Physical Sciences and Mathematics Commons^™

Selective Complexation And Reactivity Of Metallic Nitride And Oxometallic Fullerenes With Lewis Acids And Use As An Effective Purification Method, Steven Stevenson, Mary A. Mackey, Jane E. Pickens, Melissa A. Stuart, Bridget S. Confait, J. Paige Phillips

Faculty Publications

Metallic nitride fullerenes (MNFs) and oxometallic fullerenes (OMFs) react quickly with an array of Lewis acids. Empty-cage fullerenes are largely unreactive under conditions used in this study. The reactivity order is Sc₄O₂@I_h-C₈₀ > Sc₃N@C₇₈ > Sc₃N@C₆₈ > Sc₃N@D_5h-C₈₀ > Sc₃N@I_h-C₈₀. Manipulations of Lewis acids, molar ratios, and kinetic differences within the family of OMF and MNF metallofullerenes are demonstrated in a selective precipitation scheme, which can be used either alone for purifying Sc₃N@I_{h …}

Rfx2 Is A Candidate Downstream Amplifier Of A-Myb Regulation In Mouse Spermatogenesis, Gary C. Horvath, Malathi K. Kistler, Wilson Stephen Kistler

Faculty Publications

Background: Mammalian spermatogenesis involves formation of haploid cells from the male germline and then a complex morphological transformation to generate motile sperm. Focusing on meiotic prophase, some tissue-specific transcription factors are known (A-MYB) or suspected (RFX2) to play important roles in modulating gene expression in pachytene spermatocytes. The current work was initiated to identify both downstream and upstream regulatory connections for Rfx2.

Results: Searches of pachytene up-regulated genes identified high affinity RFX binding sites (X boxes) in promoter regions of several new genes: Adam5, Pdcl2, and Spag6. We confirmed a strong promoter-region X-box for Alf, a germ cell-specific variant of …

Wavepacket Approach To The Cumulative Reaction Probability Within The Flux Operator Formalism, Sophya Garashchuk, Tijo Vazhappilly

Faculty Publications

Expressions for the singular flux operator eigenfunctions and eigenvalues are given in terms of the Dirac δ-function representable as a localized Gaussian wavepacket. This functional form enables computation of the cumulative reaction probability N(E) from the wavepacket time-correlation functions. The Gaussian based form of the flux eigenfunctions, which is not tied to a finite basis of a quantum-mechanical calculation, is particularly useful for approximate calculation of N(E) with the trajectory based wavepacket propagation techniques. Numerical illustration is given for the Eckart barrier using the conventional quantum-mechanical propagation and the quantum trajectory dynamics with the approximate quantum potential. N(E) converges with …

Identification And Structural Analysis Of A Novel Carboxysome Shell Protein With Implications For Metabolite Transport, Michael G. Klein, Peter Zwart, Sarah C. Bag By, Fei Cai, Sallie W. Chisolm, Sabine Heinhorst, Gordon C. Cannon, Cheryl A. Kerfeld

Faculty Publications

Bacterial microcompartments (BMCs) are polyhedral bodies, composed entirely of proteins, that function as organelles in bacteria; they promote subcellular processes by encapsulating and co-localizing targeted enzymes with their substrates. The best-characterized BMC is the carboxysome, a central part of the carbon-concentrating mechanism that greatly enhances carbon fixation in cyanobacteria and some chemoautotrophs. Here we report the first structural insights into the carboxysome of Prochlorococcus, the numerically dominant cyanobacterium in the world's oligotrophic oceans. Bioinformatic methods, substantiated by analysis of gene expression data, were used to identify a new carboxysome shell component, CsoS1D, in the genome of Prochlorococcus strain MED4; …

Succination Of Thiol Groups In Adipose Tissue Proteins In Diabetes: Succination Inhibits Polymerization And Secretion Of Adiponectin, Norma Frizzell, Mathur Rajesh, Matthew J. Jepson, Ryoji Nagai, James A. Carson, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

