Digital Commons Network^™

The Advanced Glycation End Product, NE-(Carboxymethyl)Lysine, Is A Product Of Both Lipid Peroxidation And Glycoxidation Reactions, Min-Xin Fu, Jesus R. Requena, Alicia J. Jenkins, Timothy J. Lyons, John W. Baynes, Suzanne R. Thorpe

Faculty Publications

Nepsilon-(Carboxymethyl)lysine (CML) is an advanced glycation end product formed on protein by combined nonenzymatic glycation and oxidation (glycoxidation) reactions. We now report that CML is also formed during metal-catalyzed oxidation of polyunsaturated fatty acids in the presence of protein. During copper-catalyzed oxidation in vitro, the CML content of low density lipoprotein increased in concert with conjugated dienes but was independent of the presence of the Amadori compound, fructoselysine, on the protein. CML was also formed in a time-dependent manner in RNase incubated under aerobic conditions in phosphate buffer containing arachidonate or linoleate; only trace amounts of CML were formed from …

Pursuit Of A Chiral Amino Aldehyde Intermediate In The Synthesis Of (+)-Obafluorin, A B-Lactone Antibiotic, Jim Cwik '96

Honors Projects

This research is focused on synthesizing a chiral amino aldehyde from L-Serine. The proposed synthesis of the amino aldehyde would yield a stereochemically pure product working through an L-Serine beta-lactone intermediate. The amino aldehyde is a proposed intermediate in the synthesis of (+)-obafluorin, a beta-lactone antibiotic of interest. The proposed synthesis might provide a simpler, more versatile way to synthesize obafluorin.

Toward An Efficient Method Of Detecting Cocaine Metabolite In Urine, C.J. Summers '96

Honors Projects

The primary metabolite of cocaine is benzoyl ecognine (BE). A desirable method for detecting cocaine use is the extraction of BE from urine into an organic phase solvent and subsequent analysis by High Performance Liquid Chromatography (HPLC). The attempt to develop such a method is hindered by the extreme water solubility of BE, making extraction into an organic phase extremely difficult. The present study attempts to use an ion-pairing agent to bind with BE and form a large, organically soluble ion-pair. The ion pairing agent used was Reinecke Salt in a I% solution. An aqueous solution of 50 ug/mL BE …

Facile Liquid Chromatographic Enantioresolution Of Native Amino Acids And Peptides Using A Teicoplanin Chiral Stationary Phase, Alain Berthod, Youbang Liu, Christina Bagwill, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The glycopeptide antibiotic teicoplanin is shown to be a highly effective stationary phase chiral selector for the resolution of underivatized amino-acid and imino-acid enantiomers. Fifty four of these compounds (including all chiral protein amino acids) as well as a number of dipeptides were resolved. Hydro-organic mobile phases are used and no buffers or added salts are needed in most cases. Hence the purified analytes are easily isolated in pure form, if needed, by evaporating of the solvent. The effect of pH, organic modifier type and amount are discussed. The enantioselective separation mechanism is examined using both molecular modeling and retention …

Neutron Diffraction Studies Of Ndₙfeₘ₋ₓ₋YVₓalY [(N,M)=(1,12), (2,17), (3,29)], Z. Hu, William B. Yelon, William Joseph James

Physics Faculty Research & Creative Works

Several Nd_nFe_m-x-yV_xAl_y [(n,m)=(1,12), (2,17), (3,29)] samples were prepared and analyzed using neutron powder diffraction. Rietveld analysis of the neutron diffraction data indicates that the V and Al substituents take those sites with similar environments in all three phases, as observed in our previous study of Ti-substituted compounds. It was confirmed that the diffraction data of the 3:29 compound can be better refined using the A2/m space group than using the P2₁/c space group. The SQUID measurements show that all samples have Curie temperatures well above room temperature. The neutron diffraction results …

Site Affinity Of Substituents In Nd₂Fe₁₇₋ₓtₓ (T=Cu,Zr,Nb,Ti,V) Alloys, William B. Yelon, Z. Hu, William Joseph James, G. K. Marasinghe

