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2006

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Articles 211 - 240 of 592

Full-Text Articles in Chemistry

Effect Of Preparation Conditions On Electroluminescence Of Porous Silicon, Ya-Jun Yang, Qing-Shan Li, Xian-Yun Liu, Ning Zhang, Bo Zhao, Xue-Gang Zheng, Ming-Ji Shi, Da Chen, Jing-Jing Wang May 2006

Effect Of Preparation Conditions On Electroluminescence Of Porous Silicon, Ya-Jun Yang, Qing-Shan Li, Xian-Yun Liu, Ning Zhang, Bo Zhao, Xue-Gang Zheng, Ming-Ji Shi, Da Chen, Jing-Jing Wang

Journal of Electrochemistry

Electrically induced visible light emitting porous silicon devices with the structure of ITO/PS/p-Si/Al were fabricated by evaporation-anodic oxidation method.The light emission last for a few hours under 7.5V forward bias conditions.It was shown that the electroluminescence(EL) peaks shifted to the blue with the increasing of current density,erosion time and solution concentration.In order to achieve samples with low driven voltage,long light emission time and high EL efficiency,porous silicon should be prepared under low current density and short erosion time.

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Tyrosinase Immobilizarion On Boron-Doped Diamond Electrodes And The Determination Of Phenolic Compounds, Yan-Li Zhou, Jin-Fang Zhi May 2006

Tyrosinase Immobilizarion On Boron-Doped Diamond Electrodes And The Determination Of Phenolic Compounds, Yan-Li Zhou, Jin-Fang Zhi

Journal of Electrochemistry

As-grown BDD surfaces were first functionalized by photochemically linking vinyl groups of allylamine,producing covalently linked amine-terminated active BDD surfaces.Then the tyrosinase was immobilized onto the BDD surface through peptide linking.Cyclic voltammograms of phenol,pcresol and hydroquinone were measured using the tyrosinase-modified BDD electrode and amperometric characteristics such as sensitivity,linear response range and stability were studied.

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Electrochemical Studies On Electrocatalytic Activity Of AuCore PtShell Nanoparticles To Methanol Oxidation, Fang Bao, Jian-Lin Yao, Ren-Ao Gu May 2006

Electrochemical Studies On Electrocatalytic Activity Of AuCore PtShell Nanoparticles To Methanol Oxidation, Fang Bao, Jian-Lin Yao, Ren-Ao Gu

Journal of Electrochemistry

AucorePtshell nanoparticles with different thicknesses were prepared by using chemical reduction method,and characterized by ultraviolet-visible spectroscopy(UV-Vis),transmission electron microscopy(TEM) and cyclic voltammetry(CV).The electrocatalytic activity of AucorePtshell nanoparticles with the mean diameter of 70~80 nm to methanol oxidation was investigated by cyclic voltammetry in the acid solution.The results revealed that the prepared core-shell nanoparticles were covered by Pt shell and exhibited the similar optical property and electrocatalytic activity with the normal Pt surface.Moreover,the electrocatalytic activity increased with the electrochemical sweep in the certain potential range.It might be contributed by the special loose structure of Pt shell …

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Effects Of Eelectrolyte Salt To The Sei Layer Of Licoo2 Material, Ming-Sen Zheng, Quan-Feng Dong, Ya-Wei Zhu, Ya-Ding Zhan, Zu-Geng Lin May 2006

Effects Of Eelectrolyte Salt To The Sei Layer Of Licoo2 Material, Ming-Sen Zheng, Quan-Feng Dong, Ya-Wei Zhu, Ya-Ding Zhan, Zu-Geng Lin

Journal of Electrochemistry

The character of the solid electrolyte interface (SEI layer) on the surface of LiCoO2 formed in the electrolytes contained different salt such as LiPF6, LiClO4 and LiBF4 were studied in this paper. The results showed that the SEI film exists in all three electrolytes after the processes of charge and discharge. The morphological character and the formation voltage of the SEI layer of LiCoO2 were different in different electrolytes. The electrochemical performance of the battery such as reversible capacity, average discharge voltage and electrochemical impedance were affected significantly by SEI film formed in different …

