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Articles 901 - 930 of 1131

Full-Text Articles in Physical Sciences and Mathematics

Experimental And Theoretical Studies On The Pharmacodynamics Of Cisplatin In Jurkat Cells, Kirk A. Tacka, Dava Szalda, Abdul-Kader Souid, Jerry Goodisman, James C. Dabrowiak May 2004

Experimental And Theoretical Studies On The Pharmacodynamics Of Cisplatin In Jurkat Cells, Kirk A. Tacka, Dava Szalda, Abdul-Kader Souid, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

For Jurkat cells in culture exposed to cisplatin (1), we measured the number of platinum adducts on DNA and showed that it is proportional to the AUC, the area under the concentration vs time curve, for cisplatin. The number of platinum-DNA adducts is measured immediately following exposure to drug. The AUC is calculated either as the product of the initial cisplatin concentration and the exposure time or as the integral under the concentration vs time curve for the unreacted dichloro species, which decreases exponentially. We also show that the number of adducts correlates with decreases in respiration, with the amount …


Bohmian Dynamics On Subspaces Using Linearized Quantum Force, Vitaly A. Rassolov, Sophya Garashchuk Apr 2004

Bohmian Dynamics On Subspaces Using Linearized Quantum Force, Vitaly A. Rassolov, Sophya Garashchuk

Faculty Publications

In the de Broglie–Bohm formulation of quantum mechanics the time-dependent Schrödinger equation is solved in terms of quantum trajectories evolving under the influence of quantum and classical potentials. For a practical implementation that scales favorably with system size and is accurate for semiclassical systems, we use approximate quantum potentials. Recently, we have shown that optimization of the nonclassical component of the momentum operator in terms of fitting functions leads to the energy-conserving approximate quantum potential. In particular, linear fitting functions give the exact time evolution of a Gaussian wave packet in a locally quadratic potential and can describe the dominant …


A Subgroup Algorithm To Identify Cross-Rotation Peaks Consistent With Non-Crystallographic Symmetry, Ryan H. Lilien, Chris Bailey-Kellogg, Amy C. Anderson, Bruce R. Donald Mar 2004

A Subgroup Algorithm To Identify Cross-Rotation Peaks Consistent With Non-Crystallographic Symmetry, Ryan H. Lilien, Chris Bailey-Kellogg, Amy C. Anderson, Bruce R. Donald

Dartmouth Scholarship

Molecular replacement (MR) often plays a prominent role in determining initial phase angles for structure determination by X-ray crystallography. In this paper, an efficient quaternion-based algorithm is presented for analyzing peaks from a cross-rotation function in order to identify model orientations consistent with proper non-crystallographic symmetry (NCS) and to generate proper NCS-consistent orientations missing from the list of cross-rotation peaks. The algorithm, CRANS, analyzes the rotation differences between each pair of cross-rotation peaks to identify finite subgroups. Sets of rotation differences satisfying the subgroup axioms correspond to orientations compatible with the correct proper NCS. The CRANS algorithm was first …


Effects Of Cisplatin On Mitochondrial Function In Jurkat Cells, Kirk Tacka, James C. Dabrowiak, Jerry Goodisman, Harvey S. Penefsky, Abdul Kader Souid Jan 2004

Effects Of Cisplatin On Mitochondrial Function In Jurkat Cells, Kirk Tacka, James C. Dabrowiak, Jerry Goodisman, Harvey S. Penefsky, Abdul Kader Souid

Chemistry - All Scholarship

In this work, we measured the effects of pharmacological concentrations of cisplatin (cis-diaminedichloroplatinum II) on mitochondrial function, cell viability, and DNA fragmentation in Jurkat cells. The exposure of cells to 0-25 microM cisplatin for 3 h had no immediate effect on cellular mitochondrial oxygen consumption, measured using a palladium-porphyrin oxygen sensing phosphor. Similarly, the cell viability as measured by trypan blue staining was unchanged immediately following exposure to the drug, and no small DNA fragments, characteristic of drug-induced apoptosis, appeared. At 24 h after exposure to cisplatin, cellular respiration and viability decreased relative to controls and the amount of small …


