Chemistry Commons^™

Chemical Investigation Of Camu Camu (Myrciaria Dubia) Leaves And Roots, Jorge L. Flores

Theses and Dissertations

Flores, Jorge L., Chemical Investigation of Camu Camu (Myrciaria dubia) Leaves and Roots. Master of Science (MS), December, 2020, 45 pp., 8 Tables, 28 Figures, 21 references, 12 titles.Being the largest on the planet, the Amazon rainforest also has the greatest biodiversity of plant life on earth. In the lowland regions of the Amazon grows the Peruvian camu camu (Myrciaria dubia) plant. A short and shaggy shrub, camu camu produces a tasty but sour fruit. Camu camu’s berry-like fruit is widely consumed by the native people of the Amazon. Its distinguished richness in vitamin C, as …

Applications Of Vanadium Phthalocyanine In Catalytic, Acid-Based Medium To Couple Sugar Molecules, Juan Ricardo Luna

Theses and Dissertations

The vanadium-substituted tetraazatetrabenzoporphyrin, vanadium phthalocyanine, was synthesized via reflux and characterized using FITR and XRD analysis. Subsequent to synthesis, the vanadium phthalocyanine was studied as a catalyst in redox reactions to convert fructose to different molecules, the products were predominately levulinic methyl ester and heptadionic acid. The ability to convert fructose to other compounds, such as alkyl levulinic derivative, is an important process to help eliminate reliance on traditional chemical feed stocks and promote alternative fuels. Levulinic acid has been commonly used as a starting material in the synthesis of biofuels and a precursor for pharmaceuticals, plasticizers, THF derivatives, γ-valerolatone. …

Uptake Analysis Of As(Iii) And As(V) By Cassia Fistula Seedlings, Valeria Velazquez

Theses and Dissertations

The natural and anthropogenic contamination of water by arsenic has become a major concern to the environment and public health. Phytoremediation is an attractive alternative to ecologically friendly remove contaminants at a potential high efficiency and low cost. Absorption of As(III) and As(V) was evaluated by the measuring the content of arsenic in the roots, leaves and stems Cassia fistula grown under controlled conditions in a hydroponics system. After seeds were germinated, the plants were grown in Hoagland nutrient solution individually supplemented with 1, 2, 5 ppm of As(III) and As(V). After two weeks of exposure, samples of leaves, roots, …

Knn Based Piezo-Triboelectric Lead-Free Hybrid Energy Films, Abu Masa Abdullah, Muhtasim Ul Karim Sadaf, Farzana Tasnim, Horacio Vasquez, Karen Lozano, M. Jasim Uddin

Chemistry Faculty Publications and Presentations

In recent times, the triboelectric and piezoelectric effects have garnered significant attention towards developing advanced material composites for energy harvesting and sensory applications. In this work, potassium sodium niobate (KNN) based energy films (EF) have been developed to utilize mechanical energy while simultaneously taking advantage of triboelectric and piezoelectric mechanisms. The KNN particles were synthesized using a wet ball milling technique and then incorporated into a polyvinylidene difluoride (PVDF) matrix together with addition of multi wall carbon nanotubes (MWCNT). The film was used to develop a piezoelectric nanogenerator (PENG) fitted with copper electrodes. The piezoelectric output of the film was …

Disorder Driven Asymmetry And Singular Red Emission In Doped Lu2hf2o7 Nanocrystals With No Charge Compensating Defects, Santosh K. Gupta, Mitzy A. Penilla Garcia, Jose P. Zuniga, Bhupendra B. Srivastava, Yuanbing Mao

Chemistry Faculty Publications and Presentations

High performance luminescent materials possess low symmetry, high color purity, no charge compensating defects, and high quantum yield. In this work, we have synthesized Lu2Hf2O7 (LuHO) and Lu2Hf2O7:Eu3+ (LuHOE) nanocrystals (NCs) using a molten salt synthesis and confirmed that both are stabilized in defect fluorite structure with a high degree of structural disordering. The LuHO NCs depicted green emission under ultraviolet irradiation, which decreases and increases after being treated in oxidizing and reducing environments, respectively, confirming the role of oxygen vacancies in the emission process. The LuHOE NCs (i) show excitation wavelength-dependent host to dopant energy transfer efficiency, …