S-(2-Succinyl)cysteine (2SC) is formed by reaction of the Krebs cycle intermediate fumarate with cysteine residues in protein, a process termed succination of protein. Both fumarate and succination of proteins are increased in adipocytes cultured in high glucose medium (Nagai, R., Brock, J. W., Blatnik, M., Baatz, J. E., Bethard, J., Walla, M. D., Thorpe, S. R., Baynes, J. W., and Frizzell, N. (2007) J. Biol. Chem. 282, 34219-34228). We show here that succination of protein is also increased in epididymal, mesenteric, and subcutaneous adipose tissue of diabetic (db/db) mice and that adiponectin is a major target for succination in both …

A Spectral Time-Domain Method For Computational Electrodynamics, James V. Lambers

Faculty Publications

We present a new approach to the numerical solution of Maxwell’s equations in the case of spatially‐varying electric permittivity and/or magnetic permeability, based on Krylov subspace spectral (KSS) methods. KSS methods for scalar equations compute each Fourier coefficient of the solution using techniques developed by Gene Golub and Gérard Meurant for approximating elements of functions of matrices by Gaussian quadrature in the spectral, rather than physical, domain. We show how they can be generalized to coupled systems of equations, such as Maxwell’s equations, by choosing appropriate basis functions that, while induced by this coupling, still allow efficient and robust computation …

Interface Slippage Study Between Polyamide 12 And Ethylene Butene Copolymer Melt In Capillary Extrusion, Jinhai Yang, James L. White

Faculty Publications

Extrusion of a polyamide 12 (PA12) material through a capillary die coated with an ethylene butene copolymer (EBM) was studied. The EBM coated die significantly increased the flow rates of the PA12 melt compared to a clean die at the same extrusion pressure. Introducing a maleic anhydride grafted ethylene-octene copolymer (EOM-g-MAH) into the EBM suppressed the effect. This behavior seems only explained by significant interface slippage between PA12 and EBM melts, which could be eliminated by introducing covalent chemical bonds across the interface. A mathematical analysis was carried out to calculate the interface slippage. The shear stress where slippage began …

Cardiac And Renal Function Are Progressively Impaired With Aging In Zucker Diabetic Fatty Type Ii Diabetic Rats, John W. Baynes, David B. Murray

Faculty Publications

This study investigated the temporal relationship between cardiomyopathy and renal pathology in the type II diabetic Zucker diabetic fatty (ZDF) rat. We hypothesized that changes in renal function will precede the development of cardiac dysfunction in the ZDF rat. Animals (10 weeks old) were divided into four experimental groups: Lean Control (fa/?) LC(n = 7), untreated ZDF rats (n = 7) sacrificed at 16 weeks of age, and LC (n = 7) untreated ZDF rats (n = 9) sacrificed at 36 weeks of age. LV structural/functional parameters were assessed via Millar conductance catheter. Renal function was evaluated via markers of …

Ionic Selectivity In L-Type Calcium Channels By Electrostatics And Hard-Core Repulsion, Dezso Boda, Douglas Henderson, Monika Valisko, Bob Eisenberg, Dirk Gillespie

Faculty Publications

A physical model of selective "ion binding" in the L-type calcium channel is constructed, and consequences of the model are compared with experimental data. This reduced model treats only ions and the carboxylate oxygens of the EEEE locus explicitly and restricts interactions to hard-core repulsion and ion–ion and ion–dielectric electrostatic forces. The structural atoms provide a flexible environment for passing cations, thus resulting in a self-organized induced-fit model of the selectivity filter. Experimental conditions involving binary mixtures of alkali and/or alkaline earth metal ions are computed using equilibrium Monte Carlo simulations in the grand canonical ensemble. The model pore rejects …

Structure–Mutagenicity Relationships And Energies Of 1-, And 2-Nitrotriphenylenes [Abstract], Kefa Karimu Onchoke

Faculty Publications

No abstract provided.

