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Full-Text Articles in Chemistry

Laser Initiated Chain Reactions: The Kinetics Of The Chlorine/Cyclohexane/Oxygen Chain System, Robert Alan Forlines Jan 2007

Laser Initiated Chain Reactions: The Kinetics Of The Chlorine/Cyclohexane/Oxygen Chain System, Robert Alan Forlines

Browse all Theses and Dissertations

The combination of laser photolysis with infrared chemiluminescence detection has proven an effective technique for determining the propagation rate coefficients of halogen + RH chain reactions. This thesis will extend the technique to cyclic alkanes by determining the propagation rate coefficients of the Cl2/ cyclohexane chain system as well as the rate coefficient for the primary chain termination mechanism, R + O2 → RO2. The following reaction scheme is supported by the kinetic analysis: Cl2 → 2Cl Laser Photolysis Cl + RH → HCl(v) + R First Propagation Step (k1) R + …

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Identification And Characterization Of A New Tubulin-Binding, Susan L. Mooberry, Kimberly N. Weiderhold, Sivanesan Dakshanamurthy, Ernest Hamel, Edith J. Banner, Anastasia Kharlamova, Jonathan Hempel, John T. Gupton, Milton L. Brown Jan 2007

Identification And Characterization Of A New Tubulin-Binding, Susan L. Mooberry, Kimberly N. Weiderhold, Sivanesan Dakshanamurthy, Ernest Hamel, Edith J. Banner, Anastasia Kharlamova, Jonathan Hempel, John T. Gupton, Milton L. Brown

Chemistry Faculty Publications

We studied the mechanism of action of 3,5-dibromo-4-(3,4-dimethoxyphenyl)-1H-pyrrole-2-carboxylic acid ethyl ester (JG-03-14) and found that it is a potent microtubule depolymerizer. JG-03-14 caused a dose-dependent loss of cellular microtubules, formation of aberrant mitotic spindles, accumulation of cells in the G2/M phase of the cell cycle, and Bcl-2 phosphorylation. These events culminated in the initiation of apoptosis, as evidenced by the caspase 3-dependent cleavage of poly(ADP-ribose) polymerase (PARP). JG-03-14 has antiproliferative activity against a wide range of cancer cell lines, with an average IC50 value of 62 nM, and it is a poor substrate for transport …

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Tetrakis(N-Ethyl-9-Oxo-4-Azonia-5-Aza-9h-Fluorene) Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate, Meredith A. Tershany, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye Nov 2006

Tetrakis(N-Ethyl-9-Oxo-4-Azonia-5-Aza-9h-Fluorene) Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate, Meredith A. Tershany, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

The new iodobismuthate compound (C13H11N2O)4[Bi6I22] has been synthesized solvothermally by reacting BiI3, Zn(NO3)2·6H2O and 4,5-diazafluoren-9-one in a water/ethanol solvent mixture. The asymmetric unit of the compound contains two independent [N-ethyl-4,5-dafo]+ cations and one-half of a centrosymmetric [Bi6I22]4- anion. The average terminal Bi-I, Bi-2-I and Bi-3-I bond lengths in the anion are 2.8923 (2), 3.1403 (2) and 3.3022 (2) Å, respectively.

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Tetrakis[2-(2-Pyridyl)Pyridinium] Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate And Bis[Tris(2,2'-Bipyridine)Ruthenium(Ii)] Di-Μ4-Iodo-Octa-Μ2-Iodo-Dodecaiodohexabismuthate, Andrea M. Goforth, Meredith A. Tershansy, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye Aug 2006

Tetrakis[2-(2-Pyridyl)Pyridinium] Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate And Bis[Tris(2,2'-Bipyridine)Ruthenium(Ii)] Di-Μ4-Iodo-Octa-Μ2-Iodo-Dodecaiodohexabismuthate, Andrea M. Goforth, Meredith A. Tershansy, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

Crystals of the title compounds were grown solvothermally in an ethanol-water solvent mixture using ruthenium triiodide, 2,2'-bipyridine and bismuth triiodide as starting materials. Tetrakis[2-(2-pyridyl)pyridinium] tetra-3-iodo-hexa-2-iodo-dodecaiodohexabismuthate, (C10H9N2)4[Bi6I22], crystallizes in the triclinic space group P and is the major reaction product. The asymmetric unit of this compound consists of half a centrosymmetric [Bi6I22]4- anion and two independent 2,2'-bipyridinium cations. The minor product of the reaction is bis[tris(2,2'-bipyridine)ruthenium(II)] di-4-iodo-octa-2-iodo-dodecaiodohexabismuthate, [Ru(C10H8N2)3] …

