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- Title
- EVOLUTION OF LAMELLAR STRUCTURES IN AL-AG ALLOYS.
- Creator
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Senapati, Sephalika, Heinrich, Helge, University of Central Florida
- Abstract / Description
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In the present study, the formation and the evolution of lamellar structures in different Al-Ag alloys were investigated by transmission electron microscopy (TEM). Plates of the hexagonalÁ phase form semi-coherently on the {111} planes of the face centered cubic lattice of the alloy after the formation of Guinier-Preston zones. Guinier-Preston zones are metastable coherent preprecipitates which are silver rich in the aluminum-rich Al-Ag alloys. The decomposition of aluminum rich...
Show moreIn the present study, the formation and the evolution of lamellar structures in different Al-Ag alloys were investigated by transmission electron microscopy (TEM). Plates of the hexagonalÁ phase form semi-coherently on the {111} planes of the face centered cubic lattice of the alloy after the formation of Guinier-Preston zones. Guinier-Preston zones are metastable coherent preprecipitates which are silver rich in the aluminum-rich Al-Ag alloys. The decomposition of aluminum rich Al-Ag alloys, particularly the sequence of the later stages of precipitate formation was studied. With scanning electron microscopy and high-resolution transmission electron microscopy the development of the Á phase was investigated. Samples cut from different Al-Ag alloys were homogenized at temperatures between 530C to 560C to obtain a single phase f.c.c solid solution. The samples were then quenched to room temperature, followed by heat treatments at temperatures between 140C and 220C for varying lengths of times. While Guinier-Preston zones increase in diameter with increasing aging duration, silver rich platelets of the Á phase form. The Á phase is the next metastable phase in the decomposition sequence before finally the Á phase transforms to the stable silver-rich phase, termedÁ . For samples with silver contents above 12 at.% a parallel lamellar alignment of fine Á-plates and Alrich matrix is found after extended heat treatments. For all alloys with Ag concentrations below 12 at.% individual Á plates are found on all four possible (111) planes of the ¿ matrix. iv A method is presented to calibrate the medium-magnification high-angle annular dark-field contrast in scanning transmission electron microscopy. This calibration allows for the quantitative measurement of plate thicknesses from high-angle annular dark-field scanning transmission electron micrographs of Ag2Al plates inclined to the electron beam. Results from these measurements are in good agreement with direct bright-field micrographs of plates viewed edge-on.
Show less - Date Issued
- 2005
- Identifier
- CFE0000874, ucf:46648
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000874
- Title
- INVESTIGATING THE ROLE OF NEURONAL AGING IN FRAGILE X-ASSOCIATED TREMOR/ATAXIA SYNDROME.
- Creator
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Hencak, Katlin Marie, von Kalm, Laurence, Southwell, Amber, University of Central Florida
- Abstract / Description
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Fragile X-associated tremor/ataxia syndrome (FXTAS) is an X-linked late-onset neurodegenerative disorder caused by a noncoding trinucleotide repeat expansion in the FMR1 gene. This gene produces fragile x mental retardation protein (FMRP), an RNA binding protein whose targets are involved in brain development and synaptic plasticity. One of the proposed mechanisms of FXTAS pathogenesis is an RNA gain-of-function in which the repeat expansion causes toxic mRNA that sequesters important...
Show moreFragile X-associated tremor/ataxia syndrome (FXTAS) is an X-linked late-onset neurodegenerative disorder caused by a noncoding trinucleotide repeat expansion in the FMR1 gene. This gene produces fragile x mental retardation protein (FMRP), an RNA binding protein whose targets are involved in brain development and synaptic plasticity. One of the proposed mechanisms of FXTAS pathogenesis is an RNA gain-of-function in which the repeat expansion causes toxic mRNA that sequesters important proteins in the cell, interfering with their functions. Another suggested method of pathogenesis is through a mutant protein called FMRpolyG. This protein results from repeat-associated non-AUG (RAN) translation, in which the expanded repeats are translated where they otherwise would not be. This protein co-localizes with intranuclear inclusions and nuclear membrane proteins, causing disorganization of the nuclear lamina in FXTAS patient brain samples and neurons differentiated from FXTAS patient-derived induced pluripotent stem cells (iPSCs). iPSC technology involves reprogramming an adult somatic cell back to an embryonic-like state, allowing it to be differentiated into all cell types. A limit with iPSCs, though, is modeling late-onset disorders because the cells lose all age-related features during reprogramming. Progerin, a truncated form of the lamin A protein, has been used to age neurons differentiated from Parkinson Disease (PD) patient-derived iPSCs. Progerin-mediated aging was found to unmask PD-like phenotypes in those neurons, making it a promising technology for modeling late-onset disorders such as FXTAS. In this study, we investigated the link between the aging process and FXTAS pathogenesis in neurons differentiated from FXTAS patient-derived iPSCs with the use of progerin. Progerin transduction was successful in aging the FXTAS neurons. The presence of FMRpolyG was confirmed and an interaction with Lap2b was observed. In some neurons, there was also an observed interaction between FMRpolyG and progerin. Overall, this data suggests that there is an interaction between the mutant FMRpolyG protein and the nuclear membrane during aging, which may contribute to the cell death that causes neurodegeneration in FXTAS patients.
Show less - Date Issued
- 2019
- Identifier
- CFH2000554, ucf:45678
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000554
- Title
- STEM CELL BIOLOGY AND STRATEGIES FOR THERAPEUTIC DEVELOPMENT IN DEGENERATIVE DISEASES AND CANCER.
- Creator
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Alvarez, Angel, Sugaya, Kiminobu, University of Central Florida
- Abstract / Description
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Stem cell biology is an exciting field that will lead to significant advancements in science and medicine. We hypothesize that inducing the expression of stem cell genes, using the embryonic stem cell gene nanog, will reprogram cells and dedifferentiate human mesenchymal stem cells into pluripotent stem cells capable of neural differentiation. The aims of initial studies are as follows: Aim 1: Demonstrate that forced expression of the embryonic stem cell gene nanog induces changes in human...
