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Modification Of An Implant Material, Emily Leung, Nina A. Reger, Ashley Blystone, Ellen S. Gawalt PhD 2017 Duquesne University

Modification Of An Implant Material, Emily Leung, Nina A. Reger, Ashley Blystone, Ellen S. Gawalt Phd

Undergraduate Research and Scholarship Symposium

Titanium metal is a commonly used implant material which can be colonized by bacteria. Biofilms are formed when bacteria colonizes, attaches to a surface, and immobilizes. Bacterial infections or biofilms are hard to treat once formed on the surface of a metal implant. Coating the material may minimize bacteria attachment. Self-assembled monolayers are comprised of molecules that contain both a head and tail group, and can be used to coat metal to prevent biofilm formation and bacteria growth. 12-mercaptododecylphosphonic acid self-assembled monolayers have a phosphonic acid head group and a thiol tail group. A solution of
12-mercaptododecylphosphonic acid in tetrahydrofuran ...


Nonlinear Oscillatory Dynamics Of The Hardening Of Calcium Phosphate Bone Cements, Vuk Uskoković, Julietta V. Rau 2017 Chapman University

Nonlinear Oscillatory Dynamics Of The Hardening Of Calcium Phosphate Bone Cements, Vuk Uskoković, Julietta V. Rau

Pharmacy Faculty Articles and Research

Here we report on the nonlinear, oscillatory dynamics detected in the evolution of phase composition during the setting of different calcium phosphate cements, two of which evolved toward brushite and one toward hydroxyapatite as the final product. Whereas both brushite-forming cements contained iondoped b-tricalcium phosphate as the initial phase, the zinc-containing one yielded scholzite as an additional phase during setting and the oscillations between these two products were pronounced throughout the entire 80 h setting period, long after the hardening processes was over from the mechanical standpoint. Oscillations in the copper-containing system involved the amount of brushite as the main ...


How Strongly Do Oysters Stick?, Nicolás M. Morato, Andrés M. Tibabuzo, Jonathan J. Wilker 2017 Universidad de Los Andes - Colombia

How Strongly Do Oysters Stick?, Nicolás M. Morato, Andrés M. Tibabuzo, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biological adhesives are a type of interfacial material that has incredible potential to generate new biomimetic compounds that can replace current strong, but toxic, adhesives. Therefore, a study of the chemical composition and mechanical properties of those bio-adhesives is necessary. However, in the case of oysters, despite known chemical characterization of the adult’s adhesive, there are almost no studies on its mechanical properties. Furthermore, there is no available information on the adhesive properties of spat (oysters in their larvae state). Herein, we present the first mechanical characterization of the spat adhesive, measuring its adhesion strength by hydrodynamic determination using ...


Temperature-Dependent Exciton Dynamics Of Superacid Treatment In Monolayers Of The Metal Dichalcogenide Mos2, Mingwei Zhou, Long Yuan, Jordan Snaider, Libai Huang 2017 Purdue University

Temperature-Dependent Exciton Dynamics Of Superacid Treatment In Monolayers Of The Metal Dichalcogenide Mos2, Mingwei Zhou, Long Yuan, Jordan Snaider, Libai Huang

The Summer Undergraduate Research Fellowship (SURF) Symposium

To improve optoelectronic semiconductor materials, one of the most efficient research areas is the two-dimensional (2D) transition-metal dichalocogenides (TMDCs). It has been shown that organic nonoxidizing superacid bis(trifluoromethane)sulfonamide (TFSI) treatment of molybdenum disulfide (MoS2) monolayer could uniformly enhance its photoluminescence by more than two orders of magnitude and also extend the lifetime of excitons. This could greatly improve the efficiency of the solar energy usage, but the mechanism behind it has not been fully understood. Extreme low temperatures (approximately 7K), which slow the surface exciton mobility, were applied to investigate the changes of treated MoS2 monolayer ...


