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Extraction Of Recombinant Dog Gastric Lipase From Transgenic Corn Seed, Qixin Zhong, Zhengrong Gu, Charles E. Glatz Oct 2006

Extraction Of Recombinant Dog Gastric Lipase From Transgenic Corn Seed, Qixin Zhong, Zhengrong Gu, Charles E. Glatz

Chemical and Biological Engineering Publications

Several approaches were examined for extracting the relatively hydrophobic protein recombinant dog gastric lipase (rDGL) expressed in the endosperm of transgenic corn seed. The first approach used minimal processing of the seed before extraction (i.e. simple grinding of whole seed) followed by selective extraction to eliminate 72% of contaminant proteins without compromising rDGL recovery from the meal of whole grain. The second approach added defatting of the whole grain meal to reduce the amount of detergent in the subsequent step for extracting rDGL. The third approach incorporated dry-milling of the corn to recover an endosperm rich fraction, followed by ...


Scanning Electrochemical Mapping Of Spatially Localized Electrochemical Reactions Induced By Surface Potential Gradients, Shrisudersan Jayaraman, Erin L. May, Andrew C. Hillier Aug 2006

Scanning Electrochemical Mapping Of Spatially Localized Electrochemical Reactions Induced By Surface Potential Gradients, Shrisudersan Jayaraman, Erin L. May, Andrew C. Hillier

Chemical and Biological Engineering Publications

The influence of a surface potential gradient on the location and extent of electrochemical reactions was examined using a scanning electrochemical microscope. A linear potential gradient was imposed on the surface of a platinum-coated indium tin oxide electrode by applying two different potential values at the edges of the electrode. The applied potentials were used to control the location and extent of several electrochemical reactions, including the oxidation of Ru(NH3)62+, the oxidation of H2, and the oxidation of H2 in the presence of adsorbed CO. Scanning electrochemical mapping of these reactions was achieved by ...


Enzymatic Assay Method For Evaluating The Lipase Activity In Complex Extracts From Transgenic Corn Seed, Qixin Zhong, Charles E. Glatz May 2006

Enzymatic Assay Method For Evaluating The Lipase Activity In Complex Extracts From Transgenic Corn Seed, Qixin Zhong, Charles E. Glatz

Chemical and Biological Engineering Publications

A colorimetric method was established to determine the activity of recombinant lipase in extracts from transgenic corn seed. The system was an oil-in-water emulsion that was stabilized by a surfactant to accommodate the organic phase substrate and aqueous phase enzyme. The lipase activity was measured by monitoring the release of nitrophenol at 346 nm from the substrate, 4-nitrophenyl butyrate. Emulsions prepared with various surfactant types and concentrations were tested. For each surfactant, the measured activity was greatest when the surfactant concentration was close to the critical micelle concentration, consistent with the changing trend of oil droplet size as a function ...


Supramolecular Self-Assembly Of Multiblock Copolymers In Aqueous Solution, Michael Duane Determan, Liang Guo, Papannan Thiyagarajan, Surya K. Mallapragada Jan 2006

Supramolecular Self-Assembly Of Multiblock Copolymers In Aqueous Solution, Michael Duane Determan, Liang Guo, Papannan Thiyagarajan, Surya K. Mallapragada

Chemical and Biological Engineering Publications

A unique pH-dependent phase behavior from a copolytner micellar solution to a collapsed hydrogel with micelles ordered in a hexagonal phase was observed. Small-angle neutron scattering (SANS) was used to follow the pH-dependent structural evolution of micelles formed in a solution of a pentablock copolymer consisting of poly((diethylaminoethyl methacrylate)-b-(ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)-b-(diethylaminoethyl methacrylate)) (PDEAEM 25-b-PEO 100-b-PPO 65-b-PEO 100-b-PDEAEM 25). Between pH 3.0 and pH 7.4, we observed the presence of charged spherical micelles. Increasing the pH of the micelle solution above pH 7.4 resulted in increasing the size ...


