Digital Commons Network^™

Research Instrumentation Center (Ric), Ryan Hilger, Purdue University Office Of Research

University Research Core Facility Boilerplate Descriptions

No abstract provided.

Mapping Per- And Polyfluoroalkyl Substances (Pfas) In South Carolina Surface Waters: Are There Hotspots?, Thomas C. Geiger

Senior Theses

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals used in consumer products for their unique chemical properties. PFAS compounds are resistant to water, oil, heat, and grease, making them useful for a wide variety of everyday items such as non-stick cooking pans, food packaging, electronics, carpets, upholstery, paints, adhesives, and personal care products.¹ The resilient nature of PFAS has made these compounds immensely popular with consumers but has since been considered a potential environmental and public health hazard for their ability to bioaccumulate and for their stability in the environment. More than 6000 PFAS have been discovered in the …

Quantitation Of Female Newt Tetrodotoxin Concentrations And Their Impact In The Newt-Garter Snake Evolutionary Arms Race, Anna Frey, David Green Dr., Lee Kats Dr., Gary Bucciarelli Dr.

Seaver College Research And Scholarly Achievement Symposium

As this work is not yet published, the authors have requested the removal of the abstract.

High Performance Liquid Chromatography Monitoring Reaction Kinetics, Ken Overway, Mary Ruth Shifflett

Chemistry Faculty Scholarship

To develop a chromatographic method to characterize enantioselective kinetics, the reaction between aromatic aldehydes and ephedrine will be monitored with High Performance Liquid Chromatography (HPLC). First, develop kinetics analysis procedure with the HPLC, the decomposition of aspartame was observed with citrate and phosphate buffers. The procedure produced an activation energy in the presence of phosphate buffer of 71.9 kJ/mol with a -0.126 % error. The aromatic aldehyde, benzaldehyde, and ephedrine were run through a stereospecific column to separate peaks with various mobile phases. A more nonpolar mobile phase is required for better peak and retention time separation.

Investigation Of The Analytical Utility Of The Inductively Coupled Plasma Mass Spectrometer (Icp-Ms) For The Quantification Of Proteins Via Lanthanide Labeling, Caitlin Elizabeth Dunlap

Undergraduate Honors Thesis Collection

The discovery and ability to provide an absolute concentration of biomarkers in the body can facilitate early diagnoses of diseases. This information can also be used for more accurate and unique treatments for those patients. While major advances in molecular mass spectrometry allows for a sensitive identification of these biomarkers, they are limited to only four orders of magnitude in their dynamic ranges. Due to this, detection and quantitation of low abundant proteins, which tend to make up these vital biomarkers, is very difficult. On the other hand, ICP-MS offers a wider dynamic range (up to 12 orders of magnitude) …

Investigating Ionic Current Rectification As A Means Of Controllable Drug Delivery Using Silica Nanoparticles And Nano Porous Membranes, Katie L. Nolan

Honors College Theses

This project investigates a novel ionic current rectification (ICR) phenomenon created by the opening and closing of nanopores by charged silica nanoparticles (SNPs) under electrophoretic flow. This voltage-controlled opening and closing of the pores can be exploited to allow delivery of nicotine through the pores at programmable intervals. The ICR phenomenon was thoroughly investigated by varying pH, buffer concentration, SNP concentration, and applied voltage range. The mechanism was also verified by testing with a 2-, 3-, and 5-electrode system. Potential cake layer formation was demonstrated in a longer ICR test, and the implications of this on the drug delivery mechanism …

Analysis Of The Headspace Gases Formed From The Fermentation Of Barley, Ken Overway, Cassie Taylor

Chemistry Faculty Scholarship

Volatile compounds are compounds that can exist in a gaseous state at room temperature. These compounds contribute to the aromas that are associated with mixtures. The analysis of these gases can be completed using a gas chromatograph to provide a sort of fingerprint identification. The analysis of the volatile compounds for barley fermentation samples was completed by collecting the gas above the fermenting solution, the headspace gas, and injecting this gas into the gas chromatograph. These fermentation samples showed predominantly the formation of carbon dioxide for a significant length of time before finally ethanol was detected. A subsequent of the …

Identification And Quantification Of Atrazine In The North River Using Spe And Hplc, Kenneth Scott Overway, Youmna Moawad

Chemistry Faculty Scholarship

High-performance liquid chromatography (HPLC) is utilized for the separation, purification, and quantification of viscous and complex analyte mixtures. It is important in that it can analyze and detect low analyte concentrations, which can be useful in many industries, such as food and pharmaceutical industries, as well analyzing environmental samples. The purpose of this project was to identify and quantitate atrazine, an herbicide, in a water sample from the North River (Bridgewater, VA) using solid-phase extraction (SPE) and HPLC.

