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Title: Development and Characterization of Solid-Contact Paper-Based and Micro Ion-Selective Electrodes for Environmental Analysis.
Creator: Armas, Stephanie, Chumbimuni Torres, Karin, Beazley, Melanie, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: Ion-selective electrodes (ISEs) have extensively been used for food analysis, as medical diagnostic tools, and for some environmental applications. However, ISEs are hindered by the need of a bulky reference electrode and the pre-conditioning step of the sensor, which can often be lengthy. This work will discuss how the direct addition of target analyte into the cocktail sensing membrane can circumvent the pre-conditioning step. Furthermore, the work is presented in an optimized ready-to-use...
Show moreIon-selective electrodes (ISEs) have extensively been used for food analysis, as medical diagnostic tools, and for some environmental applications. However, ISEs are hindered by the need of a bulky reference electrode and the pre-conditioning step of the sensor, which can often be lengthy. This work will discuss how the direct addition of target analyte into the cocktail sensing membrane can circumvent the pre-conditioning step. Furthermore, the work is presented in an optimized ready-to-use single strip design, where the bulky glass reference electrode (RE) is no longer needed. The bulky RE was replaced by drop casting a simple two-component mixture consisting of the co-polymer methyl methacrylate-co-decyl methacrylate and the ionic liquid 1-Ethyl-3-methylimidazolium bis (trifluoromethane sulfonyl) amide. Furthermore, this work will also highlight the benefits of solid-contact ISEs, specifically focusing on two solid- contact platforms: 1) paper-based and 2) a micro-electrode platform. Paper-based based sensors were designed to be used as a possible diagnostic tool to be implemented in undeveloped countries to monitor low levels of potassium and iodide, as model ions. The micro((&)#181;) ISEs were applied for the in-situ analysis of zinc in citrus plants as a mean to monitor and assess disease progression or therapy.
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Date Issued: 2018
Identifier: CFE0007152, ucf:52316
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007152

Title: Metastable-State Photoacids: Synthesis, Properties, and Applications.
Creator: Patel, Parth, Chumbimuni Torres, Karin, Hernandez, Florencio, Santra, Swadeshmukul, Beazley, Melanie, Lee, Woo Hyoung, University of Central Florida
Abstract / Description: Reversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical...
Show moreReversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical sensors and harvesting solar energy. However, majority of photochromic compounds are initially activated by ultraviolet (UV) light. The use of UV light is harmful for biological applications and photo-degrade the compound over repeated use. To overcome these limitations, a new class of reversible photochromic compound was introduced, called metastable-state photoacid (mPAH). In brief, mPAH is a photochromic compound which can photo-dissociate its protons under visible light and can thermally re-capture the released protons efficiently in the dark. Based on this unique property, in this research, we (1) synthesized different mPAH, and (2) studied and characterized their physicochemical (acidity, kinetics, and optical) properties. Additionally, we (3) applied different visible light activated mPAHs towards light controllable polymeric-based ion-selective optodes for detection of calcium ions and sodium ions, and modulate fluorescence with pH. The research presented herein opens new avenues towards the synthesis of mPAH derivatives and could be applied to any proton-transfer process related applications which requires wireless controllability with high sensitivity.
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Date Issued: 2019
Identifier: CFE0007849, ucf:52769
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007849

Title: Nanoscale Characterization and Mechanism of Electroless Deposition of Silver Metal.
Creator: Grabill, Christopher, Kuebler, Stephen, Beazley, Melanie, Zou, Shengli, Frazer, Andrew, Bhattacharya, Aniket, University of Central Florida
Abstract / Description: This dissertation is an investigation of the nanoscale characteristics and mechanism of electrolessly deposited silver metal seeded by gold nanoparticles. The process of growing seed-nanoparticles on a polymer surface was studied. Several bifunctional amines and organic reducing agents were used to explore how these chemical factors affect the size and distribution of gold nanoparticles formed at the interface. The nanoparticles were characterized by transmission electron microscopy (TEM) and...
Show moreThis dissertation is an investigation of the nanoscale characteristics and mechanism of electrolessly deposited silver metal seeded by gold nanoparticles. The process of growing seed-nanoparticles on a polymer surface was studied. Several bifunctional amines and organic reducing agents were used to explore how these chemical factors affect the size and distribution of gold nanoparticles formed at the interface. The nanoparticles were characterized by transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). An electroless deposition (ED) bath developed by Danscher was selected to study electroless deposition of silver in detail. The chemical species in the bath were varied to determine how concentration, nature of the carboxylate buffering species, and the presence and absence of gum arabic affect the morphology of silver metal formed by ED and the overall rate of deposition at the surface. The kinetics of deposition using the Danscher bath was studied in detail to elucidate the mechanism of ED. Knowledge generated from this investigation can be used to expand applications of silver ED where strict control over the nanoscale morphology of the deposited metal is required to obtain specific chemical and physical properties.
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Date Issued: 2018
Identifier: CFE0007009, ucf:52051
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007009