Show moreStem cell biology is an exciting field that will lead to significant advancements in science and medicine. We hypothesize that inducing the expression of stem cell genes, using the embryonic stem cell gene nanog, will reprogram cells and dedifferentiate human mesenchymal stem cells into pluripotent stem cells capable of neural differentiation. The aims of initial studies are as follows: Aim 1: Demonstrate that forced expression of the embryonic stem cell gene nanog induces changes in human mesenchymal stem cells to an embryonic stem cell-like phenotype. Aim 2: Demonstrate that induced expression of nanog up-regulates the expression of multiple embryonic stem cell markers and expands the differentiation potential of the stem cells. Aim 3: Demonstrate that these nanog-expressing stem cells have the ability to differentiate along neural lineages in vitro and in vivo, while mock-transfected cells have an extremely limited capacity for transdifferentiation. Alternatively, we hypothesize that embryonic stem cell genes can become activated in malignant gliomas and differentially regulate the subpopulation of cancer stem cells. This study examines the role of embryonic stem cell genes in transformed cells, particularly cancer stem cells. These studies explore has the following objectives: Aim 1: Isolate different sub-populations of cells from tumors and characterize cells with stem cell-like properties. Aim 2: Characterize the expression of embryonic stem cell markers in the sub-population of cancer stem cells. Aim 3: Examine the effects of histone deacetylase inhibitors at inhibiting the growth and reducing the expression of stem cell markers. Our research has demonstrated the potential of the embryonic transcription factor, nanog, at inducing dedifferentiation of human bone marrow mesenchymal stem cells and allowing their recommitment to a neural lineage. Specifically, we used viral and non-viral vectors to induce expression of NANOG, which produced an embryonic stem cell-like morphology in transduced cells. We characterized these cells using real-time PCR and immunohistochemical staining and find an up-regulation of genes responsible for pluripotency and self-renewal. Embryonic stem cell markers including Sox2, Oct4 and TERT were up-regulated following delivery of nanog. The role of nanog in the expression of these markers was further demonstrated in our induced-differentiation method where we transfected embryonic stem cell-like cells, that have been transduced with nanog flanked by two loxP sites, with a vector containing Cre-recominase. We tested the ability of these nanog-transfected cells to undergo neural differentiation in vitro using a neural co-culture system or in vivo following intracranial transplantation. Our next study characterized patient-derived glioblastoma cancer stem cells. We found that cells isolated from serum-free stem cell cultures were enriched for stem cell markers and were more proliferative than the bulk population of cells grown in convention serum-supplemented media. These cancer stem cells expressed embryonic stem cell markers NANOG and OCT4 whereas non-tumor-derived neural stem cells do not. Moreover, the expression of stem cell markers was correlated with enhanced proliferation and could serve as a measure of drug effectiveness. We tested two different histone deacetylase inhibitors, trichostatin A and valproic acid, and found that both inhibited proliferation and significantly reduced expression of stem cell markers in our cancer stem cell lines. These data demonstrate the potential use of stem cell genes as therapeutic markers and supports the hypothesis that cancer stem cells are a major contributor to brain tumor malignancy.
Show less - Date Issued
- 2011
- Identifier
- CFE0003641, ucf:48845
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003641
- Title
- STEM Academic Engagement in Young Children with Autism: A Single Case Design Study.
- Creator
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Ji, Yixuan, Szente, Judit, Levin, Judith, Macy, Marisa, Pearl, Cynthia, University of Central Florida
- Abstract / Description
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The researcher examined the academic engagement in Circle Time activities and STEM (science, technology, engineering, and mathematics) activities for three young children with autism spectrum disorders (ASD) who attended a large Orange County Public School, enrolled in an ASD preschool classroom. Given the increasing number of children diagnosed with ASD each year and many STEM job opportunities for individuals with ASD, it is becoming important to know how young children with ASD learn and...
Show moreThe researcher examined the academic engagement in Circle Time activities and STEM (science, technology, engineering, and mathematics) activities for three young children with autism spectrum disorders (ASD) who attended a large Orange County Public School, enrolled in an ASD preschool classroom. Given the increasing number of children diagnosed with ASD each year and many STEM job opportunities for individuals with ASD, it is becoming important to know how young children with ASD learn and engage in STEM activities. Strengths of individuals with ASD in the STEM field have been reported in several research studies (Chen (&) Weko, 2009; Kirchner, Ruch (&) Dziobek, 2016; Samson (&) Antonelli, 2013). Although this study focuses on academic engagement of young children with ASD, there has been limited research investigating the learning in academic activities for this population. Moreover, there is a distinct gap in the literature specific to young children with ASD and the academic engagement in STEM learning. A single case study with an alternating treatment design and three participants was used to investigate the difference in academic engagement of children with ASD in STEM activities compared to Circle Time activities. Data were collected using observations and a social validity questionnaire. Data were analyzed and then presented using a Time Series Line Graph. The results of this study indicated all three young children with ASD had more engaged time during STEM activities than during Circle Time activities. Furthermore, the teacher's social validity questionnaire revealed she strongly agreed that STEM activities were beneficial for children with ASD. Overall, findings from this study gave direction for future studies and intervention programs focusing on improving academic engagement and learning in STEM activities for children with ASD that may support better learning outcomes. Implications and recommendations for teachers of students with ASD were discussed.
Show less - Date Issued
- 2018
- Identifier
- CFE0007198, ucf:52259
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007198
- Title
- Embryonic Stem Cell Derived Exosomes Enhance Cardiac Stem Cell Differentiation into Heart Cells.
- Creator
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Hammond, Jamillah, Singla, Dinender, Masternak, Michal, Davidson, Victor, University of Central Florida
- Abstract / Description
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Transplantation of embryonic stem (ES) cells into the ischemic and infarcted heart has proven to repopulate cardiac cell populations, attenuate structural cardiac remodeling, and rescue cardiac function. Unfortunately, the pluripotency of ES cells increases risk of teratoma formation in vivo. Exosomes, smaller in comparison to ES cells, are cell free carriers of miRNA, proteins, and lipids, and do not suggest risk of teratoma formation. Exosomes have been proposed to mediate and attenuate...
