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Articles 721 - 750 of 1553
Full-Text Articles in Chemistry
Combined Mössbauer Spectral And Density Functional Theory Determination Of The Magnetic Easy-Axis In Two High-Spin Iron(Ii) 2-Pyrazinecarboxylate Complexes, Gary J. Long, Stefania Tanase, Françoise Remacle, Ganga Periyasamy, Fernande Grandjean
Combined Mössbauer Spectral And Density Functional Theory Determination Of The Magnetic Easy-Axis In Two High-Spin Iron(Ii) 2-Pyrazinecarboxylate Complexes, Gary J. Long, Stefania Tanase, Françoise Remacle, Ganga Periyasamy, Fernande Grandjean
Chemistry Faculty Research & Creative Works
A combination of density functional theory (DFT) calculations and Mössbauer spectroscopy has been used to determine that the magnetic easy-axis is coincident with its crystallography c-axis in [Fe(pca) 2(py)2] · py, where pac is the 2- pyrazinecarboxylate ligand. This easy-axis bisects the approximately axial O-Fe-O coordination axes of molecules adjacent to each other along the c-axis. in {[Fe(pca)2(H2O)]-H2O) n the easy magnetic axis is not coincident with any of its crystallographic axes nor with the Fe-O(water) coordination axis, but is coincident with one of the Fe ... Fe axes in the crystal structure. the DFT calculations, …
Rapid Responders To Frovatriptan In Acute Migraine Treatment: Results From A Long-Term, Open-Label Study, Egilius L.H. Spierings, Egilius L.H. Spierings, Charlotte Keywood, Jeffrey Baggish, Harvey J. Blumenthal, Roger K. Cady, David H. Cook, Seymour Diamond, Keith R. Edwards, David L. Friedgood, Ronald C. Gove, Daniel B. Hier, Robert G. Kaniecki, David Kudrow
Rapid Responders To Frovatriptan In Acute Migraine Treatment: Results From A Long-Term, Open-Label Study, Egilius L.H. Spierings, Egilius L.H. Spierings, Charlotte Keywood, Jeffrey Baggish, Harvey J. Blumenthal, Roger K. Cady, David H. Cook, Seymour Diamond, Keith R. Edwards, David L. Friedgood, Ronald C. Gove, Daniel B. Hier, Robert G. Kaniecki, David Kudrow
Chemistry Faculty Research & Creative Works
Background. the Chronic Nature of Migraine and the Reliance on Acute Treatment Constitute the Basis of the Present Long-Term, Open-Label Study. Objectives. First, Assessment of the Tolerability and Safety of Frovatriptan, 2.5-7.5 Mg Taken Orally over 24 Hours, for the Acute Treatment of Migraine, Repeatedly over a 12-Month Period. Second, Assessment of the Efficacy and Tolerability of a Second, Double-Blind Dose of 2.5-Mg Frovatriptan, Compared with Placebo, for Nonresponse at 2 Hours after Treatment of Moderate or Severe Headache with 2.5-Mg Frovatriptan. Results. with Regard to the First Attack Treated, 173 (36%) of the 486 Subjects in the Study Did …
A Structural, Magnetic, And Mössbauer Spectral Study Of The Tbco₄₋ₓfeₓb Compounds With X=0, 1, And 2, Herv´ Mayot, Olivier Isnard, Fernande Grandjean, Gary J. Long
A Structural, Magnetic, And Mössbauer Spectral Study Of The Tbco₄₋ₓfeₓb Compounds With X=0, 1, And 2, Herv´ Mayot, Olivier Isnard, Fernande Grandjean, Gary J. Long
Chemistry Faculty Research & Creative Works
The TbCo4-x Fex B compounds with x=0, 1, and 2 have been investigated by x-ray and neutron diffraction, magnetic measurements, and iron-57 Mössbauer spectroscopy. The substitution of cobalt by iron induces both an anisotropic increase in the unit-cell volume and a large increase of approximately 250 K in the Curie temperature; the 4.2 K magnetization decreases continuously with increasing iron content. The powder neutron diffraction patterns and the Mössbauer spectra of the TbCo4-x Fex B compounds reveal a strong preferential substitution of iron for cobalt on the 2c site, small transition metal magnetic moments of approximately …
Developmental Expression Of Xenopus Myosin 1d And Identification Of A Myo1d Tail Homology That Overlaps Th1, Janine M. Leblanc-Straceski, Anna Sokac, William Bement, Pablo Sobrado, Laura Lemoine
Developmental Expression Of Xenopus Myosin 1d And Identification Of A Myo1d Tail Homology That Overlaps Th1, Janine M. Leblanc-Straceski, Anna Sokac, William Bement, Pablo Sobrado, Laura Lemoine