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Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams Aug 2006

Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams

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Commercially available polyethyleneimines varying in molecular weights and viscosities were synthetically modified in order to increase their hydrophobicity when dissolved in water. Used as additives for inkjet industry inks, these polymers have been designed to promote interaction between formulated inks and paper, while increasing the water-fastness of these water-soluble inks once they are dried on bond paper. Waterfastness, the ability of an ink to maintain print integrity once it becomes wet, as well as optical density, solubility, pH, molecular weight, polydispersity and viscosity are amongst the characteristics analyzed. The modifications of these polyethyleneimines (PEis) with alkyl bromides and alkyl epoxides …

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Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key Jul 2006

Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key

All Faculty Scholarship for the College of the Sciences

Within open‐ocean regions where excess macronutrients are present, phytoplankton growth is limited by the bioavailability of iron supplied to these areas primarily within atmospheric aerosols of crustal origin. However, processes that control the abundance of biologically accessible iron in these aerosols are largely unknown. Here we show that dissolution of ferrihydrite, a surrogate iron(oxy)hydroxide phase found in atmospheric waters, is enhanced in the presence of methanesulfinic acid (MSIA, CH3SO2H, a dimethylsulfide (DMS) oxidation intermediate) in laboratory irradiation experiments with aqueous suspensions that simulate marine aerosol particles. The increased release of soluble Fe(II) is attributed to a …

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Semiclassical Nonadiabatic Dynamics Based On Quantum Trajectories For The O(3P,1D)+H2 System, Sophya Garashchuk, Vitaly A. Rassolov, George C. Schatz Jun 2006

Semiclassical Nonadiabatic Dynamics Based On Quantum Trajectories For The O(3P,1D)+H2 System, Sophya Garashchuk, Vitaly A. Rassolov, George C. Schatz

Faculty Publications

The O(3P,1D)+H2→OH+H reaction is studied using trajectory dynamics within the approximate quantum potential approach. Calculations of the wave-packet reaction probabilities are performed for four coupled electronic states for total angular momentum J = 0 using a mixed coordinate/polar representation of the wave function. Semiclassical dynamics is based on a single set of trajectories evolving on an effective potential-energy surface and in the presence of the approximate quantum potential. Population functions associated with each trajectory are computed for each electronic state. The effective surface is a linear combination of the electronic states with the contributions …

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Closing The Loop: Controlling Type 1 Diabetes Mellitus, Megan Chynoweth May 2006

Closing The Loop: Controlling Type 1 Diabetes Mellitus, Megan Chynoweth

Whittier Scholars Program

Diabetes mellitus is an ever increasing pandemic. Type 1 diabetes mellitus (T1DM), although not the most prevalent form of diabetes mellitus, has had an “average annual increase of 3.09%, meaning the incidence of T1DM would increase 40% from 1998 to 2010”. T1DM leads to many complications: adverse side effects such as retinopathy, neuropathy, and nephropathy. These comorbidities are costing the United States billions of healthcare dollars per year. Delaying complications result in cost savings and improved quality of life, which can be obtained by tightly controlling blood sugars. However, strict control is difficult to attain. Optimal glucose levels may be …

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Synthesis Of Aspernigrin A, Erica Joerger Apr 2006

Synthesis Of Aspernigrin A, Erica Joerger

Undergraduate Theses and Capstone Projects

Aspernigrin A is a compound correlated with inhibiting the growth of cancer cells in the colon. A five-step synthesis was designed for aspernigrin A, projected to yield four intermediates and the final product. The intermediates were analyzed by high field 1HNMR and FT-IR spectroscopy before proceeding to the next step. A model pyridone ring system was successfully prepared from a commercially available pyrone precursor in two steps. These results provide a proof of concept that the synthetic scheme should successfully yield the natural product.