Show moreTransplantation of embryonic stem (ES) cells into the ischemic and infarcted heart has proven to repopulate cardiac cell populations, attenuate structural cardiac remodeling, and rescue cardiac function. Unfortunately, the pluripotency of ES cells increases risk of teratoma formation in vivo. Exosomes, smaller in comparison to ES cells, are cell free carriers of miRNA, proteins, and lipids, and do not suggest risk of teratoma formation. Exosomes have been proposed to mediate and attenuate regeneration following myocardial infarction (MI), however, the role of exosomes derived from ES cells (ES-Exo) in activating resident cardiac stem cells (CSCs) to undergo cardiac differentiation is not established. In the present study, Stem cell antigen 1 positive (Sca-1+ve) CSCs were isolated, incubated with exosomes, and evaluated for differentiation into the major heart cell types in vitro. Observations of in vitro cardiac differentiation were further established in an in vivo model of MI. Ligation of the coronary artery, or a sham surgery was performed in C57BL/6 mice 8-12 weeks of age. Mice were split among four study groups: sham, MI, MI + H9c2-Exo (a cell line control), (&) MI + ES-Exo. ES-Exo were transplanted via intramyocardial (IM) injection immediately following coronary artery ligation. At day 14 (D14), echocardiography was used to evaluate cardiac function. Differentiation into the major heart cells was determined by sarcomeric ?-actin (cardiomyocytes) and smooth muscle ?-actin (vascular smooth muscle cells) immunostaining. Hematoxylin and Eosin and Masson's Trichrome staining assessed cardiomyocyte hypertrophy and fibrosis, respectively. Immunostaining for major heart cellular markers revealed significant activation of resident Sca-1+ve CSCs to undergo cardiac differentiation after ES-Exo treatment. Cardiomyocyte hypertrophy and myocardial fibrosis were significantly increased following coronary artery ligation. Results from histological staining revealed significantly decreased levels of hypertrophy and fibrosis in hearts transplanted with ES-Exo following coronary ligation. In summary, our findings advocate ES-Exo as a viable treatment option to repopulate the myocardium with viable heart cells, attenuate cardiac remodeling, and rescue cardiac function.
Show less - Date Issued
- 2018
- Identifier
- CFE0007188, ucf:52254
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007188
- Title
- Computer Programming with Early Elementary Students with and without Intellectual Disabilities.
- Creator
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Taylor, Matthew, Dieker, Lisa, Vasquez, Eleazar, Hines, Rebecca, Nickels, Megan, University of Central Florida
- Abstract / Description
-
Researchers suggest students at the preschool and kindergarten grade levels are active learners and creators and need to be exposed to science, technology, engineering, and mathematics (STEM) curriculum. The need for student understanding in STEM curriculum is well documented, and positive results in robotics, computer programming, and coding are leading researchers and policy makers to introduce new standards in education. The purpose of this single case design study is to research the...
Show moreResearchers suggest students at the preschool and kindergarten grade levels are active learners and creators and need to be exposed to science, technology, engineering, and mathematics (STEM) curriculum. The need for student understanding in STEM curriculum is well documented, and positive results in robotics, computer programming, and coding are leading researchers and policy makers to introduce new standards in education. The purpose of this single case design study is to research the abilities of kindergarten students, with and without intellectual disabilities (ID), to learn skills in computer programming and coding through explicit instruction, concrete manipulatives, and tangible interfaces. While constructionist methodology is typically used to teach robotics, best practice for students with ID is explicit instruction. For this reason, a group of students with ID and a group of students without ID were taught to program a robot to move in a square, through explicit instruction, and by using the iPad application, Blockly. It was discovered that students in both groups were capable of programming the robot, though students learned at different rates. Introducing STEM to students with and without ID at an early age could prepare students for future STEM careers and encourage students with ID to pursue STEM-related paths.
Show less - Date Issued
- 2017
- Identifier
- CFE0006807, ucf:51802
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006807
- Title
- Establishment of Methods for Isolation of Pnmt+ Cardiac Progenitor Cells.
- Creator
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Varudkar, Namita, Ebert, Steven, Parthasarathy, Sampath, Muller, Mark, University of Central Florida
- Abstract / Description
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Cardiovascular disease is the leading cause of death in the United States. Millions of patients suffer each year from endothelial dysfunction and/or debilitating myocardial damage resulting in decreased quality of life and increased risk of death or disablement. Current pharmacological approaches are only partly effective at treating cardiovascular disease, and hence, better strategies are needed to provide significant improvements in treatment options. Cardiac stem/progenitorcells have the...
Show moreCardiovascular disease is the leading cause of death in the United States. Millions of patients suffer each year from endothelial dysfunction and/or debilitating myocardial damage resulting in decreased quality of life and increased risk of death or disablement. Current pharmacological approaches are only partly effective at treating cardiovascular disease, and hence, better strategies are needed to provide significant improvements in treatment options. Cardiac stem/progenitorcells have the potential to regenerate myocardial tissue and repair damaged heart muscle. There are many different types of cardiac progenitor cells, and each may have certain unique properties and characteristics that would likely be useful for particular clinical applications. A current challengein the field is to identify, isolate, and test specific cardiac stem/progenitor cell populations for their ability to repair/regenerate myocardial tissue. Our laboratory has discovered a new type of cardiac progenitor cell that expresses the enzyme, Phenylethanolamine-n-methyltransferase (Pnmt). My initial studies focused on identification of Pnmt+ cells based on knock-in of a nuclear-localized Enhanced Green Fluorescent Protein (nEGFP) reporter gene into exon 1 of the Pnmt gene in a stable recombinant Pnmt-nEGFP mouse embryonic stem cell (mESC) line. These cells were differentiated into cardiomyocytes, and I identified nEGFP+ cells using fluorescence, immunofluorescence, and phase-contrast microscopy techniques. Our results showed that only about 0.025% ( 1 per 4000) of the cardiac-differentiating stem cells expressed the nEGFP+ marker. Because of the relative rarity of these cells, optimization of isolation methods proved initially challenging. To overcome this technical barrier, I used a surrogate cell culture system to establish the methodsof isolation based on expression of either a fluorescent cell marker (EGFP), or a unique cell surface receptor represented by an inactivated (truncated) version of the human low-affinity nerve growth factor receptor (LNGFR). Plasmid DNA containing these reporter genes was transiently transfected into a permissive cell line (RS1), and reporter gene expression was used to identify and isolate transfected from non-transfected cells using either Fluorescence-Activated Cell Sorting(FACS) or Magnetic-Activated Cell Sorting (MACS) methods. The main objective of the study was to establish the isolation techniques based on the expression of reporter genes (EGFP and LNGFR) in RS1 cells. Following transfection, EGFP+ cells were successfully isolated via FACS as verified by flow cytometric and microscopic analyses, which showed that approximately 96% of the isolated cells were indeed EGFP+. Despite the relative purity of the isolated cell population, however, their viability in culture following FACS was substantially compromised ( 50% attrition). In contrast, MACS enabled efficient isolation of LNGFR+ cells, and the vast majority of these ( 90%) retained viability in culture following MACS. The LNGFR expression was verified using RT-PCR. Further, MACS methods enabled isolation of marked cells in about 5-7 mins, whereas it took 2-4 hours to using FACS to perform similar isolations from the same amount of starting material (10^6 cells). In addition, MACS is a more economical method in that it does not require the use of an expensive laser-based instrument to perform the sorting. These results suggest that MACS was a more efficient, gentle, and feasible technique than FACS for isolation of reporter-tagged mammalian cells. Consequently, future studies aimed at isolation of Pnmt+ cardiac progenitor cells will thus primarily focus on MACS methods.
