Physical Sciences and Mathematics Commons^™

Highly Plasma Etch-Resistant Photoresist Composition Containing A Photosensitive Polymeric Titania Precursor, Tony D. Flaim, Douglas J. Guerrero, Michelle R. Fowler, William Joseph James, Vladimir Petrovsky, Harlan U. Anderson

Chemistry Faculty Research & Creative Works

A composition is derived from an addition polymerizable organotitanium polymer which upon exposure to an oxygen plasma or baking in air, is converted to titanium dioxide (titania) or is converted to a mixed, titanium-containing metal oxide. The metal oxide formed in situ imparts etch- resistant action to a patterned photoresist layer. The composition may also be directly deposited and patterned into permanent metal oxide device features by a photolithographic process.

Structural Evidence That The Methionyl Aminopeptidase From Escherichia Coli Is A Mononuclear Metalloprotease, Nathaniel J. Cosper, Ventris M. D'Souza, Robert A. Scott, Richard C. Holz

Chemistry Faculty Research and Publications

The Co and Fe K-edge extended X-ray absorption fine structure (EXAFS) spectra of the methionyl aminopeptidase from Escherichia coli (EcMetAP) have been recorded in the presence of 1 and 2 equiv of either Co(II) or Fe(II) (i.e., [Co(II)_(EcMetAP)], [Co(II)Co(II)(EcMetAP)], [Fe(II)_(EcMetAP)], and [Fe(II)Fe(II)(EcMetAP)]). The Fourier transformed data of both [Co(II)_(EcMetAP)] and [Co(II)Co(II)(EcMetAP)] are dominated by a peak at ca. 2.05 Å, which can be fit assuming 5 light atom (N,O) scatterers at 2.04 Å. Attempts to include a Co−Co interaction (in the 2.4−4.0 Å range) in the …

Teaching Analytical Chemistry To The Masses: How We Went From 2 Courses To 7 Courses In 10 Years, Gary Long, Mark Anderson, Brian Tissue, John Morris

Mark R. Anderson

No abstract is currently available.

Interactive Multimedia Over The Internet For Teaching Analytical Chemistry, Mark Anderson

Mark R. Anderson

No abstract is currently available.

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.

Energetics And Cooperativity In Three-Center Hydrogen Bonding Interactions. Ii. Intramolecular Hydrogen Bonding Systems, Ruben D. Parra, Bing Gong, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

High level ab initio calculations have been carried out on a number of intramolecular two- and three-center H-bonding structures containing the amide motif, NHC=O. These structures serve as model systems for probing the stability of intramolecular three-center H bonds of the type A₁HA₂. Particular attention is given to cooperative effects in the three-center H-bonding structures. A systematic assessment of cooperativity for intramolecular H-bonding systems is presented.

Unlv Magazine, Barbara Cloud, Laurie Fruth, Mae Worthey-Flennoy

UNLV Magazine

No abstract provided.

Effect Of Surface Charges On The Rates Of Intermolecular Electron-Transfer Between De Novo Designed Metalloproteins, Anna Y. Kornilova, James F. Wishart, Michael Y. Ogawa

Chemistry Faculty Publications

A de novo designed coiled-coil metalloprotein was prepared that uses electrostatic interactions to control both its conformational and bimolecular electron-transfer properties. The title protein exists as a coiled-coil heterodimer of the [Ru(trpy)(bpy)-KK(37-mer)] and [Ru(NH3)(5)-EE(37-mer)] polypeptides which is formed by interhelix electrostatic attractions. Circular dichroism studies show that the electrostatic heterodimer has Kd 0.19 +/- 0.03 muM and is 96% helical at high concentrations. Intercomplex electron-transfer reactions were studied that involve the [Ru(NH3)(5)-H21](2+) electron-donor and the [Ru(trpy)(bpy)H21](3+) electron-acceptor belonging to different electrostatic dimers. An important feature of the designed metalloprotein is its two cationic redox centers embedded within protein surfaces having …

Crystal Structure Of Mtan, A Global Multidrug Transporter Gene Activator, Michael H. Godsey, Natalya N. Baranova, Alexander A. Neyfakh, Richard G. Brennan