Synthesis Of Healable Organic Semiconductor Through Dioxaborolane Bond, Junchen Liu, William W. Mcnutt, Jianguo Mei 2017 Purdue University

Synthesis Of Healable Organic Semiconductor Through Dioxaborolane Bond, Junchen Liu, William W. Mcnutt, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

The field of organic semiconductors have gained enormous attention the past few decades. Organic materials offer numerous advantages over their inorganic counterparts. Recently a number of works have demonstrated organic semiconductors with healable properties. We aim to investigate the healable ability of an organic semiconductor by mimicking a vitrimer system through the reversible dioxaborolane bond. Vitrimers are polymers with reversible crosslink system. It has been reported that the use of the borane-oxygen bond as the crosslink showed good mechanical performance. The electrical properties will be inspected for the vitrimer-like polymer. In this report we describe a Diketopyrrolopyrrole base polymer incorporating ...


Cellulose Reinforced Thermoplastic Composites By In-Situ Ring-Opening Polymerization, Shahab Kashani Rahimi 2017 University of Southern Mississippi

Cellulose Reinforced Thermoplastic Composites By In-Situ Ring-Opening Polymerization, Shahab Kashani Rahimi

Dissertations

Over the past two decades, the increasing concern about the negative environmental impacts of synthetic materials has led to rising interests in utilizing renewable natural resources to develop polymer materials with comparable properties and performance to their synthetic counterparts. One of the major fields of interest is polymer composites where the replacement of synthetic fibers with bio renewable natural fibers is of great potential. However, the processing difficulties, in terms of fiber dispersion and thermal stability have limited the application of cellulosic fibers to polymers with low processing temperatures which are mostly hydrophobic polymers. As a result, the true reinforcing ...


Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, Chris Mancinelli, Jeff S. Ko, Cynthia J. Jenks, Patricia A. Thiel, Amy R. Ross, Thomas A. Lograsso, Andrew J. Gellman 2017 Carnegie Mellon University

Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, Chris Mancinelli, Jeff S. Ko, Cynthia J. Jenks, Patricia A. Thiel, Amy R. Ross, Thomas A. Lograsso, Andrew J. Gellman

Thomas A. Lograsso

An experimental comparison has been made between the properties of the surfaces of an Al70Pd21Mn9quasicrystal and its Al48Pd42Mn10 approximant. The Al70Pd21Mn9 sample was a single grain icosahedral quasicrystal cut to expose its five-fold symmetric (000001) surface. The approximant was polycrystalline β-phase Al48Pd42Mn10, which has a CsCl-type cubic structure. Surfaces of both were prepared under ultra-high vacuum (UHV) conditions and then used for comparative measurements of their frictional properties and oxidation rates. Both materials are oxidized by reaction with O ...


Self-Organized Molecular Films With Long-Range Quasiperiodic Order, Vincent Fournée, Émilie Gaudry, Julian Ledieu, Marie-Cécile de Weerd, Dongmei Wu, Thomas A. Lograsso 2017 Université de Lorraine

Self-Organized Molecular Films With Long-Range Quasiperiodic Order, Vincent Fournée, Émilie Gaudry, Julian Ledieu, Marie-Cécile De Weerd, Dongmei Wu, Thomas A. Lograsso

Thomas A. Lograsso

Self-organized molecular films with long-range quasiperiodic order have been grown by using the complex potential energy landscape of quasicrystalline surfaces as templates. The long-range order arises from a specific subset of quasilattice sites acting as preferred adsorption sites for the molecules, thus enforcing a quasiperiodic structure in the film. These adsorption sites exhibit a local 5-fold symmetry resulting from the cut by the surface plane through the cluster units identified in the bulk solid. Symmetry matching between the C60 fullerene and the substrate leads to a preferred adsorption configuration of the molecules with a pentagonal face down, a feature unique ...