Physics Faculty Research & Creative Works

In order to understand the magnetic properties of the substituted rare-earth-iron alloys, it is especially important to know the location of the substitutional atoms within the iron lattice. The site distributions of some nontransition-metal substituents in the substituted Nd₂Fe_17-xT_x alloys have previously been reported. Here we report the site distributions of some transition-metal substituents (Cu,Zr,Nb,Ti,V) in the Nd₂Fe_17-xT_x alloys and compare them with those of the nontransition-metal substituted compounds. Rietveld analysis of neutron powder diffraction data indicates that the nontransition-metal substituents show very similar site affinity at low substituent content. …

Neutron Diffraction And Magnetic Studies Of Rfe₁₂₋ₓtₓcY (R=Y,Er; T=V,Ti,Mo) Alloys, Z. Hu, William B. Yelon, X. D. Zhang, William Joseph James

Physics Faculty Research & Creative Works

RFe_12-xT_xC_y, (R=Y,Er; T=V,Ti,Mo) alloys were prepared by rf induction melting and analyzed using neutron powder diffraction and superconducting quantum interference device (SQUID) measurements. Rietveld analysis of the neutron diffraction data indicates that V, Ti, and Mo atoms all prefer the 8i sites. The refined amount of carbon atoms found in the interstitial sites from neutron diffraction data is significantly less than the nominal carbon content. All samples have the easy direction along the c axis. The Er sublattice couples to the Fe sublattice antiferromagnetically. The average Fe site moments range from 1.3 to 2.8 …

Auger Resonant Raman Spectroscopy Used To Study The Angular Distributions Of The Xe 4d5/2 → 6p Decay Spectrum, B. Langer, N. Berrah, A. Farhat, Oliver Hemmers, J. Bozek

Environmental Studies Faculty Publications

The Auger resonant Raman effect can be used as a method to eliminate natural lifetime broadening in resonant Auger spectra. We have coupled this method with high-resolution photons from the Advanced Light Source to study angular distributions and decay rates of the Xe4d_5/2→6p resonant Auger lines. The angular distribution parameters β of almost all possible final ionic 5p⁴(³P, ¹D, ¹S)6p states have been determined. Our data, which remove the discrepancy between previous lower-resolution experimental results, are compared to different theoretical results.

The Effects Of Free Fatty Acids And Tocopherol On Membrane Order And Antioxidant Activity, Gina Michelle Pineda

Honors Capstones

No abstract provided.

Dynamics And Conformation Of Polymer Chains In A Porous Medium, Grace M. Foo, R.B. Pandey, D. Stauffer

Faculty Publications

No abstract provided.

Neutron Diffraction And Mössbauer Spectral Study Of The Nd₂Fe₁₆Ticₓ Solid Solutions, Gaya Kanishka Marasinghe, Peter C. Ezekwenna, William Joseph James, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean

Chemistry Faculty Research & Creative Works

Three samples of , with x equal to 0.0, 0.3, and 2.8, with the Th₂Zn₁₇-type rhombohedral structure, have been studied by powder x-ray and neutron diffraction, magnetic measurements, and Mössbauer spectroscopy. Nd₂Fe₁₆Ti and Nd₂Fe₁₆TiC_0.3 were synthesized by induction melting stoichiometric amounts of the constituent elements, whereas Nd₂Fe₁₆TiC_2.8 was synthesized by methane-derived gas phase insertion of carbon into finely ground Nd₂Fe₁₆Ti at 600 K. The neutron diffraction determined titanium site occupancies are similar in both Nd₂Fe_{16 …}

Petrochemical Analysis By Remote Fiber-Optic Raman Spectroscopy And Partial Least Squares Regression Analysis, Philip Edmund Flecher Jr.

Chemistry & Biochemistry Theses & Dissertations

A dispersive Raman system with charge coupled device (CCD) detection, distributed Bragg reflector (DBR) diode laser excitation, and a fiber optic probe has been developed for the rapid analysis of petrochemicals and fuels. Initially, mock petroleum fuels with analyte concentrations from 1.S - 16% were prepared and analyzed with the system. The inability of the original index guided diode laser to maintain a constant frequency during the mock petroleum analysis was a recurrent problem. The DBR laser was subsequently shown to have stability superior to index guided lasers, and was used in the remainder of the research.