Chemistry Faculty Research & Creative Works
Xenopus laevis myosin 1d (XlMyo1d) is a member of the myosin I class, subclass 4. Members of this class are single headed, bind calmodulin light chains and have lipid binding domains in their tails. The rat myo1d homologue has been implicated in endosome vesicle recycling in epithelial cells. Mutations in the Drosophila myosin 1d homologue cause situs inversus in the abdomen. The XlMyo1d cDNA has been cloned and the derived amino acid sequence is 80% identical to the rat and human homologues. Sequence comparison revealed a novel isoform-specific tail homology embedded in the Tail Homology 1 (TH1) domain characteristic of …
Ccsd(T) Complete Basis Set Limit Relative Energies For Low-Lying Water Hexamer Structures, Desiree M. Bates, Gregory S. Tschumper
Ccsd(T) Complete Basis Set Limit Relative Energies For Low-Lying Water Hexamer Structures, Desiree M. Bates, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
MP2 and CCSD(T) complete basis set (CBS) limit relative electronic energies (ΔE e) have been determined for eight low-lying structures of the water hexamer by combining explicitly correlated MP2-R12 computations with higher-order correlation corrections from CCSD(T) calculations. Higher-order correlation effects are quite substantial and increase ΔE e by at least +0.19 kcalmol-1 and as much as +0.59 kcalmol-1. The effects from zero-point vibrational energy (ZPVE) have been assessed from unsealed harmonic vibrational frequencies computed at the MP2 level with a correlation consistent triple-̌ basis set (cc-pVTZ for H and aug-cc-pVTZ for O). ZPVE effects are even more …
Development Of Microbial And Enzymatic Fuel Cells For Bio-Inspired Power Sources, Fatih Dogan, Shelley Minteer
Development Of Microbial And Enzymatic Fuel Cells For Bio-Inspired Power Sources, Fatih Dogan, Shelley Minteer
Materials Science and Engineering Faculty Research & Creative Works
This report is based on some of the revolutionary concepts described in the Road Map on Bioinspired Power Systems within the AFRLRW Campus Challenge II. Development of biofuel cell concepts integrated with fuel regeneration and energy storage capabilities are proposed to create a compact and self-sustaining power system. The first part of this work identified a sediment based microbial fuel cell that could power small electronics and maintain electrical activity over long periods of time. AFRLRW does not feel that this work adequately addresses the original scope nor does it provide a basis on which to continue work. The second …
Influence Of The Rare-Earth Element On The Effects Of The Structural And Magnetic Phase Transitions In Cefeaso, Prfeaso And Ndfeaso, Michael A. Mcguire, Raphäel P. Hermann, Athena S. Sefat, Brian C. Sales, Rongying Jin, David Mandrus, Fernande Grandjean, Gary J. Long
Influence Of The Rare-Earth Element On The Effects Of The Structural And Magnetic Phase Transitions In Cefeaso, Prfeaso And Ndfeaso, Michael A. Mcguire, Raphäel P. Hermann, Athena S. Sefat, Brian C. Sales, Rongying Jin, David Mandrus, Fernande Grandjean, Gary J. Long
Chemistry Faculty Research & Creative Works
We present results of transport and magnetic properties and heat capacity measurements on polycrystalline CeFeAsO, PrFeAsO and NdFeAsO. These materials undergo structural phase transitions, spin density wave-like magnetic ordering of small moments on iron and antiferromagnetic ordering of rare-earth moments. The temperature dependence of the electrical resistivity, Seebeck coefficient, thermal conductivity, Hall coefficient and magnetoresistance are reported. The magnetic behavior of the materials have been investigated using Mössbauer spectroscopy and magnetization measurements. Transport and magnetic properties are affected strongly by the structural and magnetic transitions, suggesting significant changes in the band structure and/or carrier mobilities occur, and phonon-phonon scattering is …