Extraction & Purification Of Ppix Using Hplc & Fplc, Ken Overway, Grace Rilee

Chemistry Faculty Scholarship

Porphyrins, an organic molecule, are a possible sensitizer for dye-sensitized solar cells (DSSC) because of their strong absorption in the visible spectrum. One naturally occurring porphyrin is protoporphyrin IX (PPIX), which can be found in brown eggshells. There are two reasons why PPIX is the ideal sensitizer. (1) The absorbance spectrum of PPIX can be modified by changing ring substituents, thus tuning the absorbance to the solar spectrum. (2) PPIX allows for direct attachment to the DSSC due to the carboxylic acid substituents on PPIX and the TiO₂ of the DSSC. The HPLC was used to develop a chromatographic …

Law Library Blog (January 2021): Legal Beagle's Blog Archive, Roger Williams University School Of Law

Law Library Newsletters/Blog

No abstract provided.

The Analytical And Biomedical Applications Of Carbon Dots And Their Future Theranostic Potential: A Review, Sukunya Ross, Ren-Siang Wu, Shih-Chun Wei, Gareth M. Ross, Huan-Tsung Chang

Journal of Food and Drug Analysis

In recent years, carbon dots (C-dots) have gained appreciable interest owing to their unique optical properties, including tunable fluorescence, stability against photobleaching and photoblinking, and strong fluorescence. Simple and low-cost hydrothermal and electrochemical approaches have been widely used in the preparation of biocompatible and high-quality C-dots. Various C-dots have been used for the quantitation of small analytes, mostly based on analyte induced fluorescence quenching. Depending on the nature of precursors, synthetic conditions (such as reaction temperature and time), and surface conjugation, multi-function C-dots can be prepared and used in diagnostics and therapeutics. Their strong fluorescence and photostability, enables use in …

Exploring The Multiplex Detection Capabilities Of Raman Spectroscopy On Mock Street Samples Containing Illicitly Manufactured Fentanyls, Mia Laverne Williams Burnett

Browse all Theses and Dissertations

Illicitly manufactured fentanyls (IMFs) have become a global and local epidemic and have recently caused an increase in the number of accidental exposures and overdoses in first responders and the community. The aim of the research is to explore a method to discriminate between IMFs and cutting agents in mock street samples using Raman Spectroscopy. Predominant Raman bands corresponding to the structural moieties of each individual illicit, licit drugs, and cutting agents were tracked, then used to discriminate between varying components in a mock street sample. In conclusion, discrimination between the components in the mixture was obtained using Raman Spectroscopy. …

Kinetics Of Mashing In Beer Brewing Process, Ken Overway, Austin Reed

Chemistry Faculty Scholarship

The process called mashing, which steeps malted grain in water at specific temperatures in order to optimize enzymatic sugar production, is critical for the beer brewing process. Each kind of grain used to make beer could have unique optimal mashing temperatures since the α- and β-amylase enzymes that produce the sugars are a result of genetic differences. Beer has mainly been brewed with barley, wheat, rye, and less common grains such as corn and rice. Gluten free beer options are very limited, and this is problematic for those suffering from Celiac disease. Quinoa is the focus grain of this project …

Development Of Chemical Separation Methods Using Transition Metals For Nuclear Forensic And Medicinal Applications, Lucas Peter Boron-Brenner

UNLV Theses, Dissertations, Professional Papers, and Capstones

Insufficient data exists on the effects of prompt fast neutron activation on metals found commonly in nuclear devices and the urban environment. Different metals such as Ti, Au, Fe, and Cu were activated using the Flattop Criticality Benchmark at the Device Assembly Facility on the Nevada Test Site using a known neutron spectrum and flux to determine a baseline cross section value. Cross section information gathered from these neutron activation measurements could provide information that helps government and law enforcement agencies to correctly trace the origin of a nuclear device’s fuel or component features.

