Feed-Forward Inhibitory Circuits In Hippocampus And Their Computational Role In Fragile X Syndrome,
2016
Washington University in St. Louis
Feed-Forward Inhibitory Circuits In Hippocampus And Their Computational Role In Fragile X Syndrome, Sarah Lauren Wahlstrom Helgren
McKelvey School of Engineering Graduate Student Theses & Dissertations
Feed-forward inhibitory (FFI) circuits are canonical neural microcircuits. They are unique in that they are comprised of excitation rapidly followed by a time-locked inhibition. This sequence provides for a powerful computational tool, but also a challenge in the analysis and study of these circuits. In this work, mechanisms and computations of two hippocampal FFI circuits have been examined. Specifically, the modulation of synaptic strength of the excitation and the inhibition is studied during constant-frequency and naturalistic stimulus patterns to reveal how FFI circuit properties and operations are dynamically modulated during ongoing activity. In the first part, the FFI circuit dysfunction …
Focal Adhesion Kinase Regulation In Stem Cell Alignment And Spreading On Nanofibers,
2016
University of Nebraska-Lincoln
Focal Adhesion Kinase Regulation In Stem Cell Alignment And Spreading On Nanofibers, Mohammad Nahid Andalib, Jeong Soon Lee, Ligyeom Ha, Yuris A. Dzenis, Jung Yul Lim
Department of Mechanical and Materials Engineering: Faculty Publications
While electrospun nanofibers have demonstrated the potential for novel tissue engineering scaffolds, very little is known about the molecular mechanism of how cells sense and adapt to nanofibers. Here, we revealed the role of focal adhesion kinase (FAK), one of the key molecular sensors in the focal adhesion complex, in regulating mesenchymal stem cell (MSC) shaping on nanofibers. We produced uniaxially aligned and randomly distributed nanofibers from poly(L-lactic acid) to have the same diameters (about 130 nm) and evaluated MSC behavior on these nanofibers comparing with that on flat PLLA control. C3H10T1/2 murine MSCs exhibited upregulations in FAK expression and …
Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices,
2016
University of Arkansas, Fayetteville
Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices, Avery M. Hill
Physics Undergraduate Honors Theses
Plasmonic nanostructures have been shown to act as optical antennas that enhance optical devices due to their ability to focus light below the diffraction limit of light and enhance the intensity of the incident light. This study focuses on computational electromagnetic (CEM) analysis of two devices: 1) GaAs photodetectors with Au interdigital electrodes and 2) Au thin-film microstructures. Experiments showed that the photoresponse of the interdigital photodetectors depend greatly on the electrode gap and the polarization of the incident light. Smaller electrode gap and transverse polarization give rise to a larger photoresponse. It was also shown that the response from …
Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices,
2016
University of Arkansas, Fayetteville
Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices, Avery M. Hill
Mechanical Engineering Undergraduate Honors Theses
Plasmonic nanostructures have been shown to act as optical antennas that enhance optical devices due to their ability to focus light below the diffraction limit of light and enhance the intensity of the incident light. This study focuses on computational electromagnetic (CEM) analysis of two devices: 1) GaAs photodetectors with Au interdigital electrodes and 2) Au thin-film microstructures. Experiments showed that the photoresponse of the interdigital photodetectors depend greatly on the electrode gap and the polarization of the incident light. Smaller electrode gap and transverse polarization give rise to a larger photoresponse. It was also shown that the response from …
Atomic Force Microscopy Based Dna Analysis,
2016
University of Arkansas, Fayetteville
Atomic Force Microscopy Based Dna Analysis, Drew Creighton
Mechanical Engineering Undergraduate Honors Theses
This report explores dry and wet scanning of a surface and DNA pickup using an AFM, as well as fluorescent staining of DNA. Dry and wet scans of DNA were obtained using a cantilever AFM tip in tapping mode. Dry scans were found to be clearer than wet scans; however, the drying process was found to decrease the thickness of DNA 2–4 times less than its original thickness. Alternately, wet scans were found to be less clear than dry scans and introduced more noise into the images obtained. Additionally, DNA kept its initial thickness during wet scanning. DNA was capable …
Nanoscale Frictional Properties Of Nickel With One-Dimensional And Two-Dimensional Materials,
2016
University of Arkansas, Fayetteville
Nanoscale Frictional Properties Of Nickel With One-Dimensional And Two-Dimensional Materials, Timothy K. Schlenger
Mechanical Engineering Undergraduate Honors Theses