Superconducting Properties Of Rh 9 In 4 S 4 Single Crystals, Udhara S. Kaluarachchi, Qisheng Lin, Weiwei Xie, Valentin Taufour, S. L. Bud’ko, Gordon J. Miller, Paul C. Canfield 2017 Iowa State University

Superconducting Properties Of Rh 9 In 4 S 4 Single Crystals, Udhara S. Kaluarachchi, Qisheng Lin, Weiwei Xie, Valentin Taufour, S. L. Bud’Ko, Gordon J. Miller, Paul C. Canfield

Paul C. Canfield

The synthesis and crystallographic, thermodynamic, and transport properties of single crystalline Rh9In4S4 were studied. The resistivity, magnetization, and specific heat measurements all clearly indicate bulk superconductivity with a critical temperature, Tc∼2.25 K. The Sommerfeld coefficient γ and the Debye temperature (ΘD) were found to be 34 mJ mol−1 K−2 and 217 K, respectively. The observed specific heat jump, ΔC/γTc=1.66, is larger than the expected BCS weak coupling value of 1.43. Ginzburg-Landau (GL) ratio of the low-temperature GL-penetration depth, λGL≈5750 Å, to the GL-coherence length, ξGL≈94 Å, is large: κ ∼60 ...


Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, Arielle M. Jean 2017 The University of Western Ontario

Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, Arielle M. Jean

Electronic Thesis and Dissertation Repository

In this work, experiments were carried out in order to develop a mechanistic understanding of the corrosion of copper metal in limited water volumes under gamma-radiation. When exposed to gamma-radiation, water decomposes into chemically reactive oxidizing and reducing species. Under a continuous radiation flux, the concentrations of the radiolytically produced oxidants eventually reach a pseudo-steady state that can influence the corrosion kinetics of metallic surfaces.

The evolution of the surface morphology during water droplet corrosion of copper in the presence of gamma-radiation was investigated as a function of irradiation time and pH. The oxide growth kinetics were studied by measuring ...


Mesoporous Silica Nanoparticles: Structural Design And Applications, Igor I. Slowing, Juan Luis Vivero-escoto, Brian G. Trewyn, Victor S.Y. Lin 2017 Iowa State University

Mesoporous Silica Nanoparticles: Structural Design And Applications, Igor I. Slowing, Juan Luis Vivero-Escoto, Brian G. Trewyn, Victor S.Y. Lin

Igor I. Slowing

The structural properties of mesoporous silica nanoparticles are reviewed. Different strategies for the introduction of functional groups are considered. Based on the architectural features of the material, the functionalization at defined regions of the particles is described, along with the properties emerging from the corresponding site-specific modifications of their chemistry. Many applications derived from the unique architecture and chemistry of these nanostructured composite materials are shown.


Heterogeneous Multicatalytic System For Single-Pot Oxidation And C–C Coupling Reaction Sequences, Nicholas C. Nelson, Umesh Chaudhary, Kapil Kandel, Igor I. Slowing 2017 Iowa State University

Heterogeneous Multicatalytic System For Single-Pot Oxidation And C–C Coupling Reaction Sequences, Nicholas C. Nelson, Umesh Chaudhary, Kapil Kandel, Igor I. Slowing

Igor I. Slowing

A system comprising two catalysts supported on mesoporous silica nanoparticles (MSNs) was employed to perform a sequence of two reactions in a single pot. Palladium nanoparticles catalyzed the oxidation of furfuryl alcohol with molecular oxygen at atmospheric pressure. The oxidation product, furfural, was then reacted with acetone via an aldol condensation catalyzed by amines supported on MSNs. Each reaction was first tested individually to establish optimal conditions. Both catalysts were then introduced into the same reactor under the proven conditions, and the entire reaction sequence was performed giving the desired product with high selectivity. The overall yield of the reaction ...