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Electrochemical Preparation Of Gd-Ni Alloy Film In Acetamide-Urea-Nabr Melt, Bi-Qing Chen, Jian-Chao Wang, Chen-Yu Guo, Jin-Gui Wang, Qing Liu May 2006

Electrochemical Preparation Of Gd-Ni Alloy Film In Acetamide-Urea-Nabr Melt, Bi-Qing Chen, Jian-Chao Wang, Chen-Yu Guo, Jin-Gui Wang, Qing Liu

Journal of Electrochemistry

Cyclic voltammetry was used to study the electroreduction of Ni2+ to Ni on Pt and Cu electrode in acetamide-urea-NaBr melt at 353K.It is irreversible in one step.At Pt and Cu eletrode the diffusion coefficient and electron transfer coefficient of Ni2+ in 0.063mol/dm3) NiCl2-acetamide-urea-NaBr melt were determined.The transfer coefficient α=0.28 and diffusion coefficient D_(0)=4.63×10-5 cm2·s-1 of the Pt eletrode and transfer coefficient α=0.22 and diffusion coefficient D_(0)=6.05×10-7 cm2·s-1 of the Cu eletrode were measured.It was put emphasis on that Gd3+ is not reduced to Gd alone …

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Study On Composite Organic Inhibitor Of Zinc Electrode In Alkaline Solutions, Xue-Tao Bu, Guang-Chuan Liang, Cui Li May 2006

Study On Composite Organic Inhibitor Of Zinc Electrode In Alkaline Solutions, Xue-Tao Bu, Guang-Chuan Liang, Cui Li

Journal of Electrochemistry

The synergetic influence of sodium dodecyl benzene sulfonate(SDBS) with Tween-20(Tween) on zinc electrode was studied by polarization experiment,surface tension test,discharge test and SEM.It is found that the composite inhibitor ST has a much higher efficiency.The addition of Tween reduced the critical micell concentration of SDBS on zinc electrode remarkably and the distribution of adsorption became more homogeneous.ST inhibits corrosion of zinc electrode and improves discharge capacity of the whole battery.Through electrochemical morphological observation of anodic passivation behaviors of zinc electrode,the absorption of ST on electrode surface makes discharged production much smaller and keeps crude porous structure intact.Passivation of zinc electrode …

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Electrochemical Impedance Spectrum Of Ferrocene At A Rotating Disk Glassy Carbon Electrode And Its Interaction With Dna, Can-Hui Chen, Hong Li, Jian-Zhang Zhou, Zhong-Hua Lin, Wei Zhu, Quan-Xin Zhang May 2006

Electrochemical Impedance Spectrum Of Ferrocene At A Rotating Disk Glassy Carbon Electrode And Its Interaction With Dna, Can-Hui Chen, Hong Li, Jian-Zhang Zhou, Zhong-Hua Lin, Wei Zhu, Quan-Xin Zhang

Journal of Electrochemistry

The electrochemical impedance spectrum(EIS) of ferrocene(Fc) at a rotating glassy carbon(GC) electrode and its interaction with calf thymus DNA in Tris-NaCl buffer solution(pH=7.2) have been investigated by using electrochemical techniques such as rotating disk electrode(RDE),EIS and its data fitting.A plateau of the limiting current for the voltammetric curve and two capacitance arches obtained at the rotating GC electrode are exhibited.The interaction of Fc with DNA is represented by the decrease of limiting diffusion current and the increase of electrochemical reaction resistances with the increase of DNA concentration,respectively.On the other hand,based on the theoretical analysis and data fitting of RDE and …

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Investigation On Ru-Ti-Ir Anode Coatings Modified By Adding Sn Element, Ke Wang, Yan Han, Jun-Tao Wang, Xiao-Ling Zhang, Yu-Pu Sun May 2006