CUP Faculty Research

MtaN (Multidrug Transporter Activation, N terminus) is a constitutive, transcriptionally active 109-residue truncation mutant, which contains only the N-terminal DNA-binding and dimerization domains of MerR family member Mta. The 2.75 Å resolution crystal structure of apo-MtaN reveals a winged helix-turn-helix protein with a protruding 8-turn helix (α5) that is involved in dimerization by the formation of an antiparallel coiled-coil. The hydrophobic core and helices α1 through α4 are structurally homologous to MerR family member BmrR bound to DNA, whereas one wing (Wing 1) is shifted. Differences between the orientation of α5 with respect to the core and the revolution of …

Energetics And Cooperativity In Three-Center Hydrogen Bonding Interactions. I. Diacetamide-X Dimers .X=Hcn, Ch3Oh., Ruben D. Parra, Makoto Furukawa, Bing Gong, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

High level ab initio calculations are carried out on diacetamide–X (DA–X) dimers, X=HCN, CH₃OH. The dimers are used as model systems to investigate the energetics and cooperative phenomomena in intermolecular three-center hydrogen-bond (H-bond) interactions relative to two-center H-bond interactions. The trans–trans conformer of diacetamide is chosen as a suitable model for intermolecular three-center H bonding where one H atom is interacting with two acceptor atoms. The proton–acceptor atoms are rigidly held in the same molecule. For both model systems, it is found that the calculated interaction energy per H bond is appreciably smaller in the three-center than in …

Α-Amino-Β-Sulphone Hydroxamates As Potent Mmp-13 Inhibitors That Spare Mmp-1, Daniel P. Becker Ph.D., Thomas E. Barta, Louis Bedell, Gary Decrescenzo, John Freskos, Daniel P. Getman, Susan L. Hockerman, Madeleine Li, Pramod Mehta, Brent Mischke, Grace E. Munie, Craig Swearingen, Clara I. Villamil

Chemistry: Faculty Publications and Other Works

A series of α-amino-β-sulphone hydroxamates was prepared and evaluated for potency versus MMP-13 and selectivity versus MMP-1. Various substituents were employed on the α-amino group (P1 position), as well as different groups attached to the sulphone group extending into P1′. Low nanomolar potency was obtained for MMP-13 with selectivity versus MMP-1 of >1000× for a number of analogues.

α-Amino-β-sulphone hydroxamates were prepared, which are potent MMP-13 inhibitors with selectivity versus MMP-1 of >1000× for a number of analogues. Selected compounds exhibited oral bioavailability.

Synthesis Of Cyclopropane Containing Natural Products, William Donaldson

Chemistry Faculty Research and Publications

The synthesis of select cyclopropane containing natural products is presented.

Magnetic Properties Of The Mnbi Intermetallic Compound, Jinbo Yang, Kishore Kamaraju, William B. Yelon, William Joseph James, Qingsheng Cai, A. Bollero

Physics Faculty Research & Creative Works

A MnBi alloy containing over 90 wt% low-temperature phase (LTP) has been obtained by high-temperature sintering and magnetic purification. The coercivity of the bonded MnBi magnet increases with increasing temperatures. A coercivity of 2.0 T has been achieved at 400 K. The maximum energy product (BH)_max; of the magnet is 7.7 MGOe (61 kJ/m³) and 4.6 MGOe (37 kJ/m³) at room temperature and 400 K, respectively. Neutron diffraction and magnetic data reveal a spin reorientation, which gives rise to low anisotropy fields and coercivity at lower temperatures for the LTP MnBi alloy.

Collision-Induced Electronic Energy Transfer From V=0 Of The E(0g+) Ion-Pair State In I2: Collisions With I2(X), Christopher J. Fecko , '98, Miriam Arak Freedman , '00, Thomas Alex Stephenson

Chemistry & Biochemistry Faculty Works

The collision-induced electronic energy transfer that occurs when I-2 in the E(0(g)(+)) ion-pair electronic state collides with ground electronic state I-2 has been investigated. We prepare I-2 in single rotational levels in v = 0 of the E state using two-color double resonance laser excitation. The resulting emission spectrum shows that the nearby (DeltaT(e) = -385 cm(-1)) D(0(u)(+)) electronic state is populated. The cross section for collision-induced E -->D energy transfer is found to be IS - 3 Angstrom (2). A range of D state vibrational levels are populated, consistent with a model in which overlap between the initial …