Machine Learning Using Host/Guest Energy Histograms To Predict Adsorption In Metal–Organic Frameworks: Application To Short Alkanes And Xe/Kr Mixtures, Zhao Li, Benjamin J. Bucior, Haoyuan Chen, Maciej Haranczyk, J. Ilja Siepmann, Randall Q. Snurr

Chemistry Faculty Publications and Presentations

A machine learning (ML) methodology that uses a histogram of interaction energies has been applied to predict gas adsorption in metal–organic frameworks (MOFs) using results from atomistic grand canonical Monte Carlo (GCMC) simulations as training and test data. In this work, the method is first extended to binary mixtures of spherical species, in particular, Xe and Kr. In addition, it is shown that single-component adsorption of ethane and propane can be predicted in good agreement with GCMC simulation using a histogram of the adsorption energies felt by a methyl probe in conjunction with the random forest ML method. The results …

Removal Of Arsenic (Iii) And Arsenic (V) From Aqueous Solution Via Solanum Lycopersicum Phytoremediation And Essential Nutrient Analysis, Grecia W. Garcia Salazar

Theses and Dissertations

ICP-OES was used to investigate the uptake of arsenic (V) and arsenic (III) from aqueous solution using tomato seedlings. The effect of arsenic on essential nutrient uptake by tomato was analyzed. The experiment was performed at three levels of arsenic: 1ppm, 2 ppm and 5 ppm [added as sodium arsenate (Na3AsO4) and arsenic trioxide (As2O3)], in nutrient solution. Plants remained in solution for two weeks. Arsenic accumulation depended on arsenic concentration in solution, when exposed to higher arsenic concentrations the plant uptake increased. The highest arsenic accumulation was found in roots, followed by stems and leaves in that order. Essential …

Virtual Screening For Potential New Chemotherapeutic Agents For The Gpr119 Receptor, A Target For Type Ii Diabetes, Jennifer Lizeth Bravo

Theses and Dissertations

Three frames from a molecular dynamics simulation run of a GPR119 receptor homology model were used for this study. The homology model was validated by virtually screening 76 known GPR119 receptor. 85% of these agonists bound to the receptor. Following the validation, 21,000 molecules were selected for the virtual screening study. 862 ligands came from the GPCR Selleckchem/Prestwick library, 42 compounds from the Prestwick Phytochemical library, 20,000 compounds from the ZINC library, plus four molecules from the literature. All ligands were built, geometry-optimized, and docked in the GPR119 models using a protocol combining High Throughput Virtual Screening, Standard Precision, and …

Investigation Of The C—Cn Bond Activation Of Fluorinated Benzonitriles With [Ni(Dmpe)] And Dft Benchmarking Study With [Ni(Dippe)], Dominique C. Gallegos

Theses and Dissertations

Carbon-carbon bond activation has become a rapidly growing area of research due to its extensive range of applications. Despite the significant progress that has been made in this field, the cleavage of kinetically inert and thermodynamically stable C—C σ-bonds under mild homogeneous conditions remains a challenge. The activation is primarily limited to systems in which either relief of strain or aromatization serves as a driving force. A notable exception to this is the oxidative addition of unstrained C—CN bonds of nitriles. In this study, we are looking at the effect of fluoro substituents. We hypothesized …

Limits Of Variationality In Full Configuration Interaction For The H2 Model System, Oscar Obed Rodriguez Vargas

Theses and Dissertations

We proposed a framework for exploring the limits of variationality in full configuration interaction (FCI) calculation of molecular electronic structure. We performed FCI calculations on the minimal basis (STO-3G) H2 model for the energy, gradient, and derivative coupling. These calculations were validated by finite difference. These quantities were recalculated with controlled injection of error in the FCI coefficient. The gradient was observed to be highly sensitive to error, while the energy and derivative coupling were robust to errors in the coefficients of nearly 10%. This study lays the groundwork for calculation of other derived quantities, such as the Hessian, adiabatic …

