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Chemistry

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University of Texas Rio Grande Valley

Theses and Dissertations - UTB/UTPA

Articles 31 - 41 of 41

Full-Text Articles in Physical Sciences and Mathematics

Identification Of Phosphatases Involved In E2f-Associated Apoptosis, Liza D. Morales Smith May 2010

Identification Of Phosphatases Involved In E2f-Associated Apoptosis, Liza D. Morales Smith

Theses and Dissertations - UTB/UTPA

Retinoblastoma (Rb) is a tumor suppressor protein that controls a critical checkpoint between the G1 phase and the S phase of the cell cycle. Rb is able to suppress cell proliferation by binding to the E2F family of transcription factors, inhibiting its ability to activate transcription of genes necessary for cell cycle progression. Mutations in proteins involved with the Rb/E2F pathway can result in hyper-proliferative cells that overtime can acquire and accumulate additional mutations, which could lead to tumorigenesis. To prevent hyper-proliferation, aberrant cells can be eliminated through apoptosis. E2F can induce apoptosis through two pathways: through transactivation of the …

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A Synthetic Approach Toward Novel Β-Lactams, Mohamed Hashim May 2010

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 …

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Genotyping Of Tgif Polymorphisms Associated With Schizophrenia And Psychosis, George Vera Jr. May 2010

Genotyping Of Tgif Polymorphisms Associated With Schizophrenia And Psychosis, George Vera Jr.

Theses and Dissertations - UTB/UTPA

Polymorphisms in Transforming Growth β-Induced Factor (TGIF) have been found to contribute to the risk of development of psychosis and related disorders. Identifying the genes responsible for causing schizophrenia and psychosis will allow for treatment at an earlier stage of development, saving the patient problems, time, and money. The purpose of this experiment is to determine the haplotype of DNA samples obtained from earlier experiments. The DNA samples were collected from people with schizophrenia in Costa Rica, Southern Texas, and Northern Mexico. The samples were tested using 5 single nucleotide polymorphisms (SNPs) and amplified using polymerase chain reaction (PCR). Haplotypes …

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Trace Analysis Of Volatile Organic Compounds In The Water Of The Arroyo Colorado And The Lower Laguna Madre Utilizing E.P.A.Sw846 Method 8260, Humberto Valdez May 2010

Trace Analysis Of Volatile Organic Compounds In The Water Of The Arroyo Colorado And The Lower Laguna Madre Utilizing E.P.A.Sw846 Method 8260, Humberto Valdez

Theses and Dissertations - UTB/UTPA

Volatile organic compounds (VOC) can cause a major environmental concern since they create a hazard to public health and the environment. This study focused on determining concentration of VOCs in Arroyo Colorado waters and the Lower Laguna Madre (LLM) utilizing GC/MS. Little is known on the concentration and composition of VOCs. Toluene was the most common VOC. Concentrations ranged from 0.0010 mg/L to 0.0039 mg/L. Analysis of a sediment pore water sample collected near the mouth of the Arroyo Colorado also detected toluene (0.0023 mg/L). This study showed that VOCs were concentrated near the county boat launch and somewhat downstream. …

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Utilizing Concept Mapping As A Teaching And Learning Tool To Prepare For The Science Taks Test, Rosa Linda Zuniga Dec 2009

Utilizing Concept Mapping As A Teaching And Learning Tool To Prepare For The Science Taks Test, Rosa Linda Zuniga

Theses and Dissertations - UTB/UTPA

Concept mapping was used with Donna High School students to determine its effect on the Texas Assessment of Knowledge and Skills (TAKS) test. Concept mapping was used with models such as the Sheltered Instruction Observation Protocol model (SIOP), the 5- E model, and the Learning Groups model. This measure was taken because the models used have not helped students improve their TAKS scores significantly. The findings of this research reveals that using the process of concept mapping together with the SIOP model helps students clearly see related concepts and motivates them to think more deeply. Students quickly realize what concepts …

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Effects Of Adding An Enhanced Material Instructional Model To A Collaborative Grouping Instructional Strategy In A College Preparatory Chemistry Course, Chinyere Fidelia Shaw-Nnajiofor Aug 2009

Effects Of Adding An Enhanced Material Instructional Model To A Collaborative Grouping Instructional Strategy In A College Preparatory Chemistry Course, Chinyere Fidelia Shaw-Nnajiofor