Show less - Date Issued
- 2014
- Identifier
- CFE0005558, ucf:50287
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005558
- Title
- An Analysis of the Perceived Impact of Lesson Study on Improving Secondary School STEM Teacher Effectiveness.
- Creator
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Thompson, Daniel, Taylor, Rosemarye, Baldwin, Lee, Doherty, Walter, Ellis, Amanda, University of Central Florida
- Abstract / Description
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The purpose of this study was to determine the extent to which participating in lesson study was perceived to have an impact on teacher effectiveness. Secondary STEM graduates who come into education need a model of collaborative reflective practice for continuous improvement. Lesson study is one possible model of professional learning that is both reflective and collaborative (Sims (&) Walsh, 2009, p. 731). The cyclical nature of lesson study makes it a natural fit for continuous improvement...
Show moreThe purpose of this study was to determine the extent to which participating in lesson study was perceived to have an impact on teacher effectiveness. Secondary STEM graduates who come into education need a model of collaborative reflective practice for continuous improvement. Lesson study is one possible model of professional learning that is both reflective and collaborative (Sims (&) Walsh, 2009, p. 731). The cyclical nature of lesson study makes it a natural fit for continuous improvement. Yet, little research into the effectiveness of lesson study as a tool for new teacher preparation or for middle and high school teachers exists. As part of the University of Central Florida's RTP3 program, resident teachers from three school districts participated in lesson study. Their reflections on participating in lesson study were analyzed and interviews with designees from each school district were conducted. The resident teachers' reflections and the interviews with partner school district designees were analyzed using the constant comparison method (Parry, 2004). The reflections were closely examined for trends and patterns, and as commonalities emerged, they led to the findings of this study. After review of the school district lesson study models, they were confirmed and explored during the interviews with school district designees. Analysis showed lesson study was perceived to be beneficial by the resident teachers and two of the three school district designees described positive effects gained from participating in lesson study through RTP3. The literature review and the results of this study demonstrate that lesson study is a valuable tool for professional learning in both novice and veteran teachers. Themes frequently observed in lesson study reflections included increased focus on students, the value found in collaboration, and a desire to participate on future lesson study teams. Teachers, teacher preparation programs, and school administrators should consider the benefits of participating in lesson study and attempt to develop a plan to include this method of professional learning in their school or teacher preparation program.
Show less - Date Issued
- 2015
- Identifier
- CFE0005724, ucf:50130
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005724
- Title
- Direct measurement of thicknesses, volumes or compositions of nanomaterials by quantitative atomic number contrast in high-angle annular dark-field scanning transmission electron microscopy.
- Creator
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Yuan, Biao, Heinrich, Helge, Sohn, Yongho, Coffey, Kevin, Fang, Jiyu, Roldan Cuenya, Beatriz, University of Central Florida
- Abstract / Description
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The sizes, shapes, volumes and compositions of nanoparticles are very important parameters determining many of their properties. Efforts to measure these parameters for individual nanoparticles and to obtain reliable statistics for a large number of nanoparticles require a fast and reliable method for 3-D characterization. In this dissertation, a direct measurement method for thicknesses, volumes or compositions of nanomaterials by quantitative atomic number contrast in High-Angle Annular...
Show moreThe sizes, shapes, volumes and compositions of nanoparticles are very important parameters determining many of their properties. Efforts to measure these parameters for individual nanoparticles and to obtain reliable statistics for a large number of nanoparticles require a fast and reliable method for 3-D characterization. In this dissertation, a direct measurement method for thicknesses, volumes or compositions of nanomaterials by quantitative atomic number contrast in High-Angle Annular Dark-Field (HAADF) Scanning Transmission Electron Microscopy (STEM) is presented. A HAADF detector collects electrons scattered incoherently to high angles. The HAADF signal intensity is in first-order approximation proportional to the sample thickness and increases with atomic number. However, for larger sample thicknesses this approach fails. A simple description for the thickness dependence of the HAADF-STEM contrast has been developed in this dissertation. A new method for the calibration of the sensitivity of the HAADF detector for a FEI F30 transmission electron microscope (TEM) is developed in this dissertation. A nearly linear relationship of the HAADF signal with the electron current is confirmed. Cross sections of multilayered samples provided by TriQuint Semiconductors in Apopka, FL, for contrast calibration were obtained by focused ion-beam (FIB) preparation yielding data on the interaction cross section per atom.To obtain an absolute intensity calibration of the HAADF-STEM intensity, Convergent Beam Electron Diffraction (CBED) was performed on Si single crystals. However, for samples prepared by the focused ion beam technique, CBED often significantly underestimates the sample thickness. Multislice simulations from Dr. Kirkland's C codes are used for comparison with experimental results. TEM offers high lateral resolution, but contains little or no information on the thickness of samples. Thickness maps in energy-filtered TEM (EFTEM), CBED and tilt series are so far the only methods to determine thicknesses of particles in TEM. In this work I have introduced the use of wedge-shaped multilayer samples prepared by FIB for the calibration of HAADF-STEM contrasts. This method yields quantitative contrast data as a function of sample thickness. A database with several pure elements and compounds has been compiled, containing experimental data on the fraction of electrons scattered onto the HAADF detector for each nanometer of sample thickness. The use of thick samples reveals an increased signal at the interfaces of high- and low-density materials. This effect can be explained by the transfer of scattered electrons from the high density material across the interface into the less-absorbing low-density material. The calibrations were used to determine concentration gradients in nanoscale Fe-Pt multilayers as well as thicknesses and volumes of individual Au-Fe, Pt, and Ag nanoparticles. Volumes of nanoparticles with known composition can be determined with accuracy better than 15%. Porosity determination of materials becomes available with this method as shown in an example of porous Silicon.?
Show less - Date Issued
- 2012
- Identifier
- CFE0004464, ucf:49355
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004464
- Title
- STUDIES ON THE NOVEL FUNCTION OF AMYLOID PRECURSOR PROTEIN IN GLIAL DIFFERENTIATION OF NEURAL STEM CELLS.
- Creator
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Kwak, Young-Don, Sugaya, Kiminobu, University of Central Florida
- Abstract / Description
-
Although amyloid beta (A beta) deposition has been a hallmark of Alzheimer's disease (AD), the physiological function of amyloid precursor protein (APP) is not clear. Our results suggested that high concentration of APP induces glial differentiation while physiological level of APP promotes migration and differentiation of neural stem cell (HNSC). HNSCs were mainly differentiated into astrocytes when they are transplanted into APP transgenic mouse brain or treated with a high...