Real gasoline samples …

A Spin Reorientation In Pr₂Fe₁₇D₃ As Revealed By Mössbauer Spectroscopy, Fernande Grandjean, Dimitri Hautot, Gary J. Long, Olivier Isnard, Salvatore Miraglia, Daniel Fruchart

Chemistry Faculty Research & Creative Works

The Mössbauer effect spectra of Pr₂Fe₁₇D₃, which have been measured between 85 and 295 K, indicate the presence of a spin reorientation of the iron magnetic moments at 105±5 K. At this magnetic transition a large increase of ~50 kOe in the 6c iron magnetic hyperfine field and abrupt changes in all of the remaining hyperfine fields are observed. A study of the changes in the quadrupole shifts at the transition indicates that this spin reorientation takes place within the basal plane of this rhombohedral compound. As expected, the temperature dependence of the isomer …

Carbon Monoxide Amongst Other Chemicals (Presentation), Donald H. Stedman

Fuel Efficiency Automobile Test Publications

Paper presented at the Division of Environmental Chemistry, American Chemical Society National Meeting, New Orleans, LA, March 24-28,1996.

Evaluation Of The Concentration And Enantiomeric Purity Of Selected Free Amino Acids In Fermented Malt Beverages (Beers), K. Helen Ekborg-Ott, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Even though amino acids are important trace components in the brewing of beers, they have not been extensively evaluated in these beverages. Studies involving the enantiomeric composition of these amino acids are even less prevalent. A brief summary of the brewing process for malt beverages is given. The total concentration and enantiomeric composition of three amino acids (leucine, phenylalanine, and proline) were determined in 25 different beers. Proline tended to have the highest average absolute concentration and the lowest percentage of the D-enantiomer in most samples. In some cases the relative amounts of D-phenylalanine and D-leucine exceeded 10% of the …

Computation Of Electron Affinities Of O And F Atoms, And Energy Profile Of F-H2 Reaction By Density Functional Theory And Ab Initio Methods, Branko S. Jursic

Chemistry Faculty Publications

The validity of hybrid and nonlocal DFT methods are tested on examples of systems which are difficult to model by way of quantum chemistry techniques. The electron affinities for the oxygen and fluorine atoms were calculated. The exothermicity, the barrier for the fluorine atom reaction with the hydrogen molecule, and the energy of the H–F bond and its distance were computed with DFT methods, as well as, with ROHF, MPn, and QCISD ~T! ab initio methods. The computations were performed by using various basis sets, with 6-311 11G(3d f ,3pd as the largest. The obtained results are compared …

Thermal Nucleation And Cavitation In Helium-3 Fluids, Xiao Cheng Zeng, D.W. Oxtoby, E. Cheng

Xiao Cheng Zeng Publications

We have investigated droplet nucleation and bubble cavitation in the quantum fluid helium-3 based on a nonlocal density-functional approach. A marked effect of droplet (or bubble) curvature on the rate of droplet nucleation or cavitation has been found. Without considering this curvature effect (as in the classical theory of nucleation) the droplet nucleation rate for helium-3 could be underestimated (i.e., near 1 K) or overestimated (i.e., near 2.5 K) by orders of magnitude, respectively; for bubble cavitation, the rate could be underestimated by more than twenty orders of magnitude (near 1 K).

A Magnetic Neutron Diffraction, And Mössbauer Spectral Study Of The Ce₂Fe₁₇₋ₓalₓ Solid Solutions, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, D. P. Middleton, Zhongbo Hu, William B. Yelon, Fernande Grandjean, K. H. J. Buschow

Chemistry Faculty Research & Creative Works

The magnetic properties of a series of Ce₂Fe_17-xAl_x solid solutions with x equal to 0.00, 0.88, 2.06, 2.81, 3.98, 5.15, 6.08, 7.21, 8.20, 9.08, 9.84, and 10.62 have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. The compounds crystallize in the rhombohedral Th₂Zn₁₇-type structure. Magnetization studies indicate that the Curie temperature increases uniformly from 238 K for Ce₂Fe₁₇ to 384 K for Ce₂Fe₁₄Al₃ and then decreases at higher aluminum content. Powder neutron diffraction results, obtained at 295 K, indicate that aluminum …