Investigation On Ru-Ti-Ir Anode Coatings Modified By Adding Sn Element, Ke Wang, Yan Han, Jun-Tao Wang, Xiao-Ling Zhang, Yu-Pu Sun

Journal of Electrochemistry

The anode coatings of Ru-Ti-Ir-Sn oxide with various Sn contents were prepared by thermal decomposition and characterized by the scanning electron microscopy(SEM),energy dispersive X-ray detector(EDX),X-ray diffraction(XRD),and the potential of chlorine evolution,current efficiency,cyclic voltammetry and electrochemical impedance spectroscopy(EIS).The results tests showed that there was a great change in the morphology of the coatings after adding Sn element.The addition of Sn not only reduced the potential of chlorine evolution,but also effectively improved the current efficiency of the anode coatings.

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Electrochemical Behavior And Reduction Mechanism Of High Valence Silver Oxide Ag3O4 In Alkaline Solution, Yan Cheng, Ming Yu, Man-Ming Yan, Zhi-Yu Jiang May 2006

Electrochemical Behavior And Reduction Mechanism Of High Valence Silver Oxide Ag3O4 In Alkaline Solution, Yan Cheng, Ming Yu, Man-Ming Yan, Zhi-Yu Jiang

Journal of Electrochemistry

The electrochemical properties of high-valence silver oxide Ag3O4 in alkaline solution were investigated for the first time and the reduction mechanism of Ag3O4 was proposed. It can be recognized that Ag3O4 consists of Ag(Ⅲ) and Ag(Ⅱ)~(*). From the results of voltammetry and XRD experiments it was found that the reduction process of Ag3O4 was more complicated. It could be electrochemically reduced through the series reactions of Ag(Ⅲ) →Ag(Ⅱ) →Ag(Ⅰ) →Ag(O) at low discharge rate or Ag(Ⅲ) →Ag(Ⅰ) →Ag(O) at higher discharge rate.And the Ag(Ⅱ)~(*) could be reduced to …

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An Electro-Driving High Efficiency, Continuous, No-Damage Focusing Electrophoresis Concentration Device, Hua-Shui Lin, Liang-Ge Chen, Run-Xiang Zhang, Fan Luo, Wei-Ling Hu, Zhao-Wu Tian May 2006

An Electro-Driving High Efficiency, Continuous, No-Damage Focusing Electrophoresis Concentration Device, Hua-Shui Lin, Liang-Ge Chen, Run-Xiang Zhang, Fan Luo, Wei-Ling Hu, Zhao-Wu Tian

Journal of Electrochemistry

We presented a membrane focusing concentration method and fabricatedan electro-driving high efficiency,continuous,no-damage focusing electrophoresis concentration device.In the concentration experiments of bromophenol blue and Na-fluorescein,the concentrated efficiencyof the device reached two orders of magnitude.This device can be magnified to industrial equipment with large output.It also can be miniaturized to small and simple attachment for separated and analytical instrument such as electrophoresis,chromatogram, mass spectrum and optical spectrum.When integrated into chips,it would be a pre-concentrated unit of the lab-on-chip.

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An Electrochemical Investigation Of Methanol Crossover In Dmfcs, Meng-Di You, Xuan Cheng, Lian Liu, Lu Zhang May 2006

An Electrochemical Investigation Of Methanol Crossover In Dmfcs, Meng-Di You, Xuan Cheng, Lian Liu, Lu Zhang

Journal of Electrochemistry

Methanol crossover and its effect on the open-circuit voltage(OCV) in DMFCs were studied usingcyclic voltammetry and chronoamperometry under stationary condition and at ambient temperature.An H-shapecell was constructed and a simulative DMFC test was carried out to investigate methanol crossover through Na-fion(117 from anode to cathode.The results revealed thatthe amountof methanol in the cathode side is depend-ent upon the time of penetration.As the concentration of methanol increased,the hydrogen adsorption-desorptionon the surface of electrode was suppressed and a shoulder peak appeared during the forward sweep for methanoloxidation.The simulative DMFC test also showed that the methanol crossover caused a sudden decline in theOCV.