Theses and Dissertations - UTB/UTPA

This research study investigated comparable academic achievement outcomes between an experimental group (EG) and a control group (CG) in a college preparatory chemistry course using a mixture of instructional pedagogies. The subjects comprised native and non-native English speakers, often identified as Limited English Proficiency (LEP) students. The study found no statistically significant difference between the pre-test scores of EG and CG students and a significant difference between the post-test scores of students in the experimental group compared to those of the control group. No significant difference was observed when comparing the test scores of the post-tests of the LEP-EG students …

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Electrospinning Polystyrene Reinforced With Multi-Walled Carbon Nanotubes: Parameters For Obtaining Nanofibers With Enhanced Thermal Properties, Ana Veronica Rodriguez Ybarra May 2009

Electrospinning Polystyrene Reinforced With Multi-Walled Carbon Nanotubes: Parameters For Obtaining Nanofibers With Enhanced Thermal Properties, Ana Veronica Rodriguez Ybarra

Theses and Dissertations - UTB/UTPA

Various concentrations of multi-walled carbon nanotubes (MWCNTs) were dispersed in a polystyrene matrix in order to determine the optimal MWCNT concentration that would enhance the thermal properties of the composite. The MWCNTs were dispersed in the polystyrene matrix by high energy sonication and then electrospun. The microstructural characterization such as fiber diameter, fiber orientation, fiber morphology, porosity, cross-section shape, and surface roughness of the nanofibers electrospun from these composites were made by scanning electron microscopy and transmission electron microscopy. Spectroscopic characterization for these nanofibers was conducted using Fourier Transform infrared spectroscopy and Raman spectroscopy was utilized to establish a nanotube/matrix …

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Completing Chemistry Taks Objective 4(9d): The Effect Of Flash Animation, Judith B. Dano May 2009

Completing Chemistry Taks Objective 4(9d): The Effect Of Flash Animation, Judith B. Dano

Theses and Dissertations - UTB/UTPA

This study examines the effect of flash animation on learning effectiveness. The main goal of the study was to verify if using flash animation on learning chemistry concepts particularly Chemistry TAKS Objective 4 (9D) will have an impact on students learning achievement. The subjects in this study were 10th grade students from PSJA Memorial High School. Two class sections were randomly assigned as the treatment group each with 20 subjects (n=40) and another two class sections were assigned as the control group (n=40). The treatment group was exposed to flash animation while the control group had the traditional lecture type …

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Impact Of Flash Animation In Learning Concepts Of Matter Among Elementary Students, Rhodora S. Santos May 2009

Impact Of Flash Animation In Learning Concepts Of Matter Among Elementary Students, Rhodora S. Santos

Theses and Dissertations - UTB/UTPA

This study examines the instructional effect of flash animation on students' achievement in learning specific concepts of matter. The subjects used in this study were 5th-grade students of the researcher from Dan Ramirez Elementary. Each class or section of these students was randomly assigned as the control group (n = 20) and the experimental group (n =20). The subjects in the control group were exposed to traditional textbook reading while the subjects in the experimental group were exposed to flash animation. To measure the students' achievement from the concepts learned, a pre-test and a post test were both administered to …

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Synthesis And Characterization Of Two Metal-Organic Frameworks, Roxanna Schaffino Moore May 2009

Synthesis And Characterization Of Two Metal-Organic Frameworks, Roxanna Schaffino Moore

Theses and Dissertations - UTB/UTPA

Herein, the design and synthesis of two metal-organic frameworks, Zn 4O(FMA)3 (FMA = fumaric acid) and Zn2(CNC) 2(DPT) (CNC = 4-carboxycinnamic acid; DPT = 3,6-Di-4-pyridy1-1,2,4,5-tetrazine) via solvothermal methods are reported. Zn4O(FMA)3 was isolated as light yellow cubic crystals and Zn2(CNC)2(DPT) as light pink-block shaped crystals. The structures of both MOFs were characterized by single X-ray diffraction. Integrity of both MOFs were determined via powder X-ray diffraction and thermal gravimetric analysis. Zn4O(FMA) 3 is an isoreticular MOF exhibiting 6.8 Å pores taking up 5.2 wt % of hydrogen gas at 40 bar and 77K. Zn2(CNC)2(DPT) is a 3D primative cubic net …

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Alignment, Mechanical And Thermo-Physical Characterization Of Nanofiber-Reinforced Polyethylene, Veronica M. Diaz-Serrato Dec 2002

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 …

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