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2006

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Articles 271 - 300 of 592

Full-Text Articles in Chemistry

Energy Efficient Process Heating: Insulation And Thermal Mass, Kevin Carpenter, J. Kelly Kissock Apr 2006

Energy Efficient Process Heating: Insulation And Thermal Mass, Kevin Carpenter, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

Open tanks and exterior surfaces of process heating equipment lose heat to the surroundings via convection, radiation, and/or evaporation. A practical way of reducing heat loss is by insulating or covering the surfaces. This paper presents methods to quantify heat loss and energy savings from insulating hot surfaces and open tanks. The methods include radiation and evaporation losses, which are ignored by simplified methods. In addition, thermal mass, such as refractory, conveyor and racking equipment, acts as a heat sink and increases heating energy use in process heating applications. This paper presents lumped capacitance and finite-difference methods for estimating heat …

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Making Soap From Readily Available Agricultural And Household Wastes Can Increase Cleanless In Rural Area, Eugenia Lucas, Thomas Ciaglo Apr 2006

Making Soap From Readily Available Agricultural And Household Wastes Can Increase Cleanless In Rural Area, Eugenia Lucas, Thomas Ciaglo

Student Research Posters

In some areas of the world, soap is too expensive for many people to afford. For these people an alternative exists. They can make their own soap. In general, soap is made by the reaction of triglycerides and caustic soda. However, caustic soda, too, may be difficult to find or too expensive. The aim of this project is to develop a process for making soap from readily available agricultural and household waste materials, and other inexpensive chemicals. By using this process, rural people can get the benefits of readily available, inexpensive soap. Soap is made from animal fats or vegetable …

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Synthetic Studies Of 1,10-Phenanthroline Derivatives As Novel Catalysis Ligands And Their Application In Transition Metals Catalyzed Reactions, Son Duc Tran Apr 2006

Synthetic Studies Of 1,10-Phenanthroline Derivatives As Novel Catalysis Ligands And Their Application In Transition Metals Catalyzed Reactions, Son Duc Tran

Dissertations

The preparation of 1,10-phenanthroline derivatives entailed ring opening reactions of 1,10-phenanthroline epoxide as a key transformation, affording novelbidentate nitrogen ligands with new stereogenic centers in the 5- and 6-position. This research was concerned with (i) the epoxidation of 1,10-phen, (ii) epoxide ring opening reactions, (iii) the formation of trans -5,6-disubstituted-1,10-phenanthroline metal complexes, and (iv) application of 1,10-phenanthroline derivatives in metal-catalyze reactions such as palladium-catalyzed allylic substitution and aminohalogenation reactions; Zinc-catalyzed direct aldolreaction, and acetophenone reduction; Nickel-catalyzed Michael addition reaction.

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Composition Ot Glvceride Esters Of Lauric Acid Bv Ftir Band Shape Analysis, Deniz P. Wong, Modesto Tan Chua, Erwin P. Enriquez Apr 2006

Composition Ot Glvceride Esters Of Lauric Acid Bv Ftir Band Shape Analysis, Deniz P. Wong, Modesto Tan Chua, Erwin P. Enriquez

Chemistry Faculty Publications

Synthesis of glyceride esters of a fatty acid produces a mixture of isomers that are difficult to separate and analyze, requiring high temperature GC in most cases particularly for long-chain esters. In this paper, we present a fast estimation of the composition of the glyceride esters of lauric acid and glycerol (monolaurin, dilaurin, and trilaurin) by FTIR band shape analysis. The method uses the fact that the carbonyl stretching regions of the pure glycerides have differentband shapes, which implies any composite band of a mixture of glycerides may be resolved into the component peaks due to each glyceride. The carbonyl …

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Scientific Research In A Foreign Language, Meghan Bellows Apr 2006