Energy Conserving Approximations To The Quantum Potential: Dynamics With Linearized Quantum Force, Sophya Garashchuk, Vitaly A. Rassolov Jan 2004

Energy Conserving Approximations To The Quantum Potential: Dynamics With Linearized Quantum Force, Sophya Garashchuk, Vitaly A. Rassolov

Faculty Publications

Solution of the Schrödinger equation within the de Broglie–Bohm formulation is based on propagation of trajectories in the presence of a nonlocal quantum potential. We present a new strategy for defining approximate quantum potentials within a restricted trial function by performing the optimal fit to the log-derivatives of the wave function density. This procedure results in the energy-conserving dynamics for a closed system. For one particular form of the trial function leading to the linear quantum force, the optimization problem is solved analytically in terms of the first and second moments of the weighted trajectory distribution. This approach gives exact …


The Equation, Winter 2004, College Of Science And Mathematics, Wright State University Jan 2004

The Equation, Winter 2004, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 6 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.


Water Quality Assessment: A Hands-On Approach To Environmental Education, Tracy Lynn Royse Jan 2004

Water Quality Assessment: A Hands-On Approach To Environmental Education, Tracy Lynn Royse

All Graduate Projects

A water quality assessment lab manual has been created to assist secondary educators using the HACH water quality testing kits. It consists of ten chemical tests, a geological survey and a biological assessment largely based upon Washington State University's lab format and the Walla Walla County Conservation District's water study protocol. The lab manual also contains safety guidelines, a scoring rubric and an action plan research project. The environmental approach to science education used in the lab manual meets the Essential Academic Learning Requirements adopted by the Washington State Commission on Student Learning as well as the National Science Education …


The Activity Of Silicon Carbide Particles In Al-Based Metal Matrix Composites Revealed By Scanning Electrochemical Microscopy, David O. Wipf, L. Díaz-Ballote, L. Veleva, M. A. Pech-Canul, M. I. Pech-Canul Jan 2004

The Activity Of Silicon Carbide Particles In Al-Based Metal Matrix Composites Revealed By Scanning Electrochemical Microscopy, David O. Wipf, L. Díaz-Ballote, L. Veleva, M. A. Pech-Canul, M. I. Pech-Canul

CAS Publications

Scanning electrochemical microscopy (SECM) is used to image variations in electrochemical activity over the surface of an aluminum-based metal matrix composite (MMC) in contact with buffered or unbuffered neutral solutions. The composite consists of an Al - 13.5% Si - 9% Mg alloy matrix and reinforcing silicon carbide particles (SiCp). Feedback mode SECM imaging using ferrocenemethanol as a redox mediator in 0.1 M NaCl solution and in buffer solution (pH 6.8) revealed that the SiC particles are electrochemically active. The data suggest that the electronic conductivity at these sites is higher than that of the Al2O …


Modeling Longleaf Pine (Pinus Palustris Mill) Wood Properties Using Near Infrared Spectroscopy, Brian Kipling Via Jan 2004

Modeling Longleaf Pine (Pinus Palustris Mill) Wood Properties Using Near Infrared Spectroscopy, Brian Kipling Via

LSU Doctoral Dissertations

This research demonstrated model development for important wood properties using near infrared spectroscopy (NIR); it considered the effect of outside sources of error, and the ability of NIR to measure fiber morphology. Strength, stiffness, and density were successfully modeled from wood samples taken throughout 10 longleaf (Pinus palustris Mill) trees. Principal components and multiple linear regression were compared for performance in prediction of density, strength, and stiffness. I found both modeling techniques to yield similar prediction accuracies. However, I found that density could be estimated through Beer-Lambert’s law since the absorbance at all wavelengths increased with density. Also, 5 of …


Using Microenvironmental Effects To Increase Loading And Stereoselectivity For Polymer Bound Nabh4 Reagents., James R. Blanton Jan 2004

Using Microenvironmental Effects To Increase Loading And Stereoselectivity For Polymer Bound Nabh4 Reagents., James R. Blanton

Journal of the South Carolina Academy of Science

No abstract provided.