Title: In situ Treatment Systems for Remediation of Polychlorinated Biphenyl-contaminated building materials.
Creator: Almutairi, Adibah, Yestrebsky, Cherie, Beazley, Melanie, Legron-Rodriguez, Tamra, Bridge, Candice, Randall, Andrew, University of Central Florida
Abstract / Description: Polychlorinated Biphenyls (PCBs) are a family of synthetic organohalides comprising 209 congeners which were used historically as additives in paint and caulking materials over a span of many years. Even though the production of PCBs in the USA has been banned since the late 1970s, their former prevalence and widespread use means many structures are still coated with PCB-laden paints. In addition, the presence of PCBs in elastic sealants has resulted in transport of PCBs into concrete...
Show morePolychlorinated Biphenyls (PCBs) are a family of synthetic organohalides comprising 209 congeners which were used historically as additives in paint and caulking materials over a span of many years. Even though the production of PCBs in the USA has been banned since the late 1970s, their former prevalence and widespread use means many structures are still coated with PCB-laden paints. In addition, the presence of PCBs in elastic sealants has resulted in transport of PCBs into concrete structures and has caused soil contamination around buildings. PCB-contaminated building materials have become a significant concern for the environment and building occupants due to their carcinogenic nature and potential indoor contamination. This results in an urgent need for development of a cost-effective method to extract and degrade PCBs from contaminated materials. Experiments employing reductive dehalogenation through the use of zero-valent magnesium (ZVMg) ball-milled with activated carbon (AC) in an acidified solvent system have shown that PCBs can be broken down even in the presence of water. This research describes the development of two delivery systems for effective deployment of this treatment reaction to field samples. Two treatment systems formulated in this process, the Non-Metal Treatment System (NTMS) and the Activated Metal Treatment System (AMTS), are capable of extracting or extracting and degrading, respectively, trapped PCBs within a variety of building materials. In the development of NMTS and AMTS, an acidified dual system of ethanol/ethyl lactate was used as solvent while ZVMg over activated carbon is used in the AMTS. After development, applications of the systems extended to laboratory prepared PCB-laden paint as well as field samples received from Seattle. A marked successful on PCB remediation was observed. The green solvent 2-butoxyethanol is approved by both the EPA and the FDA, and is an interesting alternative for the dechlorination of PCBs. Novel versions of NMTS and AMTS were developed by substituting 2-butoxyethanol for ethanol/EL and used on a set of paint chips and building materials from the same field site. PCBs were degraded significantly below their starting concentrations with removal efficiency greater than 99% for all samples after two weeks of treatment. The use of acidified 2-butoxyethanol and ZVMg permitted the extraction and destruction of PCBs from contaminated building materials in a one-step treatment. Additional studies were conducted on laboratory-prepared concrete where transport of the organic solvents (used in development of NMTS/AMTS) into the concrete structure was studied. PCB concentrations in concrete after treatment were reduced to below the limit of detection.
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Date Issued: 2018
Identifier: CFE0007388, ucf:52064
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007388