Scientific Research In A Foreign Language, Meghan Bellows

Senior Honors Projects

Research is a vital aspect in science and engineering. Not only does it further ideas and technology around the world, it brings people around the world together through collaborations. More often than not, the common language spoken among collaborators is English. This makes it easy for native English speakers. It becomes very difficult, however, when the common language spoken among collaborators is not one’s native tongue. New vocabulary, oftentimes very complex and technical, must be learned. It becomes even more of a challenge to present results and findings in a manner that is clear and concise. A collaboration between the …

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Styrenic Nanocomposites Prepared Using A Novel Biphenyl-Containing Clay, Grace Chigwada, Dongyan Wang, David D. Jiang, Charles A. Wilkie Apr 2006

Styrenic Nanocomposites Prepared Using A Novel Biphenyl-Containing Clay, Grace Chigwada, Dongyan Wang, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Montmorillonite was organically modified using an ammonium salt containing 4-acetylbiphenyl. This clay (BPNC16 clay) was used to prepare polystyrene (PS), acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS) nanocomposites. Polystyrene nanocomposites were prepared both by in situ bulk polymerisation and melt blending processes, while the ABS and HIPS nanocomposites were prepared only by melt blending. X-ray diffraction and transmission electron microscopy were used to confirm nanocomposite formation. Thermogravimetric analysis was used to evaluate thermal stability and the flammability properties were evaluated using cone calorimetry. By thermogravimetry, BPNC16 clay was found to show high thermal stability, and by cone calorimetry, …

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Polystyrene Nanocomposites Based On Quinolinium And Pyridinium Surfactants, Grace Chigwada, Dongyan Wang, Charles A. Wilkie Apr 2006

Polystyrene Nanocomposites Based On Quinolinium And Pyridinium Surfactants, Grace Chigwada, Dongyan Wang, Charles A. Wilkie

Chemistry Faculty Research and Publications

In this paper pyridine and quinoline-containing salts were employed to modify montmorillonite. TGA analysis shows that the quinolinium modified clay has a higher thermal stability than the pyridinium modified clay. Polystyrene nanocomposites were prepared by in situ bulk polymerisation and direct melt blending using both clays. The X-ray diffraction and transmission electron microscopy results show the formation of intercalated structures. The 50% degradation temperature of the nanocomposites is increased and so is the amount of char from TGA analysis compared to the virgin polymer. Cone calorimetric results indicate that clay reduces the peak heat release rate and average mass loss …

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Synthesis Of Aspernigrin A, Erica Joerger Apr 2006

Synthesis Of Aspernigrin A, Erica Joerger

Undergraduate Theses and Capstone Projects

Aspernigrin A is a compound correlated with inhibiting the growth of cancer cells in the colon. A five-step synthesis was designed for aspernigrin A, projected to yield four intermediates and the final product. The intermediates were analyzed by high field 1HNMR and FT-IR spectroscopy before proceeding to the next step. A model pyridone ring system was successfully prepared from a commercially available pyrone precursor in two steps. These results provide a proof of concept that the synthetic scheme should successfully yield the natural product.

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Thermal Stability And Degradation Kinetics Of Poly(Methyl Methacrylate)/Layered Copper Hydroxy Methacrylate Composites, Everson Kandare, Hongmei Deng, Dongyan Wang, Jeanne Hossenlopp Apr 2006

Thermal Stability And Degradation Kinetics Of Poly(Methyl Methacrylate)/Layered Copper Hydroxy Methacrylate Composites, Everson Kandare, Hongmei Deng, Dongyan Wang, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Poly(methyl methacrylate) (PMMA)/copper hydroxy methacrylate (CHM) composites were prepared via solution blending and bulk polymerization. Addition of 3% by weight of the CHM additive using solution blending resulted in a significant increment (~45°C) in thermogravimetric analysis (TGA) T50, the temperature at which 50% of the original polymeric mass is lost. The value T50 increased by 30°C for a PMMA composite with 4% CHM, synthesized via bulk polymerization. Activation energies, Ea, were calculated as a function of conversion fractions (TGA decomposition profile) for the polymeric materials. Analysis of multiple heating rate data using the Flynn–Wall– Ozawa …

