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Chemistry

University of Texas Rio Grande Valley

Theses/Dissertations

2012

Pure sciences

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Synthesis And Luminescence Properties Of Core-Shell Structured (Lanthanum(1-X)Europium(X))(2)Zirconium Heptoxid[At]Yttrium Orthoborate Spherical Nanoparticles, Suresh Babu Alaparthi Dec 2012

Synthesis And Luminescence Properties Of Core-Shell Structured (Lanthanum(1-X)Europium(X))(2)Zirconium Heptoxid[At]Yttrium Orthoborate Spherical Nanoparticles, Suresh Babu Alaparthi

Theses and Dissertations - UTB/UTPA

Many rare earth compounds have photoluminescent characteristics for various important applications. In this study, europium doped La2Zr2O7 nanoparticles were first synthesized morphology-controllably by using a molten-salt synthesis method. These nanoparticles were used as the core for coating with YBO3 shell. We then explored the effect of different experimental processing parameters, such as annealing temperatures, reaction times and different ratios of salt mixtures on the structure and morphology of these nanoparticles. The overall core size and shell thickness can be controlled by varying the reactant concentration both the core and shell material. These core@shell nanoparticles were then characterized mainly using power …


Electrospun Biocompatible Polyurethanes With The Addition Of Multi-Walled Carbon Nanotubes, Travis Cantu Aug 2012

Electrospun Biocompatible Polyurethanes With The Addition Of Multi-Walled Carbon Nanotubes, Travis Cantu

Theses and Dissertations - UTB/UTPA

Three different Polyurethanes (PUs) Lycra®, HydroThaneTM, and BioSpan®, were electrospun and characterized using Scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform-infrared spectroscopy (FTIR), & Raman spectroscopy. Nanofiber composites were made by incorporating MWCNTs at three different concentration 0.1wt% 0.5wt% and 1.0wt% to the three PUs. These samples were characterized and mechanical and thermal test were done. The TEM images showed MWCNT bundling in the polymer matrix at the highest concentration, the FTIR showed shifts in characteristic urethane bands indicating an interaction with the polymer and MWCNTs. Mechanical test showed a decrease in the Young’s modulus (E’) in most …


Synthesis Of Novel Bis-Β-Lactams, Jocabed Marquez Aug 2012

Synthesis Of Novel Bis-Β-Lactams, Jocabed Marquez

Theses and Dissertations - UTB/UTPA

This study presents the synthesis and structure of newly discovered β-lactams and the mechanism of their synthesis via the Staudinger reaction. β-lactams known as 2-azetidinones, are four membered cyclic amides that have been extensively used and recognized as the central motif of the β-lactam antibiotics, the most widely employed family of antimicrobial agent to date. The Staudinger reaction involves the cycloaddition between an acid chloride with an imine, in presence of a tertiary base. The possibility of cooperative effects from two therapeutic functionalities in drug molecules, has prompted interest in the synthesis of Bis-β-lactams. The synthesis of 2 novel Bis-β-lactams …


Microwave-Induced Bismuth Nitrate-Catalyzed Multicomponent Reaction Toward Heterocycles, Ashwini Bobbala Aug 2012

Microwave-Induced Bismuth Nitrate-Catalyzed Multicomponent Reaction Toward Heterocycles, Ashwini Bobbala

Theses and Dissertations - UTB/UTPA

The microwave-induced reaction for the synthesis of nitrogen containing heterocyclesis very important in medicinal chemistry. The synthesis of various other valuable compounds is also done by employing this reaction. The aza Diels-Alder reaction is one of the most powerful synthetic tools for the synthesis of nitrogen containing heterocycles. The main goal of the research is to synthesize the nitrogen containing heterocycles using Bismuth nitrate as the catalyst in the presence of microwave irradiation. In the present study we explore the catalytic activity of bismuth nitrate and the role of microwave reactor in the synthesis of 2, 3-diaryl substituted bicyclic octanone …


Synthesis And Characterization Of Biodegradable Electrospun Polyurethanes For Biomedical Applications, Xujun Zhang Aug 2012

Synthesis And Characterization Of Biodegradable Electrospun Polyurethanes For Biomedical Applications, Xujun Zhang

Theses and Dissertations - UTB/UTPA

Two types of polyesters [(Poly(ε-caprolactone) and Poly(δ-valerolactone)] were synthesized by ring-opening polymerization with diethylene glycol as a initiator and stannous octate as a catalyst. The corresponding polyurethanes were synthesized by two-step polymerization with 1,4-diisocyanate butane (BDI) and reacted with 1,4-diamino butane (Putrescine) chain extender. The polymers were characterized by Proton Nuclear Magnetic Resonance (1H NMR), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Size-exclusive Chromatography (SEC), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The resulting polyurethanes were fabricated into nanofibers using an electrospinning technique. The morphological, structural characterizations and thermal properties of the bulk polyurethanes and electrospun polyurethanes nanofibers were …


Development Of An Assay To Screen For Novel Proteins From Bacillus Thuringiensis With Antibacterial Activity, Auriole T. Tamegnon May 2012

Development Of An Assay To Screen For Novel Proteins From Bacillus Thuringiensis With Antibacterial Activity, Auriole T. Tamegnon

Theses and Dissertations - UTB/UTPA

Bacillus thuringiensis (Bt) produces the non specific Cyt protein and the specific Cry protein. Past research has shown these proteins are toxic to insects, red blood cells, cancer cells, and some bacteria. While many antibacterial substances are known to exist, efforts to find new ones still continue. In this project we used Bt 6-2-56 (containing a novel filament associated parasporal body which appears non-toxic to insects and protozoan) and Bt 4Q13 (which has been shown to have activity against E. coli and S. aureus) to develop a simple, easy, scalable assay in a 96 well Microtitre plate to look for …