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Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler Mar 2006

Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler

Chemistry Faculty Research

The effects of particle composition on heterogeneous catalysis were studied using dendrimer-encapsulated nanoparticles (DENs) as precursors to supported Pt-Cu catalysts. Bimetallic Pt-Cu DENs with varying Pt/Cu ratios were prepared in an anaerobic aqueous solution and deposited onto a high-purity commercial alumina support. The dendrimer template was then thermally removed to yield supported nanoparticle catalysts, which were studied with toluene hydrogenation and CO oxidation catalysis as well as infrared spectroscopy of adsorbed CO. Incorporating Cu into Pt nanoparticles had opposite effects on the two test reactions. Cu acted as a mild promoter for CO oxidation catalysis, and the promoting effect was …

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Development Of Dirhodium Sugar-Substituted Carboxylate And Acetamide Complexes And Evaluation Of Their Potential As Lectin Inhibitors, Bethany Masten Jan 2006

Development Of Dirhodium Sugar-Substituted Carboxylate And Acetamide Complexes And Evaluation Of Their Potential As Lectin Inhibitors, Bethany Masten

Undergraduate Review

No abstract provided.

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Solubilisation, Purification And Processing Of Single Walled Carbon Nanotubes Using Organic Molecules, Theresa Hedderman Jan 2006

Solubilisation, Purification And Processing Of Single Walled Carbon Nanotubes Using Organic Molecules, Theresa Hedderman

Doctoral

The aims of this research are seven fold; • To enhance the solubility of SWNTs in organic solvents. • To purify an untreated sample of SWNTs that contains many side products. • To gain a greater understanding of the interaction between the polycyclic aromatic hydrocarbons and SWNTs. • To debundle and disperse SWNTs. • To select SWNTs of a specific structure based on the structures of the polycyclic aromatic hydrocarbons used. • To observe and compare the interaction of polycyclic aromatic hydrocarbons with SWNTs produced by different methods. • To elucidate factors which contribute to different degrees of interaction between …

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Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor Jan 2006

Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor

Conference Papers

The following paper discusses the implications of government policy on widening of participation at third level institutes. The increase in ‘non-traditional’ students has been widely recognised on an international scale; however some inequality issues still exist. The ‘struggles’ associated with widening of participation and creating a ‘new’ student type is discussed in particular reference to chemistry education. A change in mindset of staff on their pedagogical approach to cater for a diverse student body with a broad range of learner types is required. This must be supported from a departmental and institutional level. A look at the literature to investigate …

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Kondo Resonances And Anomalous Gate Dependence In The Electrical Conductivity Of Single-Molecule Transistors, L H. Yu, Z K. Keane, Jacob W. Ciszek, L Cheng, J M. Tour, T Baruah, M R. Pederson, D Natelson Dec 2005

Kondo Resonances And Anomalous Gate Dependence In The Electrical Conductivity Of Single-Molecule Transistors, L H. Yu, Z K. Keane, Jacob W. Ciszek, L Cheng, J M. Tour, T Baruah, M R. Pederson, D Natelson

Chemistry: Faculty Publications and Other Works

We report Kondo resonances in the conduction of single-molecule transistors based on transition metal coordination complexes. We find Kondo temperatures in excess of 50 K, comparable to those in purely metallic systems. The observed gate dependence of the Kondo temperature is inconsistent with observations in semiconductor quantum dots and a simple single-dot-level model. We discuss possible explanations of this effect, in light of electronic structure calculations.

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Inhibition Of Cellular Respiration By Doxorubicin, Zhimin Tao, Henry G. Withers, Harvey S. Penefsky, Jerry Goodisman, Abdul Kader Souid Nov 2005

Inhibition Of Cellular Respiration By Doxorubicin, Zhimin Tao, Henry G. Withers, Harvey S. Penefsky, Jerry Goodisman, Abdul Kader Souid

Chemistry - All Scholarship

Doxorubicin executes apoptosis, a process known to produce leakage of cytochrome c and opening of the mitochondrial permeability transition pores. To define the loss of mitochondrial function by apoptosis, we monitored cellular respiration during continuous exposure to doxorubicin. A phosphorescence analyzer capable of stable measurements over at least 5 h was used to measure [O(2)]. In solutions containing glucose and cells, [O(2)] declined linearly with time, showing that the kinetics of oxygen consumption was zero order. Complete inhibition of oxygen consumption by cyanide indicated that oxidations occurred in the respiratory chain. A decline in the rate of respiration was evident …

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Semiclassical Nonadiabatic Dynamics Using A Mixed Wave-Function Representation, Sophya Garashchuk, Vitaly A. Rassolov, George C. Schatz Nov 2005

Semiclassical Nonadiabatic Dynamics Using A Mixed Wave-Function Representation, Sophya Garashchuk, Vitaly A. Rassolov, George C. Schatz