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Polyethylene And Polypropylene Nanocomposites Based On A Three Component Oligomerically-Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie Apr 2006

Polyethylene And Polypropylene Nanocomposites Based On A Three Component Oligomerically-Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Polyethylene and polypropylene nanocomposites were prepared using a novel oligomerically-modified clay that contains three components, styrene, lauryl acrylate and vinylbenzyl chloride. The nanocomposites were prepared by directly melt blending the polymers with the clay and they were characterized by X-ray diffraction and transmission electron microscopy, to understand their morphology, and their thermal stability, flammability and mechanical properties were evaluated using thermogravimetric analysis, cone calorimetry and mechanical testing, respectively. The reduction in peak heat release rate is about 60% at 5% inorganic clay loading and 70% at 8% inorganic clay loading.

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Thermal Degradation Of Acetate-Intercalated Hydroxy Double And Layered Hydroxy Salts, Everson Kandare, Jeanne Hossenlopp Apr 2006

Thermal Degradation Of Acetate-Intercalated Hydroxy Double And Layered Hydroxy Salts, Everson Kandare, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Two hydroxy double salts (HDSs), zinc copper hydroxy acetate (ZCA) and zinc nickel hydroxy acetate (ZNA), and an analogous layered compound, zinc hydroxy acetate (ZHA), have been prepared by a coprecipitation method. The thermal degradation of these materials was characterized via thermogravimetric analysis (TGA), differential thermal analysis (DTA), and TGA coupled with Fourier transform infrared spectroscopy of gas-phase products, TGA-FTIR. Loss of physisorbed and interlayer H2O was observed between 50 and 150 °C for all compounds. Acetic acid, acetone, water, and CO2 were released at high temperatures with relative acetone yields found to be dependent on precursor identity, with very …

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The High-Resolution Structures Of The Neutral And The Low Ph Crystals Of Aminopeptidase From Aeromonas Proteolytica, William Desmarais, David L. Bienvenue, Krzysztof P. Bzymek, Gregory A. Petsko, Dagmar Ringe, Richard C. Holz Apr 2006

The High-Resolution Structures Of The Neutral And The Low Ph Crystals Of Aminopeptidase From Aeromonas Proteolytica, William Desmarais, David L. Bienvenue, Krzysztof P. Bzymek, Gregory A. Petsko, Dagmar Ringe, Richard C. Holz

Chemistry Faculty Research and Publications

The aminopeptidase from Aeromonas proteolytica (AAP) contains two zinc ions in the active site and catalyzes the degradation of peptides. Herein we report the crystal structures of AAP at 0.95-Å resolution at neutral pH and at 1.24-Å resolution at low pH. The combination of these structures allowed the precise modeling of atomic positions, the identification of the metal bridging oxygen species, and insight into the physical properties of the metal ions. On the basis of these structures, a new putative catalytic mechanism is proposed for AAP that is likely relevant to all binuclear metalloproteases.

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On-Road Remote Sensing Of Automobile Emissions In West Los Angeles: Year 4, October 2005, Gary A. Bishop, Donald H. Stedman Apr 2006

On-Road Remote Sensing Of Automobile Emissions In West Los Angeles: Year 4, October 2005, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

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Large Scale Growth And Magnetic Properties Of Fe And Fe₃O₄ Nanowires, Jinbo Yang, H. Xu, Shaoxin You, X.-D. Zhou, C. S. Wang, William B. Yelon, William Joseph James Apr 2006

Large Scale Growth And Magnetic Properties Of Fe And Fe₃O₄ Nanowires, Jinbo Yang, H. Xu, Shaoxin You, X.-D. Zhou, C. S. Wang, William B. Yelon, William Joseph James