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Electrochemical Studies Of Iron-Doped Nickel Oxide Electrode For Oxygen Evolution Reaction, Jin-Zhao Huang, Zheng Xu, Hai-Ling Li, Guo-Hu Kang, Wen-Jing Wang May 2006

Electrochemical Studies Of Iron-Doped Nickel Oxide Electrode For Oxygen Evolution Reaction, Jin-Zhao Huang, Zheng Xu, Hai-Ling Li, Guo-Hu Kang, Wen-Jing Wang

Journal of Electrochemistry

In this paper,the iron-doped nickel oxide thin film as anode catalyst was prepared by RF reactivesputtering method.The oxygen evolution reaction(OER) on the iron-doped nickel oxide was investigated withcyclic voltammetry,liner sweep voltammetry,polarization curves and electrochemical impedance spectroscopy.Results showthat the iron acts as active site in the film which makes the overpotential lower,and changes therate-limiting from primary discharge of OH-ions to the recombination of oxygen atom.With the increasing of ox-ygen content in flu ratio during sputtering,the electrocatalytic activities of the film increase.Iron-doped nickeloxide thin film is promising material as OER electrocatalyst for hydrogen production than the nickel electrode.The oxygen overpotential on the …

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Electrodeposition Of Three-Dimensional Porous Copper Films Using Hydrogen Bubbles As Template, Ya-Feng Sun, Zhen-Jiang Niu, Shu-Qiong Cen, Ze-Lin Li May 2006

Electrodeposition Of Three-Dimensional Porous Copper Films Using Hydrogen Bubbles As Template, Ya-Feng Sun, Zhen-Jiang Niu, Shu-Qiong Cen, Ze-Lin Li

Journal of Electrochemistry

Using cathodic hydrogen bubbles as a template,the three-dimensional(3-D) porous copper films have been successfully electrodeposited from a bath of 0.2 mol·dm-3 CuSO4 and 1.5 mol·dm-3 H2SO4,effects of deposition parameters including temperature,current density and additives(Na2SO4,HCl and Polyethylene glycol(PEG)) on the morphologies of the deposits have been systematically studied.SEM results showed that both the pore size and thickness of the pore walls decreased with cooling the electrolyte temperature or adding(Na2SO4) or PEG into the bath when the other deposition parameters were fixed.With addition small amounts of HCl …

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Structure And Properties Of Electrodeposited Sn-Co Alloy Electrodes As Anode Material For Lithium-Ion Secondary Batteries, Hong-Hong Jiang, Ling Huang, Shun-Wei Zhou, Fu-Sheng Ke, Fang-Zu Yang, Xiao-Yong Fan, Shi-Gang Sun May 2006

Structure And Properties Of Electrodeposited Sn-Co Alloy Electrodes As Anode Material For Lithium-Ion Secondary Batteries, Hong-Hong Jiang, Ling Huang, Shun-Wei Zhou, Fu-Sheng Ke, Fang-Zu Yang, Xiao-Yong Fan, Shi-Gang Sun

Journal of Electrochemistry

The Sn-Co alloy deposits were prepared by electroplating.The structure and electrochemical performance of the electroplated Sn-Co alloys have been investigated in detail. Experimental results show that the porous Sn-Co alloy film exhibits hexagonal solid solution,with Sn as the solvent, Co as the solute. The texture of the Sn-Co alloy coating exhibits(110) preferred orientation. Electrochemical tests show that the porous Sn-Co alloy coating electrodes can deliver a discharge capacity of 643mAh/g in the first cycle. At the 20h cycle the charge was 461mAh/g. At initial charge curve the irreversible capacity is probably associated to a combination of processes, which may …

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Preparation Of Spherical Ni(Oh)2 Coated With Coooh And Its Fast Charge Performance, Min-Jie Yang, Jun-Min Nan, Jian-Jun Xue, Yan Cui, Ming Cui May 2006