When looking at the nanoscale, material interface interactions have been observed to exhibit particularly interesting properties. Our research looks into various combinations of carbyne and graphene atop a nickel block to look into the interface friction properties between them. Both the carbyne and graphene are tested using steered molecular dynamics (SMD) in sheering and peeling directions along the surface of the nickel block. These tests are then analyzed by comparing the magnitude of the acting force versus the displacement of the carbon allotrope sample across the nickel block. It is found that as the width of a carbon allotrope sample …
Development And Characterization Of Adhesive Hydrogels For Stem Cell Culture,
2016
University at Albany, State University of New York
Development And Characterization Of Adhesive Hydrogels For Stem Cell Culture, Erin Byrne Rousseau
Nanoscale Science & Engineering (discontinued with class year 2014)
Pluripotent embryonic stem cells (ESCs) offer the unique capacity to differentiate into almost any cell type and have sweeping implications in both basic research and clinical applications. However, unregulated differentiation can cause issues, preventing ESCs from entering clinical research. In order to maximize ESC growth, three dimensional culturing has been utilized in order to have results more similar to in vivo conditions. In the case of alginate scaffolds, cell adhesion sites are missing from the matrix, leading to differentiation. We propose that the inclusion of adhesive polymer to the alginate scaffold will increase cell attachment and maintain pluripotency. The polymer …
Optimization And Modeling Of An Energy Harvesting Optical Micropropeller For Microfluidic Applications,
2016
University at Albany, State University of New York
Optimization And Modeling Of An Energy Harvesting Optical Micropropeller For Microfluidic Applications, Jacqueline Elwood
Nanoscale Science & Engineering (discontinued with class year 2014)
The design and materials optimization of a optical micropropeller comprised of silver nanorods on a fused silica substrate was developed. A combination of surface plasmon resonance, thermophoretic and convective forces enable rotation of the micropropeller in an aqueous environment. This work aims to eliminate the dependence of optical micropropellers on the requirement for a light source by relying on a blackbody radiation energy harvesting principle. This energy harvesting principle is able to plasmonically excite noble metal nanorods of a specific aspect ratio at specific wavelengths that correspond to an ambient temperature. By investigating the dependence of the aspect ratio and …
Optimization And Modeling Of An Energy Harvesting Optical Micropropeller For Microfluidic Applications,
2016
University at Albany, State University of New York
Optimization And Modeling Of An Energy Harvesting Optical Micropropeller For Microfluidic Applications, Jerry Shih
Nanoscale Science & Engineering (discontinued with class year 2014)
Geometry for a plasmonically active micro-propeller is designed in Matlab using a Metallic Nano-Particle Boundary Element Method (MNPBEM) toolbox in order to predict its optical response in long wavelengths of electromagnetic radiation. Electric field maps are plotted to determine the feasibility generating torque using the energy harvesting principle. Results indicate electric field lines that would promote rotation and the scattering cross section would cause nano-rods sitting on the propeller to radiate thermal energy. COMSOL modeling is performed to model the evolution natural convection currents as a result of the nano-rod heating which is then optimized to further promote rotation of …
Predicting Structures And Properties Of Transition Metal Dichalcogenide Alloys Using Density Functional Theory,
2016
University at Albany, State University of New York
Predicting Structures And Properties Of Transition Metal Dichalcogenide Alloys Using Density Functional Theory, Lucas R. Bruzgulis
Nanoscale Science & Engineering (discontinued with class year 2014)
Workflows for computationally simulating transition metal dichalcogenides using density functional theoretic methods and cluster expansion were established, as implemented in the Quantum ESPRESSO and Alloy Theoretic Automated Toolkit computer codes, respectively. Effects of energy cutoff values and k-point density on convergence of DFT results were investigated for the MoS2 structure, and theoretic band structure calculations for MoS2 and WS2 were performed. The MoXW(1-X)S2 alloy system was also investigated using the maps code in the Alloy Theoretic Automated Toolkit in order to generate a composition vs energy plot. The application of Special Quasi-random Structures to further research into TMDC alloy systems …
Phase-Field Models For Simulating Physical Vapor Deposition And Microstructure Evolution Of Thin Films,
2016
University of Arkansas, Fayetteville
Phase-Field Models For Simulating Physical Vapor Deposition And Microstructure Evolution Of Thin Films, James Stewart Jr.