Materials Science and Engineering Faculty Research & Creative Works

Fe and Fe3O4 nanowires have been synthesized by thermal decomposition of Fe(CO)5, followed by heat treatments. The Fe wires are formed through the aggregation of nanoparticles generated by decomposition of Fe(CO)5. A core-shell structure with an iron oxide shell and Fe core is observed for the as-prepared Fe wires. Annealing in air leads to the formation of Fe2O3/Fe3O4 wires, which after heat treatment in a N2/alcohol atmosphere form Fe3O4 wires with a sharp Verwey [Nature (London) 144, 327 (1939)] transition at 125 K. The Fe3O4 wires have coercivities of 261 and 735 Oe along the wire axis at RT and …

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Structural And Magnetic Properties Of La Mn₁₋ₓfeₓo₃ (0 < X < 1.0), X.-D. Zhou, L. R. Pederson, Qingsheng Cai, Jinbo Yang, B. J. Scarfino, M. Kim, William B. Yelon, William Joseph James, Harlan U. Anderson, C. Wang Apr 2006

Structural And Magnetic Properties Of La Mn₁₋ₓfeₓo₃ (0 < X < 1.0), X.-D. Zhou, L. R. Pederson, Qingsheng Cai, Jinbo Yang, B. J. Scarfino, M. Kim, William B. Yelon, William Joseph James, Harlan U. Anderson, C. Wang

Materials Science and Engineering Faculty Research & Creative Works

Electronic, structural, and magnetic properties of Mn-doped lanthanum ferrites were studied by neutron diffraction, superconducting quantum interference device, and impedance spectroscopy. Neutron diffraction refinements were performed with the constraint of full La occupancy, which showed the presence of excess oxygen when x < 0.4. Mixed valent Mn cations and cation vacancies, therefore, exist in all the samples. The samples with x > 0.7 are magnetically ordered at room temperature with orthorhombic symmetry (Pbnm). When x < 0.3 the structure is rhombohedral and magnetically disordered above 16 K. The majority carriers, electron holes, correspond to high oxidation states of Mn. The carrier concentration is determined from the Seebeck coefficients, and is a function of temperature and Fe concentration. The measurements of conductivity and Seebeck coefficients show polaron hopping at elevated temperatures.

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Protein–Protein Interactions Of Tandem Affinity Purification-Tagged Protein Kinases In Rice, Jai S. Rohila, Mei Chen, Shuo Chen, Johann Chen, Ronald Cerny, Chris Dardick, Patrick Canlas, Xia Xu, Michael Gribskov, Siddhartha Kanrar, Jian-Kang Zhu, P C. Ronald, Michael E. Fromm Apr 2006

Protein–Protein Interactions Of Tandem Affinity Purification-Tagged Protein Kinases In Rice, Jai S. Rohila, Mei Chen, Shuo Chen, Johann Chen, Ronald Cerny, Chris Dardick, Patrick Canlas, Xia Xu, Michael Gribskov, Siddhartha Kanrar, Jian-Kang Zhu, P C. Ronald, Michael E. Fromm

Ronald Cerny Publications

Forty-one rice cDNAs encoding protein kinases were fused to the tandem affinity purification (TAP) tag and expressed in transgenic rice plants. The TAP-tagged kinases and interacting proteins were purified from the T1 progeny of the transgenic rice plants and identified by mass spectrometry. Ninety-five percent of the TAP-tagged kinases were recovered. Fifty-six percent of the TAP-tagged kinases were found to interact with other rice proteins. A number of these interactions were consistent with known protein complexes found in other species, validating the TAP-tag method in rice plants. Phosphorylation sites were identified on four of the kinases that interacted with either …

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Structures And Relative Stability Of Medium-Sized Silicon Clusters. V. Low-Lying Endohedral Fullerenelike Clusters Si31–Si40 And Si45, Soohaeng Yoo, N. Shao, C. Koehler, T. Fraunhaum, Xiao Cheng Zeng Apr 2006

