Digital Commons Network^™

Folding Of Bovine Pancreatic Trypsin Inhibitor (Bpti) Is Faster Using Aromatic Thiols And Their Corresponding Disulfides, Ram Prasad Marahatta

FIU Electronic Theses and Dissertations

Improvement in the in vitro oxidative folding of disulfide-containing proteins, such as extracellular and pharmaceutically important proteins, is required. Traditional folding methods using small molecule aliphatic thiol and disulfide, such as glutathione (GSH) and glutathione disulfide (GSSG) are slow and low yielding. Small molecule aromatic thiols and disulfides show great potentiality because aromatic thiols have low pKa values, close to the thiol pKa of protein disulfide isomerase (PDI), higher nucleophilicity and good leaving group ability. Our studies showed that thiols with a positively charged group, quaternary ammonium salts (QAS), are better than thiols with negatively charged groups such as phosphonic …

Drug Candidate Discovery: Targeting Bacterial Topoisomerase I Enzymes For Novel Antibiotic Leads, Shayna Sandhaus

FIU Electronic Theses and Dissertations

Multi-drug resistance in bacterial pathogens has become a global health crisis. Each year, millions of people worldwide are infected with bacterial strains that are resistant to currently available antibiotics. Diseases such as tuberculosis, pneumonia, and gonorrhea have become increasingly more difficult to treat. It is essential that novel drugs and cellular targets be identified in order to treat this resistance. Bacterial topoisomerase IA is a novel drug target that is essential for cellular growth. As it has never been targeted by existing antibiotics, it is an attractive target. Topoisomerase IA is responsible for relieving torsional strain on DNA by relaxing …

The Investigation Of Human Scent From Epileptic Patients For The Identification Of A Biomarker For Epileptic Seizures, Philip R.N. Davis

FIU Electronic Theses and Dissertations

Studies have shown that some canines have the ability to predict seizures in people with epilepsy, and that canines can be trained to recognize changes in humans before an epileptic seizure and make these predictions. It is not known with any certainty to what the canines are alerting. However, canines’ exceptional sense of smell and their ability to discriminate human scent is well established. Therefore, it is possible that the canines could be responding to an olfactory cue, such as the release of some volatile organic compounds (VOCs) prior to the onset of a seizure.

Individuals release a wide array …

Simplifying Sample Preparation Using Fabric Phase Sorptive Extraction: Analysis Of Trace Targeted Pollutant Residues In Environmental, Biological And Food Samples, Rodolfo Mesa

FIU Electronic Theses and Dissertations

Sample preparation is an essential component of analytical methods in chemistry. It is not only necessary but also presents an opportunity to increase the effectiveness of the method significantly. There are various commercially available technologies for sample preparation, including numerous variations of LLE, SPE, and SPME. However, these technologies all present significant deficiencies, including the inability to extract directly from complex samples such as whole milk. Instrumental analysis has been improved greatly in the last two decades but still is not applicable to complex samples without sample preparation.

This work presents the theory of FPSE, including the synthesis of sol-gel …

Hybrid Polymer Electrolyte For Lithium-Oxygen Battery Application, Amir Chamaani

FIU Electronic Theses and Dissertations

The transition from fossil fuels to renewable resources has created more demand for energy storage devices. Lithium-oxygen (Li-O₂) batteries have attracted much attention due to their high theoretical energy densities. They, however, are still in their infancy and several fundamental challenges remain to be addressed. Advanced analytical techniques have revealed that all components of a Li-O₂ battery undergo undesirable degradation during discharge/charge cycling, contributing to reduced cyclability. Despite many attempts to minimize the anode and cathode degradation, the electrolyte remains as the leading cause for rapid capacity fading and poor cyclability in Li-O₂ batteries. In this …

The Detection Of An Invasive Pathogen Through Chemical And Biological Means For The Protection Of Commercial Crops, Alison G. Simon

FIU Electronic Theses and Dissertations

Standoff detection of targets using volatiles is essential when considering substances that are hazardous or dangerous, or for which the presence or location is unknown. For many invasive biological threats, their presence is often not realized until they have begun visibly affecting and spreading through crops or forests. The fungus Raffaelea lauricola is a biothreat vectored by the invasive beetle Xyleborus glabratus, or redbay ambrosia beetle (RAB), whose presence in avocado groves is currently detectable by visual inspection. Once visually identified, the affected trees must be removed and destroyed to protect those remaining trees. However, if the fungus is …

Trapped Ion Mobility Spectrometry Coupled To Fourier Transform Ion Cyclotron Resonance Mass Spectrometry For The Analysis Of Complex Mixtures., Paolo Benigni

FIU Electronic Theses and Dissertations

Analytical Characterization of complex mixtures, such as crude oil, environmental samples, and biological mixtures, is challenging because of the large diversity of molecular components. Mass spectrometry based techniques are among the most powerful tools for the separation of molecules based on their molecular composition, and the coupling of ion mobility spectrometry has enabled the separation and structural elucidation using the tridimensional structure of the molecule. The present work expands the ability of analytical chemists by furthering the development of IMS-MS instrumentation by coupling Trapped Ion Mobility Spectrometry to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (TIMS-FT-ICR MS). The TIMS-FT-ICR MS …

Applications Of Paper Microfluidic Systems In The Field Detection Of Drugs Of Abuse, Ling Wang

FIU Electronic Theses and Dissertations

Over the years, colorimetric reagents and immunology have been widely used in screening tests for illicit drugs; however, the test kits are not always convenient for field use and often require the user to mix and develop a specific set of reagents. In our project, we have been working on alternative platforms based on paper microfluidic devices (uPADs) for field testing. These devices utilize wax channels printed on paper to direct the analyte towards a specific set of chemical reagents. Using the procedure, we have developed a six-channel chip that adapts known colorimetric reagents targeting cocaine, opiates, amphetamines and ketamine …

