Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons

Open Access. Powered by Scholars. Published by Universities.®

23,561 Full-Text Articles 34,436 Authors 3,813,508 Downloads 259 Institutions

All Articles in Chemistry

Faceted Search

23,561 full-text articles. Page 597 of 603.

Investigations Into The Origins Of Polyatomic Ions In Inductively Coupled Plasma-Mass Spectrometry, Sally Mcintyre 2010 Iowa State University

Investigations Into The Origins Of Polyatomic Ions In Inductively Coupled Plasma-Mass Spectrometry, Sally Mcintyre

Graduate Theses and Dissertations

The origin of certain polyatomic ions in inductively coupled plasma mass spectrometry is investigated. Ion ratios are predicted with the use of partition functions and compared to mass spectrometric measurements. It is found that the simple models for the predicted ratios work well compared to more complex formulations. Cone material and geometry is found to have the most effect on ArX+ species. Potential energy curves for ArO+ are examined. It is determined that ArO+ is best described when a Boltzmann distribution between the first two electronic energy levels is not followed. Analyte metal oxide memory was investigated and found to ...


Determination Of Saccharides And Ethanol From Biomass Conversion Using Raman Spectroscopy: Effects Of Pretreatment And Enzyme Composition, Chien-ju Shih 2010 Iowa State University

Determination Of Saccharides And Ethanol From Biomass Conversion Using Raman Spectroscopy: Effects Of Pretreatment And Enzyme Composition, Chien-Ju Shih

Graduate Theses and Dissertations

This thesis focuses on developing quantitative spectroscopic methods to determine products from hydrolysis and fermentation reaction. A dispersive Raman spectrometer with 785 nm incident light is used to measure saccharides and ethanol in complex matrices. An appropriate pretreatment step is critical prior to hydrolysis reaction for reducing spectra interference. Different pretreatment methods are compared systematically and the glucose detection limits in hydrolysates are calculated.

Multipeak fitting model is also constructed in order to analyze two main sugars produced from cellulose and hemicellulose. Different ratios of sugar mixtures are used to examine the model's accuracy. Ammonia-pretreated corn stover is hydrolyzed ...


Developing New Optical Imaging Techniques For Single Particle And Molecule Tracking In Live Cells, Wei Sun 2010 Iowa State University

Developing New Optical Imaging Techniques For Single Particle And Molecule Tracking In Live Cells, Wei Sun

Graduate Theses and Dissertations

Differential interference contrast (DIC) microscopy is a far-field as well as wide-field optical imaging technique. Since it is non-invasive and requires no sample staining, DIC microscopy is suitable for tracking the motion of target molecules in live cells without interfering their functions. In addition, high numerical aperture objectives and condensers can be used in DIC microscopy. The depth of focus of DIC is shallow, which gives DIC much better optical sectioning ability than those of phase contrast and dark field microscopies. In this work, DIC was utilized to study dynamic biological processes including endocytosis and intracellular transport in live cells ...


Activation And Inhibition Of Gtpase Translation Factors On The Prokaryotic Ribosome, Justin D. Walter 2010 Western Washington University

Activation And Inhibition Of Gtpase Translation Factors On The Prokaryotic Ribosome, Justin D. Walter

WWU Graduate School Collection

Throughout all domains of life, each protein in a cell is synthesized by a remarkable biomolecular machine called the ribosome, in a process referred to as translation. This process is regulated by proteins called translation factors, several of which belong to the GTPase superfamily of enzymes which require the binding and subsequent hydrolysis of guanosine 5'-triphosphate (GTP) to execute their function. In contrast to the regulatory role of translation factors, protein biosynthesis is inhibited by several naturally occurring antibiotics. While our understanding of translation has been revolutionized by the recent elucidation of atomic-resolution x-ray crystal structures of the ribosome ...