Structures And Relative Stability Of Medium-Sized Silicon Clusters. V. Low-Lying Endohedral Fullerenelike Clusters Si31–Si40 And Si45, Soohaeng Yoo, N. Shao, C. Koehler, T. Fraunhaum, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We have performed unconstrained search for low-lying structures of medium-sized silicon clusters Si31–Si40 and Si45, by means of the minimum-hopping global optimization method coupled with a density-functional based tight-binding model of silicon. Subsequent geometric optimization by using density-functional theory with the PBE, BLYP, and B3LYP functionals was carried out to determine the relative stability of various candidate low-lying silicon clusters obtained from the unconstrained search. The low-lying characteristics of these clusters can be affirmed by comparing the binding energies per atom of these clusters with previously determined lowest-energy clusters (Sin) in the size …

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Relative Stability Of Planar Versus Double-Ring Tubular Isomers Of Neutral And Anionic Boron Cluster B20 And B20-, Wei An, Satya S. Bulusu, Yi Gao, Xiao Cheng Zeng Apr 2006

Relative Stability Of Planar Versus Double-Ring Tubular Isomers Of Neutral And Anionic Boron Cluster B20 And B20-, Wei An, Satya S. Bulusu, Yi Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

High-level ab initio molecular-orbital methods have been employed to determine the relative stability among four neutral and anionic B20 isomers, particularly the double-ring tubular isomer versus three low-lying planar isomers. Calculations with the fourth-order Møller-Plessset perturbation theory [MP4(SDQ)] and Dunning’s correlation consistent polarized valence triple zeta basis set as well as with the coupled-cluster method including single, double, and noniteratively perturbative triple excitations and the 6-311G(d) basis set show that the double-ring tubular isomer is appreciably lower in energy than the three planar isomers and is thus likely the global minimum of neutral B20 cluster. In contrast, calculations …

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Spectral Shape As An Indicator Of Molecular Weight In Chromophoric Dissolved Organic Matter, John Robert Helms Apr 2006

Spectral Shape As An Indicator Of Molecular Weight In Chromophoric Dissolved Organic Matter, John Robert Helms

Chemistry & Biochemistry Theses & Dissertations

Spectral slope is a term used to parameterize featureless absorbance spectra according to their shape. Spectral slope is obtained by calculating the slope of the log-linearized absorption spectrum over a given range of wavelengths. Past studies have shown that spectral slope is related to molecular size in fulvic acids. A simple method of spectral analysis that compares spectral slopes obtained from two distinct regions of the UV spectra of aquatic dissolved organic matter is demonstrated. The ratio of these slopes (RS) shows considerable change during photo-oxidation, variation within estuaries, and substantial shifts with depth in the upper 1000 …

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A Comparative Genomic Analysis Of Chlorella Nc64a Virus Ny-2a And Chlorella Pbi Virus Mt325 From The Family Phycodnaviridae, Lisa A. Fitzgerald Mar 2006

A Comparative Genomic Analysis Of Chlorella Nc64a Virus Ny-2a And Chlorella Pbi Virus Mt325 From The Family Phycodnaviridae, Lisa A. Fitzgerald

Department of Chemistry: Dissertations, Theses, and Student Research

The family Phycodnaviridae consists of a morphologically similar but genetically diverse group of large dsDNA viruses which infect both fresh and marine water eukaryotic algae. Two viruses, the 370 kb Chlorella NC64A virus NY-2A and the 313 kb Chlorella Pbi virus MT325, from the family Phycodnaviridae, genus Chlorovirus, were sequenced, analyzed, and compared to the prototype chlorella virus PBCV-1. The NY-2A genome, the largest chlorella viral genome sequenced to date, contains 886 open reading frames (ORFs) of 65 codons or larger and encodes 404 putative proteins and 7 tRNAs. The MT325 genome, the smallest chlorella viral genome sequenced to date, …

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Gas Chromatography: Mass Spectrometry Of Chemical Agents And Related Interferents, Lailiang Zhai Mar 2006

Gas Chromatography: Mass Spectrometry Of Chemical Agents And Related Interferents, Lailiang Zhai

