Chemistry Commons^™

Binding Of Human Immunodeficiency Virus Type 1 Nucleocapsid Protein To Ψ-Rna-Sl3, Michael F. Shubsda, Christopher A. Kirk, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

The interaction of the nucleocapsid protein NCp7, from the pNL4-3 isolate of HIV-1, with Ψ-RNA-SL3, with the sequence 5’-GGACUAGCGGAGGCUAGUCC, was studied using non-denaturing gel electrophoresis. Two kinds of experiments were performed, using buffered solutions of radiolabeled RNA and unlabeled protein. In the ‘dilution’ experiments, the total RNA concentration, R_T, was varied for a series of solutions, but kept equal to the total protein concentration, P_T. In the ‘titration’ experiments, solutions having R_T constant but with varying P_T were analyzed. The solutions were electrophoresed and the autoradiographic spot intensities, proportional to the amounts of the …

Pyridoxamine, An Inhibitor Of Advanced Glycation Reactions, Also Inhibits Advanced Lipoxidation Reactions: Mechanism Of Action Of Pyridoxamine, Joelle M. Onorato, Alicia J. Jenkins, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

Maillard or browning reactions lead to formation of advanced glycation end products (AGEs) on protein and contribute to the increase in chemical modification of proteins during aging and in diabetes. AGE inhibitors such as aminoguanidine and pyridoxamine (PM) have proven effective in animal model and clinical studies as inhibitors of AGE formation and development of diabetic complications. We report here that PM also inhibits the chemical modification of proteins during lipid peroxidation (lipoxidation) reactions in vitro, and we show that it traps reactive intermediates formed during lipid peroxidation. In reactions of arachidonate with the model protein RNase, PM prevented modification …

Interaction Of Mitochondrial Elongation Factor Tu With Aminoacyl-Trna And Elongation Factor Ts, Ying Chun Cai, James M. Bullard, Nancy L. Thompson, Linda L. Spremulli

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Elongation factor (EF) Tu promotes the binding of aminoacyl-tRNA (aa-tRNA) to the acceptor site of the ribosome. This process requires the formation of a ternary complex (EF-Tu·GTP·aa-tRNA). EF-Tu is released from the ribosome as an EF-Tu·GDP complex. Exchange of GDP for GTP is carried out through the formation of a complex with EF-Ts (EF-Tu·Ts). Mammalian mitochondrial EF-Tu (EF-Tu_mt) differs from the corresponding prokaryotic factors in having a much lower affinity for guanine nucleotides. To further understand the EF-Tu_mt subcycle, the dissociation constants for the release of aa-tRNA from the ternary complex (K _tRNA) and for …

Synthesis And Antimalarial Activity Of Sixteen Dispiro-1,2,4,5-Tetraoxanes: Alkyl-Substituted 7,8,15,16-Tetraoxadispiro[5.2.5.2]Hexadecanes, Jonathan L. Vennerstrom, Yuxiang Dong, Walter Reed Army Institute Of Research, Arba L. Ager Jr., Hong-Ning Fu, Sheri M. Walters, James K. Wood, Geoffrey Edwards, Alexandra D. Holme, W. Graham Mclean

Chemistry Faculty Publications

Sixteen alkyl-substituted dispiro-1,2,4,5-tetraoxanes (7,8,15,16-tetraoxadispiro[5.2.5.2]hexadecanes) were synthesized to explore dispiro-1,2,4,5-tetraoxane SAR and to identify tetraoxanes with better oral antimalarial activity than prototype tetraoxane 1 (WR 148999). The tetraoxanes were prepared either by peroxidation of the corresponding cyclohexanone derivatives in H₂-SO₄/CH₃CN or by ozonolysis of the corresponding cyclohexanone methyl oximes. Those tetraoxanes with alkyl substituents at the 1 and 10 positions were formed as single stereoisomers, whereas the five tetraoxanes formed without the stereochemical control provided by alkyl groups at the 1 and 10 positions were isolated as mixtures of diastereomers. Three of the sixteen …

Investigations On The Use Of Ion Mobility Spectrometry For Clinical Chemistry Applications, Henri Parson Patten

Theses and Dissertations in Biomedical Sciences

The major objective of this research is to examine ion mobility spectrometry as a rapid screening tool for specific application to clinical chemistry research and laboratory use. Methodology was developed for target analytes representing several classes of physiologically active substances, including anesthetics, illicit drugs, and their metabolites. The IMS characteristics of animal tissues and other compounds such as amino acids and proteins were determined. Quality assurance and control procedures were developed for specific quality data objectives. Criteria were established relating to use of IMS for assessing the precision and accuracy of data, qualitative screening, and semi-quantitative analyses.