Comparison Of Polarization Consistent And Correlation Consistent Basis Sets For Noncovalent Interactions, Adel M. Elsohly, Gregory S. Tschumper
Comparison Of Polarization Consistent And Correlation Consistent Basis Sets For Noncovalent Interactions, Adel M. Elsohly, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
The convergence of the polarization consistent family of basis sets to the MP2 complete basis set (CBS) limit has been examined for the dissociation energies of five weakly bound clusters: (HF)2, (HF)3, (H2O)2, (H2O)3, and (C2H2)2. MP2 results obtained with two series of polarization consistent basis sets and the analogous series of Dunning's correlation consistent basis sets are compared to the CBS limits obtained with the explicitly correlated MP2-R12 method. Although the polarization consistent basis sets do converge systematically to the CBS …
Electrodeposition Of Inorganic Materials With Tailored Shapes And Chiral Morphologies, Elizabeth A. Kulp
Electrodeposition Of Inorganic Materials With Tailored Shapes And Chiral Morphologies, Elizabeth A. Kulp
Doctoral Dissertations
"This dissertation investigates the electrodeposition of metal oxide films and biomaterial deposits on polycrystalline and single crystal substrates. Paper I describes the mechanisms and the characterization of an electrodeposited polycrystalline insulator, ceria (CeO₂), on Hastelloy substrates produced by the electrochemical oxidation of Ce(III) acetate complexes. In Paper II, epitaxial films of magnetite (Fe₃O₄) and ferrihydrite (Fe₁₀O₁₄(OH)₂) are deposited on gold single crystals. Paper III reports the electrodeposition of epitaxial Fe₃O₄ and zinc ferrite (ZnFe₂O₄) periodic nanostructures known as superlattices by pulsing between two potentials. Papers IV and V describe chiral electrodeposition. In Paper IV, epitaxial, chiral orientations of cupric oxide …
Earth's Heat Source -- The Sun, Oliver Manuel
Earth's Heat Source -- The Sun, Oliver Manuel
Chemistry Faculty Research & Creative Works
The Sun encompasses planet Earth, supplies the heat that warms it, and even shakes it. The United Nation's Intergovernmental Panel on Climate Change (IPCC) assumed that solar influence on Earth's climate is limited to changes in solar irradiance and adopted the consensus opinion of a hydrogen-filled Sun - the Standard Solar Model (SSM). They did not consider the alternative solar model and instead adopted another consensus opinion: Anthropogenic greenhouse gases play a dominant role in climate change. The SSM fails to explain the solar wind, solar cycles, and the empirical link of solar surface activity with Earth's changing climate. The …
Phonon Confinement Effects In The Raman Spectrum Of Nanodiamond, Sebastian Osswald, Vadym Mochalin, Mickaël Havel, Gleb N. Yushin, Yury G. Gogotsi
Phonon Confinement Effects In The Raman Spectrum Of Nanodiamond, Sebastian Osswald, Vadym Mochalin, Mickaël Havel, Gleb N. Yushin, Yury G. Gogotsi
Chemistry Faculty Research & Creative Works
Nanodiamonds (ND) exhibit unique properties due to their small size and high surface-to-volume ratio compared to bulk diamonds. A reduction in crystal size also affects ND Raman spectra. The confinement of optical phonons in nanocrystals (<10 nm) results in asymmetrically broadened Raman lines, which are shifted toward lower wavenumbers. The phonon confinement model (PCM) relates the observed changes in the Raman spectra to the crystal size and can be used for size characterization at the nanoscale. While the PCM was successfully applied to a variety of materials including Si and BN, results remained unsatisfactory in the case of ND. In order to improve the agreement between the predictions of the model and experimental Raman spectra of ND, effects such as crystal size distribution, lattice defects, and the energy dispersion of the phonon modes were taken into consideration and incorporated into the PCM. This work has shown that phonon wave vectors from small vibrational domains lead to a broad shoulder peak at ~1250 cm-1, that is often observed in the Raman spectrum of ND.