Development Of Electrochemical Sensors For Monitoring Glucose, Michael Nesbitt Jan 2004

Development Of Electrochemical Sensors For Monitoring Glucose, Michael Nesbitt

Theses

The thesis focuses on evaluating calcium alginate as an immobilisation matrix for the oxidase enzyme glucose oxidase for the amperometric determination of glucose. The basic principles of enzymology and enzyme immobilisation is discussed followed by a review of a variety of first, second and third generation type enzyme electrodes. Amperometry as governed by the Cottrell equation and mass transfer models relating to amperometric electrodes are also considered.

Bovine serum albumin (BSA / GOx) enzyme electrode system was employed as a model to evaluate a calcium alginate immobilisation technique for glucose oxidase. The principal methods employed for enzyme immobilisation were:

• …


Pyridoxamine Traps Intermediates In Lipid Peroxidation Reactions In Vivo: Evidence On The Role Of Lipids In Chemical Modification Of Protein And Development Of Diabetic Complications, Thomas O. Metz, Nathan L. Alderson, Mark E. Chachich, Suzanne R. Thorpe, John W. Baynes Oct 2003

Pyridoxamine Traps Intermediates In Lipid Peroxidation Reactions In Vivo: Evidence On The Role Of Lipids In Chemical Modification Of Protein And Development Of Diabetic Complications, Thomas O. Metz, Nathan L. Alderson, Mark E. Chachich, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

Maillard or browning reactions between reducing sugars and protein lead to formation of advanced glycation end products (AGEs) and are thought to contribute to the pathogenesis of diabetic complications. AGE inhibitors such as aminoguanidine and pyridoxamine (PM) inhibit both the formation of AGEs and development of complications in animal models of diabetes. PM also inhibits the chemical modification of protein by advanced lipoxidation end products (ALEs) during lipid peroxidation reactions in vitro. We show here that several PM adducts, formed in incubations of PM with linoleate and arachidonate in vitro, are also excreted in the urine of PM-treated animals. The …


The Equation, Fall 2003, College Of Science And Mathematics, Wright State University Oct 2003

The Equation, Fall 2003, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 6 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.


Bis[Μ-1,2-Bis(2-Pyridyl)Ethyne-K2N:N']Bis[Aquadinitratocadmium(Ii)], Badruz Zaman Md., Matthew J. Davis, Mark D. Smith, Hans Conrad Zur Loye Jun 2003

Bis[Μ-1,2-Bis(2-Pyridyl)Ethyne-K2N:N']Bis[Aquadinitratocadmium(Ii)], Badruz Zaman Md., Matthew J. Davis, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

Two twisted 1,2-bis(2-pyridyl)ethyne ligands bridge two Cd2+ centers in the C2-symmetric title complex, [Cd2(NO3)4(-C12H8N2)2(H2O)2]. The bridging ligands arch across one another creating a `zigzag loop' molecular geometry. Two nitrate ions and a water molecule complete the irregular seven-coordinate Cd-atom environment. The dihedral angles between the equivalent pyridyl ring planes of the two independent ligands are 67.2 (1)°. Owater-HOnitrate hydrogen bonding creates two-dimensional layers parallel to the ab plane.

