Chemistry Commons^™

Interfacial Engineering And Photoelectrochemistry Of Patterned Metal/Semiconductor Heterostructures, Che Tan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photoelectrochemical (PEC) cells enable the conversion of solar energy into storable fuels, which is critical in overcoming the intermittent nature of this largest renewable source. However, the majority of semiconductors used as photoelectrodes in these cells have low conversion efficiencies and/or stabilities. Silicon (Si) is an attractive semiconductor material for photoelectrodes, but the development of efficient Si-based photoanodes is challenging due to their instability in alkaline solutions. Thus, one focus of this dissertation is the design and fabrication of highly stable nickel (Ni)-patterned Si photoanodes through interfacial engineering of the barrier heights. Recently, hot carriers in plasmonic metal nanostructures have …

Cyclodextrin-Based Supramolecular Drug-Delivery Nanomaterials And Shear-Thinning Hydrogels Using Ring-Opening Metathesis Polymerization, Ruihan Li

Arts & Sciences Graduate Student Theses and Dissertations

Cyclodextrins (CD) are a family of oligosaccharides that can non-covalently and precisely bind small hydrophobic drug molecules, such as antibiotics and anticancer drugs, through well-defined host-guest interactions inside the inner cavity of the macrocycle. Ring-opening metathesis polymerization (ROMP) is a versatile, functional group tolerant method of polymerization that is underexplored in biomedical applications relative to the more common controlled chain-growth polymerizations. In this dissertation, I describe my efforts to combine the supramolecular chemistry of CDs with that of ROMP using specialized functional monomers to synthesize several CD-based polymeric drug delivery nanomaterials. For example, in Chapter 2, a new type of …

Modifying The Aspect Survey To Support The Validity Of Student Perception Data From Different Active Learning Environments, Nicole Naibert, Erin E. Shortlidge, Jack Barbera

Chemistry Faculty Publications and Presentations

Measuring students’ perceptions of active learning activities may provide valuable insight into their engagement and subsequent performance outcomes. A recently published measure, the Assessing Student Engagement in Class Tool (ASPECT), was developed to assess student perceptions of various active learning environments. As such, we sought to use this measure in our courses to assess the students’ perceptions of different active learning environments. Initial results analyzed with confirmatory factor analysis (CFA) indicated that the ASPECT did not function as expected in our active learning environments. Therefore, before administration within an introductory biology course that incorporated two types of active learning strategies, …

“Transitioning Organisations From A Data Quagmire To Knowledge Nirvana Through The Digital Thread”, David Twohig, Barry Heavey

Level 3

Historically, organisations have managed product data in a combination of Microsoft Office, Sharepoint and Document Management Systems. In this paper, we explore how different technologies can be leveraged to create digital product profiles, and in doing so structure data to enable effective knowledge management.

Electrodeless Electrochemistry Enabled By Nonthermal Plasma, Harold Oldham

McKelvey School of Engineering Graduate Student Theses & Dissertations

The increasing availability and decreasing cost of electricity generated by renewable resources have motivated research into electrified chemical processing, whereby electrical energy is used to drive chemical transformations. Electricity-intensive processing techniques such as electrochemistry using solid electrodes has attracted attention in this context for the synthesis of organic compounds, such as high-value pharmaceuticals and renewable chemical production. Selective chemical transformations are achieved in conventional aqueous electrochemical systems by using external circuitry to bias solid electrodes, allowing for the preferential transfer of electrons between the electrode-liquid interface. Despite having the ability to promote controlled electrochemical reactions, configurations using solid electrodes are …

Mass Spectrometry-Based Protein Footprinting: High-Throughput Maldi Platform And Large Protein Complexes Of Baf, Ruidong Jiang

Arts & Sciences Graduate Student Theses and Dissertations

Human’s advances in understanding biological processes rely heavily on the breakthroughs in biophysical tools. Mass spectrometry (MS)-based protein footprinting, which interrogates protein structures by measuring protein solvent assessable surface area (SASA), has grown rapidly in the last decade, successful in providing valuable data for numerous protein systems. This thesis focuses mainly on this technology.We set out to push the boundary of MS-based protein footprinting further into the new areas, preparing it for potential future applications including large-scale experiments that require high-throughput analysis the structure of large, complicated protein complexes. This thesis devotes five chapters to the method development of MS-based …

