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Articles 1 - 12 of 12

Full-Text Articles in Biomedical Engineering and Bioengineering

Mechanisms Of Aqueous Extraction Of Soybean Oil, K. A. Campbell, Charles E. Glatz Nov 2009

Mechanisms Of Aqueous Extraction Of Soybean Oil, K. A. Campbell, Charles E. Glatz

Chemical and Biological Engineering Publications

Aqueous extraction processing (AEP) of soy is a promising green alternative to hexane extraction processing. To improve AEP oil yields, experiments were conducted to probe the mechanisms of oil release. Microscopy of extruded soy before and after extraction with and without protease indicated that unextracted oil is sequestered in an insoluble matrix of denatured protein and is released by proteolytic digestion of this matrix. In flour from flake, unextracted oil is contained as intact oil bodies in undisrupted cells, or as coalesced oil droplets too large to pass out of the disrupted cellular matrix. Our results suggest that emulsification is ...


Twisting Of Glycosidic Bonds By Hydrolases, Glenn P. Johnson, Luis Petersen, Alfred D. French, Peter J. Reilly Nov 2009

Twisting Of Glycosidic Bonds By Hydrolases, Glenn P. Johnson, Luis Petersen, Alfred D. French, Peter J. Reilly

Chemical and Biological Engineering Publications

Patterns of scissile bond twisting have been found in crystal structures of glycoside hydrolases (GHs) that are complexed with substrates and inhibitors. To estimate the increased potential energy in the substrates that results from this twisting, we have plotted torsion angles for the scissile bonds on hybrid Quantum Mechanics::Molecular Mechanics energy surfaces. Eight such maps were constructed, including one for α-maltose and three for different forms of methyl α-acarviosinide to provide energies for twisting of α-(1,4) glycosidic bonds. Maps were also made for β-thiocellobiose and for three β-cellobiose conformers having different glycon ring shapes to model distortions ...


Epidermal Growth Factor-Induced Contraction Regulates Paxillin Phosphorylation To Temporally Separate Traction Generation From De-Adhesion, Ian C. Schneider, Cristen K. Hays, Clare M. Waterman Jul 2009

Epidermal Growth Factor-Induced Contraction Regulates Paxillin Phosphorylation To Temporally Separate Traction Generation From De-Adhesion, Ian C. Schneider, Cristen K. Hays, Clare M. Waterman

Chemical and Biological Engineering Publications

Directed cell migration is mediated by cycles of protrusion, adhesion, traction generation on the extracellular matrix and retraction. However, how the events after protrusion are timed, and what dictates their temporal order is completely unknown. We used acute epidermal growth factor (EGF) stimulation of epidermal keratinocytes to initiate the cell migration cycle to study the mechanism of the timing of adhesion, traction generation, and de-adhesion. Using microscopic and biochemical assays, we surprisingly found that at ∼2 min after EGF stimulation protrusion, activation of myosin-II, traction generation, adhesion assembly, and paxillin phosphorylation occurred nearly simultaneously, followed by a 10-min delay during ...


Mechanism Of Cellulose Hydrolysis By Inverting Gh8 Endoglucanases: A Qm/Mm Metadynamics Study, Luis Petersen, Albert Ardèvol, Carme Rovira, Peter J. Reilly Apr 2009

Mechanism Of Cellulose Hydrolysis By Inverting Gh8 Endoglucanases: A Qm/Mm Metadynamics Study, Luis Petersen, Albert Ardèvol, Carme Rovira, Peter J. Reilly

Chemical and Biological Engineering Publications

A detailed understanding of the catalytic strategy of cellulases is key to finding alternative ways to hydrolyze cellulose to mono-, di-, and oligosaccharides. Endoglucanases from glycoside hydrolase family 8 (GH8) catalyze the hydrolysis of β-1,4-glycosidic bonds in cellulose by an inverting mechanism believed to involve a oxacarbenium ion-like transition state (TS) with a boat-type conformation of the glucosyl unit in subsite −1. In this work, hydrolysis by Clostridium thermocellum endo-1,4-glucanase A was computationally simulated with quantum mechanics/molecular mechanics metadynamics based on density functional theory. Our calculations show that the glucosyl residue in subsite −1 in the Michaelis ...