Supported Iron Nanoparticles For The Hydrodeoxygenation Of Microalgal Oil To Green Diesel, Kapil Kandel, James W. Anderegg, Nicholas C. Nelson, Umesh Chaudhary, Igor I. Slowing 2017 Iowa State University

Supported Iron Nanoparticles For The Hydrodeoxygenation Of Microalgal Oil To Green Diesel, Kapil Kandel, James W. Anderegg, Nicholas C. Nelson, Umesh Chaudhary, Igor I. Slowing

Igor I. Slowing

Iron nanoparticles supported on mesoporous silica nanoparticles (Fe-MSN) catalyze the hydrotreatment of fatty acids with high selectivity for hydrodeoxygenation over decarbonylation and hydrocracking. The catalysis is likely to involve a reverse Mars–Van Krevelen mechanism, in which the surface of iron is partially oxidized by the carboxylic groups of the substrate during the reaction. The strength of the metal–oxygen bonds that are formed affects the residence time of the reactants facilitating the successive conversion of carboxyl first into carbonyl and then into alcohol intermediates, thus dictating the selectivity of the process. The selectivity is also affected by the pretreatment ...


Substrate Inhibition In The Heterogeneous Catalyzed Aldol Condensation: A Mechanistic Study Of Supported Organocatalysts, Kapil Kandel, Stacey Marie Althaus, Chorthip Peeraphatdit, Takeshi Kobayashi, Brian G. Trewyn, Marek Pruski, Igor I. Slowing 2017 Iowa State University

Substrate Inhibition In The Heterogeneous Catalyzed Aldol Condensation: A Mechanistic Study Of Supported Organocatalysts, Kapil Kandel, Stacey Marie Althaus, Chorthip Peeraphatdit, Takeshi Kobayashi, Brian G. Trewyn, Marek Pruski, Igor I. Slowing

Igor I. Slowing

In this study, we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of ...


Exocytosis Of Mesoporous Silica Nanoparticles From Mammalian Cells: From Asymmetric Cell-To-Cell Transfer To Protein Harvesting, Igor I. Slowing, Juan L. Vivero-Escoto, Yannan Zhao, Kapil Kandel, Chorthip Peeraphatdit, Brian G. Trewyn, Victor S.Y. Lin 2017 Iowa State University

Exocytosis Of Mesoporous Silica Nanoparticles From Mammalian Cells: From Asymmetric Cell-To-Cell Transfer To Protein Harvesting, Igor I. Slowing, Juan L. Vivero-Escoto, Yannan Zhao, Kapil Kandel, Chorthip Peeraphatdit, Brian G. Trewyn, Victor S.Y. Lin

Igor I. Slowing

The exocytosis of mesoporous silica nanoparticles (MSNs) from mammalian cells is demonstrated for the first time. The differences in the degree of exocytosis of MSNs between healthy and cancer cells are shown to be responsible for the asymmetric transfer of the particles between both cell types. The exo­cytosis of highly adsorbent magnetic MSNs proves to be useful as a means for harvesting biomolecules from living cells.


Tuning Complexity By Lithiation: A Family Of Intergrowth Structures Using Condensed Hypho-Icosahedra In The Li-Doped Ca–Zn System, Qisheng Lin, Ran Zhu, Gordon J. Miller 2017 The Ames Laboratory

Tuning Complexity By Lithiation: A Family Of Intergrowth Structures Using Condensed Hypho-Icosahedra In The Li-Doped Ca–Zn System, Qisheng Lin, Ran Zhu, Gordon J. Miller

Gordon Miller

Cluster chemistry of intermetallics with valence electron counts (VECs) in the range of 2.0–3.0 is intriguing. Lithiation of polar intermetallics in this VEC region is found to be an effective chemical route to produce new complex structures with different stability mechanisms. In this work, two new complex intermetallic structures have been discovered in the Ca–Li–Zn system: Ca12LixZn59–xand Ca15LixZn75–x. Ca12LixZn59–x, x ≈ 5.65(3)–14.95(3), forms in the trigonal space group Rm, with a = 9.074(1)–9.1699(2) Å, c ...