Modeling Styrene-Styrene Interactions, Ivana Adamovic, Hui Li, Monica H. Lamm, Mark S. Gordon Jan 2006

Modeling Styrene-Styrene Interactions, Ivana Adamovic, Hui Li, Monica H. Lamm, Mark S. Gordon

Chemical and Biological Engineering Publications

This study is the first step in the systematic investigation of substituted (carboxyl) polystyrene nanoparticles. Understanding the fundamental interactions between the p-carboxyl styrene monomers, where an ethyl group is used instead of a vinyl group (referenced, for convenience, as "p-carboxyl styrene"), provides the basic information needed to construct potentials for nanoparticles composed of these monomers. In this work, low-energy isomers of p-carboxyl styrene dimer were studied. The dimer structures and their relative and binding energies were determined using both Møller-Plesset second-order perturbation theory (MP2) and the general effective fragment potential (EFP2) method. Sections of the intermolecular potential energy surface ...


Reduction Behavior Of Potassium-Promoted Iron Oxide Under Mixed Steam/Hydrogen Atmospheres, Sipho C. Ndlela, Brent H. Shanks Jan 2006

Reduction Behavior Of Potassium-Promoted Iron Oxide Under Mixed Steam/Hydrogen Atmospheres, Sipho C. Ndlela, Brent H. Shanks

Chemical and Biological Engineering Publications

Potassium-promoted iron oxide catalysts are used in large volume for the commercial ethylbenzene dehydrogenation to styrene process. Short-term deactivation of these catalysts, which is addressed by operating in excess steam, is thought to be caused due to reactive site loss through coking and/or reduction. However, the relative importance of the two mechanisms is not known. Presented are results concerning the reduction behavior of potassium-promoted iron oxide materials in the absence of carbon. Thermogravimetric experiments and X-ray diffraction analysis were used to examine the reduction behavior of potassium-promoted iron oxide materials. The reduction behavior was then compared with results from ...


Surface Plasmon Resonance Imaging Of Biomolecular Interactions On A Grating-Based Sensor Array, Bipin K. Singh, Andrew C. Hillier Jan 2006

Surface Plasmon Resonance Imaging Of Biomolecular Interactions On A Grating-Based Sensor Array, Bipin K. Singh, Andrew C. Hillier

Chemical and Biological Engineering Publications

A surface plasmon resonance sensor array based upon a grating substrate was developed for the detection of biomolecular interactions. The substrate consisted of a gold grating prepared by wet chemical treatment of a commercial recordable compact disk. A custom-built floating pin microspotter was constructed to deliver solutions containing ω-functionalized linear alkanethiols to the grating surface and produce an array of sensor elements with different exposed functional end groups. This array platform can be used to study biomolecular interactions in a label-free, sensitive, and high-throughput format. To illustrate the performance of this device, a test protein (bovine serum albumin) was exposed ...


Grating-Coupler Assisted Infrared Reflection Absorption Spectroscopy For The Characterization Of Organic Thin Films, Bipin K. Singh, Andrew C. Hillier Jan 2006

Grating-Coupler Assisted Infrared Reflection Absorption Spectroscopy For The Characterization Of Organic Thin Films, Bipin K. Singh, Andrew C. Hillier

Chemical and Biological Engineering Publications

We demonstrate how grating-coupler assisted infrared reflection absorption spectroscopy can be used to simultaneously determine the chemical identity and relative thickness of organic thin films. With a grating substrate, a threshold anomaly associated with passing off of the −1 diffracted order occurs at grazing angles of incidence, resulting in a sharp absorbance in the infrared. The position of this peak is sensitive to the grating geometry as well as the dielectric environment near its surface. Thus, shifts in the peak position can be used to determine the relative thickness of adsorbed films or quantify molecular adsorption events. To illustrate the ...


Modeling The Potential Distribution In Porous Anodic Alumina Films During Steady-State Growth, Jerrod E. Houser, Kurt R. Hebert Jan 2006

Modeling The Potential Distribution In Porous Anodic Alumina Films During Steady-State Growth, Jerrod E. Houser, Kurt R. Hebert

Chemical and Biological Engineering Publications

Porous anodic alumina (PAA) films, formed by anodic oxidation in acidic solutions, contain hexagonal arrays of parallel cylindrical pores, with pore diameter and spacing between ten and several hundred nanometers. Simulations were developed for the electrical potential distribution in the film during steady-state PAA growth, and used to calculate the rates of metal-film and film-solution interface motion. In particular, a model using the assumption of no space charge (Laplace’s equation) and one based on the current continuity equation, in each case coupled with high-field ionic conduction, were evaluated with respect to the requirement that the interface profiles are time ...