Preparation Of Spherical Ni(Oh)2 Coated With Coooh And Its Fast Charge Performance, Min-Jie Yang, Jun-Min Nan, Jian-Jun Xue, Yan Cui, Ming Cui

Journal of Electrochemistry

Spherical Ni(OH)2 was coated with CoOOH through chemical precipitation and electrolytic oxidation.The influences of CoOOH coating on fast charge performance ofMH/Ni battery were studied by preparing high capacity and fast charge AA size MH/Ni batteries.The sample coated with CoOOH was characterized by Infrared spectrum(IR) and scanning electron microscopy(SEM).The results showed that the internal resistance decreased 3.4 mΩ,the charge plateau lower and the cell temperrature was below 55 ℃ at the end of charging process when the cathode active material used Ni(OH)2 coated with CoOOH as compared with that doped by CoO.In addition,an initial discharge efficiency of 90.6% and …

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Volatile Organic Compounds Composition Of Merged And Aged Forest Fire Plumes From Alaska And Western Canada, Joost A. De Gouw, C. Warneke, A. Stohl, A. G. Wollny, C. A. Brock, O. R. Cooper, J. S. Holloway, M. Trainer, F. C. Fehsenfeld, E. L. Atlas, Stephen G. Donnelly Ph.D., V. Stroud, A. Lueb May 2006

Volatile Organic Compounds Composition Of Merged And Aged Forest Fire Plumes From Alaska And Western Canada, Joost A. De Gouw, C. Warneke, A. Stohl, A. G. Wollny, C. A. Brock, O. R. Cooper, J. S. Holloway, M. Trainer, F. C. Fehsenfeld, E. L. Atlas, Stephen G. Donnelly Ph.D., V. Stroud, A. Lueb

Chemistry Faculty Publications

The NOAA WP-3 aircraft intercepted aged forest fire plumes from Alaska and western Canada during several flights of the NEAQS-ITCT 2k4 mission in 2004. Measurements of acetonitrile (CH3CN) indicated that the air masses had been influenced by biomass burning. The locations of the plume intercepts were well described using emissions estimates and calculations with the transport model FLEXPART. The best description of the data was generally obtained when FLEXPART injected the forest fire emissions to high altitudes in the model. The observed plumes were generally drier than the surrounding air masses at the same altitude, suggesting that the fire plumes …

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Cerium-Based Spontaneous Coating Process For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Matthew O'Keefe, Eric L. Morris, Scott A. Hayes, Paul Yu, Alex Williams, Berny F. Rivera Vasquez, Xuan Lin May 2006

Cerium-Based Spontaneous Coating Process For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Matthew O'Keefe, Eric L. Morris, Scott A. Hayes, Paul Yu, Alex Williams, Berny F. Rivera Vasquez, Xuan Lin

Chemistry Faculty Research & Creative Works

A cerium-based coating for corrosion resistance is applied by exposing a cleaned aluminum-based component to a corrosion-inhibiting cerium solution containing cerium ions in the presence of an oxidizing agent. The coating deposits spontaneously without an external source of electrons.

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Geostatistical And Stochastic Study Of Radio Nuclide Transport In The Unsaturated Zone At Yucca Mountain, Ming Ye, Amy J. Smiecinski, Raymond E. Keeler May 2006

Geostatistical And Stochastic Study Of Radio Nuclide Transport In The Unsaturated Zone At Yucca Mountain, Ming Ye, Amy J. Smiecinski, Raymond E. Keeler

Publications (YM)

The U.S. Nuclear Waste Technical Review Board [Cohon et al. 1998] evaluated the technical and scientific validity of activities undertaken by the Secretary of Energy to characterize Yucca Mountain, Nevada, for its suitability as an underground repository in which to store high-level radioactive waste and spent nuclear fuel. In the report, the Board pinpointed that the study on groundwater flow and radionuclide transport in the saturated and unsaturated zones below Yucca Mountain should, over the next several years, focus on reducing prediction uncertainty. In its 2002, the Board repeated this concern by stating, “… hydrogeologic processes that affect radionuclide transport …