One-Pot Preparation Of 1,3-Dihydro-1- (Trifluoromethyl)Isobenzofuran-1-Ol Derivatives From 1,2-Dibromobenzene, Daniel Becker, Hui Li, Daniel L. Flynn

Chemistry: Faculty Publications and Other Works

A one-pot method for the preparation of 1,3-dihydro-1-(trifluoromethyl)isobenzofuran-1-ol derivatives 5from 1,2-dibromobenzene is described

Effects Of Ph, Ligand Cn-, Metallic Ions Hg2+, Cd2+ And Pb2+ On Electroactivity Of Cytochrome C, Jin Luo, Lingling Wu, Jintain Wu, Shaohua Huang, Zhonghua Lin

Journal of Electrochemistry

The effects of pH, ligtlnd CN^-, metallic ions, Hg²⁺, Cd²⁺ and Pb²⁺ on electroactivity of cytochrome c have been studied with cyclic voltammetry and UV/Vis spectroseopy. In the phosphate buffer solution containing 5 mg/mL cytochrome c, cytochrome c is electroactive at a glod electrode with suitable pretreatment if the pH value is equal to 7.0, but it is electroinactive at the gold electrode if the pH value is equal to 2.0 or 10.0. The existence of CN^- ions in the solution would cause deactivation of cytochrome c in the bulk sulurion, and would …

Electrochemical Ploymerization Of Aniline In The Alkaline Solution And Properties Of Polymer, Shaolin Mu, Jinqing Kan, Aiguang Zhang

Journal of Electrochemistry

A deep yellow polyaniline was formed at the anodic electrode during electrochemical oxidation of aniline in the alkaline solution. The peak of oxidation potential for aniline in the alkaline solution was 0.7 V (vs.Ag/AgCl with a saturated KCl solution), which is about 0.3V less than that in the acidic solution. The results from rotating ring-disk electrode experiment show that two soluble intermediates were generated during electrochemical oxidation of aniline. The colour of the polymer in the alkaline solution is independent of applied potential and pH values. An adsorption peak was observed in the UV region at 500 nm for the …

Ftis Observation Of Twin Adsorbates Of Co On Rh Electrode In Acid Solution, Wenfeng Lin, Shigang Sun

Journal of Electrochemistry

Because of its great importance both in electrocatalysis and C1 chemistry applications, the adsorption of CO on metallic electrodes such as Pt, Pd, Au, Ag, RhF, etc. has been extensively studied by in situ infrared spectroscopy Since 1981. In all these studies only three types of CO adsorbates, i. e., linear (2090～2000 cm^-1), bridgrd (2000～1900 cm^-1) or multi-bonded (1900～1800 cm^-1) species, were identified. A different absorbate, twin CO on rhodium (Rh(CO)₂), does exist on the solid/gas interface of highly dispersed Rh or Rhn clusters on supports, this species originating a doublet at …

Hydrogen Evolution Reaction On Nanocrystalline Co-Mo/Ni Composite-Coated Electrodes, Weizeng Yu, Jie Ma, Yiming Chu, Huizhe Zhu, Hongjie Wang, Shuncheng Liu

Journal of Electrochemistry

The electrochemical behaviours of the hydrogen evolution reaction (HER) at electrodes prepared by composite coating of nanocrytstalline Co-Mo alloy particles formed by ball milling on nickel base has been sludied by using sleady-state polarization and ac impedance techiu ques. The microstructure and the size of the nanocrystals of Co-Mo alloy and the morphology of the composite-coating surface of the electrodes are measured by XRD, TEM and SEM. Results show that the nanocrystalline Co-Mo alloys prepared by high energy ball milling has high electrocatalytic activity for HER. The electrocatalytic activity for the HER is enhanced and the energy of activation for …

Electrochemical Studies On Corroding Metallic Electrodes In Frequency Domain, Chunan Cao

Journal of Electrochemistry

The electrochemical studies on corroding metallic electrodes carried out in the State Key Laberatory for Corrosion and Protection are reviewed briefly: (1) General equations of faradaic admittance under potential-control condition were derived based on the stabillity conditions of steady processes. The faradaic admittance at mixed potential then was deduced based on these equations and the electrochemical impedance spectroscopy (EIS) at corrosion potentials in the solutions containing interface inhibitors was diseussed by application of the thecetical results obtained. (2) The spectral power density (SPD) curves for electrochemical noise (EN) during the initial stagu of pitting corrosion were observed for iron and …