Risk Indexes For Draft Ccl3 Chemicals, J. Alan Roberson, Matthew Lueders, Craig Adams, Jeffrey S. Rosen
Risk Indexes For Draft Ccl3 Chemicals, J. Alan Roberson, Matthew Lueders, Craig Adams, Jeffrey S. Rosen
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
To supplement the processes used for developing the draft third Contaminant Candidate List (CCL3) and better inform decisions made by the US Environmental Protection Agency on future CCLs, the authors offer an evaluation tool for efficiently synthesizing, visualizing, and organizing data for effective comparisons among contaminants. Graphical presentations of health effects-occurrence indexes were developed for more than 300 chemical contaminants, including those on the draft CCL3. a risk indexes framework was then used to elucidate the extent of available data, the data quality, and the underlying uncertainties for occurrence and toxicity. Choosing the appropriate contaminant for regulation is a complex …
Structural Study On Ammonia Borane For Hydrogen Storage, William Joseph James, L. Jagat, Q. Cai, William B. Yelon, J. B. Yang
Structural Study On Ammonia Borane For Hydrogen Storage, William Joseph James, L. Jagat, Q. Cai, William B. Yelon, J. B. Yang
Chemistry Faculty Research & Creative Works
Ammonia borane (BH3NH3) is a promising hydrogen storage material because of its high gravimetric (19.6 wt.% H2) and volumetric hydrogen density with an accompanying moderate decomposition temperature. Previously reported structures determined by using x-ray and neutron diffraction on hydrides show differences in bond lengths and atomic coordination. Here, the crystal structures of fully and half deuterated ammonia borane were investigated as a function of temperature using powder neutron diffraction. the neutron diffraction patterns show a significant difference due to large difference in the scattering length of D and H. It is evident that an order-disorder phase transition occurs around 225 …
Investigation Of The Interactions Between Selected Nanoparticles And Human Lung Carcinoma Cells At The Single Cell And Single Particle Level, Isaac Stayton
Doctoral Dissertations
"The recent advances in nanomaterials development and applications have sparked concerns regarding the safety of these materials in living organisms. This body of work investigates specific interactions between chosen nanoparticles and living human lung carcinoma (A549) cells"--Abstract, page iv.
A Study Of The Beneficial Role Of Thiol Antioxidant Supplementation In Various Forms Of Glutathione Deficiency, Linu Sara Abraham
A Study Of The Beneficial Role Of Thiol Antioxidant Supplementation In Various Forms Of Glutathione Deficiency, Linu Sara Abraham
Doctoral Dissertations
"Oxidative stress plays a major role in the pathology of numerous disorders afflicting humans, ranging from neurodegenerative diseases, to cancer, and heavy metal toxicity. Scientists are on the constant lookout for new and better antioxidants that have the ability to slow, if not stop the harmful degenerative effects of free radicals in oxidative stress related disorders. Both synthetic and naturally occurring compounds are being constantly screened for their antioxidant properties. This study attempted to evaluate the abilities of a thiol antioxidant, N-Acetylcysteine amide (NACA), to protect cells from the harmful effects of glutathione depletion in two different models of oxidative …
F₂-Isoprostanes Study After Exposure To Selected Nanoparticles By Liquid Chromatography/Tandem Mass Spectrometry And Investigation Of Nanoparticles On The Cytotoxicity Effect Of Arsenic In Vitro, Xiaoqian Liu
Doctoral Dissertations