Superconducting Properties Of Rh 9 In 4 S 4 Single Crystals, Udhara S. Kaluarachchi, Qisheng Lin, Weiwei Xie, Valentin Taufour, S. L. Bud’ko, Gordon J. Miller, Paul C. Canfield 2017 Iowa State University

Superconducting Properties Of Rh 9 In 4 S 4 Single Crystals, Udhara S. Kaluarachchi, Qisheng Lin, Weiwei Xie, Valentin Taufour, S. L. Bud’Ko, Gordon J. Miller, Paul C. Canfield

Gordon Miller

The synthesis and crystallographic, thermodynamic, and transport properties of single crystalline Rh9In4S4 were studied. The resistivity, magnetization, and specific heat measurements all clearly indicate bulk superconductivity with a critical temperature, Tc∼2.25 K. The Sommerfeld coefficient γ and the Debye temperature (ΘD) were found to be 34 mJ mol−1 K−2 and 217 K, respectively. The observed specific heat jump, ΔC/γTc=1.66, is larger than the expected BCS weak coupling value of 1.43. Ginzburg-Landau (GL) ratio of the low-temperature GL-penetration depth, λGL≈5750 Å, to the GL-coherence length, ξGL≈94 Å, is large: κ ∼60 ...


Electronic And Magnetic Properties Of Carbon-Based And Boron-Based Nano Materials, Rosi Gunasinghe 2017 Clark Atlanta University

Electronic And Magnetic Properties Of Carbon-Based And Boron-Based Nano Materials, Rosi Gunasinghe

Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University

The structural and electronic properties of covalently and non-covalently functionalized graphene are investigated by means of first-principles density-functional-theory. The electronic characteristics of non-covalently functionalized graphene by a planar covalent organic framework (COF) are investigated. The aromatic central molecule of the COF acts as an electron donor while the linker of the COF acts as an electron acceptor. The concerted interaction of donor acceptor promotes the formation of planar COF networks on graphene. The distinctive electronic properties of covalently functionalized fluorinated epitaxial graphene are attributed to the polar covalent C–F bond. The partial ionic character of the C–F bond ...


Processing And Characterization Of Nanocomposites Prepared By High Torque Melt Mixing, Lionel W. Cross Jr 2017 Clark Atlanta University

Processing And Characterization Of Nanocomposites Prepared By High Torque Melt Mixing, Lionel W. Cross Jr

Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University

The rapid development of polymer nanocomposites has received extensive attention over the last few decades. The ability to alter functionalities of composites, dramatically improving properties and performance at low filler content creates flexibility in designing materials for advanced applications in various industrial fields. This work focuses on nanocomposites relevant to the packaging and aerospace industries.

This work evaluated the ability to homogeneously distribute nanomaterials into a polymer matrix, understand the effects on rheological properties, understand changes to microstructure and effects, and characterize properties of resulting nanocomposite. High torque melt mixing was used to disperse surface modified cellulose nanocrystals in a ...


Design And Fabrication Of Nanostructures For The Enhancement Of Photovoltaic Devices, Richard M. Prevost III 2017 University of New Orleans

Design And Fabrication Of Nanostructures For The Enhancement Of Photovoltaic Devices, Richard M. Prevost Iii

University of New Orleans Theses and Dissertations

In 2012 the net world electricity generation was 21.56 trillion kilowatt hours. Photovoltaics only accounted for only 0.1 trillion kilowatt hours, less than 1 % of the total power. Recently there has been a push to convert more energy production to renewable sources. In recent years a great deal of interest has been shown for dye sensitized solar cells. These devices use inexpensive materials and have reported efficiencies approaching 12% in the lab. Here methods have been studied to improve upon these, and other, devices. Different approaches for the addition of gold nanoparticles to TiO2 films were studied ...


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