Using Single-Particle Fluorescence Microscopy To Elucidate The Role Of Structural Distortions And Defects In The Chemical Reactivity And Photophysics Of Cesium Lead Halide Perovskite Nanocrystals, Dong Wang

Arts & Sciences Graduate Student Theses and Dissertations

Colloidal cesium lead halide perovskite nanocrystals (CsPbX3, X = Cl, Br or I) are attractive for optoelectronic applications due to their unique chemical and physical properties including high photoluminescence quantum yield, tunable bandgaps, high defect tolerance, and low-cost processibility. A facile method to tune the emission wavelength of perovskite nanocrystals is through anion exchange. For light emission applications, it is desirable to prepare CsPbX3 nanocrystals of uniform size and composition. However, the complex reaction kinetics of this chemical transformation may limit the compositional uniformity and color purity of the CsPbX3 nanocrystals produced by anion exchange when the transformation is scaled …

Electro-Organic Chemistry: An Alternative Pathway To Handle Redox Organic Reactions, Tiandi Wu

Arts & Sciences Graduate Student Theses and Dissertations

Electrochemistry provides an alternative pathway to handle redox organic reactions, especially for certain chemical process that can be only achieved through electrochemical process. Herein, there research projects are introduced to enrich the whole synthetic community, including an anodic oxidative cyclization studies to develop methodology on heterocyclic ring skeleton constructions, an electroreduction pathway exploration to more effectively obtain hydrazine from nitroso compounds, as well as a study in paired electrolysis process on which both anode and cathode are simultaneously employed to maximize overall atom and energy efficiency. Future directions on these projects are also demonstrated at the end of each chapters..

Visualizing Phytochemical-Protein Interaction Networks: Momordica Charantia And Cancer, Yumi L. Briones, Alexander T. Young, Fabian M. Dayrit, Armando Jerome De Jesus, Nina Rosario L. Rojas

Chemistry Faculty Publications

The in silico study of medicinal plants is a rapidly growing field. Techniques such as reverse screening and network pharmacology are used to study the complex cellular action of medicinal plants against disease. However, it is difficult to produce a meaningful visualization of phytochemical-protein interactions (PCPIs) in the cell. This study introduces a novel workflow combining various tools to visualize a PCPI network for a medicinal plant against a disease. The five steps are 1) phytochemical compilation, 2) reverse screening, 3) network building, 4) network visualization, and 5) evaluation. The output is a PCPI network that encodes multiple dimensions of …

Antimicrobial Activity Of Bacterial Virus Components: An Empirical Investigation Of The Killing Capacity Of Toxins From Burkholderia, Kyle Walny

Honors Projects

Given the growing issue in healthcare of antibiotic resistance, effective and safe alternative treatment methods are required. One of these possible alternative treatment methods is bacteriotoxins including bacteriocins and tailocins. The focus of this study is a bacteriotoxin from Burkholderia cenocepacia (ATCC 25608), which was induced for toxin using a modified UV light induction procedure and tested against a variety of Pseudomonas and Burkholderia for its killing capacity. Various other pathogenic strains were then induced with UV light and tested. The results showed that the toxin from ATCC 25608 was very effective against most of the Burkholderia tested and warrants …

Seasonal Flammability Comparisons Of Native And Exotic Plants In The Post Oak Savannah, Blackland Prairie, And Pineywoods Ecoregions Of Texas, Michael Tiller

Electronic Theses and Dissertations

East Texas’ diverse landscape can present year-round wildfire seasons that can be influenced by seasonal and regional differences in climate and physiography. Greater insight into the fundamental thermal behavior of wildland fuels can aid in fire behavior prediction and development of fire-resistant plant lists. This study focused on estimating seasonal and regional flammability characteristics of five evergreen species: yaupon (Ilex vomitoria), Chinese privet (Ligustrum sinense), greenbrier (Smilax spp.), eastern red cedar (Juniperus virginiana), and escarpment live oak (Quercus fusiformis); and two deciduous species: Chinese tallow (Triadica sebifera) and southern …

