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Characterization Of The Atcc Α-Tc1-6 Pancreatic Alpha Cell Line To Study Glucagon Secretion, Larissa M. Ikenouye 2017 University of Denver

Characterization Of The Atcc Α-Tc1-6 Pancreatic Alpha Cell Line To Study Glucagon Secretion, Larissa M. Ikenouye

Electronic Theses and Dissertations

The endocrine pancreas is responsible for maintaining glycemic equilibrium in the body. Given the importance of this blood-glucose homeostasis and the implication an unbalance has on Diabetes mellitus, the study of the glucose-sensing alpha and beta cells in the pancreas is a popular field for scientific researchers. In this study, we use immunofluorescence, qPCR analysis, intracellular calcium experiments, and biochemical glucagon secretion assays to determine if the commercially available tumor cell line clone, α-TC1-6 obtained from American Type Culture Collection, is an appropriate model system for glucagon secretion in pancreatic alpha cells. We confirm the production of the hormone peptide ...


Assembly Of Particles Onto Rigid Cylinders And Flexible Membranes: Probing Effects Of Surface Curvature And Deformation, Derek Wood 2017 University of Massachusetts Amherst

Assembly Of Particles Onto Rigid Cylinders And Flexible Membranes: Probing Effects Of Surface Curvature And Deformation, Derek Wood

Doctoral Dissertations

In this thesis we explore two specific topics within the broad field of particle adhesion. First, we examine the effect of substrate shape and geometry on the self assembly of adsorbed particles, by performing molecular dynamics simulations of interacting particles constrained to the surface of cylinders of varying diameters. We find the diameter of the cylinder imposes a constraint on the shape and crystallographic orientation of the self-assembled lattice, essentially determining the optimal arrangement of particles a priori. We propose a simple one-dimensional model to explain the optimal arrangement of particles as a function of the particle interaction potential and ...


Conducting Polyelectrolyte Complexes: Assembly, Structure, And Transport, Michael A. Leaf 2017 University of Massachusetts Amherst

Conducting Polyelectrolyte Complexes: Assembly, Structure, And Transport, Michael A. Leaf

Doctoral Dissertations

Decades of progress have yielded a tremendous variety of organic electronics, with great strides in the development of photovoltaics, thermoelectrics and other flexible devices. Ubiquitous in these research areas are films of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) (PEDOT: PSS), a complex of oppositely-charged polyelectrolytes initially suspended in water before film formation. This material has high electronic conductivity and good water processability. Pristine film conductivity is somewhat low, but is dramatically enhanced through simple treatments like ionic liquid addition or shear. Can this enhancement be understood so that further optimization might render PEDOT: PSS commercially viable? PEDOT: PSS is a ...


Mri-Based Susceptibility Mapping For In-Vivo Iron And Blood Oximetry Measurements, Hannah Erdevig 2017 University of Colorado, Boulder

Mri-Based Susceptibility Mapping For In-Vivo Iron And Blood Oximetry Measurements, Hannah Erdevig

Undergraduate Honors Theses

MRI is increasingly used in mapping tissue susceptibility to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as Parkinson's and Alzheimer's disease [1,2]. Accurate measurement is important for determining oxygen and iron content in blood vessels and tissue in the brain, which are in turn used for noninvasive clinical diagnosis and treatment assessments. Magnetic field distortions with a resolution of a few parts per billion can be measured using MRI phase maps. The field distortion map can then be inverted to obtain a quantitative susceptibility map. The primary ...


Liquid Crystal Phase Behavior Of A Dna Dodecamer And Sunset Yellow, Joseph Theis 2017 University of Colorado, Boulder

Liquid Crystal Phase Behavior Of A Dna Dodecamer And Sunset Yellow, Joseph Theis

Undergraduate Honors Theses

The organic molecule Sunset Yellow, a chromonic dye, and reverse Dickerson dodecamer DNA, a self-complementary, 12 base pair strand of nucleic acids, both self-assemble into rod shaped aggregates that exhibit liquid crystal phases in solution. The sunset yellow molecules and the nano-DNA duplexes have similar structure with hydrophobic cores and peripheral hydrophilic ions. The focus of this research is on mixtures of these two aggregates in miscible liquid crystal states and the phase separation that occurs at higher concentrations in the columnar phase. The structure and phase space of this mixture was determined using polarized optical microscopy and x-ray diffraction ...


Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski 2016 Iowa State University

Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’Ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski

Chemistry Publications

We use high resolution angle resolved photoemission spectroscopy and density functional theory with measured crystal structure parameters to study the electronic properties of CaKFe4As4. In contrast to the related CaFe2As2 compounds, CaKFe4As4 has a high Tc of 35 K at stochiometric composition. This presents a unique opportunity to study the properties of high temperature superconductivity in the iron arsenides in the absence of doping or substitution. The Fermi surface consists of several hole and electron pockets that have a range of diameters. We find that the values of the superconducting gap are nearly isotropic (within the explored portions of the ...


Adsorption Of Dysprosium On The Graphite (0001) Surface: Nucleation And Growth At 300 K, Emma J. Kwolek, Huaping Lei, Ann Lii-Rosales, Mark Wallingford, Yinghui Zhou, Cai-Zhuang Wang, Michael C. Tringides, James W. Evans 2016 Iowa State University

Adsorption Of Dysprosium On The Graphite (0001) Surface: Nucleation And Growth At 300 K, Emma J. Kwolek, Huaping Lei, Ann Lii-Rosales, Mark Wallingford, Yinghui Zhou, Cai-Zhuang Wang, Michael C. Tringides, James W. Evans

Physics and Astronomy Publications

We have studied nucleation and growth of Dy islands on the basal plane of graphite at 300 K using scanning tunneling microscopy, density functional theory (DFT) in a form that includes van der Waals interactions, and analytic theory. The interaction of atomic Dy with graphite is strong, while the diffusion barrier is small. Experiment shows that at 300 K, the density of nucleated islands is close to the value predicted for homogeneous nucleation, using critical nucleus size of 1 and the DFT-derived diffusion barrier. Homogeneous nucleation is also supported by the monomodal shape of the island size distributions. Comparison with ...


Point Island Models For Nucleation And Growth Of Supported Nanoclusters During Surface Deposition, Yong Han, Émilie Gaudry, Tiago J. Oliveira, James W. Evans 2016 Iowa State University

Point Island Models For Nucleation And Growth Of Supported Nanoclusters During Surface Deposition, Yong Han, Émilie Gaudry, Tiago J. Oliveira, James W. Evans

Physics and Astronomy Publications

Point island models (PIMs) are presented for the formation of supported nanoclusters (or islands) during deposition on flat crystalline substrates at lower submonolayer coverages. These models treat islands as occupying a single adsorption site, although carrying a label to track their size (i.e., they suppress island structure). However, they are particularly effective in describing the island size and spatial distributions. In fact, these PIMs provide fundamental insight into the key features for homogeneous nucleation and growth processes on surfaces. PIMs are also versatile being readily adapted to treat both diffusion-limited and attachment-limited growth and also a variety of other ...


Capture Zone Area Distributions For Nucleation And Growth Of Islands During Submonolayer Deposition, Yong Han, Maozhi Li, James W. Evans 2016 Iowa State University

Capture Zone Area Distributions For Nucleation And Growth Of Islands During Submonolayer Deposition, Yong Han, Maozhi Li, James W. Evans

Physics and Astronomy Publications

A fundamental evolution equation is developed to describe the distribution of areas of capture zones (CZs) associated with islands formed by homogeneous nucleation and growth during submonolayer deposition on perfect flat surfaces. This equation involves various quantities which characterize subtle spatial aspects of the nucleation process. These quantities in turn depend on the complex stochastic geometry of the CZ tessellation of the surface, and their detailed form determines the CZ area distribution (CZD) including its asymptotic features. For small CZ areas, behavior of the CZD reflects the critical island size, i. For large CZ areas, it may reflect the probability ...


Investigating High Speed Localization Microscopy Through Experimental Methods, Data Processing Methods, And Applications Of Localization Microscopy To Biological Questions, Andrew J. Nelson 2016 University of Maine

Investigating High Speed Localization Microscopy Through Experimental Methods, Data Processing Methods, And Applications Of Localization Microscopy To Biological Questions, Andrew J. Nelson

Electronic Theses and Dissertations

Fluorescence Photoactivation Localization Microscopy(FPALM) and other super resolution localization microscopy techniques can resolve structures with nanoscale resolution. Unlike techniques of electron microscopy, they are also compatible with live cell and live animal studies, making FPALM and related techniques ideal for answering questions about the dynamic nature of molecular biology in living systems. Many processes in biology occur on rapid sub second time scales requiring the imaging technique to be capable of resolving these processes not just with a high enough spatial resolution, but with an appropriate temporal resolution. To that end, this Dissertation in part investigates high speed FPALM ...