Flexible And Surface Modified Znsno3 Nanocubes For Enhanced Piezoelectric Power Generation And Wireless Sensory Application, Sk Md Ali Zaker Shawon

Theses and Dissertations

Piezoelectric systems and their mechanisms are held in high regard, due to their cost-effective structure and mechanical proficiency to harvest renewable energy. In the present article, we propose an aluminum-doped zinc stannate (ZnSnO3) piezoelectric nanogenerator that can be employed for the harvest of energy and sensory applications. In order to ensure and further enrich the piezoelectric mechanics and product outcome in our device, ZnSnO3 was doped with 1 wt% to 5 wt% of aluminum nanoparticles. We reported that 2 wt% of aluminum-doped ZnSnO3 showed the highest electrical output in terms of open circuit voltages and short circuit current.

The nanogenerator …

A Study Of Nanogenerator Based Flow Sensor, Farzana Tasnim

Theses and Dissertations

The utilization of kinetic energy from fluid flow to power sensory systems is experiencing an all-time high research focus. Invention of nanogenerators have fueled this research focus with unprecedented flexibility of applications. Many studies have reported on utilizing the mechanism of nanogenerator for sensing fluid flow. In this short work, we have summarized different types of self-powered nanogenerator-based flow sensors and their applications. We have also classified the use of Nanogenerator based flow sensors in different fields, such as Bio-medical Application, Fluid velocity sensing, and Chemical Detection. In the Bio-medical field, the flow sensor can be used for the patient’s …

Rare Earth Free Bright And Persistent White Light Emitting Zinc Gallo-Germanate Nanosheets: Technological Advancement To Fibers With Enhanced Quantum Efficiency, Bhupendra B. Srivastava, Santosh K. Gupta, Raul Barbosa, Alexa Villarreal, Karen Lozano, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Recent materials science and engineering research focused on defects, dopants, hosts, and morphological structures has resulted in novel cost efficient and sustainable phases with extraordinary properties and performance. Contributing in this direction we have designed dopant and rare earth free white lightemitting zincgallogermanate (ZGG) phosphors in nanosheet (NS) morphology. These ZGG NSs with interlayer and interfacial defects display bright white photoluminescence (PL) with significant quantum yield (QY). Thermal treatment of the as-synthesized ZGG NSs at 750 1C does not degrade their sheet-like morphology while resulting in long persistent luminescence (PerL) with a duration of approximately one hour. Furthermore, to improve …

Chemical Shift Assignments Of The N-Terminal Domain Of Psd95 (Psd95-Nt), Yonghong Zhang, Johannes W. Hell, James B. Ames

Chemistry Faculty Publications and Presentations

Postsynaptic density protein-95 (PSD95) contributes to the postsynaptic architecture of neuronal synapses and plays an important role in controlling synaptic plasticity. The N-terminal domain of PSD95 (residues 1–71, called PSD95-NT) interacts with target proteins (calmodulin, α-actinin-1 and CDKL5), which regulate the Ca2+-dependent degradation of glutamate receptors. We report complete backbone NMR chemical shift assignments of PSD95-NT (BMRB No. 50752).

Polymer Based Triboelectric Nanogenerator For Cost‐Effective Green Energy Generation And Implementation Of Surface‐Charge Engineering, Diana Lopez, Aminur Rashid Chowdhury, Abu Masa Abdullah, Muhtasim Ul Karim Sadaf, Isaac Martinez, Brishty Deb Chowdhury, Serena Danti, Christopher J. Ellison, Karen Lozano, Mohammed Jasim Uddin

Chemistry Faculty Publications and Presentations

Performance of triboelectric nanogenerators for harvesting mechanical energy from the ambient environment has been limited by structural complexity, cost-effectiveness, and mechanical weakness of materials. Herein, a cost-effective vertical contact separation mode triboelectric nanogenerator using polyethylene (PE) and polycarbonate (PC) in a regular digital versatile disc is reported. This cost-effective nanogenerator with simplified structures is able to generate an open-circuit voltage of 215.3 V and short-circuit current of 80 μA. The effects of the distance of impact and the air gap between the triboelectric layers have also been tested from 3 to 9 cm, and 0.25 to 1 cm, respectively. It …