Comparative Toxicity, Phytochemistry, And Use Of 53 Philippine Medicinal Plants, Lydia M. Clemen-Pascual, Rene Angelo S. Macahig, Nina Rosario L. Rojas

Chemistry Faculty Publications

The study compares the toxicity of 53 selected medicinal plants commonly used in the Philippines to treat various diseases. It uses as a benchmark Vitex negundo L., which was approved by the Philippine Food and Drug Administration as an herbal drug for cough and asthma after passing clinical trials for safety and efficacy. The methods were chosen for their simplicity and accessibility even for resource-limited laboratories. Extracts (95 % ethanol) of the medicinal parts of the plants were (1) chemically profiled using qualitative phytochemical tests that detect the presence of key classes of bioactive compounds; and (2) evaluated for toxicity …

Developing Techniques For The Identification Of Non-Canonical Rna Pairing And Analysis Of Lc-Ms Datasets, Christopher Jurich

Department of Chemistry: Dissertations, Theses, and Student Research

Non-canonical pairing dynamics in ribonucleic acid (RNA) structureand statistical analysis of metabolomics liquid chromatography mass spectrometry (LC-MS) datasets are two difficult problems that stand as open challenges.

RNA folding algorithms are used across a variety of disciplines to predict structures when experimental elucidation techniques are inconvenient or impractical. Though successful and widely adopted, folding algorithms make simplifying assumptions for loop regions due to their complex interactions and associated difficulty with generating energy parameters for relevant non-canonical pairing interactions. Modeling assumptions and a lack of energy parameters for loops limit accuracy in these functional critical regions of RNA. This work describes …

Corn Oil-Based Highly Flame Retardant Rigid Polyurethane Foams For Industrial Application, Muhammad Rizwan Sulaiman

Electronic Theses & Dissertations

The synthesis of flame retardant polyurethane (PU) foam was carried out using two different flame retardants, such as triethyl phosphate (TEP) and triphenyl phosphate (TPP). The thermal and mechanical characteristics of the foam were analyzed. The obtained TGA results confirmed that the flame retardant acts in the gaseous form to stop the fire. All the prepared samples displayed excellent closed cell content, which was above 90 %. The burning time were reduced from 80 s to 7.5 s with the weight loss 3.2% of for sample E-12 (19.29 % TEP) and from 80 s to 11 s with the weight …

Uniting Non-Empirical And Semi-Empirical Density Functional Approximation Strategies Using Constraint-Based Regularization, Trine K. Quady

University Honors Theses

In this work, we present a general framework that unites the two primary strategies for constructing density functional approximations (DFAs): non-empirical (NE) constraint satisfaction and semi-empirical (SE) data-driven optimization. The proposed method employs B-splines--bell-shaped spline functions with compact support--to construct each inhomogeneity correction factor (ICF). This choice offers several distinct advantages over a polynomial basis by enabling explicit enforcement of linear and non-linear constraints as well as ICF smoothness using Tikhonov regularization and penalized B-splines (P-splines). As proof of concept, we use this approach to construct CASE21--a Constrained And Smoothed semi-Empirical global hybrid generalized gradient approximation that completely satisfies all …

Disease Biomarker Discovery And Fungal Metabolites Extraction Protocol Optimization Using Gcms Based Metabolomics, Chathuri Udeshika Gamlath Mohottige

Theses and Dissertations

Metabolomics is a powerful science that can be applied for the discovery of disease biomarkers, and investigation of altered metabolomes due to abiotic and biotic perturbations. This dissertation is focused on untargeted metabolomic applications to investigate fungal metabolite alterations associated with pathogenicity, fungal disease propagations, and symbiosis. This dissertation employs qualitative analysis of metabolite mixtures using HS-SPME coupled GC-MS and TMS derivatization followed by GC-MS analytical platforms. In the first study, we discovered a biomarker combination to diagnose fungal soft tissue disease in sweet potato at an early stage of disease propagation. We used an HS-SPME GC-MS untargeted metabolomics workflow …