Title: Thermo- and Zero-Valent Iron-Activated Persulfate Oxidation of 3,5,6-Trichloro-2-pyridinol in an Aquatic System.
Creator: Mogharbel, Roaa, Yestrebsky, Cherie, Beazley, Melanie, Zou, Shengli, Legron-Rodriguez, Tamra, Randall, Andrew, University of Central Florida
Abstract / Description: The compound 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the broad-spectrumorganophosphorous insecticide chlorpyrifos, is both more persistent and more water soluble thanits parent compound. This difference, which allows TCPy to more readily leach into surface waterand groundwater, has led to widespread contamination of TCPy in soils and aquatic environments.In this study, the degradation of TCPy by sulfate radicals was evaluated using zero valent ironactivatedpersulfate systems and...
Show moreThe compound 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the broad-spectrumorganophosphorous insecticide chlorpyrifos, is both more persistent and more water soluble thanits parent compound. This difference, which allows TCPy to more readily leach into surface waterand groundwater, has led to widespread contamination of TCPy in soils and aquatic environments.In this study, the degradation of TCPy by sulfate radicals was evaluated using zero valent ironactivatedpersulfate systems and heat activated persulfate system in aqueous media. Responsesurface methodology coupled with Box-Behnken design was applied in these studies to evaluatethe effects of the independent variables on the mineralization of TCPy by both systems. In eachsystem, the interactions, coefficients, and residuals of these variables were statically evaluated byAnalysis of variance. Results indicate that both systems can effectively oxidized TCPy in water.While ZV/PS exhibited a high mineralization rate of TCPy up to 81.1%, TCPy was completelymineralized in heat activated PS system. The reaction kinetics of the degradation process wereexamined as functions of experimental parameters in each system and the result revealed that theoxidation of TCPy in both systems followed a pseudo-first-order model under all conditions tested.Radical scavenging tests indicated that sulfate radicals are the predominated species in zero valentiron activated persulfate system, whereas hydroxyl radicals are the predominated species in heatactivated persulfate system. The presence of chloride, sulfate and phosphate anions showednegligible effects on TCPy oxidation by heat activated PS system. The degradation pathways ofTCPy were proposed based on the products identified by GC-MS. Calculated ?G values usingdensity functional theory agreed with the proposed experimental pathway.
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Date Issued: 2018
Identifier: CFE0007762, ucf:52386
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007762

Title: Improved system for fabrication and characterization of nanophotonic devices by multi-photon lithography.
Creator: Sharma, Rashi, Kuebler, Stephen, Zou, Shengli, Huo, Qun, Beazley, Melanie, Phanstiel, Otto, University of Central Florida
Abstract / Description: A new system for multi-photon lithography (MPL) was developed and used to fabricate three-dimensional (3D) structures with higher aspect ratio, better resolution, improved fidelity, and reduced structural distortion relative to a conventional implementation of MPL.A set of curved waveguides (Rbend = 19 (&)#181;m, and 38 (&)#181;m) and straight waveguides (length = 50 (&)#181;m, Rbend = ?) were fabricated in an epoxide photopolymer and optically characterized using light having a wavelength in...
Show moreA new system for multi-photon lithography (MPL) was developed and used to fabricate three-dimensional (3D) structures with higher aspect ratio, better resolution, improved fidelity, and reduced structural distortion relative to a conventional implementation of MPL.A set of curved waveguides (Rbend = 19 (&)#181;m, and 38 (&)#181;m) and straight waveguides (length = 50 (&)#181;m, Rbend = ?) were fabricated in an epoxide photopolymer and optically characterized using light having a wavelength in vacuum of ?0 = 2.94 (&)#181;m. The optical performance of the waveguides was compared to novel spatially-variant photonic crystals (SVPCs) previously studied in the group. The waveguides were found to guide light with 90% lower efficiency, due to mode leakage. The study provides further evidence that SVPCs operate not through total internal reflection, but rather through self-collimation, as designed.3D uniform-lattice photonic crystals (ULPCs) were fabricated by MPL using a commercial acrylate photopolymer. The ULPCs were optically characterized at ?0 = 1.55 (&)#181;m. A laser beam with adjustable bandwidth was used to measure the self-collimation in the ULPCs. For the low bandwidth beam, vertically polarized light was self-collimated, whereas horizontally polarized light diverged. The transmission efficiency of the ULPCs was also measured as a function of fill factor. The ULPC having a fill factor of 48% exhibited 80% transmission.An etching process was also developed for non-destructively removing Au/Pd coatings that must be deposited onto structures to image them by scanning electron microscopy. The structural and optical integrity of the samples was found to be maintained despite etching. The sputter-coated sample sustained no structural damage when exposed to the ?0 = 1.55 (&)#181;m. However, the metal coating resulted in diminished transmission efficiency due to the high reflection of the 1.55 (&)#181;m beam by the metal coating.
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Date Issued: 2018
Identifier: CFE0007767, ucf:52380
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007767

