatives is reported. Sarcosine anhydride (4) is brominated and immediately reacted with the corresponding indole to produce the products, namely 3,6-bis(5′-methoxy-3′-indolyl)-1,4-dimethylpiperazine-2,5-dione (1), 3,6-bis(7′-methyl-3′-indolyl)-1,4-dimethylpiperazine-2,5-dione (2) and 3,6-bis-(6′-chloro-3′-indolyl)-1,4-dimethylpiperazine-2,5-dione (3), which are characterized by ¹H-NMR.

Multi-Configurational Investigation Of Thermolytic Pathways Of Highly Strained Ring Systems, Jeffrey Dwayne Veals

Electronic Theses and Dissertations

The isomerization pathways of model high energy structures are of interest because of their relation to high energy density fuels. Electron resonance has been found to greatly affect the relative activation barriers for several isomerization pathways, and the major goal of this research is to accurately describe its role in determining the relative barriers for strain energy release pathways. This research is centered around the potential energy surfaces (PES's) for ? bond breaking and ? bond rotation in these highly strained structures. Of particular interest was how would resonance and or electronegativity affect the allowed/disallonature of the activation barriers in …

Electrochemistry, Transport Properties And Electronic Spectroscopy Of Lanthanide Solutes In Bis(Trifluoromethylsulfonyl)Imide-Based Ionic Liquids, Yunfeng Pan

Electronic Theses and Dissertations

No abstract provided.