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Molecular Dynamics Of Polystyrene Solutions In Microwave Fields, Mark J. Purdue, James M. D. Macelroy, D. F. O'Shea, Macduff O. Okuom, Frank D. Blum May 2006

Molecular Dynamics Of Polystyrene Solutions In Microwave Fields, Mark J. Purdue, James M. D. Macelroy, D. F. O'Shea, Macduff O. Okuom, Frank D. Blum

Chemistry Faculty Research & Creative Works

Equilibrium and nonequilibrium molecular dynamics simulation techniques were used to assess the influence of an applied microwave field on the dynamics of methylamine-methanol and methylamine-dimethylformamide (DMF) solutions bound within atactic polystyrene over a range of polymer densities from 35 to 96 wt % polymer. Atomistically detailed systems were studied, ranging from 3000 to 10 644 particles, using previously established potential models. Structural and dynamical properties were determined in the canonical (NVT) ensemble at 298 K. The simulated DMF self-diffusion coefficients in polystyrene solutions were compared with the zero-field experimental results established with pulsed-gradient spin-echo NMR spectrometry. A simulated external microwave …

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Studies By Biointeraction Chromatography Of Binding By Phenytoin Metabolites To Human Serum Albumin, Corey M. Ohnmacht, Shirley Chen, Zenghan Tong, David S. Hage May 2006

Studies By Biointeraction Chromatography Of Binding By Phenytoin Metabolites To Human Serum Albumin, Corey M. Ohnmacht, Shirley Chen, Zenghan Tong, David S. Hage

David Hage Publications

Biointeraction studies based on high performance affinity chromatography were used to investigate the binding of human serum albumin (HSA) to two major phenytoin metabolites: 5-(3-hydroxyphenyl)-5-phenylhydantoin (m-HPPH) and 5-(4-hydroxyphenyl)-5-phenylhydantoin (p-HPPH). This was initially examined by conducting self-competition zonal elution experiments in which m-HPPH or p-HPPH were placed in both the mobile phase and injected sample. It was found that each metabolite had a single major binding site on HSA. Competitive zonal elution experiments using l-tryptophan, warfarin, digitoxin, and cis-clomiphene as site-selective probes indicated that m-HPPH and p-HPPH were interacting with the indolebenzodiazepine …

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10,10′-Dinitro-10,10′-(Propane-1,3-Di­Yl)Di-10h-Anthracen-9-One, Mustafa Arslan, Erol Asker, John Masnovi, Ronald J. Baker May 2006

10,10′-Dinitro-10,10′-(Propane-1,3-Di­Yl)Di-10h-Anthracen-9-One, Mustafa Arslan, Erol Asker, John Masnovi, Ronald J. Baker

Chemistry Faculty Publications

The title compound, C31H22N2O6, was obtained as the decomposition product of (E,E)-1,3-bis­[9,10-dihydro-9-nitro-10-(trinitro­meth­yl)-9-anthr­yl]propane, which was synthesized via a photochemical reaction of 1,3-di-9-anthrylpropane with tetra­nitro­methane. Inter­molecular C—H⋯O inter­actions are the most prominent features of the crystal packing; no indications of any inter­molecular π–π stacking were found.