Title: Magnesium-based treatment for the degradation of octachlorodibenzofuran and trinitrotoluene.
Creator: Mogharbel, Amal, Yestrebsky, Cherie, Beazley, Melanie, Zou, Shengli, Legron-Rodriguez, Tamra, Randall, Andrew, University of Central Florida
Abstract / Description: The aim of the present research is to investigate the efficacy of using ball-milled zero-valent magnesium (ZVMg) with and without activated carbon (AC) for the dechlorination of polychlorinated dibenzofurans. Three different solvent systems are presented here which are ethanol, ethanol/ethyl lactate (90:10), and 2-butoxyethanol. These solvents in combination with ZVMg with and without activated carbon were tested towards the degradation of octachlorodibenzofuran (OCDF, the most highly...
Show moreThe aim of the present research is to investigate the efficacy of using ball-milled zero-valent magnesium (ZVMg) with and without activated carbon (AC) for the dechlorination of polychlorinated dibenzofurans. Three different solvent systems are presented here which are ethanol, ethanol/ethyl lactate (90:10), and 2-butoxyethanol. These solvents in combination with ZVMg with and without activated carbon were tested towards the degradation of octachlorodibenzofuran (OCDF, the most highly chlorinated PCDF congener). All the tested systems were very powerful and reductively dechlorinated OCDF to less chlorinated congeners. However, the system of ball-milled ZVMg and ethanol was the only system which converted OCDF and all byproducts to dibenzofuran, the chlorine- free compound. Kinetic results for all the studied systems fit a pseudo-first-order decay model with respect to OCDF degradation. A detailed study of the formed byproducts during the dechlorination process and a proposed degradation pathway for OCDF are present in this research. The systems consisting of ZVMg and ZVMg/AC in acidified ethanol and acidified 2-butoxyethanol were examined towards the degradation of the low-chlorinated congener 2,8-dichlorodibenzofuran. This compound was degraded efficiently in all systems. The addition of activated carbon enhanced the degradation kinetics of 2,8-dichlorodibenzofuran degradation. Another study using ZVMg and ZVMg/AC in acidified ethanol was conducted to evaluate the efficiency of the system towards the remediation of the explosive contaminant trinitrotoluene (TNT). Both systems were effective in the degradation of TNT and the reactions were found to follow pseudo-first-order kinetics. A plausible degradation pathway is proposed in this study based on the identified degradation products.
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Date Issued: 2018
Identifier: CFE0007761, ucf:52374
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007761

Title: Remediation of chlorinated alkanes by zero valent iron with vitamin B12 and Utilization of a modified Gradual Release of Responsibility model in a large enrollment chemistry course.
Creator: Lapeyrouse, Nicole, Yestrebsky, Cherie, Beazley, Melanie, Chen, Gang, Rex, Matthew, Randall, Andrew, University of Central Florida
Abstract / Description: The following dissertation looks at addressing environmental contaminants in the environment and the integration of an active learning style in an introductory chemistry course. It begins with addressing the concern for chlorinated propanes and ethane in the environment and the importance of looking into environmental remediation applications. This research looks at incorporating vitamin B12 as an environmentally friendly catalyst in the presence of zero valent iron for the reduction of...
Show moreThe following dissertation looks at addressing environmental contaminants in the environment and the integration of an active learning style in an introductory chemistry course. It begins with addressing the concern for chlorinated propanes and ethane in the environment and the importance of looking into environmental remediation applications. This research looks at incorporating vitamin B12 as an environmentally friendly catalyst in the presence of zero valent iron for the reduction of chlorinated propanes and ethane. Chapter 2 presents the analytical methods and conditions in which samples were run. The results from these experiments are discussed in length in Chapter 3. Our results confirmed the hypothesis that vitamin B12 could act as an electron mediator to facilitate the reduction of the chlorinated propanes and ethane. Degradation was examined by observing the formation of byproduct peaks and the release of free chloride into solution. In Chapter 4, vitamin B12 is integrated into an already established industrial application technique, emulsified zero valent iron, and we observed the degradation of 1,2,3-trichloropropane with the formation of byproducts as the reaction progressed. In Chapter 5, this section of the dissertation focused on chemical education and observing an active learning technique in a fundamental chemistry course. The following study was designed to increase students' positive attitude, engagement, and responsibility in a large enrollment chemistry course by utilizing a modified Gradual Release of Responsibility (GRR) model. GRR progressively transfers responsibility from the instructor to the student, allowing students to be more independent and helping them to address atypical problems. Students were assessed using iClickers to monitor their understanding and engagement, as well as surveys to determine their attitudes regarding this specific style of teaching. The results from this study demonstrated that implementing the GRR teaching style had a positive effect on student academic performance and shows the importance of using an active teaching model in a large enrollment course.
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Date Issued: 2018
Identifier: CFE0007759, ucf:52373
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007759