Solution Of Population Balance Equations In Applications With Fine Particles: Mathematical Modeling And Numerical Schemes, Tan Trung Nguyen, Frédérique Laurent, Rodney O. Fox, Marc Massot 2016 Université Paris-Saclay

Solution Of Population Balance Equations In Applications With Fine Particles: Mathematical Modeling And Numerical Schemes, Tan Trung Nguyen, Frédérique Laurent, Rodney O. Fox, Marc Massot

Chemical and Biological Engineering Publications

The accurate description and robust simulation, at relatively low cost, of global quantities (e.g. number density or volume fraction) as well as the size distribution of a population of fine particles in a carrier fluid is still a major challenge for many applications. For this purpose, two types of methods are investigated for solving the population balance equation with aggregation, continuous particle size change (growth and size reduction), and nucleation: the extended quadrature method of moments (EQMOM) based on the work of Yuan et al.[52]and a hybrid method (TSM) between the sectional and moment methods, considering two ...


Splitting Nodes And Linking Channels: A Method For Assembling Biocircuits From Stochastic Elementary Units, Cameron Ferwerda, Ovidiu Lipan 2016 University of Richmond

Splitting Nodes And Linking Channels: A Method For Assembling Biocircuits From Stochastic Elementary Units, Cameron Ferwerda, Ovidiu Lipan

Physics Faculty Publications

Akin to electric circuits, we construct biocircuits that are manipulated by cutting and assembling channels through which stochastic information flows. This diagrammatic manipulation allows us to create a method which constructs networks by joining building blocks selected so that (a) they cover only basic processes; (b) it is scalable to large networks; (c) the mean and variance-covariance from the Pauli master equation form a closed system; and (d) given the initial probability distribution, no special boundary conditions are necessary to solve the master equation. The method aims to help with both designing new synthetic signaling pathways and quantifying naturally existing ...


125te Nmr And Seebeck Effect In Bi2te3 Synthesized From Stoichiometric And Te-Rich Melts, E. M. Levin, Trevor M. Riedemann, A. Howard, Na Hyun Jo, Sergey L. Bud’ko, Paul C. Canfield, Thomas A. Lograsso 2016 Iowa State University and Ames Laboratory

125te Nmr And Seebeck Effect In Bi2te3 Synthesized From Stoichiometric And Te-Rich Melts, E. M. Levin, Trevor M. Riedemann, A. Howard, Na Hyun Jo, Sergey L. Bud’Ko, Paul C. Canfield, Thomas A. Lograsso

Materials Science and Engineering Publications

Bi2Te3 is a well-known thermoelectric material and, as a new form of quantum matter, a topological insulator. Variation of local chemical composition in Bi2Te3 results in formation of several types of atomic defects, including Bi and Te vacancies and Bi and Te antisite defects; these defects can strongly affect material functionality via generation of free electrons and/or holes. Nonuniform distribution of atomic defects produces electronic inhomogeneity, which can be detected by 125Te nuclear magnetic resonance (NMR). Here we report on 125Te NMR and Seebeck effect (heat to electrical energy conversion) for two single crystalline samples: (#1) grown from stoichiometric ...


Catalytic Conversion In Nanoporous Materials: Concentration Oscillations And Spatial Correlations Due To Inhibited Transport And Intermolecular Interactions, Andrés García, James W. Evans 2016 Iowa State University

Catalytic Conversion In Nanoporous Materials: Concentration Oscillations And Spatial Correlations Due To Inhibited Transport And Intermolecular Interactions, Andrés García, James W. Evans

Physics and Astronomy Publications

We show that steady-state catalytic conversion in nanoporous materials can occur in a quasi-counter-diffusion mode with the reactant (product) concentration strongly decaying (growing) into the pore, but also with oscillations in the total concentration. These oscillations reflect the response of the fluid to the transition from an extended to a confined environment near the pore opening. We focus on the regime of strongly inhibited transport in narrow pores corresponding to single-file diffusion. Here, limited penetration of the reactant into the pores and the associated low reaction yield is impacted by strong spatial correlations induced by both reaction (non-equilibrium correlations) and ...


Heart Attack Physics, John Zwart 2016 Dordt College

Heart Attack Physics, John Zwart

Faculty Work Comprehensive List

I recently had a first-hand opportunity to learn some interesting biomedical applications of physics which provide application examples for introductory classes. While there were many such applications, from X-rays to ultrasonic imaging, I’ll focus on fluid flow through clogged coronary arteries and the use of radioactive materials in a nuclear stress test.