Multifunctional Conductive Paths Obtained By Laser Processing Of Non-Conductive Carbon Nanotube/Polypropylene Composites, Federico Cesano, Mohammed Jasim Uddin, Alessandro Damin, Domenica Scarano

Chemistry Faculty Publications and Presentations

Functional materials are promising candidates for application in structural health monitoring/self-healing composites, wearable systems (smart textiles), robotics, and next-generation electronics. Any improvement in these topics would be of great relevance to industry, environment, and global needs for energy sustainability. Taking into consideration all these aspects, low-cost fabrication of electrical functionalities on the outer surface of carbon-nanotube/polypropylene composites is presented in this paper. Electrical-responsive regions and conductive tracks, made of an accumulation layer of carbon nanotubes without the use of metals, have been obtained by the laser irradiation process, leading to confined polymer melting/vaporization with consequent local increase of the nanotube …

Heterocycles In The Treatment Of Neglected Tropical Diseases, Kush K. Maheshwari, Debasish Bandyopadhyay

Chemistry Faculty Publications and Presentations

Background: Neglected Tropical Diseases (NTDs) affect a huge population of the world and the majority of the victims belong to the poor community of the developing countries. Until now, the World Health Organization (WHO) has identified 20 tropical diseases as NTDs that must be addressed with high priority. However, many heterocyclic scaffolds have demonstrated potent therapeutic activity against several NTDs.

Objective: There are three major objectives: (1) To discuss the causes, symptoms, and current status of all the 20 NTDs; (2) To explore the available heterocyclic drugs, as well as their mechanisms of action (if known), that are being used …

Carbon Fibers Coated With Ternary Ni-Co-Se Alloy Particles As Low-Cost Counter Electrode For Flexible Dye Sensitized Solar Cell, Brishty Deb Choudhury, Chen Lin, Sk Md Ali Zaker Shawon, Javier Soliz-Martinez, Jose Gutierrez, Muhammad N. Huda, Federico Cesano, Karen Lozano, Jin Zhong Zhang, M. Jasim Uddin

Chemistry Faculty Publications and Presentations

Compared to flat devices based on rigid substrates, cable-shaped dye-sensitized solar cells hold advantages of smaller size, light weight, facile fabrication, flexibility, and low cost, thus a promising direction for applications such as wearable electronic devices. However, most reported fiber-shaped dye-sensitized solar cells use Pt wires as counter electrodes, which are high in cost. Herein, a flexible Pt-free counter electrode is fabricated via depositing ternary nickel cobalt selenide (Ni–Co–Se) particles on the surface of carbon fibers. Scanning electron microscopy and X-ray diffraction are used to characterize the counter electrode and alloy material. Results from bare and modified carbon fiber counter …

Total Synthesis Of Cytotoxic Mansouramycins From Amino Acids, Beatriz Gamez

Theses and Dissertations

Natural products produced by plants, animals, and microorganisms are of significant importance in chemistry for being major sources of molecular scaffolds essential for new drug discovery. Mansouramycins are cytotoxic bioactive compounds containing isoquinoline skeletons with substituents on the quinone and pyridine rings that may be difficult to synthesize. Synthetic processes exist for compounds B and D, however, there exists an absence of simple synthetic approaches to all four alkaloids.

This project aims to provide a general total synthetic pathway to Mansouramycins A—D from amino acids for possible use in cancer treatment via these isoquinolinequinones. Preliminary experimentation suggests there may be …

The Dmap-Catalyzed Acylation Of Alcohol -- A Mechanistic Study, Tania Veronica Alvarez Castro

Theses and Dissertations

The mechanistic studies of Acylation of Alcohols catalyzed by 4-(N,N- Dimethyl-amino)-pyridine (DMAP) has been heavily studied in the literature. This reaction has attracted considerable interest from the synthetic and mechanistic points of view in recent years. In this research, the acylation of alcohols is prepared from cyclohexanol and acetic anhydride that is catalyzed by DMAP using triethyl amine (NEt3) as the auxiliary base and dichloromethane (DCM) as solvent. The reaction and final product will be analyzed by using gas chromatography (GC) and reaction progress kinetic analysis (RPKA). The mechanistic insights obtained in the present study should be useful for understanding …