Controlled Assembly Of Rodlike Viruses With Polymers, Tao Li, Laying Wu, Nisaraporn Suthiwangcharoen, Michael A. Bruckman, Dayton Cash, Joan S. Hudson, Soumitra Ghoshroy, Qian Wang

Faculty Publications

A practical method to assemble rodlike tobacco mosaic virus and bacteriophage M13 with polymers was developed, which afforded a 3D core–shell composite with morphological control.

Mammaglobin As A Potential Molecular Target For Breast Cancer Drug Delivery, Lian Zuo, Ly Li, Qian Wang, Timothy P. Fleming, Shaojin You

Faculty Publications

Background Mammaglobin (MAM) has been used as a specific molecular marker for breast cancer diagnosis. Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule. Some of the strategies are based upon an essential but not demonstrated hypothesis - mammaglobin is associated with the surface of breast cancer cells, which strongly disputes the therapeutic strategies. Results We conducted a computer-based predictive analysis and identified a small fragment at the N-end of MAM as a potential transmembrane domain. We provided several evidences to demonstrate the presence of the membrane-associated MAM. We isolated the membrane protein components from …

Tobacco Mosaic Virus Templated Synthesis Of One Dimensional Inorganic–Polymer Hybrid Fibres, Jianhua Rong, Fiona Oberbeck, Xinnan Wang, Xiaodong Li, Jerry Oxsher, Zhongwei Niu, Qian Wang

Faculty Publications

Inorganic–polymer hybrid nanofibres were prepared by using a rod-like tobacco mosaic virus (TMV) as a template. With tetraethylorthosilicate (TEOS) as a precursor, long silica-coated TMVfibres were formed via a head-to-tail assembly, which showed a substantial increase of the elastic modulus. Furthermore, homogenous titania–TMV hybrid fibres could be prepared using polyaniline-coated TMV fibres as a template, which were used to form a composite film that was able to sense liquefied petroleum gases.

Tetraquabis(5-Fluorosaccharinato)Nickel(Ii), Larnelle Peterson, Jennifer Kelley, Leroy Peterson Jr., Mark D. Smith, Hans-Conrad Zur Loye

Faculty Publications

In the centrosymmetric title complex, [Ni(C₇H₃FNO₃S)₂(H₂O)₄], the Ni^II atom exhibits a slightly distorted trans-NiN₂O₄ octahedral coordination. The nitrogen donors are provided by two 5-fluorosaccharinate ligands and the oxygen donors are provided by four water molecules. The crystal structure features O-HO and bifurcated O-H(F,O) hydrogen bonds, the latter involving the F atom of the 5-fluorosaccharinate ligand.

Diaquabis(5-Fluoro-2-Hydroxybenzoato-Κo1)Zinc(Ii), Diana Rishmawi, Jennifer Kelley, Mark D. Smith, Leroy Peterson, Hans-Conrad Zur Loye

Faculty Publications

The title compound, [Zn(C₇H₄FO₃)₂(H₂O)₂], is a monomeric Zn^II complex. The Zn^II atom, which lies on a twofold rotation axis, is situated in a distorted tetrahedral environment composed of two monodentate carboxlyate O atoms and two water O atoms. O-HO hydrogen bonds link these units, forming sheets that are stacked along the c axis.

Singlet Oxygen Delivery Through The Porous Cap Of A Hollow-Core Fiber Optic Device, Matibur Zamadar, David Aebisher, Alexander Greer

Faculty Publications

The development of the first photosensitizer/fiber optic device is reported. An oxygen-flowing, fiber-capped configuration is used for the application of heterogeneous, spatially confined singlet oxygen delivery in aqueous media. This is a unique device, unlike other heterogeneous photosensitizers, in which local concentrations of singlet oxygen can be delivered via introduction and withdrawal of the fiber tip.