Graduate Theses and Dissertations
The focus of this research is to develop, implement, and utilize phase-field models to study microstructure evolution in thin films during physical vapor deposition (PVD). There are four main goals to this dissertation. First, a phase-field model is developed to simulate PVD of a single-phase polycrystalline material by coupling previous modeling efforts on deposition of single-phase materials and grain evolution in polycrystalline materials. Second, a phase-field model is developed to simulate PVD of a polymorphic material by coupling previous modeling efforts on PVD of a single-phase material, evolution in multiphase materials, and phase nucleation. Third, a novel free energy functional …
Non-Directional Conjugation Of Fluorescent Antibodies To Gold Nanoparticles For Stem Cell Therapy,
2016
University of Arkansas, Fayetteville
Non-Directional Conjugation Of Fluorescent Antibodies To Gold Nanoparticles For Stem Cell Therapy, Kunal B. Shah
Biomedical Engineering Undergraduate Honors Theses
The objective of this study was to design citrate-coated gold nanoparticles conjugated with FITC-IgG, a fluorescent antibody, and to qualitatively and quantitatively measure the resulting fluorescent emission. Optical properties of the gold nanoparticles were measured at various stages to provide evidence of successful conjugation. The absorbance spectrum of the citrate gold nanoparticles was compared to that of the reaction mixture containing the gold nanoparticles and the FITC-IgG. A noticeable broadening of the absorption peak was observed at 519 nm indicating a surface modification of the gold nanoparticles. Fluorescence data was obtained with a fluorospectrometer and revealed a significant amount of …
Gold Nanoparticle Colorimetric Sensing Technology,
2016
University at Albany, State University of New York
Gold Nanoparticle Colorimetric Sensing Technology, Eve Borden
Nanoscale Science & Engineering (discontinued with class year 2014)
No abstract provided.
Size Controlled Formation Of A Collagen-Based Drug Delivery System,
2016
University at Albany, State University of New York
Size Controlled Formation Of A Collagen-Based Drug Delivery System, Leonardo Bezerra
Nanoscale Science & Engineering (discontinued with class year 2014)
This study investigates and troubleshoots various factors involved in the generation of collagen-based particles, such as volume of solution, temperature, and incubation time for the purposes of a potential colorectal cancer targeting drug vehicle. The particles were generated via loading into a gel mold and show a 20-200 fold decrease in size compared to those created only under chemical means.
Fundamental Interdiffusion Analysis Of Ruthenium And Cobalt Films,
2016
University at Albany, State University of New York
Fundamental Interdiffusion Analysis Of Ruthenium And Cobalt Films, Bartlet Deprospo
Nanoscale Science & Engineering (discontinued with class year 2014)
No abstract provided.