It was found …

Carbon Nanotube-Based Nonvolatile Random Access Memory For Molecular Computing, Thomas Rueckes, Kyoungha Kim, Ernesto Joselevich, Greg Y. Tseng, Chin Li Cheung, Charles M. Lieber

Barry Chin Li Cheung Publications

A concept for molecular electronics exploiting carbon nanotubes as both molecular device elements and molecular wires for reading and writing information was developed. Each device element is based on a suspended, crossed nanotube geometry that leads to bistable, electrostatically switchable ON/OFF states. The device elements are naturally addressable in large arrays by the carbon nanotube molecular wires making up the devices. These reversible, bistable device elements could be used to construct nonvolatile random access memory and logic function tables at an integration level approaching 1012 elements per square centimeter and an element operation frequency in excess of 100 gigahertz. The …

Synthesis And Characterization Of The Dimethyl-Substituted Bisbenzimidazole Ligand And Its Manganese Complex, Dean Johnston

Chemistry Faculty Scholarship

Macrocycles with unique properties provide new avenues for the design of novel catalysts and materials. Here, we report, for the first time, the synthesis and characterization of the dimethyl-substituted bisbenzimidazole ligand (Me2BBZ) and its manganese complex (Mn-Me2BBZ). The Me2BBZ ligand is similar to porphyrin and phthalocyanine macrocycles in terms of its cavity size and metal-binding mode, but owing to electronic and charge differences, it exhibits properties that make it distinct from its structural counterparts. For instance, the optical spectra of bisbenzimidazoles lack transitions in the 500-900 nm region. Perhaps the most significant feature of the Me2BBZ ligand, however, is its …

Effects Of Ozone/Hydrogen Peroxide Pretreatment On Aerobic Biodegradability Of Nonionic Surfactants And Polypropylene Glycol, Mehmet Kitis, Craig D. Adams, John Kuzhikannil, Glen T. Daigger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Studies were conducted which used the ozone/hydrogen peroxide (O₃/H₂O₂) advanced oxidation process to pretreat three classes of compounds prior to aerobic biological treatment. The study compounds included ethylene oxide/propylene oxide (EO/PO) block copolymers, polypropylene glycols (PPGs), linear secondary alcoholethoxylates (LSAES), and alkylphenolethoxylates (APEs). After preoxidation with ozone and hydrogen peroxide (added at their stoichiometric ratio), 300 mg/L as COD samples were bioassayed in aerobic batch bioassays with a mixed liquor suspended solids concentration of 1500 mg/L. It was found that unoxidized polypropylated compounds (EO/PO block copolymers and PPGs) and LSAEs tended to be biorecalcitrant, …

Spectroscopy Of Hydrogen-Bonded Formanilide Clusters In A Supersonic Jet: Solvation Of A Model Trans Amide, A. V. Fedorov, John R. Cable

Chemistry Faculty Publications

The gas-phase structures of trans-formanilide (FA) clusters containing varying numbers of water and ammonia molecules have been investigated by resonant two-photon ionization spectroscopy in a supersonic jet expansion. A single structure is found for the 1:1 cluster of FA with ammonia in which the amide NH group functions as a hydrogen bond donor to the ammonia nitrogen. In contrast, vibronically resolved spectra reveal two distinct structures for the 1:1 cluster with water in which either the amide NH group functions as a hydrogen bond donor or the carbonyl oxygen functions as a hydrogen bond acceptor. The 1:1 clusters with both …