An Indirect Electrochemical Oxidation Of Toluene─Catalytic Effects Of Ag(Ⅰ) On Mn(Ⅱ)/Mn(Ⅲ) Couple Transition At Pt Electrode, Zhonghua Wang, Yunan Qu, Xingguo Yan, Qngmin Hua, Guacai Chen, Zhongquan Wang

Journal of Electrochemistry

The Catalytic effects of Ag(Ⅰ) on toluene oxidation by Mn(Ⅲ) as well as the anodic generation of Mn(Ⅲ) were investigated. The rates of toluene oxidation were first order with respect to both Ag(Ⅰ) and Mn(Ⅲ). Ag(Ⅱ) formed on the surface of the platinum anode when Ag(Ⅰ) was present in the anolyte, which catalyic the Mn(Ⅱ) to Mn(Ⅲ) in solution.

Study Of The Calcium-Thionyl Chloride Cells, Baohong Zhang, Meng Chen, Yingdong Wang, Dongsheng Xu

Journal of Electrochemistry

The properties of CaCl₂ SEI covered on the ca electrode surface in thionyl chloride, the influence of various salts in thionyl chloride on the porformance of the Ca anode and carbon cathode, and the function of the additive CuCl₂ and CuBr₂ to cathode in the improvement of the cathode performance were studied by AC impedance, constant current discharge, and SEM. As a result, the Ca-SOCl₂ cell was able to discharge at 50 mA·cm^-2 and the capacity reached 17.5 mAh·cm^-2.

A Study On Performance Of Electroless Nickel Coatings Containing Low Phsphorus, Huilin Guo, Xinguo Hu, Guipin Su

Journal of Electrochemistry

The low phosphorus coatings (LP) had superior corrosion resistence to that of high phosphorus (HP) in alkaline and neutral NaCl solutions. The microhardness of the coatings increaed from 454 Hv to 890 Hv when they were heated at 350℃ for one hour. Two exothermic peaks were observed at 341.6 ℃and 406.2 ℃, which respectively corresponded to form the new phases Ni₅P₂ and Ni₃P in the differential thermal analysis. The atomic structure of as-deposited coatings in the terms of X-ray diffraction had confirmed that the coatings coasisted of extremely fine crystallites.

Research On Molten Carbnate Fuel Cell, Naichao Li, Baolian Yi, Lianying Kong, Enjun Zhang, Huaxin Lin, Tianxi Qu, Yingcai Cheng

Journal of Electrochemistry

Cold-roll-milling has been evaluated as a technique for preparing porous LiAlO₂ matrices for use as a molten carbonate fuel cell electrolyte matrix. This technique produces reliable electrolyte structures with the following characteristics and advantages: ease of handling, uniform thickness, using nontoxic inorganic solvents, controlled pore size distribution, and ability to be impregnated with the alkali carbonate without fracrure.

The Molren Carbnatod Fuel Cell (MCFC) was assembled from sintered Ni electrodes and LiAlO₂ electrolyte matrix, the electrode area is 28 cm², the effect of operating conditions on cell performance was tested, it was found that the cell …

Study Of Electrochemical Behaviour Of Myoglobin Using Cyclic Voltammetry And Synchronous Fluorescence Spectroscopy, Ju Chou, Haihong Zhou, Tianhong Lu, Yue Wu

Journal of Electrochemistry

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The Inhibition Of Amphipathic S- And N-Containing Compounds On Carbon Steel Corrosion, Wei Xing, Yibin Shan, Du Guo, Tianhog Lu, Shiquan Xi

Journal of Electrochemistry

Ordered monolayers of S- and N-containing amphipathic corrosion inhibitors were depoitod onto the surfaces of carbon steel electrode with super-molecular assembly technique. The effect of molecular aggregation of monolayers on carbon steel corrosion in 0.05 mol·cm^-3 H₂SO₄ and the mechanisms of these inhibitors were discussed in details. It was found that the transport of hydrated hydrogen ion to the surface of steel depends strongly on the inhibitor molecular aggregation in the monolayers.