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An Investigation Into The Antifungal Activities Of N-Thiolated Beta- Lactams Against Selected Candida Species, Marci Culbreath May 2006

An Investigation Into The Antifungal Activities Of N-Thiolated Beta- Lactams Against Selected Candida Species, Marci Culbreath

USF Tampa Graduate Theses and Dissertations

β-lactam antibiotics have long been a reliable course of treatment for bacterial infections. However, with recent increases in resistance and rising populations of immunocompromised patients new β-lactams have been synthesized and tested. The Turos laboratory has recently discovered novel β-lactams that have a mode of action distinct from penicillin and other β-lactam antibiotics as cell lysis is not observed. In the current investigations, these compounds are shown to also have antifungal properties. The rising incidence and prevalence of invasive fungal infections has become an increasing concern. The most common fungal pathogens involved in these infections are species in the genus …

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Criticality Studies Of Dilute Plutonium Mixtures For Urex Processes, Denis Beller May 2006

Criticality Studies Of Dilute Plutonium Mixtures For Urex Processes, Denis Beller

Separations Campaign (TRP)

The completion of criticality experiments for mixtures of higher actinides (HA, includes neptunium, plutonium, americium, and curium) that will be created during the separation of used nuclear fuel has been identified as a requirement to construct prototype plants such as the Engineering-Scale Demonstration (ESD) and the Advanced Fuel Cycle Facility (AFCF) for the Global Nuclear Energy Partnership (GNEP). GNEP is a program to develop a worldwide consensus to enable the expanded use of economical, environmental nuclear energy to meet growing electricity demand. In this program and the Advanced Fuel Cycle R&D program (AFC) that supports it, we are developing economic …

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Single-Molecule Transistors: Electron Transfer In The Solid State, Douglas Natelson, Lam H. Yu, Jacob W. Ciszek, Zachary K. Keane, James M. Tour May 2006

Single-Molecule Transistors: Electron Transfer In The Solid State, Douglas Natelson, Lam H. Yu, Jacob W. Ciszek, Zachary K. Keane, James M. Tour

Chemistry: Faculty Publications and Other Works

Single-molecule transistors (SMTs) incorporating individual small molecules are unique tools for examining the fundamental physics and chemistry of electronic transport in molecular systems at the single nanometer scale. We describe the fabrication and characterization of such devices, and the synthesis and surface attachment chemistry of novel transition metal complexes that have been incorporated into such SMTs. We present gate-modulated inelastic electron tunneling vibrational spectroscopy of single molecules, strong Kondo physics (TK ∼ 75 K) as evidence of excellent molecule/electrode electronic coupling, and a demonstration that covalent attachment chemistry can produce SMTs that survive repeated thermal cycling to room …

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Thermal Analysis Of Adsorbed Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Erin N. Young, Gregory Smith, Oliver C. Sitton May 2006

Thermal Analysis Of Adsorbed Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Erin N. Young, Gregory Smith, Oliver C. Sitton

Chemistry Faculty Research & Creative Works

Modulated differential scanning calorimetry has been used to quantify the glass transitions of small, adsorbed amounts of poly (methyl methacrylate) (PMMA) on silica. While a relatively narrow, single glass transition was found for bulk PMMA, broader two-component transitions were found for the adsorbed polymer. a two-state model based on loosely bound polymer (glass transition similar to bulk) and more tightly bound polymer (glass transition centered around 156°C) was used to interpret the thermograms. on the basis of this model, the amount of tightly bound polymer was found to be approximately 1.3 mg/m 2, corresponding to a 1.1 nm thick layer. …

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Functional Replacement Of The Ketosynthase Domain Of Fum1 For The Biosynthesis Of Fumonisins, A Group Of Fungal Reduced Polyketides, Xiangcheng Zhu, Fengan Yu, R. S. Bojja, K. Zaleta-Rivera, Liangcheng Du May 2006

Functional Replacement Of The Ketosynthase Domain Of Fum1 For The Biosynthesis Of Fumonisins, A Group Of Fungal Reduced Polyketides, Xiangcheng Zhu, Fengan Yu, R. S. Bojja, K. Zaleta-Rivera, Liangcheng Du

Liangcheng Du Publications

The genetic manipulation of the biosynthesis of fungal reduced polyketides has been challenging due to the lack of knowledge on the biosynthetic mechanism, the difficulties in the detection of the acyclic, non-aromatic metabolites, and the complexity in genetically manipulating filamentous fungi. Fumonisins are a group of economically important mycotoxins that contaminate maize-based food and feed products worldwide. Fumonisins contain a linear dimethylated C18 chain that is synthesized by Fum1p, which is a single module polyketide synthase (PKS). Using a genetic system that allows the specific manipulation of PKS domains in filamentous fungus Fusarium verticillioides, we replaced the KS domain …