"Nanopartices as a new class of materials found their applications in industry, aerospace, clinical diagnosis and cancer therapy. Recently, the health effects of nanoparticles have caused people great concerns. This dissertation studies the mechanisms of nanoparticle cytotoxicity in human lung epithelial cells (A549). F₂-isoprostanes are novel reliable biomarkers for lipid peroxidation. In the first part of this work, total free F₂-isoprostanes were quantified by high performance liquid chromatography/mass spectrometry followed by the exposure of SiO₂ (15 nm), CeO₂ (20 nm), Fe₂O₃ (30 nm), and ZnO (70 nm) nanoparticles for 24 hours. For the first time, the results showed that F₂-isoprostanes …
Using Clinical Decision Support To Maintain Medication And Problem Lists: A Pilot Study To Yield Higher Patient Safety, Chiang S. Jao, Daniel B. Hier, William L. Galanter
Using Clinical Decision Support To Maintain Medication And Problem Lists: A Pilot Study To Yield Higher Patient Safety, Chiang S. Jao, Daniel B. Hier, William L. Galanter
Chemistry Faculty Research & Creative Works
To Investigate Whether Clinical Decision Support that Automates the Matching of Ordered Drugs to Problems (Clinical Diagnoses) on the Problem List Can Enhance the Maintenance of Both Medication and Problem Lists in the Electronic Medical Record, We Designed a Clinical Decision Support System to Match Ordered Drugs on the Medication List and Ongoing Problems on the Problem List. We Evaluated the Capability and Performance of This Clinical Decision Support System in Medication-Problem Matching using Physician Expert Chart Audits to Match Ordered Drugs to Ongoing Clinical Problems. a Clinical Decision Support System Was Shown to Be Useful in Improving Medication-Problem Matches …
Probing Phenylalanine/Adenine Π-Stacking Interactions In Protein Complexes With Explicitly Correlated And Ccsd(T) Computations, Kari L. Copeland, Julie A. Anderson, Adam R. Farley, James R. Cox, Gregory S. Tschumper
Probing Phenylalanine/Adenine Π-Stacking Interactions In Protein Complexes With Explicitly Correlated And Ccsd(T) Computations, Kari L. Copeland, Julie A. Anderson, Adam R. Farley, James R. Cox, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
To examine the effects of π-stacking interactions between aromatic amino acid side chains and adenine bearing ligands in crystalline protein structures, 26 toluene/(N9-methyl) adenine model configurations have been constructed from protein/ligand crystal structures. Full geometry optimizations with the MP2 method cause the 26 crystal structures to collapse to six unique structures. The complete basis set (CBS) limit of the CCSD(T) interaction energies has been determined for all 32 structures by combining explicitly correlated MP2-R12 computations with a correction for higher-order correlation effects from CCSD(T) calculations. The CCSD(T) CBS limit interaction energies of the 26 crystal structures range from -3.19 to …
Three-Dimensional Modeling Of The Plasma Arc In Arc Welding, Gu Xu, J. Hu, Hai-Lung Tsai
Three-Dimensional Modeling Of The Plasma Arc In Arc Welding, Gu Xu, J. Hu, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Most previous three-dimensional modeling on gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) focuses on the weld pool dynamics and assumes the two-dimensional axisymmetric Gaussian distributions for plasma arc pressure and heat flux. In this article, a three-dimensional plasma arc model is developed, and the distributions of velocity, pressure, temperature, current density, and magnetic field of the plasma arc are calculated by solving the conservation equations of mass, momentum, and energy, as well as part of the Maxwell's equations. This three-dimensional model can be used to study the nonaxisymmetric plasma arc caused by external perturbations such as …
Ex Situ Variable Angle Spectroscopic Ellipsometry Studies On Chemical Vapor Deposited Boron-Doped Diamond Films: Layered Structure And Modeling Aspects, S. Gupta, A. Dudipala, O. A. Williams, K. Haenen, Eric W. Bohannan
Ex Situ Variable Angle Spectroscopic Ellipsometry Studies On Chemical Vapor Deposited Boron-Doped Diamond Films: Layered Structure And Modeling Aspects, S. Gupta, A. Dudipala, O. A. Williams, K. Haenen, Eric W. Bohannan
