Physical Sciences and Mathematics Commons^™

Oxidation Of Dibenzothiophene To Dibenzothiophene-Sulfone Using Molybdenum (Vi) Oxide, Tungsten (Vi) Oxide, And Ratios Of Molybdenum (Vi) Oxide And Tungsten (Vi) Oxide At Atomspheric Pressure, Sean M. Pelfrey

Theses and Dissertations - UTB/UTPA

This is a study of the catalytic oxidation of dibenzothiophene to dibenzothiophene sulfone using molybdenum (VI) oxide, tungsten (VI) oxide, and mixtures of molybdenum (VI) oxide and tungsten (VI) oxide at atmospheric pressure. The oxidative desulfurization reaction is studied with respect to the kinetics and thermodynamics of the process. Five catalysts were synthesized using a precipitation reaction. The five catalysts were 100% MoO3, 75/25% MoO3/WO3, 50/50% MoO3/WO3, 25/75% MoO3/WO3, and 100% WO3. Each catalyst was calcinated at three different temperatures 250oC, 500oC, 750oC and characterized using X-Ray Diffraction. Reactions of DBT-catalyst were held, under reflux, at temperatures from 140 oC …

Effect Of Crimping, Multilayering, And Twisting On Polymer Fibers For Acl Replacement, Mariana Ocampo

Theses and Dissertations - UTB/UTPA

The Anterior Cruciate Ligament (ACL) is the most common knee injury in the United States; roughly 150,000 ACL surgeries are performed annually. The ACL lacks self-healing properties due to its location inside the knee’s intra – articular environment (IA). Treatments for ACL ruptures involve the use of autogenous grafts or allografts. More suitable treatments can be found in new bio engineered tissue scaffolds, composed of natural and synthetic polymers. The polymers provide stronger mechanical properties and the ability to promote cell adhesion. It is believed that mimicking the crimping pattern of human ligaments will enhance polymer properties. Four polymers were …

Electrospinning Polymer Blends For Biomimetic Scaffolds For Acl Tissue Engineering, Vanessa Lizeth Garcia

Theses and Dissertations - UTB/UTPA

The anterior cruciate ligament (ACL) rupture is one of the most common knee injuries. Current ACL reconstructive strategies consist of using an autograft or an allograft to replace the ligament. However, limitations have led researchers to investigate tissue engineered grafts, known as scaffolds, through electrospinning. Scaffolds made of natural and synthetic polymer blends have the potential to promote cell adhesion while having strong mechanical properties. However, enzymes found in the knee are known to degrade tissues and affect the healing of intra-articular injuries. Results suggest that the natural polymers used in this study modify the thermal properties and tensile strength …

Oxidation Of Dibenzothiophene To Dibenzothiophene Sulfone Using Tio2, Juan H. Leal

Theses and Dissertations - UTB/UTPA

The oxidation of dibenzothiophene (DBT) to dibenzothiophene-sulfone has been considered as an alternate method to remove sulfur from crude oil. This study demonstrates that the oxidative desulfurization (ODS) of DBT to DBT-sulfone occurs using rutile TiO2 as a catalyst with the aid of O2. In addition, anatase and brookite were synthesized and tested in the reaction. Particle size of the catalysts was calculated and morphology was explored using SEM. A kinetic study was performed to determine the catalytic effect and activation energy of TiO2. The oxidation reaction was carried out by refluxing TiO2 and DBT in decahydronapthalene while flowing O2 …

Electrospinning Nanofibers For Controlled Drug Release, Indrani Banik

Theses and Dissertations - UTB/UTPA

Electrospinning is the most widely studied technique for the synthesis of nanofibers. Electrospinning is considered as one of the technologies that can produce nanosized drugs incorporated in polymeric nanofibers. In vitro and in vivo studies have demonstrated that the release rates of drugs from these nanofiber formulations are enhanced compared to those from original drug substance. This technology has the potential for enhancing the oral delivery of poorly soluble drugs [1]. The electrospun mats were made using Polycaprolactone/PCL, Poly(DL-lactide)/PDL 05 and Poly(DL-lactide-co-glycolide)/PLGA. The drugs incorporated in the electrospun fibers were 5-Fluorouracil and Rapamycin. The evidence of the drugs being embedded …