Based on activation products produced in …

Improvement And Development Of Analytical Forensic Methods: Arson Investigation And Drug Detection In Fingerprints And Hair, Sarah Anne Glenn

Electronic Theses and Dissertations

Forensic science is the cornerstone of criminal investigations. Due to the overexposure of forensic science in the media, the true nature of forensic science is often overlooked. Forensic science is a rigorous exacting science that applies methods developed in the wider scientific community to the analysis of evidence collected from crime scenes. As far back as the 6th century people were using forensics to solve crimes. Since then the science behind forensic science has increased exponentially with new methods being researched and developed. This research aims to address two of the larger subsections of forensic science, arson and drug detection. …

Terahertz Molecular Spectroscopy As A Tool For Analytical Probing Of Cellular Metabolism, Mitchell Cameron Paul

Browse all Theses and Dissertations

Terahertz spectroscopy has found use as an analytical tool in determining chemical composition of exhaled human breath. This thesis demonstrates a novel application of this technology - analytical sensing of gaseous metabolic products of several types of human cell cultures. An innovative experimental system was developed for probing cellular metabolism using terahertz [THz] rotational spectroscopy. Gaseous emissions of cell cultures were analyzed and compared between several cell types. Cancerous and healthy lung cells as well as cancerous liver cells were studied. This technique carries a lot of promise as a noninvasive method of distinguishing between cell types and identifying cell …

Terahertz Molecular Spectroscopy As A Tool For Analytical Probing Of Cellular Metabolism, Mitchell Cameron Paul

Browse all Theses and Dissertations

Terahertz spectroscopy has found use as an analytical tool in determining chemical composition of exhaled human breath. This thesis demonstrates a novel application of this technology - analytical sensing of gaseous metabolic products of several types of human cell cultures. An innovative experimental system was developed for probing cellular metabolism using terahertz [THz] rotational spectroscopy. Gaseous emissions of cell cultures were analyzed and compared between several cell types. Cancerous and healthy lung cells as well as cancerous liver cells were studied. This technique carries a lot of promise as a noninvasive method of distinguishing between cell types and identifying cell …

Probe Current Determination In Analytical Tem/Stem And Its Application To The Characterization Of Large Area Eds Detectors, David R. G Mitchell, Mitchell John Bromley Nancarrow

Australian Institute for Innovative Materials - Papers

A simple procedure, which enables accurate measurement of transmission electron microscopy (TEM)/STEM probe currents using an energy loss spectrometer drift tube is described. The currents obtained are compared with those measured on the fluorescent screen to enable the losses due to secondary and backscattered electrons to be determined. The current values obtained from the drift tube allow the correction of fluorescent screen current densities to yield true current. They also enable CCD conversion efficiencies to be obtained, which in turn allows images to be calibrated in terms of electron fluence. Using probes of known current in conjunction with a NiO …

Advances In Understanding The Molecular Composition Of Dissolved Organic Matter And Its Reactivity In The Environment, Rajaa Mesfioui

Chemistry & Biochemistry Theses & Dissertations

Dissolved organic matter (DOM) is the ultimate product of Earth's systems dynamics. DOM chemical signature is strongly shaped by the interaction among Earth's spheres, such as the atmosphere, the geosphere, the biosphere, and the hydrosphere, but also life and human activity. DOM source, composition, photochemical alteration and availability affect freshwater ecosystems, their carbon and nitrogen fluxes and, thus, the global carbon and nitrogen cycles. The aim of this thesis was to gain an understanding of the molecular composition of DOM and its photochemical and biological reactivity in an environment impacted by anthropogenic disturbance. The York and James River systems within …

Generalised Diffusive Delay Logistic Equations: Semi-Analytical Solutions, H Y. Alfifi, Timothy R. Marchant, M I. Nelson

Tim Marchant

This paper considers semi-analytical solutions for a class of generalised logis- tic partial dierential equations with both point and distributed delays. Both one and two-dimensional geometries are considered. The Galerkin method is used to approximate the governing equations by a system of ordinary dierential delay equations. This method involves assuming a spatial structure for the solution and averaging to obtain the ordinary dierential delay equation models. Semi-analytical results for the stability of the system are derived with the critical parameter value, at which a Hopf bifurcation occurs, found. The results show that diusion acts to stabilise the system, compared to …

Solitary Waves And Their Stability In Colloidal Media: Semi-Analytical Solutions, Timothy R. Marchant, N F. Smyth

Tim Marchant

Spatial solitary waves in colloidal suspensions of spherical dielectric nanopartides are considered. The interaction of the nanoparticles is modelled as a hard-sphere gas, with the Carnahan-Starling formula used for the gas compressibility. Semi-analytical solutions, for both one and two spatial dimensions, arc derived using an averaged Lagrangian and suitable trial functions for the solitary waves. Power versus propagation constant curves and neutral stability curves are obtained for both cases, which illustrate that multiple solution branches occur for both the one and two dimensional geometries. For the one-dimensional case it is found that three solution branches (with a bistable regime) occur. …