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Optimization Of A Ribosomal Structural Domain By Natural Selection, Corina Maeder, G. L. Conn, D. E. Draper May 2006

Optimization Of A Ribosomal Structural Domain By Natural Selection, Corina Maeder, G. L. Conn, D. E. Draper

Chemistry Faculty Research

A conserved, independently folding domain in the large ribosomal subunit consists of 58 nt of rRNA and a single protein, L11. The tertiary structure of an rRNA fragment carrying the Escherichia coli sequence is marginally stable in vitro but can be substantially stabilized by mutations found in other organisms. To distinguish between possible reasons why natural selection has not evolved a more stable rRNA structure in E. coli, mutations affecting the rRNA tertiary structure were assessed for their in vitro effects on rRNA stability and L11 affinity (in the context of an rRNA fragment) or in vivo effects on cell …

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Platinum(Ii) Diimine Diacetylides: Metallacyclization Enhances Photophysical Properties, Fei Hua, Solen Kinayyigit, John R. Cable, Felix N. Castellano May 2006

Platinum(Ii) Diimine Diacetylides: Metallacyclization Enhances Photophysical Properties, Fei Hua, Solen Kinayyigit, John R. Cable, Felix N. Castellano

Chemistry Faculty Publications

The synthesis, structural characterization, and photoluminescence properties of a new platinum(II) diimine complex bearing the bidentate diacetylide ligand tolan- 2,2'-diacetylide (tda), Pt(dbbpy)( tda) [dbbpy) = 4,4'-di-tert-butyl-2,2'-bipyridine], are described. In CH2Cl2, Pt( dbbpy)( tda) exhibits a strong visible charge-transfer absorption and broad emission centered at 562 nm. The photoluminescence quantum yield and excited-state lifetime are 0.52 and 2.56 mu s, respectively, at room temperature. These parameters indicate that the planarization and rigidity introduced by the cyclic diacetylide leads to a lower-energy-absorbing species displaying enhanced photophysics relative to the analogous Pt( dbbpy)( C = CPh)(2). Time-dependent density functional theory calculations, which include …

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Oxidative Damage Caused By Iron Loading Into Ferritin, Talina Christensen Watts May 2006

Oxidative Damage Caused By Iron Loading Into Ferritin, Talina Christensen Watts

Undergraduate Honors Capstone Projects

Ferritin is the iron storage protein found in humans, animals, plants, fungi and bacteria. We are interested in how iron is loaded and stored in mammalian ferritin. Ferrous iron must be oxidized to ferric iron in order to be stored in ferritin. It is generally believed that ferritin does the loading itself, dependant upon a "ferroxidase activity." Oxidation of iron can result in the production of the hydroxyl radical which can cause oxidative damage to surrounding proteins and other biomolecules. An indicator of oxidative damage to proteins is the formation of carbonyl groups. Using only the H subunit of human …

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Closing The Loop: Controlling Type 1 Diabetes Mellitus, Megan Chynoweth May 2006

Closing The Loop: Controlling Type 1 Diabetes Mellitus, Megan Chynoweth

Whittier Scholars Program

Diabetes mellitus is an ever increasing pandemic. Type 1 diabetes mellitus (T1DM), although not the most prevalent form of diabetes mellitus, has had an “average annual increase of 3.09%, meaning the incidence of T1DM would increase 40% from 1998 to 2010”. T1DM leads to many complications: adverse side effects such as retinopathy, neuropathy, and nephropathy. These comorbidities are costing the United States billions of healthcare dollars per year. Delaying complications result in cost savings and improved quality of life, which can be obtained by tightly controlling blood sugars. However, strict control is difficult to attain. Optimal glucose levels may be …

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