A Cooperative Molecular Modeling Exercise— The Hypersurface As Classroom, Christopher J. Cramer, Bethany L. Kormos, Paul Winget, Vanessa M. Audette, Jeremy M. Beebe, Carolyn S. Brauer, W.Russ Burdick, Eric W. Cochran, Brian M. Eklov, Timothy J. Giese, Yongseok Jun, Lakshmi S.D. Kesavan, Christopher R. Kinsinger, Mikhail E. Minyaev, Ramkumar Rajamani, Jonathon S. Salsbury, John M. Stubbs, Jack T. Surek, Jason D. Thompson, Vincent A. Voelz, Collin D. Wick, Ling Zhang

Eric W. Cochran

Quantum chemistry has been a staple of undergraduate curricula for several decades. For the most part, however, it has been the rare course in quantum chemistry that advances much beyond the hydrogen atom (or perhaps H2) in terms of describing the electronic structure of real molecular systems. Driven in part by staggering advances in computer technology during the last 15 years or so, which have rendered possible on a laptop calculations that once would have taxed the largest mainframes available, this situation now seems to be changing (1–3).

Dynamical Relativistic Effects In Photoionization: Spin-Orbit-Resolved Angular Distributions Of Xenon 4d Photoelectrons Near The Cooper Minimum, H. Wang, G. Snell, Oliver Hemmers, M. M. Sant'anna, I. A. Sellin, N. Berrah, Dennis W. Lindle, P. C. Deshmukh, N. Haque, S. T. Manson

Environmental Studies Faculty Publications

Two decades ago, it was predicted [Y. S. Kim et al., Phys. Rev. Lett. 46, 1326 (1981)] that relativistic effects should alter the dynamics of the photoionization process in the vicinity of Cooper minima. The present experimental and theoretical study of the angular distributions of Xe 4d_3/2 and 4d_5/2 photoelectrons demonstrates this effect for the first time. The results clearly imply that relativistic effects are likely to be important for intermediate- Z atoms at most energies.

Infrared Spectroscopy Of H-Bonded Bridges Stretched Across The Cis-Amide Group: Ii. Ammonia And Mixed Ammonia/Water Bridges, A. V. Fedorov, John R. Cable, Joel R. Carney, Timothy S. Zwier

Chemistry Faculty Publications

Clusters of two model cis amides, oxindole and 3,4-dihydro-2(IH)-quinolinone, containing one and two ammonia molecules have been studied in the IR hydride stretch region using resonant ion-dip IR spectroscopy. The spectra confirm that ammonia is able to form hydrogen-bonded bridges across the adjacent amide N-H and C=O sites in a manner very similar to that of water. Such bridged structures require that ammonia assume the role of a hydrogen bond donor. Further similarities of the hydrogen bonding capabilities of ammonia and water have been revealed by investigations of ternary clusters containing an amide, one ammonia, and one water molecule. Experimentally, …

Immobilization Of Long-Strand Dna Onto Gold Surface And Electrochemical Labeling Of Hybridization Of Dna, Jian Zhang Zhou, Ling Ling Wu, Li Qin Dong, Zhong-Yu Lin, Jia Wei Yan, Ping Dong, Yue Bao, Zhong Hua Lin

Journal of Electrochemistry

Poly(diallyldimethylammonium chloride)(PDDA) was used to facilitate long strand DNA immobilization onto gold surface using self assembly method. Characterization of the PDDA self assembled film and subsequently immobilized DNA were carried out by Diffuse Reflectance Infrared, XPS, STM and electrochemical measurements. Hybridization of DNA was labeled by electrochemical method.

Microstructure And Electrochemical Properties Of The Melt_Spinning Zr_(0.9)Ti_(0.1) (Ni,Co,Mn,V)_(2.1) Alloy, Ming-Fen Wen, Yu-Chun Zhai, Lian Chen, Min Tong, Hua Zhen, Rong-Jun Ma

Journal of Electrochemistry

The microstructure and electrochemical properties of Zr 0.9 Ti 0.1 (Ni,Co,Mn,V) 2.1 alloys prepared by both the melt_spinning method and the conventional induction melting were investigated. XRD studies show that Zr 0.9 Ti 0.1 (Ni,Co,Mn,V) 2.1 alloys at as_cast,melt_spinning and annealing are all face center cubic structure with C15 laves phase,the higher the melt_spinning rate,the more the amorphous content.The electrochemical measurements show that melt_spinning alloys have better active behavior,low discharge capacity(<280 mAh/g); but after annealed,the alloys are activated completely with 30 cycles, the capacities about 340 mAh/g are higher than those of as_cast and melt_spinning alloys;the annealec alloys have a better cycle stability than that of as_cast alloy, and the higher the melt_spinning rate is, the more stable the alloy becomes; at 300 mAh/g current density,the capacity of annealed 40 m/s alloy is up to 85% of the maximum capacity after 800 cycles, the capacity decay rate is about 6.9%.