Chemistry Faculty Research & Creative Works
We report the optical property measurements on boron-doped diamond (BDD) films which were synthesized by microwave plasma-assisted chemical vapor deposition technique on Si (100) using methane in high hydrogen dilution and trimethylboron as precursors with varying boron concentration such that [B] [C]gas =100, 500, 1000, 2000, 4000, and 6467 ppm. These BDD films were investigated using a rotating analyzer variable angle spectroscopic ellipsometry (SE) from the near IR to UV range (830-193 nm). by applying the conventional Bruggeman effective medium approximation and linear regression analyses to the raw SE data that is, [ψ (λi),Δ (λi)] and pseudodielectric function (〈 εr …
Iron Oxide Deposits Associated With The Ectosymbiotic Bacteria In The Hydrothermal Vent Shrimp Rimicaris Exoculata, Laure Corbari, Marie Anne Cambon-Bonavita, Gary J. Long, Fernande Grandjean, Magali Zbinden, Françoise Gaill, Philippe Compère
Iron Oxide Deposits Associated With The Ectosymbiotic Bacteria In The Hydrothermal Vent Shrimp Rimicaris Exoculata, Laure Corbari, Marie Anne Cambon-Bonavita, Gary J. Long, Fernande Grandjean, Magali Zbinden, Françoise Gaill, Philippe Compère
Chemistry Faculty Research & Creative Works
The Rimicaris exoculata shrimp is considered as a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR) hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The structure and elemental composition of the mineral concretions associated with these bacteria have been investigated by using LM, ESEM, TEM STEM and EDX microanalyses. The nature of the iron oxides in shrimps obtained from the Rainbow vent field has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three layers of mineral crust in the …
Phase Transitions In Lafeaso: Structural, Magnetic, Elastic, And Transport Properties, Heat Capacity And Mössbauer Spectra, Michael A. Mcguire, Andrew D. Christianson, Athena S. Sefat, Brian C. Sales, Mark D. Lumsden, Rongying Jin, Edward Andrew Payzant, David G. Mandrus, Yanbing Luan, Veerle M. Keppens, Vijayalaksmi Varadarajan, Joseph W. Brill, Raphäel P. Hermann, M. T. Sougrati, Fernande Grandjean, Gary J. Long
Phase Transitions In Lafeaso: Structural, Magnetic, Elastic, And Transport Properties, Heat Capacity And Mössbauer Spectra, Michael A. Mcguire, Andrew D. Christianson, Athena S. Sefat, Brian C. Sales, Mark D. Lumsden, Rongying Jin, Edward Andrew Payzant, David G. Mandrus, Yanbing Luan, Veerle M. Keppens, Vijayalaksmi Varadarajan, Joseph W. Brill, Raphäel P. Hermann, M. T. Sougrati, Fernande Grandjean, Gary J. Long
Chemistry Faculty Research & Creative Works
We present results from a detailed experimental investigation of LaFeAsO, the parent material in the series of “FeAs” based oxypnictide superconductors. Upon cooling, this material undergoes a tetragonal-orthorhombic crystallographic phase transition at ~160 K followed closely by an antiferromagnetic ordering near 145 K. Analysis of these phase transitions using temperature dependent powder x-ray and neutron-diffraction measurements is presented. A magnetic moment of ~0.35µB per iron is derived from Mössbauer spectra in the low-temperature phase. Evidence of the structural transition is observed at temperatures well above the transition temperature (up to near 200 K) in the diffraction data as well …
Photorefractivity In A Polymeric Composite Photosensitized With Nis Nanocrystals, Tyler M. Fears, Charles Anderson, Jeffrey G. Winiarz
Photorefractivity In A Polymeric Composite Photosensitized With Nis Nanocrystals, Tyler M. Fears, Charles Anderson, Jeffrey G. Winiarz
Chemistry Faculty Research & Creative Works