Theses and Dissertations

One of the main problems encountered in chemical analysis operations in the field is collecting sufficient sample from the source and transferring that sample to the measurement instrument for fast separation and identification. I have been involved in developing a field-portable gas chromatography-mass spectrometry (GC-MS) system with solid phase microextraction (SPME) sampling for point detection of chemical agents. The objective is to minimize the analysis time between sampling and detection of a potential chemical threat. SPME offers a convenient means for sampling gaseous and liquid samples, concentrating the analytes, and transferring the analytes to the injection port of a GC …

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Constancy In Integrated Cisplatin Plasma Concentrations Among Pediatric Patients, Jerry Goodisman, Abdul-Kader Souid Mar 2006

Constancy In Integrated Cisplatin Plasma Concentrations Among Pediatric Patients, Jerry Goodisman, Abdul-Kader Souid

Chemistry - All Scholarship

The authors report on the variability in the integrated quantity of free (unbound) plasma cisplatin (area under curve of plasma concentration versus time, AUC). The AUC was measured in 19 patients receiving cisplatin doses proportional to body surface areas (BSA), 30mg/m2 over 1 hour. The relative standard deviation (RSD, population standard deviation divided by mean value) for the maximum free plasma cisplatin concentration (Cmax, μM) was 0.338; for the half-life (t½, minute), 0.210; and for the AUC (μM minute), 0.320. Thus, BSA-based dosing gave significant variability in the AUC. We attempted to use (weight)a(height)b, seeking values of a and b …

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Electrolytic Deposition Of Coatings For Prosthetic Metals And Alloys, Jody G. Redepenning Mar 2006

Electrolytic Deposition Of Coatings For Prosthetic Metals And Alloys, Jody G. Redepenning

Department of Chemistry: Faculty Publications

An article coated with an electrolytically deposited biocompatible composite layer useful as an internal prosthetic device is disclosed. The bio-compatible composite coating that is electrolytically deposited onto the article comprises hydroxyapatite and chitosan. The introduction of chitosan into the crystal matrix of brushite/hydroxyapatite significantly improves the adhesive and chemical and mechanical stability properties of the coating.
United States Patent Number 7,014,749 B2

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The Structure Of Β-Carbonic Anhydrase From The Carboxysomal Shell Reveals A Distinct Subclass With One Active Site For The Price Of Two, Michael R. Sawaya, Gordon C. Cannon, Sabine Heinhorst, Shiho Tanaka, Eric B. Williams, Todd O. Yeates, Cheryl A. Kerfeld Mar 2006

The Structure Of Β-Carbonic Anhydrase From The Carboxysomal Shell Reveals A Distinct Subclass With One Active Site For The Price Of Two, Michael R. Sawaya, Gordon C. Cannon, Sabine Heinhorst, Shiho Tanaka, Eric B. Williams, Todd O. Yeates, Cheryl A. Kerfeld

Faculty Publications

CsoSCA (formerly CsoS3) is a bacterial carbonic anhydrase localized in the shell of a cellular microcompartment called the carboxysome, where it converts HCO-3 to CO2 for use in carbon fixation by ribulose-bisphosphate carboxylase/oxygenase (RuBisCO). CsoSCA lacks significant sequence similarity to any of the four known classes of carbonic anhydrase (α, β, γ, or δ), and so it was initially classified as belonging to a new class, ϵ. The crystal structure of CsoSCA from Halothiobacillus neapolitanus reveals that it is actually a representative member of a new subclass of β-carbonic anhydrases, distinguished by a lack of active site …

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Membrane-Based Protein Preconcentration Microfluidic Devices, Yi Li Mar 2006

Membrane-Based Protein Preconcentration Microfluidic Devices, Yi Li

Theses and Dissertations

Interest in microchip capillary electrophoresis (CE) is growing due to the rapid analysis times provided and small sample input requirements. However, higher-concentration samples are typically needed because of the small (~pL) detection volumes in these devices. I have made membrane-based protein preconcentration systems in capillary and microchip designs to increase the detectability of low-concentration biological samples. A photopolymerized ion-permeable membrane interfaced with a microchannel in poly(methyl methacrylate) (PMMA) formed the preconcentrator. When a voltage was applied between the sample reservoir and the ionically conductive membrane in a capillary-based system, R-phycoerythrin was concentrated more than 1,000 fold, as determined by laser-induced …