Nutritional Aspects Of Trans Unsaturated Fatty Acids, Mary Cantwell

Doctoral

Dietary trans unsaturated fatty acids from hydrogenated vegetable and fish oils have been shown to raise plasma low density lipoprotein cholesterol and lower high density lipoprotein cholesterol levels at 10%, 6% and 3% of energy intake. As trans fatty acid intake has not been previously assessed in Ireland a food frequency questionnaire (FFQ) was developed to assess fat intake with particular focus on trans fatty acids. A nutrient database was developed which included the fatty acid and total trans fatty acid composition of foods (measured by gas chromatography and infra-red spectroscopy) which are sources of fat in the Irish diet. …

Thermochemical Properties Of Methyl And Chloro-Methyl Hyplochlorites And Ethers And Reaction Of Methyl Radical With Clo, Dawoon Jung

Theses

Hypochlorites are formed from reactions of chlorine monoxide (ClO) addition to unsaturates and association with radicals. ClO is a prevalent and an important species in chemistry of the atmosphere and in combustion systems where chlorine is present. Thermochemical property data on these oxy-chlorocarbon species are important to understanding the reaction pathways and kinetics in these environments. Enthalpy, ΔH_f°_298, entropy, S°_298, and heat capacities, C_p(T) from 300 to 1500 K are determined for methyl hypochlorite and three chloro-methyl hypochlorites and formaldehyde-C1 atomcomplex radicals (CH₂O--Cl, CHClO--CI, CCI₂O--Cl) by density functional, and ab …

Structures, Intermolecular Rotation Barriers, And Thermodynamic Properties Of Chlorinated Methanols And Chlorinated Methyl Hydroperoxides, Hongyan Sun

Theses

Thermochemical property data on chlorinated methanols and methyl hydroperoxides are important in oxidation, combustion and atmospheric photochemistry of chlorocarbons, Enthalpy, entropy, and heat capacities are determined for three chlorinated methanols and three chlorinated methyl hydroperoxides using density frnctional, B3LYP/6-31G(d,p), B3LYP/6-311+G(3df,2p), ab initio QCISD(T)/6-31G(d,p) and the composite CBSQ/B3LYP/6-31G(d,p) calculation methods. Molecular structures and vibration frequencies are determined at the B3LYP/6-31G(d,p) density functional calculation level. Vibration frequencies are scaled for zero point energies and for thermal corrections. ΔH°_{f 298} are determined at each calculation level using the ΔH_rxn,298 with known enthalpies of other reactants and products in each of five …

Electrocrystallization Mechanism And Grain Sizes Of Ni-W-B Alloy Eletrodeposits, Fang-Zu Yang, Gang-Min Cao, Xiao Hu, Shu-Kai Xu, Shao-Min Zhou

Journal of Electrochemistry

The electrodeposition characteristics and grain sizes of Ni-W-B alloy have been studied by cyclic voltammetry, potentiostatic step and X-ray diffraction (XRD). The results showed that Ni-W-B alloy electrodeposit obtained from the solution containing ammonium citrate as a complexing agent was presented in the lower electrochemical activity compared with Ni-W alloy. Based upon the i～t curves of potentiostatic step, it was revealed that electrocrystallization of Ni-W-B alloy on glassy carbon followed the mechanism of instantaneous nucleation and three dimensional growth with diffusion controlled. The crystal nucleus number on the surface of electrode was raised by the increase of overpotential. According to …

A Review On Impressed Current Anodes Of Cathodic Protection For Underground Structures, Li-Kun Xu, Ting-Yong Wang, Liang-Qian You, Rong-Chun Qian, Guang-Zhang Chen

Journal of Electrochemistry

The requirements of impressed current anodes for the protection of underground structures were presented in this paper according to the analysis of working conditions. The characteristics and performance of various anodes such as scrap steel, graphite, high silicon cast iron, magnetite, platinized anode, conductive polymer cable anode and mixed metal oxide anode were reviewed. The development trend of impressed current anodes for underground applications was also discussed.