The Effect Of Terminal Group Modification On The Solution Properties Of Dendrimers: A Molecular Dynamics Simulation Study, Nicholas W. Suek, Monica H. Lamm Jan 2006

The Effect Of Terminal Group Modification On The Solution Properties Of Dendrimers: A Molecular Dynamics Simulation Study, Nicholas W. Suek, Monica H. Lamm

Chemical and Biological Engineering Publications

We study the static and dynamic properties of amphiphilic dendrimers of generation 3 through 7 in an explicitly modeled solvent with molecular dynamics. All interior monomers are solvophobic while the terminal monomers are varied from all solvophobic to all solvophilic, with a number of nonuniform solvophobic/ solvophilic terminal monomer arrangements investigated. For generations 6 and 7, crowding at the dendrimer surface forces some solvophilic monomers into the interior of the molecule. The nonuniformly surface-modified dendrimers are studied to examine how different arrangements of terminal monomers might affect dendrimer conformation. In all cases with solvophilic terminal monomers we find the solvophilic ...


A Novel Data Mining Method To Identify Assay-Specific Signatures In Functional Genomic Studies, Derrick K. Rollins Sr., Dongmei Zhai, Alrica L. Joe, Jack W. Guidarelli, Abhishek Murarka, Ramon Gonzalez Jan 2006

A Novel Data Mining Method To Identify Assay-Specific Signatures In Functional Genomic Studies, Derrick K. Rollins Sr., Dongmei Zhai, Alrica L. Joe, Jack W. Guidarelli, Abhishek Murarka, Ramon Gonzalez

Chemical and Biological Engineering Publications

Background: The highly dimensional data produced by functional genomic (FG) studies makes it difficult to visualize relationships between gene products and experimental conditions (i.e., assays). Although dimensionality reduction methods such as principal component analysis (PCA) have been very useful, their application to identify assay-specific signatures has been limited by the lack of appropriate methodologies. This article proposes a new and powerful PCA-based method for the identification of assay-specific gene signatures in FG studies. Results: The proposed method (PM) is unique for several reasons. First, it is the only one, to our knowledge, that uses gene contribution, a product of ...


Acidic Mesoporous Silica For The Catalytic Conversion Of Fatty Acids In Beef Tallow, Isa Kipkoech Mbaraka, Kyle J. Mcguire, Brent H. Shanks Jan 2006

Acidic Mesoporous Silica For The Catalytic Conversion Of Fatty Acids In Beef Tallow, Isa Kipkoech Mbaraka, Kyle J. Mcguire, Brent H. Shanks

Chemical and Biological Engineering Publications

Propylsulfonic acid-functionalized mesoporous silica materials were synthesized using a co-condensation technique. The catalytic performance of the resulting acidic mesoporous materials was evaluated in the methanol esterification of free fatty acids in beef tallow as a pretreatment step for alkyl ester production. The multicycle stability of the acid-functionalized mesoporous silica catalysts was studied. Issues concerning impurities in the feedstocks as well as a means of improving performance of the acidic solid catalyst through alternative strategies are discussed. Introduction of a hydrophobic group into the organosulfonic acid-functionalized mesoporous silica catalyst significantly enhanced the catalytic performance of the catalyst. The catalytic activity of ...


Electrochemically Modulated Permeability Of Poly(Aniline) And Composite Poly(Aniline)−Poly(Styrenesulfonate) Membranes, D. L. Pile, Y. Zhang, Andrew C. Hillier Jan 2006

Electrochemically Modulated Permeability Of Poly(Aniline) And Composite Poly(Aniline)−Poly(Styrenesulfonate) Membranes, D. L. Pile, Y. Zhang, Andrew C. Hillier

Chemical and Biological Engineering Publications

The influence of oxidation state on the permeability of several probe molecules through conducting polymer membranes comprising composites of poly(aniline) and poly(styrenesulfonate) was examined in aqueous solution. Pure poly(aniline) membranes displayed a characteristic increase in permeability between reduced and half-oxidized states for neutrally charged phenol and negatively charged 4-hydroxybenzenesulfonate. In contrast, positively charged pyridine experienced decreased permeability through the membrane when poly(aniline) was switched from the reduced to the half-oxidized state. This behavior can be explained by a combination of oxidation-induced film swelling and the anion-exchange character of the positively charged membrane. The membrane composition was ...