Title: Engineering Noble-metal Nanostructures for Biosensing Applications.
Creator: Ye, Haihang, Xia, Xiaohu, Kuebler, Stephen, Chen, Gang, Beazley, Melanie, Feng, Xiaofeng, University of Central Florida
Abstract / Description: The ability to engineer noble-metal nanostructures (NMNSs) in a controllable manner and to understand the structure-dependent properties greatly boost our knowledge in rational design of biosensing technologies. In particular, as a type of highly efficient peroxidase mimics, NMNSs hold promising potential to break through the bottleneck of conventional enzyme-based in vitro diagnostics.During the time of my Ph.D. study, I have successfully: 1) directed a two-step method involving seed...
Show moreThe ability to engineer noble-metal nanostructures (NMNSs) in a controllable manner and to understand the structure-dependent properties greatly boost our knowledge in rational design of biosensing technologies. In particular, as a type of highly efficient peroxidase mimics, NMNSs hold promising potential to break through the bottleneck of conventional enzyme-based in vitro diagnostics.During the time of my Ph.D. study, I have successfully: 1) directed a two-step method involving seed-mediated growth and chemical etching for the synthesis of Ru nanoframes (RuNFs) with face-centered cubic crystal phase and enhanced catalytic activities; 2) demonstrated, for the first time, the inherent peroxidase-like activity of RuNFs as a type of efficient peroxidase mimics, opening up possibilities for their bioapplications; 3) developed an enzyme-free signal amplification technique for ultrasensitive colorimetric assay of disease biomarkers by using Pd-Ir nanooctahedra encapsulated gold vesicles as labels; 4) prepared polyvinylpyrrolidone (PVP)-capped Pt nanocubes with superior peroxidase-like catalytic activity and record-high specific catalytic activity; 5) developed a facile colorimetric method for the detection of Ag(I) ions with picomolar sensitivity by using the PVP-capped Pt nanocubes as the probes; 6) developed a non-enzyme cascade amplification strategy for colorimetric assay of disease biomarkers by taking advantage of the interaction between the Ag(I) ions and PVP-capped Pt nanocubes; and 7) established a highly sensitive colorimetric lateral flow assay platform by using Au@Pt core-shell nanoparticles as the labels that possess both plasmonic and catalytic properties.
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Date Issued: 2019
Identifier: CFE0007559, ucf:52626
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007559

Title: Novel Fuel-producing Fungi and Methodologies for Increasing Fuel Production.
Creator: Wang, Yuemin, Harper, James, Bridge, Candice, Frazer, Andrew, Beazley, Melanie, Blair, Richard, University of Central Florida
Abstract / Description: An endophytic fungus Hypoxylon sp. (BS15) has recently been isolated and found to produce volatile organic compounds (VOCs) that have potential relevance as hydrocarbon fuels. In the work described here, the traditional refined carbohydrate (e.g., sucrose) diet source was replaced by simple sugars produced using a solvent free green chemistry mechanocatalytic method involving ball milling in the solid. BS15 is able to grow on this degraded cellulose as well as the more traditional potato...
Show moreAn endophytic fungus Hypoxylon sp. (BS15) has recently been isolated and found to produce volatile organic compounds (VOCs) that have potential relevance as hydrocarbon fuels. In the work described here, the traditional refined carbohydrate (e.g., sucrose) diet source was replaced by simple sugars produced using a solvent free green chemistry mechanocatalytic method involving ball milling in the solid. BS15 is able to grow on this degraded cellulose as well as the more traditional potato dextrose broth. The volatile compounds produced from both media were largely the same. Unfortunately, it is observed that long term in vitro growth of BS15 results in diminished VOC production. The VOC production was partially restored by cultivating BS15 in growth media containing finely ground woody tissue from the original host plant (Taxodium distichum). Extracts from this woody tissue were made by sequentially extracting with dichloromethane, methanol, and water with a goal of isolating VOC production modulators. Both the dichloromethane and water extracts place on bio-mimicking filter paper were found to modulate VOC production, while the methanol extract had no significant impact. Surprisingly, the woody tissue remaining after exhaustive extraction also acted as a VOC production modulator when combined with the growth media, with noticeable changes in the production of four compounds. This woody tissue also induced production of two compounds not observed in the original BS15 extract, and their changes are inheritable. Remarkably filter paper had the same modulating effect as exhaustively extracted woody tissue, suggesting the modulation was partially due to cellulose degradation products. Extraction of the maximum amounts of VOCs is desirable and here a comparison of solid phase extraction (SPE) and solid phase micro-extraction (SPME) techniques is made. This comparison involves two endophytes, BS15C and Streptomyces ambofaciens (SA 40053). The SPE technique is more effective in retaining compounds having lower vapor pressures and higher boiling points with nearly three to five times more VOC mass obtained versus SPME.
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Date Issued: 2019
Identifier: CFE0007552, ucf:52598
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007552