Study On Carbon From Pyrolyzing Phenol-Formaldehyde Resin For The Negative Electrode Of Li-Ion Secondary Battery, Zhi-Yuan Tang, Xin-Guo Zhuang, Yu-Mei Zhai, Jian-Gang Li, Jian-Jun Xue, Chun-Yan Liu

Journal of Electrochemistry

Li-ion secondary batteries negative electrodes were prepared by low temperature (<1 000 ℃) pyrolysis of commercial phenol-formaldhyde resin. A thermogravimetric analysis (TGA) and an X-ray diffraction (XRD) studies were peoformed for the pyrolytic carbonaceous materials. The results indicated that these samples are amorphous polyacenic structure materials. With increasing pyrolytic temperature, these materials become structurally order, and the first charge-discharge special capacities reduce. The specific capacities base on pyrolytic temperature, involving lithium storage nanometer cavities.

Preparation And Characteristics Of A Enzyme Electrode Based On Immobilization Of Tyrosinase In Electropolymerized Polypyrrole Film, Liu-Shui Yan, Qia Wei, Cheng-Yi Wang, Rong-Rong Shi, Xiao-Tong Ma

Journal of Electrochemistry

A sensitive and stable amperometric enzyme electrode was constructed, based on the immobilization of tyrosinase in potentiostatically electropolymerized polypyrrole film at a platinum electrode. The influence of pH and potential on immbilization was discussed. SEM micrographs and CV curves of films obtained before and after incorparation of tyrosinase molecular were analyzed and compared each other. The enzyme electrode responds linearly to p-cresol over a concentration range of 5×10 -8 ～1×10^-6 mol/L with an optimum pH of 6.6, It exhibited kinetic characteristics of the typical enzyme-catalyzed reaction with an apparent Michaelis constant of 2.2 ×10^-5 mol/L.

Electrochemical Codeposition Of Palladium And Glucose Oixdase In The Presence Of Glycine As Complexing Agent, Kan Zhu, Hui-Huang Wu

Journal of Electrochemistry

Glycine and Pd(NH₃)₂Cl₂ consist of a solution for the electrochemical codeposition of Pd and glucose oxidase (GOD) to prepare a metallized enzyme electrode. The experiments by UV/V spectroscopy show that the complexing of Pd ion with glycine can occur, which makes the plating bath has relatively stable chemical composition in a certain pH range. The voltammetric experiments indicate that the presense of glycine decreases the potential of Pd deposition ,facilitating to prevent the formation of palladium hydride. The appropriate conditions for the electrochemical codeposition of Pd and GOD are discussed.

Technical Investigaton Of Thin-Film Plasticizing Lithium Ion Battery, Xin-Ping Ai, Xin-Lin Hong, Quan-Feng Dong, Sheng-Xian Li, Han-Xi Yang

Journal of Electrochemistry

A number of polymer materials as candidates of host matrix of plastic polymer electrolyte were examined and techniques for preparation of thin-film electrolyte were reported. The results showed that the polymer electrolyte prepared with P(VDF-HFP) copolymer as host matrix and DBP as plasticizer exhibit the satisfactory mechanical strength and ionic conductivity. In comprison with liquid electrolyte systems, thin-film lithium ion battery has almost similar charge-discharge capacity and cycleability. The manufacture methods and the technical factors in making plasticizing lithium ion battery were also described in details.

Study On The Effect Of Sodium Ion On Cycle Performance Of Lithium/Improved Graphite Lithium Ion Cell, Wen-Huang Huang, Yu-Shun Yan, Chun-Rong Wan, Chang-Yin Jiang

Journal of Electrochemistry

The different concentration of Na⁺ was introduced into the non-aqueous eletrolyte system EC/DEC/LiClO 4 with 4A molecular sieve and lithiated 4A molecular sieve, by which the trace amount of water was removed. The concentrations of Na⁺ and Li⁺ were determined by atomic adsorption spectrometry. The cycle performance of lithium/improved graphite cells was then examined by charging and discharging under the constant electric current. The results demonstrated that the cycle performance of the cells was destroyed by the high concentration of Na⁺ under the small electric current. With the increase of electric current the cell became less …

Effect Of N-Ion Implantation On The Anodic Polarization Behavior Of Surgery Medical Materials In Artificial Body Fluid, Liang Guo, Cheng-Hao Liang, Hong-Yan Sui