1,2-Diazetidine As A New Amidomethylative Reagent To Control The Selectivity For The Synthesis Of N-Heterocycles And Ru(Ii)-Catalyzed Enantioselective Hydroarylation To Form Chromane Derivatives, Chaminda Lakmal Hetti Handi

Theses and Dissertations

1,2-Diazetidine is a four-membered ring heterocyclic compound which has two adjacent nitrogen atoms. However, the syntheses of C-unsubstituted 1,2-diazetidines are rarely reported in the literature. C-unsubstituted 1,2-diazetidines were synthesized through an operationally simple intermolecular vicinal disubstitution reaction between 1,2-dibromoethane and hydrazine with N-arylsulfonyl as the protecting group. Several different types of C-unsubstituted 1,2-diazetidines derivatives were synthesized with either two of the same or two different N-arylsulfonyl groups. The electronic and steric properties were analyzed using Raman spectroscopy and computational calculations. Then, several synthetic applications were demonstrated with 1,2-ditosyl-1,2-diazetidine (DTD). As a synthetic application, a nucleophilic ring-opening reaction of the diazetidine …

Characterization Of Small Molecules And Ions By Atmospheric Pressure Ionization-Mass Spectrometry, Maleesha De Silva

Theses and Dissertations

Mass spectrometry (MS) has become a widely used technique for the characterization of a wide range of substances in diverse fields. The selection of appropriate ionization techniques, source parameters, charge carriers based on the analyte’s polarity is essential in MS as only the ions are detected. When using a soft ionization technique, single stage-MS at best provides only chemical composition; thus, tandem MS is needed to determine structural information and dissociation pathways. This dissertation focuses on the characterization of various small molecules and ions using different ionization techniques, charge carriers, and collision-induced dissociation (CID).

In Chapter II, commercially available ionic …

Synthesis And Characterization Of A Ccc-Nhc Manganese Complex And Its Catalytic Activity In Alpha-Alkylation Reactions Of Ketones Using Alcohols – Acceptorless Dehydrogenative Coupling Reaction, Thi Bao Tran Nguyen

Theses and Dissertations

N-heterocyclic carbenes are essential for the synthesis and stabilization of various metal complexes due to the tendency to act as sigma-donor of sp2 hybridized lone pair in carbene into sigma-accepting orbital of metals. Meanwhile, the electronic and steric properties of pincer complexes can be fine-tuned by modifying three sites bonded to the metals. Utilizing advantages of both NHCs and the pincer structures, NHCs-based pincer complexes have become increasingly developed in recent years. After the discovery of zirconium and rhodium complexes with CCC-NHC backbones reported in 2005, Hollis’s group has been interested in applying the CCC-NHC pincer precursor for other transition …

Mechanism Of Thermal Protein Aggregation: Experiments And Molecular Dynamics Simulations On The High-Temperature Behavior Of Myoglobin., Yuen Ki Ng, Nastaran N Tajoddin, Pablo M Scrosati, Lars Konermann

Chemistry Publications

Proteins that encounter unfavorable solvent conditions are prone to aggregation, a phenomenon that remains poorly understood. This work focuses on myoglobin (Mb) as a model protein. Upon heating, Mb produces amorphous aggregates. Thermal unfolding experiments at low concentration (where aggregation is negligible), along with centrifugation assays, imply that Mb aggregation proceeds via globally unfolded conformers. This contrasts studies on other proteins that emphasized the role of partially folded structures as aggregate precursors. Molecular dynamics (MD) simulations were performed to gain insights into the mechanism by which heat-unfolded Mb molecules associate with one another. A prerequisite for these simulations was the …

Modeling Nitrous Oxide Emissions From Large-Scale Intensive Cropping Systems In The Southern Amazon, Ciniro Costa Jr., Gillian L. Galford, Michael T. Coe, Marcia Macedo, Kathijo Jankowski, Christine S. O'Connell, Christopher Neill