Title: A deoxyribozyme sensor and isothermal amplification for human sex determination.
Creator: Smith, Alexandra, Kolpashchikov, Dmitry, Campiglia, Andres, Harper, James, Beazley, Melanie, Tetard, Laurene, University of Central Florida
Abstract / Description: Ribozymes are known to catalyze biochemical reactions and behave like enzymes. They are naturally occurring and have very diverse functions within a cell. After investigating ribozymes that next step was to find if DNA can exhibit the same characteristics since RNA and DNA only differ by a ribose 2'-hydroxyl group. This evolution in curiosity gave rise to artificial DNA enzymes that can catalyze certain reactions and have been created by in vitro selection methods. Due to the ability to...
Show moreRibozymes are known to catalyze biochemical reactions and behave like enzymes. They are naturally occurring and have very diverse functions within a cell. After investigating ribozymes that next step was to find if DNA can exhibit the same characteristics since RNA and DNA only differ by a ribose 2'-hydroxyl group. This evolution in curiosity gave rise to artificial DNA enzymes that can catalyze certain reactions and have been created by in vitro selection methods. Due to the ability to manipulate and control DNA hybridization, the deoxyribozyme is advantageous to the field of molecular diagnostics. Other hybridization probes like Taqman for PCR (polymerase chain reaction) or a molecular beacon are more conventional methods for molecular diagnostics, but deoxyribozyme-based nucleic acid sensors are overall more sensitive due to their catalytic enhancement of a signal and more selective due to structural design. When the deoxyribozyme is split into two probes, it is very efficient in identifying a minute difference in sequence compared to the monolith structure. This binary deoxyribozyme sensor (BiDz) has two probes, each containing an analyte binding arm, substrate binding arm, and half of the catalytic core. The monolith structure, known as a catalytic molecular beacon (CMB), contains a hairpin that contains the analyte binding arm in the loop and the substrate binding arms in the stem. The catalytic core is fully intact but deemed inactive due to the substrate binding arms being complimentary to an inhibitory sequence forming the stem. Once the sensor binds the analyte, catalytic core is formed/activated and cleaves a substrate containing a fluorophore and quencher. When the substrate is cleaved a fluorescent signal is given off denoting the detection of the target DNA. Deoxyribozyme sensors can be applied to the field of human sex determination by detecting the Amelogenin gene. Found on both sex chromosomes, the Amelogenin gene is the most common marker used for sex determination because it exhibits dimorphism in length and sequence. Sex identification from ancient skeletal remains is crucial to understanding the social structure of our history. When conventional methods, such as metric analysis, are not an option due to the fragmented or prepubescent remains, molecular diagnostics are needed. Amplification of DNA is required to be able to detect the target sequence in human samples. Isothermal loop-mediated amplification (LAMP) is a fast and simple technique that provides ample amounts of amplicon. It is advantageous over PCR because it amplifies at one temperature and no thermal cycler is needed. Two different sensors have been designed to detect the X and Y specific sequences with high selectivity. From a direct comparison between the CMB and BiDZ, the binary structure has shown to be simpler and less expensive to design, and highly selective toward single base substitutions (SNS). While both sensors contain detection limits in the picomolar range, which is consistent with data published by other research groups, the CMB sensors failed to function at higher temperatures (55oC). BiDz sensors are shown to be superior to the CMB design, particularly when selectivity based analysis is desired. For human sex determination, the binary sensor detected sex specific sequences with great selectivity. The sensor then detected LAMP amplified DNA from male and female teeth after 30 minutes of amplification. Combining a binary deoxyribozyme sensor and isothermal amplification can provide a new and valuable method for human sex determination.
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Date Issued: 2017
Identifier: CFE0007133, ucf:52306
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007133