Faculty Publications

Nonadiabatic effects in quantum dynamics are described using a mixed polar/coordinate space representation of the wave function. The polar part evolves on dynamically determined potential surfaces that have diabatic and adiabatic potentials as limiting cases of weak localized and strong extended diabatic couplings. The coordinate space part, generalized to a matrix form, describes transitions between the surfaces. Choice of the effective potentials for the polar part and partitioning of the wave function enables one to represent the total wave function in terms of smooth components that can be accurately propagated semiclassically using the approximate quantum potential and small basis sets. …

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Catena-Poly[[Bis(Α-Thenoyltrifluoroacetonato)Copper(Ii)]-Μ-1,4-Di-4-Pyridyl-2,3-Diazabuta-1,3-Diene], William J. Perkins, Tamara Maxwell, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye Sep 2005

Catena-Poly[[Bis(Α-Thenoyltrifluoroacetonato)Copper(Ii)]-Μ-1,4-Di-4-Pyridyl-2,3-Diazabuta-1,3-Diene], William J. Perkins, Tamara Maxwell, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

In the one-dimensional title polymer, [Cu(C8H4F3O2S)2(C12H10N4)]n or [Cu(L)2(tta)2] [tta is -thenoyltrifluoroacetonato and L is 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene], Cu2+ lies on a center of inversion. It is axially coordinated by two pyridyl N atoms from two different L ligands and equatorially coordinated by four O atoms from two chelating tta ligands. The ligand L propagates the one-dimensional chain structure by serving as a bridging ligand between two Cu octahedra via Cu-N coordinate bonds.

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Activation Of Carboplatin By Carbonate, Anthony J. Di Pasqua, Jerry Goodisman, Deborah J. Kerwood, Bonnie B. Toms, James C. Dabrowiak Sep 2005

Activation Of Carboplatin By Carbonate, Anthony J. Di Pasqua, Jerry Goodisman, Deborah J. Kerwood, Bonnie B. Toms, James C. Dabrowiak

Chemistry - All Scholarship

Carboplatin, [Pt(NH3)2(CBDCA-O,O')], 1, where CBDCA is cyclobutane-1,1-dicarboxylate, is in wide clinical use for the treatment of ovarian, lung, and other types of cancer. Because carboplatin is relatively unreactive toward nucleophiles, an important question concerning the drug is the mechanism by which it is activated in vivo. Using [1H,15N] heteronuclear single quantum coherance spectroscopy (HSQC) NMR and 15N-labeled carboplatin, we show that carboplatin reacts with carbonate ion in carbonate buffer to produce ring-opened products, the nature of which depends on the pH of the medium. The assignment of HSQC NMR resonances was facilitated by studying the reaction of carboplatin in strong …

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Tris(1,10-Phenanthroline)Cobalt(Ii) Triiodide, Meredith A. Tershany, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye Aug 2005

Tris(1,10-Phenanthroline)Cobalt(Ii) Triiodide, Meredith A. Tershany, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

The asymmetric unit of the title compound, [Co(C12H8N2)3](I3)2, contains one [Co(1,10-phenanthroline)3]2+ cation, half each of two centrosymmetric triiodide anions, and one complete triiodide anion. The title compound was synthesized solvothermally from Co(NO3)2, 1,10-phenanthroline, and SnI2, where the SnI2 reagent serves only as a source of I atoms.

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Tris(Ethylenediamine)Cobalt(Iii) Nonaiododibismuthate, Andrea M. Goforth, Rachael E. Hipp, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye Jul 2005

Tris(Ethylenediamine)Cobalt(Iii) Nonaiododibismuthate, Andrea M. Goforth, Rachael E. Hipp, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

The asymmetric unit of the title compound, [Co(C2H8N2)3][Bi2I9], crystallizes in the orthorhombic space group Cmc21. The asymmetric unit contains half of a [Co(en)3]3+ cation (en is ethylenediamine) and half of a [Bi2I9]3- anion. Both species are located on mirror planes, requiring the [Co(en)3]3+ cation to be present as a statistically disordered mixture of both enantiomeric forms. Crystals were grown solvothermally from an ethanol-water solvent mixture using rac-[Co(en)3]I3 and bismuth triiodide …

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Promoting Learning Through Peer Group Work, Christine O'Connor, Renli Ma Jul 2005

Promoting Learning Through Peer Group Work, Christine O'Connor, Renli Ma

Conference Papers

The session aimed to help the Summer School participants develop tasks and assessment strategies of peer group work in their own teaching.