Charge/Discharge Characteristics And Structural Changing Of Spherical Β-Ni(Oh)_2 Prepared From Different Nickel Salt, Shu-Ting Yang, Yan-Hong Yin, Hong-Jun Chen, Jun-Hua Jia, Ming-Chum Zhang, Li Ding

Journal of Electrochemistry

Spherical β Ni(OH) 2 was prepared from different nickel salt by homogeneous complexing precipitation method. Its charge/discharge and cyclic voltammetry properties were studied. The authors found that there are many differences in the electrochemical properties of the prepared Ni(OH) 2.The specific capacity, cycling life and the discharging plateau of the material prepared from NiSO 4 were superior to those of the material prepared from Ni(NO 3) 2.The reasons of the differences were analyzed by XRD and FTIR measurements, which will become abasis for the selection of raw materials.

Simultaneous Determination Of Gold(Ⅲ) And Copper(Ⅱ) With Two-Way Stripping Voltammetry, Rong-Zong Hu, Dong-Ping Wei, Guang Wei, Yue-Ying Liu

Journal of Electrochemistry

A novel Two_way Stripping Voltammetry method for simultaneous determination of Au 3+ and Cu 2+ was reported in this paper. Because of the strongly electrostatic attraction of carbon paste electrode towards Au(Ⅲ) ion at positive potential and the biochemical contribution of Gram_positive bacteria strain DO1, the ion can be determined by cathodic stripping voltammetry. At the same time, Cu(Ⅱ) is reduced readily under the catalysis of ultra_fine gold particles, thereafter it can be determined by anode stripping voltammetry. There is no interference between the determination of Au 3+ and Cu 2+ . A perfect liner relationship between the concentrations of …

The Dissolution Of Perfluorinated Proton Exchange Membrane And The Analysis On The Performance Of The Recast Membrane, Hong-Feng Xu, Xi-Qiang Yan, Xuan Li, Li Wan

Journal of Electrochemistry

Perfluorinated resin solution is useful in proton exchange membrane fuel cell. At 270～280 ℃ and protected with N 2, the proton exchange membrane(Nafion 115) was dissolved in the dimethyl sulfoxide, and two kinds of membrane solutions were obtained. With those solutions, a recast membrane was prepared. The exchange capacity, rate of water content and conductivity of the recast membrane were measured. The results show that the properties of the recast membrane are lower than those of its mother membrane. This may be caused by that some sulfonic acid groups were destroyed in the dissolving process.

The Influence Of Membrane Resistance On The Electrochemical Behavior Of Gold Electrode Modified By Self-Assembled Monolayer, Xiao-Li Cui, Zhi-Yu Jiang

Journal of Electrochemistry

The electrochemical behavior of gold electrode modified by hexadecanethiol self_assembled monolayer (SAM) in the solution of Fe(CN) 6 3- /Fe(CN) 6 4- was investigated by cyclic voltammetry and ac impedance spectroscopy. The pinhole_free SAM_modified gold electrode has excellent blocking properties to the interfacial electron transfer from redox couple in solution to the substrate. The current increased exponentially with the overpotential at the high potential region. A good linear relationship between ln( I/η ) and η 1/2 was observed. A model system Au/SAM/Hg was constructed and its I～V curve was measured. Similar phenomena were observed. There was also a linear relationship …

The Activation Mechanism Of Al Alloys With Tin And Gallium In Alkaline Electrolytes, Zhen Ya Li, Ling Yi, Zhi Hui Liu, Lin Yang, Jing Xin Su, Yan Ying Chen