Title: Biogeochemical effects of sea level rise-induced transitions within coastal wetlands.
Creator: Steinmuller, Havalend, Chambers, Lisa, Hinkle, Ross, Bohlen, Patrick, Beazley, Melanie, University of Central Florida
Abstract / Description: As sea level rise (SLR) affects coastal wetlands, ecosystem responses can include vertical accretion, landward transgression, or submergence. Sea level rise-induced transitions can alter key biogeochemical transformations within wetland soils, impacting the ability of these systems to provide ecosystem services, specifically carbon (C) storage and water quality regulation. Through a series of complementary laboratory and field-based studies, biogeochemical responses to salinity, vegetation...
Show moreAs sea level rise (SLR) affects coastal wetlands, ecosystem responses can include vertical accretion, landward transgression, or submergence. Sea level rise-induced transitions can alter key biogeochemical transformations within wetland soils, impacting the ability of these systems to provide ecosystem services, specifically carbon (C) storage and water quality regulation. Through a series of complementary laboratory and field-based studies, biogeochemical responses to salinity, vegetation shifts, and submergence were investigated. Changes in nutrient dynamics associated with saltwater intrusion were evaluated by artificially adding saline water to different freshwater wetland soil types, indicating that potential exports of critical nutrients (forms of nitrogen, phosphorus, and C) out of freshwater wetland soils is mediated by soil type. A controlled laboratory experiment was conducted to determine the potential degradability of C stored within submerging coastal wetland soils under both aerobic and anaerobic conditions. Under aerobic conditions, 66% more carbon dioxide was produced than under anaerobic conditions and 4x greater carbon dioxide was produced at 90-100cm depths than at the surface. At the same site, the degradability of carbon stores was examined through organic matter fractionation, stable isotopic examination, and determining the abundance of key microbial genes. Both total soil C and stores of bioavailable nutrients increased with depth, while organic matter quality decreased. Finally, the biogeochemical impacts of two separate vegetation transitions occurring co-incidentally with sea level rise were investigated: mangrove encroachment into salt marsh, and more salt- and inundation-tolerant herbaceous encroachment into herbaceous marsh. Conclusions from these studies demonstrate that vegetation transitions alter both soil nutrient storage and fast-cycling nutrient pools, indicating that biogeochemical transitions occur in advance of changes in vegetative species dominance. Results from these chapters holistically address how biogeochemical functioning, specifically nutrient cycling, regulation of water quality, and C sequestration, within coastal wetlands responds to stressors associated with SLR.
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Date Issued: 2019
Identifier: CFE0007536, ucf:52584
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007536