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Nitrogen (N) fertilizer use is rapidly intensifying on tropical croplands and has the potential to increase emissions of the greenhouse gas, nitrous oxide (N₂O). Since about 2005 Mato Grosso (MT), Brazil has shifted from single-cropped soybeans to double-cropping soybeans with maize, and now produces 1.5% of the world's maize. This production shift required an increase in N fertilization, but the effects on N₂O emissions are poorly known. We calibrated the process-oriented biogeochemical DeNitrification-DeComposition (DNDC) model to simulate N₂O emissions and crop production from soybean and soybean-maize cropping systems in MT. After model validation with …

Thermodynamic And Kinetic Of Eriochrome Black-T Adsorption Onto Yemeni Palm-Date Stones, Abdulrahman Yousef Wahoud, Sawsan Awadh Almaqdi

Hadhramout University Journal of Natural & Applied Sciences

Removal of eriochrome black-T (EB-T) dye from aqueous solutions was performed by adsorption onto Yemeni palmdate stones. The adsorption isotherm was found to follow the Langmuir model. Two simplified kinetic models including pseudo-first order and pseudo-second order equation were selected to follow the adsorption processes. Kinetic studies showed that the adsorption followed pseudo-first order kinetic model. Various thermodynamic parameters such as Δ𝐻 = -3465.3 J/mole and Δ𝑆 = -10.1 J/K/mole. Δ𝐺 was found to be -4495.5, -2195.2, -2235.7 and -45.39 J/mole at 298, 318, 328 and 338 K respectively, the maximum adsorption capacity was equal to 142 mg/g. The results …

Effect Of Calcium Carbonate, Ph, Mud And Organic Carbon On Soil Phosphate Sedimentation For Some Farms In Wadi Hadramout, Abdul Aziz Salem Dayan

Hadhramout University Journal of Natural & Applied Sciences

This study was conducted to determine the effect of calcium carbonate, pH, the amount of clay on phosphate adsorption, and the effect of early fertilization of phosphatic fertilizer on the amount of fertilizer. Three samples of surface soil (0-30 cm) were obtained from Al-Mashhad (Cotton) and (Sweiri) farms, Hadramout governorate, which differ in their content for: Total calcium carbonate ratio. The amount of clay in its mechanical analysis. Organic carbon.pH (pH).The samples were incubated at room temperature (24-28° C) and at varying concentrations of Monocalsumphosphate. The correlation coefficient was used to find the statistical relationship between the adsorption and release …

Quantum Mechanics-Based Computational Chemistry Has Become A Powerful Partner In The Scientific Research Of Nitrogen-Rich Compounds, Paving The Way For Important Advances In Biochemical, Pharmacological And Other Related Fields, Dobrushe Denburg

Student Theses and Dissertations

The Computational Chemistry of Nitrogen-Rich Compounds; Insight into Pioneering Research

Nitrogen-rich functional groups have long been studied for their diversity; nitrogen can form single, double and triple bonds with itself, and will therefore exist in a very broad range of molecular arrangements. Poly-nitrogen compounds are highly energetic and electron rich, and many compounds display unique properties that allow participation in very specialized chemical reactions. Of import is their ubiquity in biological systems, and throughout the past century and currently, their biological relevance is deeply and widely explored in biochemistry and biomedicine, from their involvement in natural biological processes and complex …

Mass Spectra Of Mesonic Molecules At Finite Temperature, Arezu Jahanshir, Mohammad Reza Soltani

Karbala International Journal of Modern Science

At a finite temperature, exotic hadronic systems, mass spectrum was studied using the quark structure and the radial Schrödinger equation with the Cornell interaction potential representing the hadronic interaction. The projective unitary representation has been used in the study of hadronic ground states in physics. A relativistic bound state's mass spectrum with temperature dependence is shown to have a unique feature. The resulting values are compared to experimental and theoretical values, and the study showed a high level of conformity with additional values wherever feasible.