Journal of Electrochemistry

The major reason for Al_anode's activation is that Ga and Sn deposit on the aluminum surface and form activated points. The Al_Sn and Al_Ga binary alloys can't be activated in alkaline medium. During the dissolution of the Al_Sn_Ga ternary anode, Sn and Ga dissolve into the solution and transform into ions. After the Sn ions deposit on the surface of Al_anode, the Ga ions will deposit on Sn. The higher activation of the polynary alloy anode is caused by much more new activated points composed of Ga_Sn alloy being continually formed. Ga_Sn alloy with low melting point deposited on the …

Study Of Cathodic Protection For Underground Structures At Gas Station, Jiunn Shyong Luo, Yin Chieh Chang, Jun Chou Oung, Wen Chih Yang

Journal of Electrochemistry

Underground structures in gas station include storage tanks, transportation pipelines, and rebar inconcrete. If rebar contacted with tanks or pipelines, effects of cathodic protection will be interfered. Present study was focused upon the effectiveness of impressed current cathodic protection for underground structures at gas station as rebar contacted with/or without tanks and pipelines. It was founded that the -850 mV criterion could not be applied to evaluate effectiveness of cathodic protection systems in gas station. Quantity of polarization of protected structures should be calculated and evaluated.

A New Method For Impregnating Nafion Solution Into The Electrode Of Pemfc, Qian Tang, Ming Han, Bao-Lian Yi, Zhi-Yin Lin

Journal of Electrochemistry

We have developed a new method for impregnating Nafion solution into the catalyst layer of homemade hydrophobic electrode using capillary process. Those electrodes show better performance and higher utilization of catalyst (detected by CV and TEM) than traditional spray method in PEMFC. According to the results of SEM photograph and linear_analysis of sulfur and platinum for the electrode cross_section, we can conclude that the resin is uniform in the catalyst layer and has almost same depth as catalyst in the impregnated electrode. While in traditional method resin is not uniform in the catalyst layer and penetrates into the diffusion layer, …

The Coulostatic Method For Evaluating Corrosion In Reinforced Concrete, Yong Tao Zhao, Jian Hua Wu, Chang-Jiu Zhao

Journal of Electrochemistry

In the present paper, the application of the coulostatic method to the corrosion of steel in concrete was reviewed. By comparing with other electrochemical techniques, the results obtained in the previous work reveal that the coulostatic method is an interesting alternative to the usual procedures for estimation of corrosion rate, and is better than them in some respects. The main advantages are as follows. The signal to be used can be instantaneous and as small as desired, so the electrode is minimally perturted during the measuring process. In addition, it is as rapid and quantitative, and at least as reliable …

Uneven Anodic Dissolution Of Iron Induced By Magnetic Field, Zhan-Peng Lv, De-Lun Huang, Wu Yang

Journal of Electrochemistry

The effects of magnetic field on anodic dissolution of iron in sulfuric acid were studied by potentiostatic polarization measurements and scanning electron microscopy observation. Magnetic field would reduce the surface film coverage fraction on electrode by enhancing the film dissolution process, thus made the electrode prone to active dissolution state. With increasing the applied potentials, magnetic field would accelerate the anodic dissolution, change the oscillation state or passive state to active dissolution state, or maintain the passive state, respectively. Potential for onset of passivation moved in the noble direction when magnetic field was imposed. At specific anodic potentials, denting occurred …

In Situ Ftir Reflection Spectroscopy Of Bioelectrode, Sa-Ying Dong, Guang-Yu Zhao, Yuzhu Gao, Guang-Zhang Chen, Ming-Xiang Lv

Journal of Electrochemistry

In situ FTIR reflection spectroscopy was used to study mediated enzyme electrode and immunoelectrode. We determined and analyzed IR characteristic spectra of GOD and glucose by the use of potential difference spectra and single beam subtractive spectra. At last, we explored the IR absorption characters of enzyme_immunoelectrode.

Characterization And Electrochemical Investigation Of Boron-Doped Mesocarbon Microbeads Anode Materials For Lithium-Ion Battery, Mao-Hui Chen, Guo-Tao Wu, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

The anodic performances of boron doped and undoped mesocarbon microbeads(MCMBs) were comparatively studied and the structures were characterized by XPS,SEM,XRD and electrochemical measurements. It was found that boron doping samples greatly increased the degree of graphitization and the crystallite size,leading to quite different morphology. Electrochemical discharge/charge cycle tests indicate that lithium intercalation occurred at a little higher potential for the boron doped MCMBs, being attended by greater irreversible capacity loss.