Formula: [Cd2(NO3)4(C …


Regulation And Localization Of Endogenous Human Tristetraprolin, Anna-Marie Fairhurst, John E. Connolly, Katharine A Hintz, Nicolas J Goulding May 2003

Regulation And Localization Of Endogenous Human Tristetraprolin, Anna-Marie Fairhurst, John E. Connolly, Katharine A Hintz, Nicolas J Goulding

Dartmouth Scholarship

Tumor necrosis factor (TNF) has been implicated in the development and pathogenicity of infectious diseases and autoimmune disorders, such as septic shock and arthritis. The zinc-finger protein tristetraprolin (TTP) has been identified as a major regulator of TNF biosynthesis. To define its intracellular location and examine its regulation of TNF, a quantitive intracellular staining assay specific for TTP was developed. We establish for the first time that in peripheral blood leukocytes, express


Sr3Mgpto6, Mark D. Smith, Hans Conrad Zur Loye May 2003

Sr3Mgpto6, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

Single crystals of the mixed alkaline earth platinate, tristrontium magnesium platinum hexaoxide, Sr3MgPtO6, were grown from a KOH flux at 1273 K. The compound adopts the rhombohedral K4CdCl6 structure type, featuring chains of face-shared, distorted MgO6 trigonal prisms (Mg site symmetry 32) and PtO6 octahedra (Pt site symmetry ) surrounded by columns of Sr2+ ions (Sr site symmetry 2).


Asymmetric Transfer Hydrogenation Of Allylic Alcohols, Joseph M. Laquidara May 2003

Asymmetric Transfer Hydrogenation Of Allylic Alcohols, Joseph M. Laquidara

Seton Hall University Dissertations and Theses (ETDs)

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Semiclassical Dynamics With Quantum Trajectories: Formulation And Comparison With The Semiclassical Initial Value Representation Propagator, Sophya Garashchuk, Vitaly A. Rassolov Feb 2003

Semiclassical Dynamics With Quantum Trajectories: Formulation And Comparison With The Semiclassical Initial Value Representation Propagator, Sophya Garashchuk, Vitaly A. Rassolov

Faculty Publications

We present a time-dependent semiclassical method based on quantum trajectories. Quantum-mechanical effects are described via the quantum potential computed from the wave function density approximated as a linear combination of Gaussian fitting functions. The number of the fitting functions determines the accuracy of the approximate quantum potential (AQP). One Gaussian fit reproduces time-evolution of a Gaussian wave packet in a parabolic potential. The limit of the large number of fitting Gaussians and trajectories gives the full quantum-mechanical result. The method is systematically improvable from classical to fully quantum. The fitting procedure is implemented as a gradient minimization. We also compare …


Investigation Of Model Cell Membrane Disruption Via Fluorescence And Light Scattering Techniques, Imara Charles Jan 2003

Investigation Of Model Cell Membrane Disruption Via Fluorescence And Light Scattering Techniques, Imara Charles

Seton Hall University Dissertations and Theses (ETDs)

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The Biophysical Basis Of Triplet Repeat Dna Expansion In Genetic Disease, Anthony M. Paiva Aug 2002

The Biophysical Basis Of Triplet Repeat Dna Expansion In Genetic Disease, Anthony M. Paiva

Seton Hall University Dissertations and Theses (ETDs)

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Novel Synthesis Of 2-Methyl-3, 4, 5-Trichloropyrimidine, Daniel M. Goldman May 2002

Novel Synthesis Of 2-Methyl-3, 4, 5-Trichloropyrimidine, Daniel M. Goldman

Theses

A one-step synthesis of the heterocycle 2-methyl-3,4,5-trichloropyrimidine by the cycloaddition of hexachloropropene with acetamidine hydrochloride in methanolic NaOH was attempted. The product was dark amber oil. A by-product of this reaction was sodium chloride. The proposed reaction was expected to proceed via a SN2 nucleophilic displacement of three chlorine atoms on hexachloropropene by acetamidine, the nucleophile. The proposed driving force for this transformation is the lone pair of electrons on the amidine nitrogen along with the electron withdrawing ability of three chlorines on hexachloropropene which induces a partial positive charge on the carbon. It is proposed that the chlorine atoms …