The photorefractive performance of a polymeric composite photosensitized through the inclusion of NiS nanocrystals is described. The nanocrystals were characterized using visible-absorption spectroscopy, energy-dispersive x-ray spectroscopy, and transmission electron microscopy. We further demonstrate the ability to enhance various aspects of the composite's photorefractive performance by performing ligand exchange on the nanocrystals prior to their incorporation into the polymer composite. This procedure resulted in a lowering of the overmodulation voltage from ~70 to ~50 V/µm without affecting the maximum diffraction efficiency of ~40%. An increase in the two-beam-coupling gain coefficient was similarly observed, increasing from 38 to 79 cm−1. The photoconductivities …
Photolithographically Patterned Covalently Bonded Polythiophene Films Using In Tandem Sol-Gel, Surface Initiated Free Radical And Redox Polymerization Methods, Anand Ghanashyam Sedekar, Naveen Chandrasekaran, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis
Photolithographically Patterned Covalently Bonded Polythiophene Films Using In Tandem Sol-Gel, Surface Initiated Free Radical And Redox Polymerization Methods, Anand Ghanashyam Sedekar, Naveen Chandrasekaran, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis
Chemistry Faculty Research & Creative Works
A bifunctional monomer, 3,4-bis(vinyloxy)thiophene (BVOT), that can be polymerized both by radical as well as by redox chemistry was utilized in the fabrication of lithographic patterns of conducting polymer films via a sol-gel method. The judicious use of several chemistries yields polythiophene patterns covalently bonded to substrate showing superior adhesion relative to physically bonded counterparts. The films were characterized electrically and mechanically. Surface confinement starts with a bidentate free radical initiator (Si-AIBN) synthesized via condensation reaction between 3-aminopropyltriethoxysilane (APTES) and azobiscyano-valeric acid. Si-AIBN is attached to the surface of glass by hydrolysis of the ethoxy groups and reaction with the …
Preparation Of Macroporous Conductive Carbon Cerogels From Pyrolysis Of Isocyanate-Crosslinked Resorcinol Formaldehyde Aerogels, Sudhir Mulik, Nicholas Leventis, Chariklia Sotiriou-Leventis
Preparation Of Macroporous Conductive Carbon Cerogels From Pyrolysis Of Isocyanate-Crosslinked Resorcinol Formaldehyde Aerogels, Sudhir Mulik, Nicholas Leventis, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
Carbon aerogels combine typical aerogal properties such as high surface area and low density with electrical conductivity. They are prepared by pyrolysis under N2 or Ar at 600-2100 degrees C of resorcinol formaldehyde (RF) aerogels, which in turn are prepared via aqueous sol-gel chemistry. Carbon aerogels are considered for numerous applications such as separation media in HPLC, as supercapacitors, as materials for hydrogen storage, as non-reflective materials, and as anodes in lithium-ion batteries. Meanwhile, porous carbons with high hydrophobic surface areas and large pore volumes are used as industrial adsorbents. In addition, macropores enhance mass transport for applicatoins in energy …
Probing The Effects Of Heterogeneity On Delocalized Π⋯Π Interaction Energies, Desiree M. Bates, Julie A. Anderson, Ponmile Oloyede, Gregory S. Tschumper
Probing The Effects Of Heterogeneity On Delocalized Π⋯Π Interaction Energies, Desiree M. Bates, Julie A. Anderson, Ponmile Oloyede, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
Dimers composed of benzene (Bz), 1,3,5-triazine (Tz), cyanogen (Cy) and diacetylene (Di) are used to examine the effects of heterogeneity at the molecular level and at the cluster level on π⋯π stacking energies. The MP2 complete basis set (CBS) limits for the interaction energies (E int) of these model systems were determined with extrapolation techniques designed for correlation consistent basis sets. CCSD(T) calculations were used to correct for higher-order correlation effects (δECCSD(T)MP2) which were as large as +2.81 kcal mol-1. The introduction of nitrogen atoms into the parallel-slipped dimers of the aforementioned molecules causes significant changes to E …
A Structural, Magnetic, And Mössbauer Spectral Study Of The Dyco₄₋ₓfeₓb Compounds, With X=0-3, Hervé Mayot, Olivier Isnard, Fernande Grandjean, Gary J. Long