Rhombohedrally Distorted Γ-Brasses Cr1−Xfexga, Hyujin Ko, Olivier Gourdon, Delphine Gout, Eun-Deok Mun, Srinivasa Thimmaiah, Gordon J. Miller 2010 Iowa State University

Rhombohedrally Distorted Γ-Brasses Cr1−Xfexga, Hyujin Ko, Olivier Gourdon, Delphine Gout, Eun-Deok Mun, Srinivasa Thimmaiah, Gordon J. Miller

Chemistry Publications

A series of rhombohedrally distorted γ-brass structures containing a mixture of magnetically active 3d elements, Cr and Fe, Cr1−xFexGa, is investigated crystallographically. These structures consist of chains of trans-face-sharing Ga-centered transition metal icosahedra. Neutron powder diffraction specifically on Cr0.5Fe0.5Ga, which could be prepared as a single phase material, gave lattice constants (11 K) a = 12.5172(2) Å and c = 7.8325(2) Å and a refined composition of Cr0.502(6)Fe0.498Ga = Cr6.523Fe6.477Ga13 and revealed partial ordering ...


Periodic Step Arrays On The Aperiodic I-Al-Pd-Mn Quasicrystal Surface At High Temperature, Y. Sato, Barış Ünal, Thomas A. Lograsso, Patricia A. Thiel, A. K. Schmid, T. Duden, N. C. Bartelt, K. F. McCarty 2010 University of California, Davis

Periodic Step Arrays On The Aperiodic I-Al-Pd-Mn Quasicrystal Surface At High Temperature, Y. Sato, Barış Ünal, Thomas A. Lograsso, Patricia A. Thiel, A. K. Schmid, T. Duden, N. C. Bartelt, K. F. Mccarty

Chemistry Publications

We have observed the configuration and motion of surface steps on the aperiodic icosahedral (i-) Al-Pd-Mn quasicrystal using low-energy electron microscopy and scanning tunneling microscopy. As the quasicrystal is cooled from high temperature, bulk vacancies migrate to the surface causing the surface to be etched. Surprisingly, this etching occurs by two types of steps with different heights moving in different directions with different velocities. The steady-state surface morphology is a uniformly spaced rhomboidal step network. This network requires that the layer stacking near the surface deviates from the bulk quasicrystal stacking.


Calculations Of The Binding Affinities Of Protein-Protein Complexes With The Fast Multipole Method, Bongkeun Kim, Jiming Song, Xueyu Song 2010 Iowa State University

Calculations Of The Binding Affinities Of Protein-Protein Complexes With The Fast Multipole Method, Bongkeun Kim, Jiming Song, Xueyu Song

Chemistry Publications

In this paper, we used a coarse-grained model at the residue level to calculate the binding free energies of three protein-protein complexes. General formulations to calculate the electrostatic binding free energy and the van der Waals free energy are presented by solving linearized Poisson–Boltzmann equations using the boundary element method in combination with the fast multipole method. The residue level model with the fast multipole method allows us to efficiently investigate how the mutations on the active site of the protein-protein interface affect the changes in binding affinities of protein complexes. Good correlations between the calculated results and the ...


K23au12sn9—An Intermetallic Compound Containing A Large Gold−Tin Cluster: Synthesis, Structure, And Bonding, Bin Li, Sung-Jin Kim, Gordon J. Miller, John D. Corbett 2010 Iowa State University

K23au12sn9—An Intermetallic Compound Containing A Large Gold−Tin Cluster: Synthesis, Structure, And Bonding, Bin Li, Sung-Jin Kim, Gordon J. Miller, John D. Corbett

Chemistry Publications

A polyanionic unit {Au12Sn9} with a novel “corrugated sheet” shape occurs in K23Au12Sn9. The compound was obtained by fusion of the pure elements in tantalum ampules at high temperatures followed by programmed cooling, and the structure was determined by X-ray diffraction: I4̅2m (No. 121), a = 20.834(3), c = 6.818(1) Å, Z = 2. The large heteroatomic cluster has D2d point symmetry and features a central four bonded (4b-) Sn, eight 3b- or 2b-Sn on the perimeter, and 24 linking nearly linear ...