Linking Organic Matter Dynamics To Management, Restoration, And Climate In The Florida Everglades, Peter Regier

FIU Electronic Theses and Dissertations

The Florida Everglades is a massive and highly managed subtropical wetland ecosystem, strongly influenced by anthropogenic control of freshwater distribution and highly susceptible to a changing climate, including rising sea-level and changes in temperature and rainfall. Shifting hydrologic regimes impact ecosystem function and biogeochemistry, which in turn control the sources, fate, and transport of organic matter. As a master environmental variable, it is essential to understand how organic matter dynamics will respond to changes in the balance between freshwater and saltwater associated with landscape-scale Everglades restoration efforts and climate change. The research comprising this dissertation improves current understanding of the …

In Situ Arsenic Speciation Using Surface-Enhanced Raman Spectroscopy, Mingwei Yang

FIU Electronic Theses and Dissertations

Arsenic (As) undergoes extensive metabolism in biological systems involving numerous metabolites with varying toxicities. It is important to obtain reliable information on arsenic speciation for understanding toxicity and relevant modes of action. Currently, popular arsenic speciation techniques, such as chromatographic/electrophoretic separation following extraction of biological samples, may induce the alternation of arsenic species during sample preparation. The present study was aimed to develop novel arsenic speciation methods for biological matrices using surface-enhanced Raman spectroscopy (SERS), which, as a rapid and non-destructive photon scattering technique. The use of silver nanoparticles with different surface coating molecules as SERS substrates permits the measurement …

Novel Nucleoside Analogues With Bases Modified With (Β-Halo)Vinyl Sulfone Or Β-Keto Sulfone As Probes To Study Rna/Dna-Proteins Interactions, Sk Md Sazzad Hossain Suzol

FIU Electronic Theses and Dissertations

The C-5 modified pyrimidine analogues are well-known anticancer and antiviral drugs which underscore further development of novel probes to study their physical, chemical, and biological properties. In my dissertation the syntheses and properties of (β-halo)vinyl sulfone and/or (β-keto)sulfone analogues of C-5 modified pyrimidine have been discussed. In the first part of the dissertion, the synthesis of 5-(β-halo)vinyl sulfones either by transition metal-catalyzed or iodine-mediated halosulfonylation reaction of 5-acetylene pyrimidine nucleosides have been explored. The novel (β-chloro/bromo/iodo)vinyl sulfones efficiently undergo addition-elimination reaction with different nucleophiles such as thiols, amines, amino acid, peptides to provide (β-substituted)vinyl sulfone analogues. The rate of these …

The Identification Of Volatile Organic Compounds From Synthetic Cathinone Derivatives For The Development Of Odor Mimic Training Aids, Vanquilla Shellman Francis

FIU Electronic Theses and Dissertations

Methylone, Ethylone, Methylenedioxypyrovalerone (MDPV), and α-Pyrrolidinopentiophenone (α-PVP) collectively referred to as bath salts are a new trend of illicit substances known as synthetic cathinones. Designed by chemically modifying the core structure of the compound cathinone, synthetic cathinones became prevalent within the United States around the mid-2000s. As a cheap and less controlled alternative to methylenedioxymethamphetamine (MDMA, ecstasy), it has become heavily abused, prompting emergency scheduling by federal regulators. Although regulations have been placed to halt incoming traffic of these drugs, lack of ground efforts still leave a large percentage of bath salts available.

This study is two-fold, as it seeks …

Nanomaterial-Based Electrochemical And Colorimetric Sensors For On-Site Detection Of Small-Molecule Targets, Bhargav Guntupalli

FIU Electronic Theses and Dissertations

An ideal biosensor is a compact and in-expensive device that is able to readily and rapidly detects different types of analytes with high sensitivity and specificity. The affectability of a biosensing methodology is subject to the limit of nanomaterials to transduce the target binding process to an improved perceptible signal, while the selectivity is accomplished by considering the binding and specificity of certain moieties to their targets. Keeping these requirements in mind we have chosen nanomaterials such as carbon nanotubes (CNTs) and gold nanoparticles (AuNPs) that has catalytic properties combined with their size, shape and configuration dependent chemical and physical …

Evaluation Of Cryofocusing Capillary Microextraction Of Volatiles For Improved Detection Of Organic Gunshot Residue On The Hands Of Shooters, Jerome Mulloor

FIU Electronic Theses and Dissertations

The capillary microextraction of volatiles (CMV) device was equipped with a novel Peltier cooler to investigate cryofocused extraction of organic gunshot residue (OGSR) for the first time. Prior research demonstrated the CMV’s capabilities for detecting nitroglycerin, 2,4-dinitrotoluene, diphenylamine, and ethyl centralite on shooters’ hands via gas chromatography-mass spectrometry. Further method development increased the recoveries of these four target compounds with an optimal 20-minute equilibrium time at 80˚C followed by extracting 3 L at a 1 L/min flow rate. The Cryo-CMV was evaluated for detection of semi-volatile OGSR compounds. The unique challenges presented with sampling of semi-volatiles were overcome by sample …

Capture And Densification Of Floating Hydrophobic Liquids By Natural Granular Materials, Daria Boglaienko

FIU Electronic Theses and Dissertations

Densification and submergence of floating crude oil is proposed as a novel oil spills treatment method. Surface application of dry granular materials (e.g., quartz sand, limestone) on top of a floating oil layer increases the density of the floating oil phase/granule mixture and leads to formation of relatively large and stable aggregates with significant amounts of captured oil. The aggregates separate from the floating hydrophobic phase and settle by gravity. Implementation of this method will reduce the impact radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna.

The major objective of this research …