Journal of Electrochemistry

Effect of N-ion implantation on the anodic polarization behavior of surgery medical materials, such as SUS316L stainless steel, Co-Cr alloy and Ti₆Al₄V alloy, has been investigated with electrochemical technology in artificial body fluid Hank's solution. With the tests of corrosion potential and anodic polarization curves, it can be seen that the anti-corrosion behavior is developed after implantion. XRD and AES profiles have shown that the metal nitride coated on the matrix after N-ion implantation, which isolates the matrix from environmental solution. The metal nitride film with high electrochemical capability plays an important role in inhibiting corrosion …

Powder Microelectrode Modified With Nafion-Os(Bpy)3Â 2+ And Pvp Composite And Its Catalysis For No2- Reduction, Pei-Fang Liu, Jia-Wei Yan

Journal of Electrochemistry

The modified powder microelectrode was prepared by etching a Pt (0.1 mm diameter) disk microelectrode and filling in thus formed cavity with Nation-Os(bpy)₃²⁺/PVP composite modified carbon powder. The composite modified powder microelectrode showed cyclic voltammetric behaviors changing with the mole ratio (denoted X) of SO₃^- to Os(bpy)₃²⁺ in Nafion. When X=3, a single pair of current peaks appeared near 0.6V (vs. SCE) due to Os(bpy)₃^2+/3+ redox couple. In contrast, for X=20, a pair of additional current peaks occurred near 0.4V. Both X=3 and X=20 modified powder microelectrodes strongly catalyzed the first …

An Investigation On The Corrosion Potential Imaging At The Interface Of Concrete/Reinforcing Bar In Corrosion Media, Rong-Zong Hu, Chang-Jian Lin, Xiang Zhou, Jian-Guang Tan, Xiong-Chao Zhao

Journal of Electrochemistry

The iron array electrode covered with concrete as a new electrochemical technique is applied to map the potential imaging and to investigate on the iron electrode corrosion process under concrete: In Cl^_- solution the corrosion of the iron array electrode covered with concrete had been prevented for a short term since the concrete protection, but the corrosion still occurreed and developed after immersed for a long time. In SO₄^2- solution although the sample had being immersed for a long time and the concrete was possibly broken, the corrosion did not develop. In Cl^_- solution the corrosion …

Electrochemical Quartz Crystal Microbalance Study On The Promoted Electron Transfer Process At Gold Electrode, Xia-Qin Wu, Zhe-Su Wang, Xiao-Yun Meng, Zong-Rang Zhang

Journal of Electrochemistry

The adsorption behavior of amino acids, such as L-cysteine, histidine and arginine at gold-quartz crystal microbalance (Au-QCM) was investigated. The adsorption quantity of cysteine is more appreciable than others because of the stronger interaction between its thiol group and the gold electrode surface. The electron-transfer process of superoxide dismutase (SOD) in presence of cysteine at Au-QCM has also been studied using the electrochemical quartz crystal microbalance (EQCM) technique which reveals clearly the quasi-reversible electron-transfer process accompanied by the frequency shift cycle. The reversible adsorption and disorption processes are discussed.

Effects Of Temperature On The Proton Diffusion Of Doped Ni(Oh)2, Jian-Hua Liu, Jing-Wu Yang, Zhi-Yuan Tang

Journal of Electrochemistry

The Chronoamperometry of powder spherical Ni(OH)₂ microelectrode was used to study the proton diffusion coefficients of Ni(OH)₂. The proton diffusion coeefficients and the apparent diffusion active energy in anode and cathode processes at different temperature were obtained. Compared with pure Ni(OH)₂, the apparent diffusion active energy (E_a) of Ni(OH)₂ doped with Co and Co + Zn was decreased and the diffusion constant (D_o) was increased in the anode and the cathode processes, respectively, the effect of Co was greater. In contrast, for Ni(OH)₂ doped with Zn, its E_{a …}

Template Synthesis And Uv-Vis Absorption Spectra Of The Nanowire Arrays Of Cadmium Chalcogenides, Shi-Min Xu, Kuan-Hong Xue, Jing-Lin Kong, Dong-Mei Sun, Yu-Ying Feng, Hai-Yan Lu, Guang-Hou Wang