Efficiency Of +Idonblender Photogrammetric Tool In Facial Prosthetics Rehabilitation – An Evaluation Study, Mohammed R. Falih, Fanar M. Abed, Rodrigo Salazar-Gamarra, Luciano Lauria Dib

Karbala International Journal of Modern Science

Several open-source 3D modeling software tools have recently been featured to reconstruct a 3D image-based model using Structure from Motion (SfM) algorithms such as +IDonBlender. It is, therefore, necessary to evaluate the accuracy of the models extracted from this tool to prove effectiveness for different applications. This paper aims to evaluate the +IDonBlender methodology tool in rehabilitating facial deformations. +IDonBlender is an add-on tool programmed within Blender software and designed for medical applications. In this research, two individuals from different genders have volunteered to contribute to this study, one with severe facial deformation and the other is healthy with no …

Proposed Hybrid Correlationfeatureselectionforestpanalizedattribute Approach To Advance Idss, Doaa Nteesha Mhawi, Prof. Soukaena H. Hashem

Karbala International Journal of Modern Science

NetworkIntrusionDetectionSystem(NIDS), widely used network infrastructure. Although many datamining has been used to increase the effectiveness of IDSs, current ID still struggle to perform well. therfore; proposed a new NIDS focused on feature_selection. The proposed CorrelationFeatureSelection_ForestPanalizedAttributes(CFS_FPA) used for dimensionality_reduction and selects the optimal_subset. based on two steps: first check each feature with a target(class) and choose only features that most effective by applying CFS filter using a statistical_method, then applied FPA to select only features will enhance ID and reduce_dimensionality. proposal tested with the NSLKDD experimental results of accuracy 0.997% and 0.004 FAR, wherein UNSWNB15_dataset accuracy and FAR are 0.995%, 0.008 …

Analysis Of Modern Communication Protocols For Iot Applications, Neerendra Kumar, Pragti Jamwal

Karbala International Journal of Modern Science

To facilitate increasing interactions of machines, various protocols are building up for IoT applications. Safeguarding communication among devices is necessary. In this paper, various protocols have been studied and compared using six parameters: Communication overhead, Security, Packet Loss, Throughput, Bandwidth and Support to QoS. LIDOR is found as the most successful communication protocol. A tabulated comparison of various communication protocols have been provided by comparing the parameters. Further, six star rating for the various protocols have been proposed. The study shows that LIDOR increases reliability under DoS attacks. Considering the existing literature, new research gaps and challenges have been presented.

The Effect Of Diode Laser On The Life And Appearance Of White Ant (Psammotermes Hypostoma), Estabraq Mahmood Mahdi Msc, Sahar Naji Rashid Msc., Saeed Maher Lafta Ph.D., Arshad Mahdi Hamad Msc

Karbala International Journal of Modern Science

This work focused on studying effect of diode laser on external appearance of white ants, and finding the percentage of mortality resulting from this beam of (650nm),(5mW),exposure times (60,70,80,90,100)sec at (3,5)cm for each exposure. The results recorded showed a clear increase in death rates, and increase in deformations as laser exposure times increased (higher percentage at lower distance), where laser was used to capture results of this therapeutic effect after passage time periods (12,24,48,72)hours. These results, show laser thermal effects resulting from its interaction with tissues, thermal propagation leads to ravage to the structures, thus to an increase death rates.

Calculation And Comparison Of Certain Physical Properties Of Sample Irregular Galaxies With The Milky Way Galaxy, Hasanain Hassan Al-Dahlaki Msc

Karbala International Journal of Modern Science

Irregular galaxies often include a mix of old and young celestial populations, as well as dust and gas. This study makes an early effort at the morphological classification of irregular galaxies. These sources have been chosen from (70) irregular galaxies data samples from a Catalogue survey. We present a statistical analysis of the physical properties for the chosen data from the database and a collection of tools that used to study the physics of galaxies and cosmology HYPERLEDA (http://atlas.obshp.fr/hyperleda/) and NASA /IPAC Extragalactic Database NED (https://ned.ipac.caltech.edu/) survey.