Purification And Characterization Of A 44-Kda Recombinant Collagen I Α 1 Fragment From Corn Grain, Cheng Zhang, Julio Baez, Charles E. Glatz Feb 2009

Purification And Characterization Of A 44-Kda Recombinant Collagen I Α 1 Fragment From Corn Grain, Cheng Zhang, Julio Baez, Charles E. Glatz

Chemical and Biological Engineering Publications

This paper demonstrates that a fibrous, repetitive amino acid sequence collagen-related protein, a 44-kDa fragment of human collagen I α 1 (CIα1), was expressed in corn grain molecularly equivalent to that produced in recombinant yeast. The recombinant CIα1 was extracted and purified from early generation plants having low levels of recombinant protein accumulation. It was selectively extracted at low pH and purified by ion exchange and gel filtration chromatography, resulting in a 44-kDa CIα1 with >70% purity and 60% recovery. The N-terminal sequence, amino acid composition, and immunoreactivity closely matched those of an analogous 44-kDa CIα1 fragment produced by the ...


A Comparative Study Of Macroporous Metal Oxides Synthesized Via A Unified Approach, Sikander H. Hakim, Brent H. Shanks Jan 2009

A Comparative Study Of Macroporous Metal Oxides Synthesized Via A Unified Approach, Sikander H. Hakim, Brent H. Shanks

Chemical and Biological Engineering Publications

A variety of macroporous metal oxides was synthesized via a spontaneous self-assembly process in aqueous solution starting from organic alkoxide precursors under a common set of conditions to present a consistent set of data for evaluation of macropore formation in these materials that are known to yield such structural patterns. Sol-gel-type chemistry appears to be governing the structure formation in these materials, so the influence of sol-gel parameters such as the alkyl group in the alkoxide, the central metal atom, and the pH of the reaction mixture were investigated in order to gain insight on the denning mechanism dictating the ...


Turbulence In A Microscale Planar Confined Impinging-Jets Reactor, Ying Liu, Michael G. Olsen, Rodney O. Fox Jan 2009

Turbulence In A Microscale Planar Confined Impinging-Jets Reactor, Ying Liu, Michael G. Olsen, Rodney O. Fox

Chemical and Biological Engineering Publications

Confined impinging-jets reactors (CIJR) offer many advantages for rapid chemical processing at the microscale in applications such as precipitation and the production of organic nanoparticles. It has been demonstrated that computational fluid dynamics (CFD) is a promising tool for ‘‘experiment-free’’ design and scale-up of such reactors. However, validation of the CFD model used for the microscale turbulence applications requires detailed experimental data on the unsteady flow, the availability of which has until now been very limited. In this work, microscopic particle-image velocimetry (microPIV) techniques were employed to measure the instantaneous velocity field for various Reynolds numbers in a planar CIJR ...


Combinatorial/High Throughput Methods For The Determination Of Polyanhydride Phase Behavior, Jon B. Thorstenson, Latrisha Kay Petersen, Balaji Narasimhan Jan 2009

Combinatorial/High Throughput Methods For The Determination Of Polyanhydride Phase Behavior, Jon B. Thorstenson, Latrisha Kay Petersen, Balaji Narasimhan

Chemical and Biological Engineering Publications

Combinatorial methods have been developed to study the phase behavior of biodegradable polyanhydrides for drug delivery applications. The polyanhydrides of interest are poly[l,6-bis(p-carboxyphenoxy) hexane] (CPH) and poly[sebacic anhydride] (SA). Both continuous and discrete polymer blend libraries were fabricated by using a combination of solution-based gradient deposition and rapid prototyping. Blend compositions were characterized via a high throughput transmission Fourier transform infrared (FTIR) sampling technique and compared against theoretical mass balance predictions. To obtain phase diagrams of CPH/S A, the effect of blend composition and annealing temperature on the miscibility of the blend was studied. This ...