Footprinting And Circular Dichroism Studies On Paromomycin Binding To The Packaging Region Of Human Immunodeficiency Virus Type-1, Mark P. Mcpike, Jerry Goodisman, James C. Dabrowiak Apr 2002

Footprinting And Circular Dichroism Studies On Paromomycin Binding To The Packaging Region Of Human Immunodeficiency Virus Type-1, Mark P. Mcpike, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

We have studied the interaction of the aminoglycoside drug, paromomycin, with a 171-mer from the packaging region of HIV-1 (ψ-RNA), using quantitative footprinting and circular dichroism spectroscopy. The footprinting autoradiographic data were obtained by cutting end-labeled RNA with RNase I or RNase T1 in the presence of varying paromomycin concentrations. Scanning the autoradiograms produced footprinting plots showing cleavage intensities for specific sites on the ψ-RNA as functions of drug concentration. Footprinting plots showing binding were analyzed using a two-state model to give apparent binding constants for specific sites of the ψ-RNA. These plots show that the highest-affinity paromomycin binding site …


A Post-Amadori Inhibitor Pyridoxamine Also Inhibits Chemical Modification Of Proteins By Scavenging Carbonyl Intermediates Of Carbohydrate And Lipid Degradation, Paul A. Voziyan, Thomas O. Metz, John W. Baynes, Billy G. Hudson Feb 2002

A Post-Amadori Inhibitor Pyridoxamine Also Inhibits Chemical Modification Of Proteins By Scavenging Carbonyl Intermediates Of Carbohydrate And Lipid Degradation, Paul A. Voziyan, Thomas O. Metz, John W. Baynes, Billy G. Hudson

Faculty Publications

Reactive carbonyl compounds are formed during autoxidation of carbohydrates and peroxidation of lipids. These compounds are intermediates in the formation of advanced glycation end products (AGE) and advanced lipoxidation end products (ALE) in tissue proteins during aging and in chronic disease. We studied the reaction of carbonyl compounds glyoxal (GO) and glycolaldehyde (GLA) with pyridoxamine (PM), a potent post-Amadori inhibitor of AGE formation in vitro and of development of renal and retinal pathology in diabetic animals. PM reacted rapidly with GO and GLA in neutral, aqueous buffer, forming a Schiff base intermediate that cyclized to a hemiaminal adduct by intramolecular …


“[Cu(Pyrazine-2-Carboxylate)2]2Cd4I8: Unprecedented 1-D Serpentine Chains And Regular 2-D Regular Metal-Organic Square Grids In A 3-D Framework., Delia M. Ciurtin, Mark D. Smith, Hans Conrad Zur Loye Dec 2001

“[Cu(Pyrazine-2-Carboxylate)2]2Cd4I8: Unprecedented 1-D Serpentine Chains And Regular 2-D Regular Metal-Organic Square Grids In A 3-D Framework., Delia M. Ciurtin, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

A novel three-dimensional coordination polymer containing
an unprecedented one-dimensional serpentine motif conjoined
with a two-dimensional square grid motif is presented.


Three Unique Coordination Geometries Involving 1,2-Dimethoxy-4,5-Bis(2-Pyridylethynyl)Benzene, Jeffrey E. Fiscus, Sandra Shotwell, Ralph C. Layland, Mark D. Smith, Hans Conrad Zur Loye, Uwe H. F. Bunz Dec 2001

Three Unique Coordination Geometries Involving 1,2-Dimethoxy-4,5-Bis(2-Pyridylethynyl)Benzene, Jeffrey E. Fiscus, Sandra Shotwell, Ralph C. Layland, Mark D. Smith, Hans Conrad Zur Loye, Uwe H. F. Bunz

Faculty Publications

Reaction of the new ligand 1,2-dimethoxy-4,5-bis(2-pyridylethynyl) benzene with different metal centers under similar reaction conditions led to three distinct structure formation processes: molecular ring closure, dimerization, and polymer formation.