Show moreAlthough amyloid beta (A beta) deposition has been a hallmark of Alzheimer's disease (AD), the physiological function of amyloid precursor protein (APP) is not clear. Our results suggested that high concentration of APP induces glial differentiation while physiological level of APP promotes migration and differentiation of neural stem cell (HNSC). HNSCs were mainly differentiated into astrocytes when they are transplanted into APP transgenic mouse brain or treated with a high concentration of secreted-type APP (sAPP) in culture. Staurosporine (STS) induced a distinctive astrocytic morphology in NT-2/D1 neural progenitor cells with expressions of APP and astrocyte-specific markers, glial fibrillary acidic protein (GFAP), aspartate transporter, and glutamate transporter-1. Expression of APP is correlated with GFAP expression in both mRNA and protein level in this experiment. Inhibition of APP expression by RNA interference (RNAi) or treatment with MEK1 inhibitor (PD098059), which reduces APP expression by suppressing ERK phosphorylation, abolished GFAP expression. These results indicate that STS induces glial differentiation of neuronal progenitor cells by increasing APP levels through activation of ERK pathway. We also found that APP-induced glial differentiation of neural progenitor NT-2/D1 cells is mediated by activation of IL-6/gp130 and notch signaling pathway. Treatment of APP activated IL-6/gp130 signal pathway via protein-protein interaction between APP and gp130 and it increased the gene expressions of CNTF, gp130 and JAK1, and phosphorylation of STAT3 while gene silencing of CNTF, JAK1 or STAT3 by RNAi, or treatment the cells with antibodies recognizing gp130 suppressed GFAP expression, indicating these molecules are crucial for APP-induced glial differentiation. Thus treatment of sAPP may promote glial differentiation of neural progenitor cells by activation of IL-6/gp130 signaling cascade. Treatment of sAPP increased the generation of notch intracellular domain as well as gene expression of Hes1 but did not change expression levels of notch or its ligands. We also found protein-protein interaction of APP and notch using immunoprecipitation suggesting that glial differentiation of NT-2/D1 cells is mediated by the physical interaction between APP and notch. N-terminal domain of APP (1-205 a.a.) alone can bind to notch and activate these signaling cascade in NT-2/D1 cells. Thus, APP may induce glial differentiation through activation of IL-6/gp130 and notch signal cascade by binding with its N-terminal domain. Taken together, our results suggest that APP regulates neural stem cell (NSC) differentiation through IL-6/gp130 and notch signaling pathway. Furthermore, the activation of both glial differentiation mechanisms may be necessary to potentiate APP-induced glial differentiation of NSC. Altered APP metabolism in Down syndrome and Alzheimer's disease may accelerate premature glial differentiation of NSCs, resulting in gliosis found in these diseases. Although it is not clear that how adult neurogenesis contributes to maintain normal brain function, destruction of neuroreplacement mechanism by NSCs may pose a problem. We may also have to consider effect of APP on the stem cell therapy for these diseases, since HNSCs may not properly differentiate into neurons under these pathological conditions.
Show less - Date Issued
- 2006
- Identifier
- CFE0001375, ucf:46980
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001375
- Title
- USER-DEFINED PATTERNING OF NEURAL PROGENITOR CELLS ON 3D MICROPILLAR ARRAYS USING ROUND CROSS-SECTIONAL GEOMETRY, SPECIFIC DIMENSIONS AND THIOL-BASED CHEMICAL ADHESION.
- Creator
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Wesser, Andrea, Cho, Hyoung Jin, University of Central Florida
- Abstract / Description
-
The ability to control stem cell functions, particularly neuronal progenitors, has long since been believed to be the key to successful treatment of neurodegenerative disorders such as Alzheimer's, Parkinson's and accidents involving head trauma. The neurology field calls for many new solutions to address the controlled neural stem cell seeding and placement of cells for neural tissue regeneration. Self-assembled monolayers (SAM) from the alkanethiol group provide a straightforward...
Show moreThe ability to control stem cell functions, particularly neuronal progenitors, has long since been believed to be the key to successful treatment of neurodegenerative disorders such as Alzheimer's, Parkinson's and accidents involving head trauma. The neurology field calls for many new solutions to address the controlled neural stem cell seeding and placement of cells for neural tissue regeneration. Self-assembled monolayers (SAM) from the alkanethiol group provide a straightforward applicable, reliable treatment for cell adhesion. An ODT/gold treatment was used to adhere the cells to patterned areas, due mainly to a high confluence of cells attracted to it, as well as the viable environment it produced for the cells. Arrays of micropillars, made of SU-8 photoresist, then covered with a thin film of gold and treated with the ODT, created scaffolding allowing manipulation of neural stem cells. Based on multiple trials of observing varying cross-sectional geometric parameters, metal layer thicknesses and the ODT/Gold treatment, this study explores seeding density control, base and circumferential cell population dependence on those parameters.
Show less - Date Issued
- 2008
- Identifier
- CFE0002054, ucf:47563
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002054
- Title
- THE ROLE OF ACTIVIN A SIGNALING IN GASTRIC REFLUX-RELATED DISEASES AND THE PROGRESSION TO ESOPHAGEAL ADENOCARCINOMA.
- Creator
-
Roudebush, Cedric J., Andl, Claudia, University of Central Florida
- Abstract / Description
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Gastroesophageal reflux disease (GERD), or acid reflux, affects 6-9 million people in the United States. It is characterized by a reflux of gastric acid and bile salts from the stomach into the esophagus, causing injuries to the esophagus known as Barrett's esophagus (BE). BE is the main risk factor for the development of esophageal adenocarcinoma (EAC), a devastating cancer in the esophagus whose molecular roots remain poorly understood. In recent years, evidence points to the esophageal...