A Novel Analytical Solution To Steady-State Evaporation From Soil And Film Region Thickness, Morteza Sadeghi, Nima Shokri, Scott B. Jones

Plants, Soils, and Climate Faculty Publications

Evaporation from soil and other porous media constitutes a significant source of water loss affecting global water balance and energy exchange between land and atmosphere. The presence of a shallow water table can lead to sustained water loss that is dependent on porous media hydraulic properties and water table depth among other factors. In this paper, an exact analytical solution to steady state evaporation from porous media is developed using the Brooks-Corey hydraulic conductivity model. The solution is presented in terms of a set of infinite series. An advantage of this solution compared to previous derivations is that the infinite …

Solitary Waves And Their Stability In Colloidal Media: Semi-Analytical Solutions, Timothy R. Marchant, N F. Smyth

Faculty of Informatics - Papers (Archive)

Spatial solitary waves in colloidal suspensions of spherical dielectric nanopartides are considered. The interaction of the nanoparticles is modelled as a hard-sphere gas, with the Carnahan-Starling formula used for the gas compressibility. Semi-analytical solutions, for both one and two spatial dimensions, arc derived using an averaged Lagrangian and suitable trial functions for the solitary waves. Power versus propagation constant curves and neutral stability curves are obtained for both cases, which illustrate that multiple solution branches occur for both the one and two dimensional geometries. For the one-dimensional case it is found that three solution branches (with a bistable regime) occur. …

Generalised Diffusive Delay Logistic Equations: Semi-Analytical Solutions, H Y. Alfifi, Timothy R. Marchant, M I. Nelson

Faculty of Informatics - Papers (Archive)

This paper considers semi-analytical solutions for a class of generalised logis- tic partial dierential equations with both point and distributed delays. Both one and two-dimensional geometries are considered. The Galerkin method is used to approximate the governing equations by a system of ordinary dierential delay equations. This method involves assuming a spatial structure for the solution and averaging to obtain the ordinary dierential delay equation models. Semi-analytical results for the stability of the system are derived with the critical parameter value, at which a Hopf bifurcation occurs, found. The results show that diusion acts to stabilise the system, compared to …

On Relativistic Disk Spectroscopy In Compact Objects With X-Ray Ccd Cameras, J. M. Miller, A. D'Aì, M. W. Bautz, S. Bhattacharyya, D. N. Burrows, E. M. Cackett, A. C. Fabian, M. J. Freyberg, F. Haberl, J. Kennea, M. A. Nowak, R. C. Reis, T. E. Strohmayer, M. Tsujimoto

Physics and Astronomy Faculty Research Publications

X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/ΔE), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be …

Discovery And Identification Of New Dna Photoproducts And Investigation Of The Redox Mechanism Of Human Apurinic/Apyrimidinic Endonuclease 1 (Hape1) Protein, Dian Su

All Theses and Dissertations (ETDs)

Exposure of cells to ultraviolet light results in the formation of DNA photoproducts, many of which have been linked to skin cancer. The majority of these photoproducts arise from a photoreaction between two pyrimidines. Irradiation of double stranded B form DNA under physiological conditions mainly produces adjacent dimers. Nonadjacent photodimers of both intrastrand and interstrand types are much rarer. Intrastrand-type nonadjacent dimers form when one or more nucleotides between two pyrimidines become extrahelical owing to the formation of single strand DNA or a slipped structure. This allows the two pyrimidines to photodimerize in a colinear arrangement, as if the intervening …

Retention Of Ionizable Compounds In Hplc, Rosario Lobrutto

Seton Hall University Dissertations and Theses (ETDs)

No abstract provided.

Geohydrology: Analytical Methods, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

This guide analyzes the field methods involved in conducting a geohydrologic analysis, including pretest water level monitoring, pumping phase, and recovery phase. Selectd methods of analytical analysis are reviewed with reference to the geohydrologic setting, the stress placed on the aquifer by the pumping well, the observation of aquifer response, the mathematical solution to the hydraulic head response in the aquifer, and the technique for calculating the hydraulic properties of the aquifer. Type curves are included for selected aquifer test methods.

The Media, Risk Assessment And Numbers: They Don't Add Up, Sharon M. Friedman

RISK: Health, Safety & Environment (1990-2002)

Professor Friedman argues that, for risks to be reported accurately, journalism educators must help their students understand science, numbers and statistics.