Graphene’S Electronic Surface States On Metal Substrates,
2016
University at Albany, State University of New York
Graphene’S Electronic Surface States On Metal Substrates, Alex De Palma
Nanoscale Science & Engineering (discontinued with class year 2014)
Graphene is a 2-‐D sheet of sp2 bonded carbon atoms with exceptional electrical properties. Particularly, graphene has a very high carrier mobility (~200,000 cm2/V·∙s). This is largely due to graphene’s unique electronic structure, wherein charge carriers are effectively massless Dirac fermions. However, the unique electronic structure of graphene has been shown to be affected by the underlying substrate. In this study, we characterize the electronic structure of graphene on copper. Electron energy loss spectroscopy is employed to observe the surface plasmon excitations of graphene. A small pi plasmon excitation is observed, suggesting that the graphene/Cu interaction is weak and non-‐covalent. …
Modeling Secondary Electron Trajectories In Scanning Electron Microscopes,
2016
University at Albany, State University of New York
Modeling Secondary Electron Trajectories In Scanning Electron Microscopes, Kevin Mcnamara, Joshua Miller
Nanoscale Science & Engineering (discontinued with class year 2014)
The efficiency of secondary electron collection by a scanning electron microscope detector is not generally known, particularly as the electric field on the detector is varied. It is often assumed that the detector collects almost all of the secondary electrons emitted from the sample. This works seeks to better understand the mechanism of secondary electron collection by the detector in order to optimize collection efficiency. The benefit of collecting more secondary electrons is the enhancement of the signal-to-noise ratio, which means better quality images can be obtained, allowing us to better understand the relationship between secondary electron images and the …
Modeling Secondary Electron Trajectories In Scanning Electron Microscopes,
2016
University at Albany, State University of New York
Modeling Secondary Electron Trajectories In Scanning Electron Microscopes, Joshua Miller, Kevin Mcnamara
Nanoscale Science & Engineering (discontinued with class year 2014)
The efficiency of secondary electron collection by a scanning electron microscope detector is not generally known, particularly as the electric field on the detector is varied. It is often assumed that the detector collects almost all of the secondary electrons emitted from the sample. This works seeks to better understand the mechanism of secondary electron collection by the detector in order to optimize collection efficiency. The benefit of collecting more secondary electrons is the enhancement of the signal-to-noise ratio, which means better quality images can be obtained, allowing us to better understand the relationship between secondary electron images and the …
Direct Band Gap Gallium Antimonide Phosphide (Gasbxp1-X) For Solar Fuels.,
2016
University of Louisville
Direct Band Gap Gallium Antimonide Phosphide (Gasbxp1-X) For Solar Fuels., Harry Benjamin Russell
Electronic Theses and Dissertations
Photoelectrochemical water splitting has been identified as a promising route for achieving sustainable energy future. However, semiconductor materials with the appropriate optical, electrical and electrochemical properties have yet to be discovered. In search of an appropriate semiconductor to fill this gap, GaSbP, a semiconductor never tested for PEC performance is proposed here and investigated. Density functional theory (DFT+U) techniques were utilized to predict band gap and band edge energetics for GaSbP alloys with low amount of antimony. The overall objective of this dissertation is to understand the suitability of GaSbxP1-x alloys for photoelectrochemical water splitting application. Specifically, …
Acceleration Of Ddscat Computation By Parallelization On A Supercomputer,
2016
University of Arkansas, Fayetteville
Acceleration Of Ddscat Computation By Parallelization On A Supercomputer, Manoj V. Seeram
Chemical Engineering Undergraduate Honors Theses
The DDSCAT software is enabled for use of MPI or OpenMP to distribute calculation of different particle orientations amongst multiple processors on a high performance system. Run times for these simulations have been tested to take hours or days however and simulating varying orientations is not always necessary. If a simulation with only one particle orientation is submitted, DDSCAT could still potentially parallelize the simulation by wavelength calculations but it is unknown if this is the case. In this paper, we will be (i) quantifying the reduction in computation time that MPI provides relative to an equivalent MPI disabled simulation …