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 …

Biocompatibility Of Electrospun Polymer Nanofibers (Epns) With Nih 3t3 Cell Line And Interaction Of Quercetin With Different Flavonoids: Induction Of Phase Ii Enzymes In Vitro Cancer Cell Lines, Brenda S. Benavides

Theses and Dissertations - UTB/UTPA

Part I: In this study Electrospun nanofibers, Elasthane™ 55D, Elasthane™ 75D, Biospan®, Hydrothane™ and Lycra® were evaluated for their biocompatibility to be artificial tissue substitutes using NIH-3T3 fibroblast cells. A colorimetric based MTT dye reduction assay demonstrated that EPNs did not stop cell growth in vitro. Additionally, fluorescence confocal microscope images verified that cell adhesion occurred in the nanofibers, and cell growth on the EPNs over two weeks period was confirmed by DNA quantification.

Part II: This section of the thesis is focused on evaluation of chemopreventive properties of various phytochemicals by induction of Phase II enzymes. The interaction of …

Synthesis And Characterization Of 4,4-Prime-Distyrylbiphenyl And Its Applications In Organic Field Effect Transistors, Nestor A. Santos Jr.

Theses and Dissertations - UTB/UTPA

4,4’-distyrylbiphenyl (DSBP), an ambipolar small molecule with electroluminescent properties, was synthesized following two synthetic protocols. Accordingly, biphenyl was bromomethylated using a mixture of paraformaldehyde and hydrogen bromide in 20% to 60% isolated yields. Bromomethylated biphenyl was then reacted with triphenyl phosphine, or with triethyl phosphate to yield the corresponding triphenyl phosphonium bromide or triethyl phosphonate, respectively. DSBP was synthesized by reaction of the triphenyl phosphonium bromide or triethyl phosphonate with freshly distilled benzaldehyde according to the Wittig, or Horner-Wadsworth-Emmons protocols. DSBP from the Wittig reaction resulted in a mixture of cis-trans isomers, while the product from the Horner-Wadsworth-Emmons reaction yielded …

Study On Energy Absorption Behaviors Of Hydrophobic Mesoporous Materials, Zhongyuan Sun

Theses and Dissertations - UTB/UTPA

Nanoporous energy absorption system has been developed tremendously as an advanced energy storage system in recent years. This research is to optimize the mesoporous energy absorption matrixes via surface treatment to find out the optimum conditions for higher energy conversion efficiency. Five mesoporous silica matrixes with pore size in a range of 3 to 31.6 nm were investigated. Six alkylchlorosilanes were used as the modification reagents. The results showed that the energy absorption density via pressure-induced infiltration is as high as 8.0 J/g which is 100 times larger than that of conventional energy absorption materials. The controllability of the energy …

A Synthetic Approach Toward Novel Β-Lactams, Mohamed Hashim

Theses and Dissertations - UTB/UTPA

β-lactam antibiotics which is a class by itself, covers a wide range of antibiotics that includes penicillin, penicillin derivatives, cephalosporins, carbapenems, and any antibiotic agent that contains a 2-azetidinone ring.[2] In recent past research it has been established that β-lactams show therapeutic and anticancer activity with low toxicity. [2] It has also been reported by our lab that N-chrysenyl and N-phenanthrenyl 3-acetoxy-4-aryl-2- azetidinone can exhibit potent selective anticancer activity towards prostate, colon, pancreatic cancer and leukemia at low concentrations, all of this was revealed by means of a structure activity study. [2] The goal of our research is the synthesis …

Alignment, Mechanical And Thermo-Physical Characterization Of Nanofiber-Reinforced Polyethylene, Veronica M. Diaz-Serrato

Theses and Dissertations - UTB/UTPA

Alignment of vapor grown carbon nano-reinforced polyethylene composites was performed using conventional extrusion processing methods. The alignment of the nanofibers within polyethylene, PE; the matrix, produced a material with anisotropic behavior. Mechanical and thermo-physical properties of the nanocomposite were studied. Enhancements in mechanical properties were investigated for pure PE, misaligned, and aligned specimens for stress versus strain, maximum load, and Young's modulus as high as 185, 273, and 80%, respectively. In fact, toughness was considerably high for the 10 rpm specimen when compared to other samples of different windup speeds. Thermo-physical studies were performed using differential scanning calorimetry (DSC) and …