Show moreGastroesophageal reflux disease (GERD), or acid reflux, affects 6-9 million people in the United States. It is characterized by a reflux of gastric acid and bile salts from the stomach into the esophagus, causing injuries to the esophagus known as Barrett's esophagus (BE). BE is the main risk factor for the development of esophageal adenocarcinoma (EAC), a devastating cancer in the esophagus whose molecular roots remain poorly understood. In recent years, evidence points to the esophageal epithelium itself as responsible for causing and promoting inflammation upon injury by gastric reflux, namely via an increase in inflammatory cytokine secretion. This project was focused on a cytokine of interest, Activin A, which is known for its importance during embryogenesis and stem cell differentiation. It has recently been studied for its role in inflammation and tumor formation, but not in the case of esophageal diseases. Here, we demonstrate that Activin A signaling in esophageal epithelial cells is heavily upregulated shortly after exposure to bile salts and acid. We show evidence that this upregulation causes an increase in cell migration upon a reconstituted extracellular matrix. We also provide further evidence that bile and acid injury causes epithelial cells to secrete cytokines, which drive inflammation. We show that the upregulated Activin A secretion and signaling plays an important role in promoting this inflammatory state. Finally, we provide evidence that bile salts and acid exposure, as well as increased Activin A signaling, causes esophageal epithelial cells to upregulate stem cell and transdifferentiation markers, supporting the latest theories on the origin of Barrett' esophagus stem cells as well as paligenosis.
Show less - Date Issued
- 2019
- Identifier
- CFH2000485, ucf:45887
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000485
- Title
- IMPLEMENTING GROWTH MINDSET PRINCIPLES FOR GIRLS IN STEM ELEMENTARY CLASSROOMS THROUGH THE CREATION OF A CHILDREN'S BOOK.
- Creator
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Van Westering, Jessica, Buchoff, Rita, University of Central Florida
- Abstract / Description
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With an emphasis on STEM education in schools, young girls begin to have an idea that math and science skills are based on one's natural ability. A fixed mindset is the belief that one possesses an ability that comes naturally. Many girls, starting at the elementary level tend to interpret a lack of skill for being dumb, and therefore, give up on difficult subjects like math and science. On the other hand, a fluid theory of intelligence, or growth mindset is when a student values effort and...
Show moreWith an emphasis on STEM education in schools, young girls begin to have an idea that math and science skills are based on one's natural ability. A fixed mindset is the belief that one possesses an ability that comes naturally. Many girls, starting at the elementary level tend to interpret a lack of skill for being dumb, and therefore, give up on difficult subjects like math and science. On the other hand, a fluid theory of intelligence, or growth mindset is when a student values effort and understands that these "abilities" come from hard work and taking on new challenges. Students in a growth mindset see intelligence as something that can be developed overtime, while every learning opportunity, challenge, and failure is seen as an important step to becoming more knowledgeable. As a teacher, promoting a growth mindset in the classroom is key for student success; praising and encouraging students through the process of learning is more valuable then giving a grade for the final product. This thesis not only researched the differences between a growth versus fixed mindset, but also the value of fluid theories of intelligence, and the effects on elementary aged girls. This thesis includes a children's book that promotes the idea of a growth mindset with a protagonist who learns to see the importance of persevering, working hard, and attaining success. With the picturebook intended for elementary aged students, its hope is to bring awareness to students and teachers that having a growth mindset mentality is important.
Show less - Date Issued
- 2016
- Identifier
- CFH2000089, ucf:45505
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000089
- Title
- THE LABEL OF MADNESS: THE EFFECTS OF CAREER CHOICE AND GENDER ON PERCEPTIONS OF MENTAL ILLNESS.
- Creator
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Vanella, Angela, Whitten, Shannon, University of Central Florida
- Abstract / Description
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People with creative abilities have often been stereotyped as insane, neurotic, and prone to addiction (Kaufman, Bromley, & Cole, 2006; Corrigan, 2005). These labels have perpetuated the stigma for many generations (Ludwig, 1995). In addition, females have often been stereotyped as "bad at math," but are assumed to be more verbal and creative (Quinn & Spencer, 2001). The present study hypothesized that creative writers would be stereotyped as more mentally ill, neurotic, and addicted to...
Show morePeople with creative abilities have often been stereotyped as insane, neurotic, and prone to addiction (Kaufman, Bromley, & Cole, 2006; Corrigan, 2005). These labels have perpetuated the stigma for many generations (Ludwig, 1995). In addition, females have often been stereotyped as "bad at math," but are assumed to be more verbal and creative (Quinn & Spencer, 2001). The present study hypothesized that creative writers would be stereotyped as more mentally ill, neurotic, and addicted to substances compared to scientists. It was also predicted that gender would exacerbate the phenomenon such that females would be particularly vulnerable to this stereotype. Statistical analyses revealed some interesting gender by major interactions: female creative writers were perceived as the most mentally ill, but were closely followed by male science majors. Male creative writers were actually perceived to have a relatively low level of mental illness. Interestingly, male scientists were rated as having the highest levels of drug and alcohol abuse, whereas male creative writers were perceived to have relatively fewer symptoms of substance abuse. The reverse pattern was true for females. This research confirmed the stereotype of insanity among artists for females but also revealed a tendency towards pathology-based stereotyping of male scientists. Stereotypes negatively affect the targeted populations and perpetuate the stigmas against them. This research attempted to advance understanding as an initial step towards alleviating unwarranted stereotypes.
Show less - Date Issued
- 2013
- Identifier
- CFH0004384, ucf:44983
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004384
- Title
- Embryonic Stem Cell-Derived Exosomes Inhibit Doxorubicin-Induced Pyroptosis in Cell Culture Models.
- Creator
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Tavakoli Dargani, Zahra, Singla, Dinender, Masternak, Michal, Siddiqi, Shadab, Steward, Robert, University of Central Florida
- Abstract / Description
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Doxorubicin (Dox) is a potent chemotherapeutic drug used for the treatment of various cancers. Unfortunately, its use is limited as Dox induces adverse cardiotoxicity (DIC) and muscle toxicity (DIMT), which are mediated through oxidative stress, ER stress, and inflammation. However, it remains unknown whether Dox induces an inflammation mediated cell death, called (")pyroptosis("). The current study is designed to determine whether Dox induces pyroptosis in cardiac and muscle cell culture...
