Physical Sciences and Mathematics Commons^™

Self-Aligned Mechanical Attachment Of Carbon Nanotubes To Silicon Dioxide Structures By Selective Silicon Dioxide Chemical-Vapor Deposition, Jed D. Whittaker, Ghaleb A. Husseini, Matthew A. Linford, Robert C. Davis, Markus Brink

Faculty Publications

A self-aligned thin-film deposition technique was developed to mechanically attach carbon nanotubes to surfaces for the fabrication of structurally robust nanotube-based nanomechanical devices. Single-walled carbon nanotubes were grown by thermal chemical-vapor deposition (CVD) across 150-nm-wide SiO2 trenches. The nanotubes were mechanically attached to the trench tops by selective silicon tetraacetate-based SiO2 CVD. No film was deposited on the nanotubes where they were suspended across the trenches.

Synthesis Of Adenosine Derivatives As Transcription Initiators And Preparation Of 5 ' Fluorescein- And Biotin-Labeled Rna Through One-Step In Vitro Transcription, Faqing Huang, Guocan Wang, Tricia Coleman, Na Li

Faculty Publications

Expanding our previous finding of an adenosine-initiated transcription system, we now demonstrate that either the 5' site or the N6 site of adenosine nucleotides can be modified extensively without abolishing their ability to initiate transcription under the T7 phi2.5 promoter. Two series of amino derivatives of adenosine nucleotides were synthesized. Fluorescein and biotin groups were coupled to AMP derivatives through linkers of different sizes and hydrophobicities. Both fluorescein- and biotin-conjugated (at either the 5' or N6 site) adenosine nucleotides can act as efficient transcription initiators, producing fluorescein- and biotin-labeled RNA at the specific 5' end by a one-step transcription procedure, …

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 …

Markov Chains And Dynamic Geometry Of Polygons, Jiu Ding, L. Richard Hitt, Xin-Min Zhang

Faculty Publications

In this paper we construct sequences of polygons from a given n-sided cyclic polygon by iterated procedures and study the limiting behaviors of these sequences in terms of non-negative matrices and Markov chains. (C) 2003 Elsevier Science Inc. All rights reserved.

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)°. O_water-HO_nitrate hydrogen bonding creates two-dimensional layers parallel to the ab plane.

Formula: [Cd₂(NO₃)₄(C …

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).

A High Throughput Method For The Conversion Of Co2 Obtained From Biochemical Samples To Graphite In Septa-Sealed Vials For Quantification Of 14c Samples Via Accelerator Mass Spectrometry, Ted J. Ognibene, Graham Bench, John S. Vogel, Graham F. Peaslee, Steve Murov

Faculty Publications

The growth of accelerator mass spectrometry as a tool for quantitative isotope ratio analysis in the biosciences necessitates high-throughput sample preparation. A method has been developed to convert CO2 obtained from carbonaceous samples to solid graphite for highly sensitive and precise 14C quantification. Septa-sealed vials are used along with commercially available disposable materials, eliminating sample cross contamination, minimizing complex handling, and keeping per sample costs low. Samples containing between 0.25 and 10 mg of total carbon can be reduced to graphite in 4 h in routine operation. Approximately 150 samples per 8-h day can be prepared by a single technician.

Review Of The Final Frontier, Michael F. Russo

Faculty Publications

No abstract provided.

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 …

Efficient Incorporation Of Coa, Nad And Fad Into Rna By In Vitro Transcription, Faqing Huang

Faculty Publications

Protein enzymes frequently recruit small molecule coenzymes to perform a variety of biochemical reactions. While the catalytic activities of RNA have been expanding rapidly, a similar strategy for RNA to utilize coenzymes and to increase its functional capabilities has yet to be demonstrated. A general in vitro transcription procedure has been developed to efficiently prepare RNA with coenzymes CoA, NAD and FAD covalently attached to the 5' end. These adenosine-containing coenzymes initiate transcription under the T7 class II promoter by T7 RNA polymerase. In addition to the three coenzymes, other adenosine-containing molecules may be incorporated into the first nucleotide position …

Tetratricopeptide Repeat Motif-Mediated Hsc70-Msti1 Interaction Molecular Characterization Of The Critical Contacts For Successful Binding And Specificity*, Odutayo O. Odunuge, Judith A. Hornby, Chrisiane Bies, Richard Zimmermann, David J. Pugh, Gregory L. Blatch

Faculty Publications

Murine stress-inducible protein 1 (mSTI1) is a cochaperone that is homologous with the human Hsp70/ Hsp90-organizing protein (Hop). Guided by Hop structural data and sequence alignment analyses, we have used site-directed mutagenesis, co-precipitation assays, circular dichroism spectroscopy, steady-state fluorescence, and surface plasmon resonance spectroscopy to both qualitatively and quantitatively characterize the contacts necessary for the N-terminal tetratricopeptide repeat domain (TPR1) of mSTI1 to bind to heat shock cognate protein 70 (Hsc70) and to discriminate between Hsc70 and Hsp90. We have shown that substitutions in the first TPR motif of Lys8 or Asn12 did not affect binding of mSTI1 to Hsc70, …

Dendritic Surfactants Show Evidence For Frustrated Intercalation: A New Organoclay Morphology, Erick J. Acosta, Youjun Deng, G. Norman White, Joe B. Dixon, Kevin J. Mcinnes, Scott A. Senseman, Alyx S. Frantzen, Eric E. Simanek

Faculty Publications

Mixing a smectite clay with some dendritic surfactants shows that despite the large size of some of these molecules, a property that frustrates complete intercalation into the gallery of the clay, organoclay materials are obtained. X-ray powder diffraction (XPD) reveals no significant increases in lattice spacing as these surfactants are added. Infrared (IR) spectroscopy and thermal gravimetric analysis (TGA) show that interlayer water is preserved. Consistent with an undisturbed interlayer, the amount of organic material in organoclays derived from frustrated surfactants does not exceed 15% of the cationic exchange capacity (CEC) of the composite. Smaller dendritic surfactants do not display …

Crystal Structure Of Boc-Trp(Cho)-Dphe-Ile-Dphe-Leu-Och3, C48h59n6o10, Vijayaraghavan Rangachari, J. Makker, P. Kumar, S. Dey, Tej P. Singh

Faculty Publications

No abstract provided.

Nitroalkane Anomaly: Computational Study With Cluster And Continuum Modeling, H. Yamataka, Salai Cheettu Ammal

Faculty Publications

The origin of anomalous relation between rates and equilibria for the proton-transfer reactions of nitroalkanes, known as nitroalkane anomaly, was investigated by theoretical calculations with a cluster model, in which three water molecules are explicitly considered in the system, as well as the PCM solvent continuum model. For the CH3NO2/CH3CH2NO2 system, B3LYP and MP2 computations reproduced the anomaly, and the imbalance in the charge distribution at the transition state (TS) was observed. In contrast, although the TS imbalance was detected for the substituted phenylnitromethane system, the Brønsted plots did not show any anomaly. The experimentally observed abnormally large Brønsted coefficient …