Pd2.28(1)Zn10.37(1)Al0.35(1), A Ternary Y-Brass-Type Structure, Srinivasa Thimmaiah, Gordon J. Miller 2010 Iowa State University

Pd2.28(1)Zn10.37(1)Al0.35(1), A Ternary Y-Brass-Type Structure, Srinivasa Thimmaiah, Gordon J. Miller

Chemistry Publications

No abstract provided.


Multiple Nonstoichiometric Phases With Discrete Composition Ranges In The Caau5-Caau4bi-Biau2 System. A Case Study Of The Chemistry Of Spinodal Decomposition, Qisheng Lin, John D. Corbett 2010 The Ames Laboratory

Multiple Nonstoichiometric Phases With Discrete Composition Ranges In The Caau5-Caau4bi-Biau2 System. A Case Study Of The Chemistry Of Spinodal Decomposition, Qisheng Lin, John D. Corbett

Chemistry Publications

Synthetic explorations in the CaAu5−CaAu4Bi−BiAu2 system at 400 °C reveal five separate solid solution regions that show three distinct substitution patterns in the CaAu5 parent: (I) CaAu4(Au1−mBim) with 0 ≤ m ≤ 0.15(1), (II) 0.33(1) ≤ m ≤ 0.64(1), (III) 0.85(4) ≤ m ≤ 0.90(2); (IV) (Ca1−rAur)Au4(Bi1−sAus) with 0 ≤ r ≤ 0.39(1) and 0 ≤ s ≤ 0.12(2); (V) (Ca1−pqAupBiq)Au4Bi with 0.09(2) ≤ p ≤ 0.13(1) and 0.31(2) ≤ q ≤ 0 ...


Development Of An Icosahedral Quasicrystal And Two Approximants In The Ca-Au-Sn System: Syntheses And Structural Analyses, Qisheng Lin, John D. Corbett 2010 The Ames Laboratory

Development Of An Icosahedral Quasicrystal And Two Approximants In The Ca-Au-Sn System: Syntheses And Structural Analyses, Qisheng Lin, John D. Corbett

Chemistry Publications

The realm of Tsai-type (YCd6-type) quasicrystals (QCs) and their approximants (ACs) continues to expand to the east in the periodic table. The heavy tetrel Sn is now one of the major components in the new Ca15.0(5)Au60.0(4)Sn25.0(2) (atom %) icosahedral QC and in the corresponding 1/1 and 2/1 ACs. (The 2/1 AC with Yb is also established.) Single-crystal X-ray diffraction on a 1/1 AC gives the refined formula of Ca3Au14.36(3)Sn4.38(5) in space group Im3̅, a = 15.131(1) Å, whereas a representative 2/1 ...


Open-Shell Formulation Of The Fragment Molecular Orbital Method, Spencer Pruitt, Dmitri G. Fedorov, Kazuo Kitaura, Mark S. Gordon 2010 Iowa State University

Open-Shell Formulation Of The Fragment Molecular Orbital Method, Spencer Pruitt, Dmitri G. Fedorov, Kazuo Kitaura, Mark S. Gordon

Chemistry Publications

Performing accurate calculations on large molecular systems is desirable for closed- and open-shell systems. In this work, the fragment molecular orbital method is extended to open-shell systems and implemented in the GAMESS (General Atomic and Molecular Electronic Structure System) program package. The accuracy of the method is tested, and the ability to reproduce reaction enthalpies is demonstrated. These tests also demonstrate its utility in providing an efficient means to model large open-shell systems.