Chemical Investigation Of Avocado (Persea Americana) Seed Husk (Testa): A Waste Of Waste, Orlando A. Castillo Scheren

Theses and Dissertations

Food chemistry is a new field in the world and is currently still expanding into the types of market in which it can be tapped into. There are about 1.3 billion tons of food waste produced in 2016 in the world, and food chemistry is going to help get rid of that waste by finding new and exciting applications to the things currently considered as waste. In these products, there might be new and undiscovered drugs that can be used in the market to help treat diseases for which might not have a cure at the current moment. The avocado …

Synthesis, Characterization, And Application Of Meso-Tetraphenyl Metalloporphyrin Photocatalysts Under Visible Light, Alexis Echavarria

Theses and Dissertations

The photocatalytic activity of meso-Tetraphenyl Metalloporphyrins with different metal centers was investigated. The synthesized metalloporphyrin photocatalysts was performed and analyzed using FT-IR spectroscopy, UV-VIS spectroscopy, and powder X-Ray Diffraction analysis. The synthesized TPP crystals were determined to be tetragonal crystal structure and the structure was observed in all synthesized metalloporphyrin catalysts. The Soret (B) bands, Q bands, FT-IR functional groups were identified. Reaction progress was investigated by sampling at intervals of one hour and analysis of the samples was performed using Gas Chromatography-Mass Spectrometry. GC-MS analysis was used to identify the products of the photochemical catalytic redox reactions performed under …

Chemical Modification And In Silico Validation Of Medicinally Privileged Molecular Scaffolds As Kras And Sars-Cov-2 Protease Inhibitors, Precious M. Okwuchukwu

Theses and Dissertations

Coronavirus disease was declared a global pandemic by WHO in March 2020, cancer is the second leading cause of death by a disease. Several scientists around the world are working relentlessly to discover an effective remedy to eradicate these deadly diseases. A natural polyphenol (magnolol) has been isolated from a tree Magnolia grandiflora (family Magnoliaceae) found on UTRGV campuses. This research is focused on design of a series of chemically modified sulfonyl derivatives based on the isolated magnolol framework and other medicinally privileged molecular scaffolds framework that can effectively bind to the COVID-19 main protease, SARS- CoV-2 3CL protease …

Thermal And Spectroscopic Investigations On Polymer-Based Nanofibers, Omosola Oriretan

Theses and Dissertations

Nanofibers of Poly (ethylene oxide), PEO, Poly (vinylpyrrolidone) PVP, Co-nanofiber of PEO-PVP and PEO nanocomposite of various Fullerene compositions were prepared by dissolving PEO, PVP and Fullerene in water. The Fullerene nanoparticles were added to the PEO solutions, the mixtures were homogenized under high power sonication. The PEO solutions, PVP solutions, the co-polymer solutions of PEO-PVP and the PEO -Fullerene solutions were centrifugally spun using Force spinning™ machine. The obtained nanofibers and the nanocomposites were subjected to FTIR analysis, Raman analysis and various heating and cooling cycles with heating and cooling rates ranging from 10C/min to 600C/min using differential scanning …

Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda

Chemistry Faculty Publications and Presentations

No abstract provided.

Electromagnetic-Triboelectric-Hybrid Energy Tile For Biomechanical Green Energy Harvesting, Elaijah Islam, Abu Musa Abdullah, Aminur Rashid Chowdhury, Farzana Tasnim, Madelyne Martinez, Carolina Olivares, Karen Lozano, Mohammed Uddin

Chemistry Faculty Publications and Presentations

Highlights

• Hybrid nanogenerator based floor-tile was developed to convert the Bio-Mechanical energy of human footsteps to Electrical Energy.

• Hybridization of Triboelectric Nanogenerator and Electro-Magnetic Generator consisting of Aluminum and Kapton.

• MoS2 is working as an electron acceptor.