A Microscale Multi-Inlet Vortex Nanoprecipitation Reactor: Turbulence Measurement And Simulation, Janine C. Cheng, Michael G. Olsen, Rodney O. Fox Jan 2009

A Microscale Multi-Inlet Vortex Nanoprecipitation Reactor: Turbulence Measurement And Simulation, Janine C. Cheng, Michael G. Olsen, Rodney O. Fox

Chemical and Biological Engineering Publications

Microscale reactors capable of generating turbulent flow are used in Flash NanoPrecipitation, an approach to produce functional nanoparticles with unique optical, mechanical and chemical properties. Microreactor design and optimization could be greatly enhanced by developing reliable computational models of the nanoprecipitation process. A microscale multi-inlet vortex nanoprecipitation reactor was investigated using microscopic particle image velocimetry and computational fluid dynamics. Velocity data such as the mean velocity and turbulent kinetic energy displayed good agreement between experiment and simulation over flow conditions ranging from fully laminar to turbulent, demonstrating the accuracy of the simulation model over the entire turbulent transition range.


Effect Of Electrolytes On Co-Water Mass Transfer, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel Jan 2009

Effect Of Electrolytes On Co-Water Mass Transfer, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel

Chemical and Biological Engineering Publications

The influence of various electrolytes such as sulfate, nitrate, and chloride on CO-water mass transfer was investigated in this study. The results indicate that the enhancement in the CO-water volumetric masstransfer coefficient ranged from 1.5 to 4.7 times that of a baseline system without electrolytes, depending on electrolyte type and concentration. For those electrolytes with the same anions, copper-containing electrolytes provided stronger enhancement, whereas for those electrolytes with the same cations, sulfate-containing electrolytes showed stronger enhancement. By measuring both the CO-water volumetric mass-transfer coefficient (kLa) and the mass-transfer coefficient (kL), it was found that the electrolytes inhibit gas ...


Validation Of Two-Fluid Simulations Of A Pseudo-Two-Dimensional Bubble Column With Uniform And Nonuniform Aeration, Sarah M. Monahan, Rodney O. Fox Jan 2009

Validation Of Two-Fluid Simulations Of A Pseudo-Two-Dimensional Bubble Column With Uniform And Nonuniform Aeration, Sarah M. Monahan, Rodney O. Fox

Chemical and Biological Engineering Publications

The multiphase flow simulated in this work corresponds to the pseudo-2D bubble-column experiments at Delft University of Technology (Harteveld et al. Can. J. Chem. Eng. 2003, 81, 389-394). As in the work of Monahan and Fox (AIChE J. 2007, 53, 9-18), the complete set of interphase force models includes drag, added-mass, lift, rotation, and strain. The simulation results are presented in the form of comparisons with the experimental data for the time-averaged gas holdup and the instantaneous and time-averaged air and liquid velocity fields. Overall, the qualitative and quantitative comparisons between experiments and simulations are satisfactory for both uniform and ...


Optimal Moment Sets For Multivariate Direct Quadrature Method Of Moments, Rodney O. Fox Jan 2009

Optimal Moment Sets For Multivariate Direct Quadrature Method Of Moments, Rodney O. Fox

Chemical and Biological Engineering Publications

The direct quadrature method of moments (DQMOM) can be employed to close population balance equations (PBEs) governing a wide class of multivariate number density functions (NDFs). Such equations occur over a vast range of scientific applications, including aerosol science, kinetic theory, multiphase flows, turbulence modeling, and control theory, to name just a few. As the name implies, DQMOM uses quadrature weights and abscissas to approximate the moments of the NDF, and the number of quadrature nodes determines the accuracy of the closure. For nondegenerate univariate cases (i.e., a sufficiently smooth NDF), the N weights and N abscissas are uniquely ...