Title: Measuring and Modeling NMR and Emission Spectra to Gain New Insight into Challenging Organic Compounds.
Creator: Powell, Jacob, Harper, James, Campiglia, Andres, Beazley, Melanie, Richardson, David, Blair, Richard, University of Central Florida
Abstract / Description: The advancement of theoretical methods in recent years has allowed the calculation of highly accurate spectroscopic parameters. Comparing these values to the corresponding experimental data can allow molecular structures to be elucidated. This dissertation details the use of experimental and theoretical data from nuclear magnetic resonance (NMR) and fluorescence spectroscopy to determine structure. Herein the NMR focus is on measuring (&) modeling chemical shift anisotropy and one-bond carbon...
Show moreThe advancement of theoretical methods in recent years has allowed the calculation of highly accurate spectroscopic parameters. Comparing these values to the corresponding experimental data can allow molecular structures to be elucidated. This dissertation details the use of experimental and theoretical data from nuclear magnetic resonance (NMR) and fluorescence spectroscopy to determine structure. Herein the NMR focus is on measuring (&) modeling chemical shift anisotropy and one-bond carbon-carbon J-coupling constants (1JCC). The fluorescence analysis models vibrationally resolved fluorescence spectra.Chemical shift anisotropy techniques were used to study two conflicting crystal structures of the n-alkyl fatty acid, lauric acid. These two crystal structures differ only in their COOH conformation. Lattice-including density functional theory (DFT) refinements of each crystal structure failed to match experimental data leading to the proposal of a third crystal structure with a hydrogen disordered COOH moiety. This disorder strengthens the hydrogen bond providing a new rationalization to the long observed non-monotonic melting behavior of fatty acids having even and odd numbers of carbons.The INADEQUATE is a NMR experiment that directly establishes the skeleton of organic compounds by measuring the 1JCC throughout a molecule. The low occurrence of 13C-13C pairs (1 in 10,000) and breaks in connectivity due to the presence of heteroatoms causes challenges to INADEQUATE analysis. Here, the insensitivity problem is overcome using analysis software that automatically processes data and identifies signals, even when they are comparable in magnitude to noise. When combined with DFT 1JCC predictions,configuration and confirmations of the natural products 5-methylmellein and hydroheptelidic acid are elucidated.Vibrationally resolved fluorescence spectra of high molecular weight PAHs can be accurately calculated through time-dependent density functional theory (TD-DFT) methods. Here, the theoretical spectral profiles of certain PAHs are shown to match experimental high- resolution fluorescence spectra acquired at cryogenic temperatures. However, in all cases, theoretical spectra were systematically offset from experimental spectra. To decrease these uncertainties spectra were empirically corrected and an automated scheme employed to match theoretical spectra with all possible experimental spectra. In all cases the theoretical spectra were correctly matched to the experimental spectra.
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Date Issued: 2017
Identifier: CFE0006953, ucf:51680
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006953

fluorescence (2)	+ -
04/02/2018 (1)	+ -
1JCC (1)	+ -
3 (1)	+ -
5 (1)	+ -

5-methylmellein (1)	+ -
6-trichloro-2-pyridinol (1)	+ -
Activated carbon (1)	+ -
Ball-milled zero-valent magnesium (1)	+ -
DFT (1)	+ -
Deoxyribozyme (1)	+ -
Electroless deposition (1)	+ -
FIREMAT (1)	+ -
Hypoxylon sp. (1)	+ -
INADEQUATE (1)	+ -
IP-Dip (1)	+ -
LAMP (1)	+ -
Laser characterization (1)	+ -
Multi-photon lithography (1)	+ -
NMR (1)	+ -
Noble metal ? nanostructures ? peroxidase mimics ? in vitro diagnostics ? biosensing technique ? colorimetric detection (1)	+ -
Octachlorodibenzofuran (1)	+ -
PAH (1)	+ -
Polychlorinated dibenzofuran (1)	+ -
Polycyclic aromatic hydrocarbons (1)	+ -
Remediation (1)	+ -
SSNMR (1)	+ -
SU-8 (1)	+ -
VOC production (1)	+ -
Volatile organic compounds (1)	+ -

Beazley, Melanie (13)	+ -
University of Central Florida (13)	+ -
Randall, Andrew (4)	+ -
Yestrebsky, Cherie (4)	+ -
Zou, Shengli (4)	+ -

Harper, James (3)	+ -
Kuebler, Stephen (3)	+ -
Legron-Rodriguez, Tamra (3)	+ -
Blair, Richard (2)	+ -
Bridge, Candice (2)	+ -
Campiglia, Andres (2)	+ -
Chen, Gang (2)	+ -
Chumbimuni Torres, Karin (2)	+ -
Frazer, Andrew (2)	+ -
Santra, Swadeshmukul (2)	+ -
Almutairi, Adibah (1)	+ -
Armas, Stephanie (1)	+ -
Bhattacharya, Aniket (1)	+ -
Bohlen, Patrick (1)	+ -
Chambers, Lisa (1)	+ -
Feng, Xiaofeng (1)	+ -
Grabill, Christopher (1)	+ -
Hernandez, Florencio (1)	+ -
Hinkle, Ross (1)	+ -
Huo, Qun (1)	+ -
Kolpashchikov, Dmitry (1)	+ -
Lapeyrouse, Nicole (1)	+ -
Lee, Woo Hyoung (1)	+ -
Mogharbel, Amal (1)	+ -
Mogharbel, Roaa (1)	+ -

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