• The maximum output is 1200V as open-circuit voltage, 5mA as short-circuit current, and 6W as power.

• Produces 20% more power than a commercially sold energy-harvester floor tile.

Abstract

Since the invention of Piezoelectric Nanogenerator in 2006, nanogenerators has become an attractive technology to the researchers for scavenging mechanical energy from the ambient environment for real life applications. Hybridization of these nanogenerators has been …

The Efficient Synthesis Of D-Xylulose And Formal Synthesis Of Syringolide 1, Sudhakar Kalagara, Gabriel Orozco, Shizue Mito

Chemistry Faculty Publications and Presentations

Wittig reaction and asymmetric dihydroxylation were used as the key steps in the synthesis of D-xylulose, a commercially available but costly carbohydrate. The effects of protecting groups and reactions conditions on asymmetric dihydroxylation are demonstrated. Optically pure D-xylulose was obtained after 4-6 steps from readily available hydroxyacetone and ethylene glycol. The method also involves some other valuable intermediates along the synthesis. Those intermediates were applied in the formal synthesis of Syringolides. A key precursor butenolide to Syringolide 1, the first non-proteinaceous specific elicitors of plant hypersensitive response, was obtained after 3 steps from the intermediate (8–10 steps from hydroxyacetone and …

Two Forms Of Tyrosyl-Trna Synthetase From Pseudomonas Aeruginosa: Characterization And Discovery Of Inhibitory Compounds, Casey Anne Hughes, Varesh Gorabi, Yaritza Escamilla, Frank B. Dean, James M. Bullard

Chemistry Faculty Publications and Presentations

Pseudomonas aeruginosa is a multidrug-resistant (MDR) pathogen and a causative agent of both nosocomial and community-acquired infections. The genes (tyrS and tyrZ) encoding both forms of P. aeruginosa tyrosyl-tRNA synthetase (TyrRS-S and TyrRS-Z) were cloned and the resulting proteins purified. TyrRS-S and TyrRS-Z were kinetically evaluated and the Km values for interaction with Tyr, ATP, and tRNATyr were 172, 204, and 1.5 μM and 29, 496, and 1.9 μM, respectively. The kcatobs values for interaction with Tyr, ATP, and tRNATyr were calculated to be 3.8, 1.0, and 0.2 s–1 and 3.1, 3.8, and 1.9 s–1, …

Effect Of Lanthanum Doping On The Reactivity Of Unsupported Comos2 Catalysts, Carolina Valdes, Diego Gonzalez, Kenneth Flores, Thomas Eubanks, John Valle, Agnelia Tiffany Hernandez, Carlos Hernandez, Jorge Lopez, Mataz Alcoutlabi, Jason Parsons

Chemistry Faculty Publications and Presentations

In the present study, catalytic systems based on La-doping were developed to improve the activity and performance of CoMoS2 hydrodesulfurization catalysts. Lanthanum-doped at 5, 10, or 25% of the Co content in CoMoS2 hydrodesulfurization catalysts were synthesized through a solvothermal process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the catalysts were triphasic consisting of Co9S8, MoS2, and La2S3. The La doped catalysts showed enhanced catalytic activity compared with CoMoS2 synthesized under the same conditions. The CoMoS2 prepared under solvothermal synthesis conditions showed a catalytic activity of 6.80 mol g-1 s-1, however, the La0.05Co0.95MoS2 doping showed a catalytic …

Molten Salt Synthesized Submicron Perovskite La1–Xsrxcoo3 Particles As Efficient Electrocatalyst For Water Electrolysis, Swati Mohan, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Perovskite oxides are an important and effective class of mixed oxides which play a significant role in the fields of energy storage and conversion systems. Here we present a series of cobaltite perovskite LaCoO3 particles which have been doped with 0, 5, 10, 20, and 30% of Sr2C and have been synthesized by a combined sol– gel and molten-salt synthesis procedure, which provides a regular morphology of the particles. These Sr2C-doped LaCoO3 particles have been characterized by powder X-ray diffraction, Raman spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Moreover, these Sr2C doped LaCoO3 particles have been demonstrated …