Ca4Iro6, Ca3Mgiro6 And Ca3Zniro6, Matthew J. Davis, Mark D. Smith, Hans Conrad Zur Loye Nov 2001

Ca4Iro6, Ca3Mgiro6 And Ca3Zniro6, Matthew J. Davis, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

Single crystals of tetracalcium iridium hexaoxide, Ca4IrO6, tricalcium magnesium iridium hexaoxide, Ca3MgIrO6, and tricalcium zinc iridium hexaoxide, Ca3ZnIrO6, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The three compounds are isostructural and adopt the K4CdCl6 structure type, comprised of chains of alternating face-shared [CaO6], [MgO6] or [ZnO6] trigonal prisms and [IrO6] octahedra, surrounded by columns of Ca2+ ions.

Formula: Ca4IrO6, Ca3.34Mg0.66IrO6 and …


Two Different One-Dimensional Structural Motifs In The Same Coordination Polymer: A Novel Interpenetration Of Infinite Ladders By Bundles Of Infinite Chains, Badruz Zaman, Mark D. Smith, Hans Conrad Zur Loye Oct 2001

Two Different One-Dimensional Structural Motifs In The Same Coordination Polymer: A Novel Interpenetration Of Infinite Ladders By Bundles Of Infinite Chains, Badruz Zaman, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

A coordination polymer with a novel structural motif
consisting of stacks of infinite ladders interpenetrated by
bundles of infinite chains is described; geometrical arguments
are made for the requirements that can lead to such
interpenetration as a function of ligand dimensions.


Crystal Growth, Structure Determination And Magnetism Of A New Hexagonal Rhodate: Ba9rh8o24, Katharine E. Stitzer, M. D. Smith, J. Darriet, Hans Conrad Zur Loye Aug 2001

Crystal Growth, Structure Determination And Magnetism Of A New Hexagonal Rhodate: Ba9rh8o24, Katharine E. Stitzer, M. D. Smith, J. Darriet, Hans Conrad Zur Loye

Faculty Publications

Single crystals of Ba9Rh8O24, grown from a molten potassium carbonate flux, crystallize in the spacegroup R¯3c with lattice parameters of a = 10.0899(4) and c = 41.462(2) Å. Magnetic measurements on oriented single crystals reveal the existence of magnetic anisotropy


Theoretical Study On The Mechanism Of Removing Nitrogen Oxides Using Isocyanic Acid., Taraneh Nowroozi-Isfahani Aug 2001

Theoretical Study On The Mechanism Of Removing Nitrogen Oxides Using Isocyanic Acid., Taraneh Nowroozi-Isfahani

Electronic Theses and Dissertations

The mechanism of RAPRENOx reactions - RAPid REduction of Nitrogen Oxides using Isocyanic acid - proposed by Robert A. Perry1 in an attempt to help control the emission of nitrogen oxides pollutant into the atmosphere, has been re-investigated theoretically. The study of reaction mechanisms was carried out using Chemist software2. All mathematically possible elementary steps have been evaluated and the chemically reasonable ones have been considered to propose new sets of reaction mechanisms. Density Functional Theory (B3LYP/6-31 G**) calculations using Gaussian 983 were made in order to study the relative energies of all species and …


Sr3Znpto6 And Sr3Cdpto6, Mark D. Smith, Hans Conrad Zur Loye Apr 2001

Sr3Znpto6 And Sr3Cdpto6, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

The flux synthesis of single crystals of the isostructural compounds tristrontium zinc platinum hexaoxide, Sr3ZnPtO6, and tristrontium cadmium platinum hexaoxide, Sr3CdPtO6, is reported. The compounds adopt the pseudo-one-dimensional rhombohedral K4CdCl6 structure type, and feature chains of face-shared distorted ZnO6 or CdO6 trigonal prisms and PtO6 octahedra, surrounded by columns of Sr2+ ions. All transition metals are located on the threefold axis of symmetry, while the Sr2+ cations lie on twofold axes.

Formula: Sr3ZnPtO6 and Sr3CdPtO6