Show moreDoxorubicin (Dox) is a potent chemotherapeutic drug used for the treatment of various cancers. Unfortunately, its use is limited as Dox induces adverse cardiotoxicity (DIC) and muscle toxicity (DIMT), which are mediated through oxidative stress, ER stress, and inflammation. However, it remains unknown whether Dox induces an inflammation mediated cell death, called (")pyroptosis("). The current study is designed to determine whether Dox induces pyroptosis in cardiac and muscle cell culture models. Moreover, the protective effects of embryonic stem cell-derived exosomes (ES-Exos) in inhibiting pyroptosis will also be determined. For this purpose, we designed two different cell culture models using H9c2 cadiomyoblasts and Sol 8 cells. For the DIC model, H9c2 were exposed to Dox to induce pyroptosis and then treated with exosomes. Cells were divided into 4 groups: Control, Dox, Dox+ES-Exos, and Dox+MEF-Exos (negative control). Furthermore, to generate the DIMT model, Sol 8 cells were incubated with Dox+THP-1 conditioned medium (TCM) to induce toxicity and inflammation, which was followed by exosomes treatment. We assigned cells into 5 groups: Control, Dox+TCM, Dox+TCM+ES-Exos, Dox+TCM+MEF-Exos (negative control), and Dox+TCM+ES-Exos+GW4869 compound (exosomes inhibitor, negative control). Our data shows that Dox treatment significantly increased pyroptotic marker expression including TLR-4, NLRP3, caspase-1, IL1-?, Caspase-11, and gasdermin-D as well as increased pro-inflammatory TNF-? and IL-6 expression in H9c2 cells. There was also a significant increase in caspase-1, IL1-?, and IL-18 expression in Dox+TCM treated Sol 8 cells. Conversely, increased pyroptosis and inflammation post-Dox treatment were inhibited by ES-Exos in both culture models. No significant changes observed upon MEF-Exos and GW4869 compound treatments. In conclusion, our data shows Dox induces pyroptosis and inflammation within cardiac and skeletal muscle cells, which can be inhibited following treatment with ES-exosomes. This is a novel study with new mechanistic observations on the pathophysiological role of pyroptosis in Dox-induced cardio and muscle toxicities.
Show less - Date Issued
- 2018
- Identifier
- CFE0007416, ucf:52700
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007416
- Title
- Regulation of Extra-Pituitary Prolactin in Monocytes and Macrophages.
- Creator
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Barrett, Richard, Parthasarathy, Sampath, McKinstry, Karl, Masternak, Michal, Zhao, Jihe, University of Central Florida
- Abstract / Description
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Recently it has been shown that leukocytes are capable of producing prolactin (PRL). Evidence of extra-pituitary PRL (ePRL) production is so far been limited to primates and is not shared across other mammal species such as mice and rats. While ePRL is characterized as an identical protein to traditional pituitary PRL, it is controlled under an alternative promoter and is thus regulated differently from pituitary PRL. Little is known about what regulates ePRL or its direct role in human...
Show moreRecently it has been shown that leukocytes are capable of producing prolactin (PRL). Evidence of extra-pituitary PRL (ePRL) production is so far been limited to primates and is not shared across other mammal species such as mice and rats. While ePRL is characterized as an identical protein to traditional pituitary PRL, it is controlled under an alternative promoter and is thus regulated differently from pituitary PRL. Little is known about what regulates ePRL or its direct role in human physiology, but given that PRL has well over 300 described functions, it is likely that the autocrine and paracrine effects of this hormone could have far reaching implications in overall physiology. This work takes some of the first steps in understanding how leukocyte ePRL is regulated. Our results show that, adrenergic hormones are one key stimulus in ePRL expression in monocytes/macrophages. This is particularly intriguing considering the opposing role of these two signals in settings such as adipose tissue where adipose tissue macrophages are constantly exposed to pro-lipolytic adrenergic hormones that would in turn stimulate production of an anti-lipolytic hormone, PRL. Further, our work shows that the inflammatory phenotype of the leukocytes influences basal expression of PRL and overall ePRL expression increases significantly as monocytes differentiate into macrophages, as is a common occurrence in adipose tissue. The final portion of our work shows how monocytes/macrophages also respond to preadipocytes directly. These stem cell precursors to mature adipose cells release an unknown factor that stimulates ePRL production in monocytes/macrophages. Analysis of our gene array shows many of the genes stimulated by adipose stem cells alongside PRL are important genes in tissue regeneration and remodeling, a possible role that fits well with known effects of PRL. Understanding such primate specific interactions between the immune system and major metabolic tissues such as adipose fills vital gaps in knowledge that may explain why so many treatments fail when transitioning from mouse models to humans.
Show less - Date Issued
- 2018
- Identifier
- CFE0007309, ucf:52164
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007309
- Title
- The Relationship of Computer Science Immersion in Elementary Schools to Achievement of High Poverty Students.
- Creator
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Erickson, Keith, Taylor, Rosemarye, Ceballos, Marjorie, Gordon, William, Clark, M. H., University of Central Florida
- Abstract / Description
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The purpose of this study was to determine if a relationship existed between the implementation of a computer science immersive learning experience and achievement on the Florida Standards Assessment (FSA) English Language Arts (ELA) or the FSA Mathematics. Two research questions, each with two sub-questions, guided the research of the study. The sub-questions addressed historically underrepresented groups in computer science. These subgroups included African Americans, Hispanics, Mixed Race...
Show moreThe purpose of this study was to determine if a relationship existed between the implementation of a computer science immersive learning experience and achievement on the Florida Standards Assessment (FSA) English Language Arts (ELA) or the FSA Mathematics. Two research questions, each with two sub-questions, guided the research of the study. The sub-questions addressed historically underrepresented groups in computer science. These subgroups included African Americans, Hispanics, Mixed Race individuals, and females. Research Question 1 analyzed the relationship between the implementation of the computer science immersive learning experience when a cohort control group design was used. Research Question 2 determined if a relationship existed when the treatment schools were compared to demographically similar schools that did not receive the treatment of computer science immersion. A two-way analysis of variances (ANOVA) was run for each of the research questions with the subgroups of students used as moderators for the treatment. Statistical significance was found for the following groups; fourth grade ELA Hispanic cohort, fourth grade Hispanic mathematics cohort, third grade ELA cohort, third grade mathematics cohort, the ELA treatment group, and the mathematics treatment group. Statistically significant findings showed negative, positive, and neutral effects on the treatment groups. These findings provide implications for the implementation of computer science immersion in other elementary schools with similar student demographic variables. Further investigation is needed to determine other potential impacts on student achievement over time.
Show less - Date Issued
- 2019
- Identifier
- CFE0007627, ucf:52559
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007627
- Title
- TRANSPLANTATION OF IPS CELLS REDUCES APOPTOSIS AND FIBROSIS AND IMPROVES CARDIAC FUNCTION IN STREPTOZOTOCIN-INDUCED DIABETIC RATS.
- Creator
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Neel, Sarah, Singla, Dinender, University of Central Florida
- Abstract / Description
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Background: Streptozotocin (STZ) induced diabetes leads to various complications including cardiomyopathy. Recent data suggests transplanted bone marrow stem cells improve cardiac function in diabetic cardiomyopathy. However, whether modified ES, iPS cells, or factors released from these cells can inhibit apoptosis and fibrosis remains completely unknown. The present study was designed to determine the effects of transplanted ES cells overexpressing pancreatic transcription factor 1 a (Ptf1a)...