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9,9′-Diethyl-3,3′-Di-9h-Carbazol­Yl, Erol Asker, John Masnovi Mar 2006

9,9′-Diethyl-3,3′-Di-9h-Carbazol­Yl, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the title compound, C28H24N2, the carbazole ring systems are essentially planar to within 0.076 (3) Å. The dihedral angle between the planes of the ring systems is 40.38 (4)°. The contribution of inter­molecular π–π inter­actions to the mol­ecular stacking is observed.

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Bis(9-Ethyl­Carbazol-3-Yl)Methane, Erol Asker, John Masnovi Mar 2006

Bis(9-Ethyl­Carbazol-3-Yl)Methane, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the title compound, C29H26N2, the carbazole ring systems are essentially planar. There is no indication of π–π interactions in the crystal structure, adjacent carbazole groups being non-parallel.

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Rapid, Sequence-Specific Detection Of Unpurified Pcr Amplicons Via A Reusable, Electrochemical Sensor, Rebecca Lai, Eric T. Hagally, Sang-Ho Lee, H. T. Soh, Kevin W. Plaxco, Alan J. Heeger Mar 2006

Rapid, Sequence-Specific Detection Of Unpurified Pcr Amplicons Via A Reusable, Electrochemical Sensor, Rebecca Lai, Eric T. Hagally, Sang-Ho Lee, H. T. Soh, Kevin W. Plaxco, Alan J. Heeger

Rebecca Lai Publications

We report an electrochemical method for the sequence-specific detection of unpurified amplification products of the gyrB gene of Salmonella typhimurium. Using an asymmetric PCR and the electrochemical E-DNA detection scheme, single-stranded amplicons were produced from as few as 90 gene copies and, without subsequent purification, rapidly identified. The detection is specific; the sensor does not respond when challenged with control oligonucleotides based on the gyrB genes of either Escherichia coli or various Shigella species. In contrast to existing sequence-specific optical- and capillary electrophoresis- based detection methods, the E-DNA sensor is fully electronic and requires neither cumbersome, expensive optics nor …

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Fabrication Of Nanopillars By Nanosphere Lithography, Chin Li Cheung, R. J. Nikolic, C. E. Reinhardt, T. F. Wang Mar 2006

Fabrication Of Nanopillars By Nanosphere Lithography, Chin Li Cheung, R. J. Nikolic, C. E. Reinhardt, T. F. Wang

Barry Chin Li Cheung Publications

A low cost nanosphere lithography method for patterning and generation of semiconductor nanostructures provides a potential alternative to the conventional top-down fabrication techniques. Forests of silicon pillars of sub-500 nm diameter and with an aspect ratio up to 10 were fabricated using a combination of the nanosphere lithography and deep reactive ion etching techniques. The nanosphere etch mask coated silicon substrates were etched using oxygen plasma and a timemultiplexed “Bosch” process to produce nanopillars of different length, diameter and separation. Scanning electron microscopy data indicate that the silicon etch rates with the nanoscale etch masks decrease linearly with increasing aspect …

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Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler Mar 2006

Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler

Chemistry Faculty Research

The effects of particle composition on heterogeneous catalysis were studied using dendrimer-encapsulated nanoparticles (DENs) as precursors to supported Pt-Cu catalysts. Bimetallic Pt-Cu DENs with varying Pt/Cu ratios were prepared in an anaerobic aqueous solution and deposited onto a high-purity commercial alumina support. The dendrimer template was then thermally removed to yield supported nanoparticle catalysts, which were studied with toluene hydrogenation and CO oxidation catalysis as well as infrared spectroscopy of adsorbed CO. Incorporating Cu into Pt nanoparticles had opposite effects on the two test reactions. Cu acted as a mild promoter for CO oxidation catalysis, and the promoting effect was …

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