Hygroscopic Growth And Deliquescence Of Nacl Nanoparticles Mixed With Surfactant Sds, Christopher W. Harmon, Ronald L. Grimm, Theresa M. McIntire, Mark D. Peterson, Bosiljka Njegic, Vanessa M. Angel, Ahmad Alshawa, Joelle S. Underwood, Douglas J. Tobias, R. Benny Gerber, Mark S. Gordon, John C. Hemminger, Sergey A. Nizkorodov 2010 University of California - Irvine

Hygroscopic Growth And Deliquescence Of Nacl Nanoparticles Mixed With Surfactant Sds, Christopher W. Harmon, Ronald L. Grimm, Theresa M. Mcintire, Mark D. Peterson, Bosiljka Njegic, Vanessa M. Angel, Ahmad Alshawa, Joelle S. Underwood, Douglas J. Tobias, R. Benny Gerber, Mark S. Gordon, John C. Hemminger, Sergey A. Nizkorodov

Chemistry Publications

Several complementary experimental and theoretical methodologies were used to explore water uptake on sodium chloride (NaCl) particles containing varying amounts of sodium dodecyl sulfate (SDS) to elucidate the interaction of water with well-defined, environmentally relevant surfaces. Experiments probed the hygroscopic growth of mixed SDS/NaCl nanoparticles that were generated by electrospraying aqueous 2 g/L solutions containing SDS and NaCl with relative NaCl/SDS weight fractions of 0, 5, 11, 23, or 50 wt/wt %. Particles with mobility-equivalent diameters of 14.0(±0.2) nm were size selected and their hygroscopic growth was monitored by a tandem nano-differential mobility analyzer ...


Aqueous Solvation Of Bihalide Anions, Daniel David Kemp, Mark S. Gordon 2010 Iowa State University

Aqueous Solvation Of Bihalide Anions, Daniel David Kemp, Mark S. Gordon

Chemistry Publications

Second-order Møller−Plesset perturbation theory (MP2) is used to perform geometry optimizations on XHX−·(H2O)n for X = Br, I, with n = 1 to 6 water molecules. Of particular interest is the manner in which the solvent molecules orient themselves around the solute and which configurations are lowest in energy. Although for most values of n, water molecules may donate all of their hydrogen atoms for hydrogen bonding to the solute, this type of structure is the lowest in energy only for n = 0 to 2 and is only a local minimum for n = 3, 4, and 6. For n ...


Dynamics Of Porous Silicon Formation By Etching In Hf + V2o5 Solutions, Kurt W. Kolasinski, Justin B. Hartline, Bryan T. Kelly, Julia Yadlovskiy 2010 West Chester University of Pennsylvania

Dynamics Of Porous Silicon Formation By Etching In Hf + V2o5 Solutions, Kurt W. Kolasinski, Justin B. Hartline, Bryan T. Kelly, Julia Yadlovskiy

Chemistry Faculty Publications

No abstract provided.


Charge Transfer And Nanostructure Formation During Electroless Etching Of Silicon, Kurt W. Kolasinski 2010 West Chester University

Charge Transfer And Nanostructure Formation During Electroless Etching Of Silicon, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.


Resin-Modified Glass-Ionomer Setting Reaction Competition, David W. Berzins, S. Abey, M. C. Costache, Charles A. Wilkie, H. W. Roberts 2010 Marquette University

Resin-Modified Glass-Ionomer Setting Reaction Competition, David W. Berzins, S. Abey, M. C. Costache, Charles A. Wilkie, H. W. Roberts

Chemistry Faculty Research and Publications

Resin-modified glass ionomers (RMGI) set by at least 2 mechanisms dependent upon reactant diffusion prior to gelation. Each reaction’s kinetics and setting mechanism may rely on and/or compete with the other. In this study, we investigated RMGI setting reaction interactions using differential scanning calorimetry (DSC) by varying light-cure initiation times. A RMGI was analyzed with isothermal and dynamic temperature scan DSC with light-curing occurring immediately, or at 5 or 10 minutes after mixing as well as without light-activation. Results show that as time allowed for the acid-base reaction increased, the light-activation polymerization exotherm decreased. Conversely, analysis of DSC ...