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Cisplatin Carbonato Complexes. Implications For Uptake, Antitumor Properties, And Toxicity, Corey R. Centerwall, Jerry Goodisman, Deborah J. Kerwood, James C. Dabrowiak May 2005

Cisplatin Carbonato Complexes. Implications For Uptake, Antitumor Properties, And Toxicity, Corey R. Centerwall, Jerry Goodisman, Deborah J. Kerwood, James C. Dabrowiak

Chemistry - All Scholarship

The reaction of aquated cisplatin with carbonate which is present in culture media and blood is described. The first formed complex is a monochloro monocarbonato species, which upon continued exposure to carbonate slowly forms a biscarbonato complex. The formation of carbonato species under conditions that simulate therapy may have important implications for uptake, antitumor properties, and toxicity of cisplatin.

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Simulations Of Nanopore Formation And Phosphatidylserine Externalization In Lipid Membranes Subjected To A High-Intensity, Ultrashort Electric Pulse, Q. Hu, R. P. Joshi, K. H. Schoenbach Jan 2005

Simulations Of Nanopore Formation And Phosphatidylserine Externalization In Lipid Membranes Subjected To A High-Intensity, Ultrashort Electric Pulse, Q. Hu, R. P. Joshi, K. H. Schoenbach

Bioelectrics Publications

A combined MD simulator and time dependent Laplace solver are used to analyze the electrically driven phosphatidylserine externalization process in cells. Time dependent details of nanopore formation at cell membranes in response to a high-intensity (100kV∕cm), ultrashort (10ns) electric pulse are also probed. Our results show that nanosized pores could typically be formed within about 5ns. These predictions are in very good agreement with recent experimental data. It is also demonstrated that defect formation and PS externalization in membranes should begin on the anode side. Finally, the simulations confirm that PS externalization is a nanopore facilitated event, rather than the …

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Crystal Structure Of The Gtpase Domain Of Rat Dynamin 1, Thomas F. Reubold, Susanne Eschenburg, Andreas Becker, Marilyn Leonard, Sandra L. Schmid, Richard B. Vallee, F. Jon Kull, Dietmar J. Manstein Jan 2005

Crystal Structure Of The Gtpase Domain Of Rat Dynamin 1, Thomas F. Reubold, Susanne Eschenburg, Andreas Becker, Marilyn Leonard, Sandra L. Schmid, Richard B. Vallee, F. Jon Kull, Dietmar J. Manstein

Dartmouth Scholarship

Here, we present the 1.9-A crystal structure of the nucleotide-free GTPase domain of dynamin 1 from Rattus norvegicus. The structure corresponds to an extended form of the canonical GTPase fold observed in Ras proteins. Both nucleotide-binding switch motifs are well resolved, adopting conformations that closely resemble a GTP-bound state not previously observed for nucleotide-free GTPases. Two highly conserved arginines, Arg-66 and Arg-67, greatly restrict the mobility of switch I and are ideally positioned to relay information about the nucleotide state to other parts of the protein. Our results support a model in which switch I residue Arg-59 gates GTP binding …

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Sm2Nairo6, A Monoclinically Distorted Double Perovskite, Samuel J. Mugavero Iii, Irina V. Puzdrjakova, Mark D. Smith, Hans-Conrad Zur Loye Dec 2004

Sm2Nairo6, A Monoclinically Distorted Double Perovskite, Samuel J. Mugavero Iii, Irina V. Puzdrjakova, Mark D. Smith, Hans-Conrad Zur Loye

Faculty Publications

Single crystals of the lanthanide-containing iridate, disamarium sodium iridium hexaoxide, Sm2NaIrO6, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n and is a double perovskite, consisting of a 1:1 ordered rock-salt-type lattice of corner-shared NaO6 and IrO6 distorted octahedra. Samarium occupies the eightfold coordination site generated by the connectivity of the octahedra.