A Structural, Magnetic, And Mössbauer Spectral Study Of The Dyco₄₋ₓfeₓb Compounds, With X=0-3, Hervé Mayot, Olivier Isnard, Fernande Grandjean, Gary J. Long
Chemistry Faculty Research & Creative Works
The DyCo4-xFexB compounds, with x=0, 1, 1.5, 2, 2.5, and 3, have been investigated by x-ray diffraction, magnetic measurements, and iron-57 Mössbauer spectroscopy. The substitution of cobalt by iron induces both an anisotropic increase in the unit-cell volume and a large increase in the Curie temperature. The 4.2 K magnetization decreases with increasing iron content. The Mössbauer spectra of the DyCo4-xFexB compounds with x=1, 1.5, and 2 reveal rather small iron hyperfine fields of approximately 16 T and large quadrupole interactions of +1.0 and -1.0 mms, for the 6i and 2c sites, …
Method Of Preparing A Chiral Substrate Surface By Electrodeposition, Jay A. Switzer, Hiten M. Kothari, Shuji Nakanishi, Eric W. Bohannan
Method Of Preparing A Chiral Substrate Surface By Electrodeposition, Jay A. Switzer, Hiten M. Kothari, Shuji Nakanishi, Eric W. Bohannan
Chemistry Faculty Research & Creative Works
A solid substrate comprising a surface comprising an achiral array of atoms having thereupon a chiral metal oxide surface. The chiral metal oxide surface is prepared by electrodeposition of a chiral metal oxide array from a solution of a chiral salt of the metal. In one embodiment, chiral CuO is grown on achiral Au(001) by epitaxial electrodeposition. The handedness of the film is determined by the specific enantiomer of tartrate ion in the deposition solution. (R,R)- tartrate produces an S—CuO(l 1 T) film, while (S,S)-tartrate produces an R—CuO(Tl 1) film. These chiral CuO films are enantiospecific for the electrochemical oxidation …
Synthesis And Characterization Of Two Metallic Spin-Glass Phases Of Femo₄Ge₃, Peter J. Baker, Peter D. Battle, Stephen J. Blundell, Fernande Grandjean, Thomas M. Lancaster, Gary J. Long, Sophie E. Oldham, Timothy John Prior
Synthesis And Characterization Of Two Metallic Spin-Glass Phases Of Femo₄Ge₃, Peter J. Baker, Peter D. Battle, Stephen J. Blundell, Fernande Grandjean, Thomas M. Lancaster, Gary J. Long, Sophie E. Oldham, Timothy John Prior
Chemistry Faculty Research & Creative Works
Polycrystalline samples of FeMo4Ge3 have been synthesized by the reduction of an oxide mixture at 1248 K and characterized by a combination of diffraction, muon spin relaxation (µ+SR), Mössbauer spectroscopy, magnetometry, transport, and heat-capacity measurements. The compound adopts a tetragonal W5Si3 structure (space group I4/mcm); the iron and molybdenum atoms are disordered over two crystallographic sites, 16k and either 4a or 4b. The synthesis conditions determine which fourfold site is selected; occupation of either leads to the presence of one-dimensional chains of transition metals in the structure. In both cases, …
Effects Of Ionic Strength, Temperature, And Ph On Degradation Of Selected Antibiotics, Keith A. Loftin, Craig D. Adams, Michael T. Meyer, Rao Surampalli
Effects Of Ionic Strength, Temperature, And Ph On Degradation Of Selected Antibiotics, Keith A. Loftin, Craig D. Adams, Michael T. Meyer, Rao Surampalli
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Aqueous degradation rates, which include hydrolysis and epimerization, for chlorretracycline (CTC), oxytetracycline (OTC), tetracycline (TET), lincomycin (LNC), sulfachlorpyridazine (SCP), sulfadimethoxine (SDM), sulfathiazole (STZ), trimethoprim (TRM), and tylosin a (TYL) were studied as a function of ionic strength (0.0015, 0.050, or 0.084 mg/L as Na2HPO4), temperature (7, 22, and 35°C), and pH (2, 5, 7, 9, and 11). Multiple linear regression revealed that ionic strength did not significantly affect (α = 0.05) degradation rates for all compounds, but temperature and pH affected rates for CTC, OTC, and TET significand (α = 0.05). Degradation also was observed for TYL at pH 2 …