Polystyrene-Supported Aluminum Chloride As An Efficient And Reusable Catalyst For Condensation Of Indole With Various Carbonyl Compounds, Bahman Tamami, Amir Nasrolahi Shirazi, Kaveh Parvanak Borujeni 2010 Shiraz University

Polystyrene-Supported Aluminum Chloride As An Efficient And Reusable Catalyst For Condensation Of Indole With Various Carbonyl Compounds, Bahman Tamami, Amir Nasrolahi Shirazi, Kaveh Parvanak Borujeni

Pharmacy Faculty Articles and Research

Crosslinked polystyrene-supported aluminum chloride (PS-AlCl3) is a stable, recyclable and environmental friendly heterogeneous catalyst for the condensation of indole with aldehydes and ketones to afford diindolylmethanes. In addition, PS-AlCl3 shows satisfactory selectivity in the reaction of mixtures of an aldehyde and a ketone with indole. Although AlCl3 is a water sensitive, corrosive and environmentally harmful compound, PS-AlCl3 is a stable and water-tolerant species. The mild reaction conditions, short reaction times, easy work-up, high to excellent yields, chemoselectivity, reuse of the catalyst for at least ten times without significant change in its catalytic activity, low cost, and easy preparation and handling ...


Part I: Syntheses, Characterizations, And Investigations Of Molecular Micelles And Imidazolium-Based Ionic Liquids For Protein Separations In Electrophoresis Part Ii: Investigating The Mentoring Canon Through Exploration Of Thirty Years Of Mentoring By An Exemplar, Monica R. Sylvain 2010 Louisiana State University and Agricultural and Mechanical College

Part I: Syntheses, Characterizations, And Investigations Of Molecular Micelles And Imidazolium-Based Ionic Liquids For Protein Separations In Electrophoresis Part Ii: Investigating The Mentoring Canon Through Exploration Of Thirty Years Of Mentoring By An Exemplar, Monica R. Sylvain

LSU Doctoral Dissertations

The research reported in this dissertation is presented in two parts. The first part is the Syntheses, Characterizations, and Investigations of Molecular Micelles and Imidazolium-Based Ionic Liquids for Protein Separations in Electrophoresis, and the second part is a case study entitled Investigating the Mentoring Canon through Exploration of Thirty Years of Mentoring by an Exemplar. Protein separations in the gel electrophoretic format are ubiquitous analyses used on a daily basis throughout biochemistry, analytical chemistry, and biotechnology. The goal of the research reported in the first part of this dissertation is to synthesize and characterize molecular micelles and ether-functionalized imidazolium-based ionic ...


Liquid Crystals For Functional Nanomaterials: Electroclinic Artificial Muscle Polymers, Nanorods From Achiral Bent-Core Mesogens, And Thiophenic Photovoltaics, Jacqueline Mae Richardson 2010 University of Colorado at Boulder

Liquid Crystals For Functional Nanomaterials: Electroclinic Artificial Muscle Polymers, Nanorods From Achiral Bent-Core Mesogens, And Thiophenic Photovoltaics, Jacqueline Mae Richardson

Chemistry & Biochemistry Graduate Theses & Dissertations (1986-2018)

Three different projects are described, in which target molecules are synthesized based on specific functional goals: electromechanical response, bent-core phase formation, and charge transport behavior. The bulk properties of these materials are then characterized with respect to these goals.

The first project entails the synthesis and characterization of several variations on W317, a calamitic liquid crystal with a strong electroclinic effect. Alpha, omega-diene analogues of this molecule were synthesized and reacted via ADMET into a main-chain polymer, with the goal of creating electromechanical actuators. To improve the bulk strength and macroscopic response of the polymers, attempts were made at cross-linking ...


Digital Commons powered by bepress