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Modified Quantum Trajectory Dynamics Using A Mixed Wave Function Representation, Sophya Garashchuk, Vitaly A. Rassolov Nov 2004

Modified Quantum Trajectory Dynamics Using A Mixed Wave Function Representation, Sophya Garashchuk, Vitaly A. Rassolov

Faculty Publications

Dynamics of quantum trajectories provides an efficient framework for description of various quantum effects in large systems, but it is unstable near the wave function density nodes where the quantum potential becomes singular. A mixed coordinate space/polar representation of the wave function is used to circumvent this problem. The resulting modified trajectory dynamics associated with the polar representation is nonsingular and smooth. The interference structure and the nodes of the wave function density are described, in principle, exactly in the coordinate representation. The approximate version of this approach is consistent with the semiclassical linearized quantum force method [S. Garashchuk and …

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Resonance-Enhanced Multiphoton Ionization For Real-Time Monitoring Of Trichloroethylene Formed By Degradation Of Tetrachloroethylene Using Zero-Valent Zinc, Kui Chen, Jack E. Pender, John L. Ferry, S. Michael Angel Nov 2004

Resonance-Enhanced Multiphoton Ionization For Real-Time Monitoring Of Trichloroethylene Formed By Degradation Of Tetrachloroethylene Using Zero-Valent Zinc, Kui Chen, Jack E. Pender, John L. Ferry, S. Michael Angel

Faculty Publications

Resonance-enhanced multiphoton ionization (REMPI) is investigated as a potential technique for real-time monitoring of selected volatile organochloride compounds (VOCs). In a proof-of-concept experiment, the progress of the reductive-degradation of tetrachloroethylene (PCE) to trichloroethylene (TCE) by zero-valent zinc was monitored by REMPI measurements performed in the headspace above the PCE solution. Two-photon resonant REMPI spectra of TCE and PCE were recorded over the wavelength range 305–320 nm. The concentrations of PCE and TCE in the headspace were monitored by measurement of the ionization signal with 315.64- and 310.48-nm excitation for PCE and TCE, respectively. Calibration curves yielded a linear range of …

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Synthesis And Characterization Of Dendrimer Templated Supported Bimetallic Pt-Au Nanoparticles, Huifang Lang, S. Maldonado, K. J. Stevenson, Bert D. Chandler Sep 2004

Synthesis And Characterization Of Dendrimer Templated Supported Bimetallic Pt-Au Nanoparticles, Huifang Lang, S. Maldonado, K. J. Stevenson, Bert D. Chandler

Chemistry Faculty Research

Bimetallic dendrimer-stabilized nanoparticles (DSNs) were used to prepare supported Pt-Au catalysts within the bulk miscibility gap for this binary system. Hydroxy-terminated generation 5 PAMAM dendrimers were used to prepare Cu0 nanoparticles (NPs). The Cu0 NPs were subsequently used to reduce K2PtCl4 and HAuCl4, preparing stabilized bimetallic Pt-Au NPs with a 1:1 stoichiometry. The stabilized NPs were adsorbed onto a high surface area silica support and thermally activated to remove the dendrimers. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and infrared spectroscopy of adsorbed CO showed that this preparation route resulted in NPs in …

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Examination Of Technologies For Student-Generated Work In A Peer-Led, Peer-Review Instructional Environment, Brian P. Coppola, Alan L. Kiste Aug 2004

Examination Of Technologies For Student-Generated Work In A Peer-Led, Peer-Review Instructional Environment, Brian P. Coppola, Alan L. Kiste

Chemistry and Biochemistry

There is a growing literature demonstrating the effectiveness of using computer environments to assist students’ in visualizing science and mathematics concepts. However, with many of these computerized learning environments, students do not have the option of manipulating the environment. Instead, they are presented with pre-made visualizations. Enabling students to display their understanding through multiple representational forms is more interesting. In our peer-led, peer-review environment, students generate a complex, literature-based, multimedia text on which their final examination is based. However, there are great time and personnel costs in this design. Collaborating with SRI Inc., we are addressing these demands via the …

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Geminal Model Chemistry Ii. Perturbative Corrections, Vitaly A. Rassolov, Feng Xu, Sophya Garashchuk Jun 2004

Geminal Model Chemistry Ii. Perturbative Corrections, Vitaly A. Rassolov, Feng Xu, Sophya Garashchuk

Faculty Publications

We introduce and investigate a chemical model based on perturbative corrections to the product of singlet-type strongly orthogonal geminals wave function. Two specific points are addressed (i) Overall chemical accuracy of such a model with perturbative corrections at a leading order; (ii) Quality of strong orthogonality approximation of geminals in diverse chemical systems. We use the Epstein–Nesbet form of perturbation theory and show that its known shortcomings disappear when it is used with the reference Hamiltonian based on strongly orthogonal geminals. Application of this model to various chemical systems reveals that strongly orthogonal geminals are well suited for chemical models, …

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