Comparison Of S-Adsorption On (111) And (100) Facets Of Cu Nanoclusters, Jeffrey S. Boschen, Jiyoung Lee, Theresa L. Windus, James W. Evans, Patricia A. Thiel, Da-Jiang Liu 2016 Iowa State University

Comparison Of S-Adsorption On (111) And (100) Facets Of Cu Nanoclusters, Jeffrey S. Boschen, Jiyoung Lee, Theresa L. Windus, James W. Evans, Patricia A. Thiel, Da-Jiang Liu

Physics and Astronomy Publications

In order to gain insight into the nature of chemical bonding of sulfur atoms on coinage metal surfaces, we compare the adsorption energy and structural parameters for sulfur at four-fold hollow (4fh) sites on (100) facets and at three-fold hollow (3fh) sites on (111) facets of Cu nanoclusters. Consistent results are obtained from localized atomic orbital and plane-wave based density functional theory using the same functionals. PBE and its hybrid counterpart (PBE0 or HSE06) also give similar results. 4fh sites are preferred over 3fh sites with stronger bonding by ∼0.6 eV for nanocluster sizes above ∼280 atoms. However, for ...


Exposure Of Fibrinogen And Thrombin To Nitric Oxide Donor Prolinonoate Affects Fibrin Clot Properties, Christine C. Helms, Shannon Kapadia, Anne C. Gilmore, Zhexi Lu, Swati Basu, Daniel B. Kim-Shapiro 2016 University of Richmond

Exposure Of Fibrinogen And Thrombin To Nitric Oxide Donor Prolinonoate Affects Fibrin Clot Properties, Christine C. Helms, Shannon Kapadia, Anne C. Gilmore, Zhexi Lu, Swati Basu, Daniel B. Kim-Shapiro

Physics Faculty Publications

Fibrin fibers form the structural backbone of blood clots. The structural properties of fibrin clots are highly dependent on formation kinetics. Environmental factors such as protein concentration, pH, salt, and protein modification, to name a few, can affect fiber kinetics through altered fibrinopeptide release, monomer association, and/or lateral aggregation. The objective of our study was to determine the effect of thrombin and fibrinogen exposed to nitric oxide on fibrin clot properties. ProliNONOate (5 [mu]mol/l) was added to fibrinogen and thrombin before clot initiation and immediately following the addition of thrombin to the fibrinogen solution. Resulting fibrin fibers ...


Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton 2016 Hope College

Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton

Faculty Publications

Porous metals and alloys, such as those fabricated via electrochemical dealloying, are of interest for a variety of energy applications, ranging from their potential for enhanced catalytic behavior to their use as high surface area supports for pseudocapacitor materials. Here, the electrochemical dealloying process was explored for electrodeposited binary NiCo and ternary NiCoCu thin films. For each of the four different metal ratios, films were dealloyed using linear sweep voltammetry to various potentials in order to gain insight into the evolution of the film over the course of the linear sweep. Electrochemical capacitance, scanning electron microscopy, and energy dispersive X-ray ...


Emergence Of A Potent Multidrug Efflux Pump Variant That Enhances Campylobacter Resistance To Multiple Antibiotics, Hong Yao, Zhangqi Shen, Yang Wang, Fengru Deng, Dejun Liu, Gaowa Naren, Lei Dai, Chih-Chia Su, Bing Wang, Shaolin Wang, Congming Wu, Edward W. Yu, Qijing Zhang, Jianzhong Shen 2016 China Agricultural University

Emergence Of A Potent Multidrug Efflux Pump Variant That Enhances Campylobacter Resistance To Multiple Antibiotics, Hong Yao, Zhangqi Shen, Yang Wang, Fengru Deng, Dejun Liu, Gaowa Naren, Lei Dai, Chih-Chia Su, Bing Wang, Shaolin Wang, Congming Wu, Edward W. Yu, Qijing Zhang, Jianzhong Shen

Veterinary Microbiology and Preventive Medicine Publications

Bacterial antibiotic efflux pumps are key players in antibiotic resistance. Although their role in conferring multidrug resistance is well documented, the emergence of “super” efflux pump variants that enhance bacterial resistance to multiple drugs has not been reported. Here, we describe the emergence of a resistance-enhancing variant (named RE-CmeABC) of the predominant efflux pump CmeABC in Campylobacter, a major zoonotic pathogen whose resistance to antibiotics is considered a serious antibiotic resistance threat in the United States. Compared to the previously characterized CmeABC transporters, RE-CmeABC is much more potent in conferring Campylobacter resistance to antibiotics, which was shown by increased MICs ...


Koh Etching Of (100) Si Wafer, No 2, Inayat Bajwa 2016 Quattrone Nanofabrication Facility

Koh Etching Of (100) Si Wafer, No 2, Inayat Bajwa

Protocols and Reports

This report describes KOH etching of (100) Si wafer through a hard mask of silicon oxide, and reveals that the scattered etch rate is ascribed to the etch rates of the different crystal planes exposed during the etching.


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