Show moreBackground: Streptozotocin (STZ) induced diabetes leads to various complications including cardiomyopathy. Recent data suggests transplanted bone marrow stem cells improve cardiac function in diabetic cardiomyopathy. However, whether modified ES, iPS cells, or factors released from these cells can inhibit apoptosis and fibrosis remains completely unknown. The present study was designed to determine the effects of transplanted ES cells overexpressing pancreatic transcription factor 1 a (Ptf1a), a pro-pancreatic endodermal transcription factor, iPS cells, or their respective conditioned media (CM) on diabetic cardiomyopathy. Methods: Experimental diabetes was induced in male Sprague Dawley rats (8-10 weeks old) by intraperitoneal STZ injections (65 mg/kg body weight for 2 consecutive days). Animals were divided into six experimental groups including control, treated with sodium citrate buffer IP, STZ, STZ + ES-Ptf1a cells, STZ + iPS cells, STZ + ES-Ptf1a CM and STZ + iPS CM. Following STZ injections, appropriate cells (1 X 106/mL/injection/day) or CM (2 mL injection/day) were given intravenously for 3 consecutive days. Animals were sacrificed and hearts were harvested at day 28. Histology, TUNEL staining, and Caspase-3 activity were used to assess apoptosis and fibrosis. ERK1/2 phosphorylation was quantified using ELISAs. M-mode echocardiography fractional shortening was used to assess cardiac function. Results: Animals transplanted with ES cells, iPS cells, or both CMs showed a significant (p<0.05) reduction in interstitial fibrosis, and apoptosis compared with STZ group. ERK expression was not significantly different compared with STZ. Echocardiography showed a significant (p<0.05) improvement in fractional shortening in cell and media transplanted groups compared with STZ. Conclusions: Our data suggest that ES cells, iPS cells, and/or CMs inhibit apoptosis, reduce fibrosis, and improve cardiac function in STZ-treated diabetic rats.
Show less - Date Issued
- 2010
- Identifier
- CFE0003512, ucf:48964
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003512
- Title
- Project iCAN: A STEM Learning and Persistence Model for Postsecondary Students with Disabilities.
- Creator
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Koch, Aaron, Vasquez, Eleazar, Dieker, Lisa, Marino, Matthew, Raij, Andrew, University of Central Florida
- Abstract / Description
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Education and work in Science, Technology, Engineering, (&) Math (STEM) are of utmost importance in a post-modern society. Yet American performance in the STEM disciplines has waned over recent years. In order to recapture a global advantage in STEM, efforts are being made by educators and policy makers to compile and implement instructional supports. Of particular interest to this study are post-secondary students with disabilities (SWDs) who persist and learn in STEM degree paths. This...
Show moreEducation and work in Science, Technology, Engineering, (&) Math (STEM) are of utmost importance in a post-modern society. Yet American performance in the STEM disciplines has waned over recent years. In order to recapture a global advantage in STEM, efforts are being made by educators and policy makers to compile and implement instructional supports. Of particular interest to this study are post-secondary students with disabilities (SWDs) who persist and learn in STEM degree paths. This population is an (")untapped resource(") with limitless potential for contribution to the collective fields of STEM (Leddy, 2010, p. 3; Alston, Hampton, Bell, (&) Strauss, 1998, p. 5). The National Science Foundation (NSF) has funded Project Interdisciplinary Coaching as a Nexus for Transforming How Institutions Support Undergraduates in STEM (Project iCAN) at Landmark College as a model to develop a successful STEM support model. Post hoc interview data from students and staff at Landmark revealed themes pertaining to educational and vocational-training supports that may generalize to larger, urban institutions of higher education for further development of STEM persistence and learning models.
Show less - Date Issued
- 2016
- Identifier
- CFE0006340, ucf:51564
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006340
- Title
- Predicting Undergraduate Retention in STEM Majors Based on Demographics, Math Ability, and Career Development Factors.
- Creator
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Belser, Christopher, Shillingford-Butler, Ann, Van Horn, Stacy, Taylor, Dalena, Daire, Andrew, Witta, Eleanor, University of Central Florida
- Abstract / Description
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Science, technology, engineering, and math (STEM) fields are currently facing a crisis with respect to filling jobs with qualified workers (NSF, 2013; NAS, 2011). While advancements in these industries have translated into job growth, post-secondary declaration and retention rates within STEM majors lag behind industry needs (Carnevale et al., 2011; Chen, 2013; Koenig et al., 2012). Although researchers previously investigated demographic variables and math-related variables in the context of...
Show moreScience, technology, engineering, and math (STEM) fields are currently facing a crisis with respect to filling jobs with qualified workers (NSF, 2013; NAS, 2011). While advancements in these industries have translated into job growth, post-secondary declaration and retention rates within STEM majors lag behind industry needs (Carnevale et al., 2011; Chen, 2013; Koenig et al., 2012). Although researchers previously investigated demographic variables and math-related variables in the context of STEM retention (Beasley (&) Fischer, 2012; CollegeBoard, 2012; Cundiff et al., 2013; Gayles (&) Ampaw, 2014; Le et al., 2014; Nosek (&) Smyth, 2011; Riegle-Crumb (&) King, 2010), the need exists for additional research examining the impact of career-related variables (Belser et al., 2017; Folsom et al., 2004; Parks et al., 2012; Reardon et al., 2015). Additionally, prior STEM retention research primarily focused on students with declared STEM majors, as opposed to undeclared students considering STEM majors. In the present study, the researcher sought to determine the degree to which demographic variables (gender and ethnicity), math ability variables (SAT Math scores and Math Placement Test--Algebra scores), and career development related variables (initial major, STEM course participation, and Career Thoughts Inventory [CTI] change scores) could predict undergraduate retention in STEM for participants in a STEM recruitment and retention program. Using binary logistic regression, the researcher found that initially having a declared STEM major was the best predictor of STEM retention. Higher scores on math variables consistently predicted higher odds of STEM success, and the data revealed higher odds of STEM retention for ethnic minority students. Gender only showed to be a significant predictor of STEM attrition with the undecided students with first-to-third year retention. Finally, larger decreases in CTI scores predicted increased odds of STEM retention. Implications from the findings relate to a variety of professionals from higher education, counseling, and research. The findings provide guidance and new perspectives on variables associated with better rates of STEM retention, and as such, inform STEM initiatives targeting undergraduate STEM recruitment and retention.
Show less - Date Issued
- 2017
- Identifier
- CFE0006565, ucf:51326
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006565