Journal of Electrochemistry

The porous alumina membrane formed in the anodic oxidation of highly pure aluminum foil has attracted a great deal of attention in recent years. It can be served as a desired template to prepare nanometer scale materials due to its unique structure of discrete and cylindrical nanopores, paralleled one another, with the homogeneous size and distribution. Chalcogenide semiconductors have promising prospect in the applications of photovoltaic and photoconducting devices and have been extensively exploited for many years. Olbright and his co-workers studied experimentally and theoretically the optical nonlinearties of CdS_xSe_1-x-doped glass; Britt and Ferekides reported that …

Study Of The Cathod Of The Amperometric Glucose Sensor, Xiu-Juan Yu, Ding Zhou

Journal of Electrochemistry

The possibility for several kinds of conducting materials used as the cathode of glucose sensor was studied by the cathode polarization curves. It was shown that the titanium coated by RuO₂/TiO₂ is stable to the electrochemical corrosion and it could promote the generation of hydrogen. H₂O₂ could be detected in the electrochemical system constructed by the anode of graphite powder and epoxy resin composite and the cathode of titanium coated by RuO₂/TiO₂ in the potential range of 0.6V～0.8 V. It can be used as the cathode of glucose sensor instead of …

A Study For The Data Analysis Of Electrochemical Noise With Wavelet Analysis, Hong-Bo Ding, Bao-Yun Xia, Zhong-Xiao Pan, Chang-Jian Lin

Journal of Electrochemistry

In the process of electrochemical dynamics system, the phenomenon of the random fluctuations of electrochemical parameters (electrode potential, cell current, etc.) is called “Electrochemical Noise”(ECN). Wavelets analysis is one new data analysis technique which has undergone a breakthrough in the area of mathematics and singnal processing in recent years. In this paper, the technique of continuous wavelet transform has been employed to investigate electrochemical noise data, and the chaotic nature of corrosion process has been manifested.

The Studies On Nanosized Materials For Lithium Ion Batteries, Hong Li, Jing-Ze Li, Li-Hong Shi, Guang-Yan Zhu, Qing Chen, Wei Lu, Xue-Jie Huang, Li-Quan Chen

Journal of Electrochemistry

Our recent works about nanosized materials for lithium ion batteries are reported, including the synthesis of nanosized Sb, SnSb, CuSn_x, Si and CuS, their electrochemical performance as anode or cathode active materials, the variation of crystal structure and morphology during discharge and charge cycling. In addition, the self-plasticization of lithium salt with nanosized anion ion in polymer electrolyte, the influence of the electrochemical Li-doping on the Raman spectra and photoluminescence of nano-Si are also introduced. Furthermore, the relationship between intrinsic properties of nanosized materials and their electrochemical behaviors are discussed. The prospect of nanosized materials for lithium ion …

Determination Of Kinetic Parameters Of Enzyme-Immunoelectrode For Sec Assay, Sa-Ying Dong, Xin-Miao Liu, Yuan-Zhi Wang, Guang-Zhang Chen, Ming-Xiang Lv, Bo-Yi Tian

Journal of Electrochemistry

Reaction mechanism of enzyme immunoelectrode is studied by potentiostatic. Rotating disk electrode is used to determine the controlling step of bioelectrode. Under different potentials and different modifying conditions, kinetic parameters of bioelectrodes were measured on the base of electrochemical impendance spectra. At the same time, these parameters are compared and discussed.

The Influence Of Surface Diffusion Of Adsorbed Intermediate On Hydrogen Evolution Reaction At Pt/Nafion Composite Electrodes, Wei-Yi Tu, Lei Su, Wen-Jun Liu, Bing-Liang Wu

Journal of Electrochemistry

The decrease of over-potential of hydrogen evolution reaction at Pt black powder/Nafion microelectrode, comparing that of the Pt microdisk/Nafion electrode, was evident from the polarization curves of the Pt microdisk/Nafion electrode, platinized Pt micrdisk/Nafion electrode and Pt black powder/Nafion microelectrode. It is also evidenced by a plane Pt electrode with an additional free Pt surface. The surface diffusion and the surface recombination reaction of the adsorbed intermediate at the free surface of the Pt particles were supposed. It is an additional reaction path that induced the decrease of the concentration of the adsorbed intermediate. Thereby, the over-potential decreased.