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Articles 1 - 9 of 9

Full-Text Articles in Biomedical Engineering and Bioengineering

Ruminal Fermentation Of Propylene Glycol And Glycerol, Steven Trabue, Kenwood Scoggin, Siska Tjandrakusuma, Mark A. Rasmussen, Peter J. Reilly Jul 2007

Ruminal Fermentation Of Propylene Glycol And Glycerol, Steven Trabue, Kenwood Scoggin, Siska Tjandrakusuma, Mark A. Rasmussen, Peter J. Reilly

Chemical and Biological Engineering Publications

Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h, all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in decreasing order, all increased with incubation time. Addition of any of the three substrates somewhat decreased acetate formation, while addition of either propylene glycol increased propionate formation but decreased that of butyrate. R- and S-propylene glycol did not differ significantly in either their rates of disappearance or the products formed when they were added to the ...


Puckering Coordinates Of Monocyclic Rings By Triangular Decomposition, Anthony D. Hill, Peter J. Reilly Mar 2007

Puckering Coordinates Of Monocyclic Rings By Triangular Decomposition, Anthony D. Hill, Peter J. Reilly

Chemical and Biological Engineering Publications

We describe a new method of describing the pucker of an N-member monocyclic ring using N−3 parameters. To accomplish this, three ring atoms define a reference plane, and the remainder of the ring is decomposed into triangular flaps. The angle of incidence for each flap upon the reference plane is then measured. The combination of these angles is characteristic of the ring's pucker. This puckering coordinate system is compared to existing reduced parameter systems to describe rings using a cyclohexane molecule. We show that this method has the same descriptive power of previous systems while offering advantages ...


The Fate Of Β-D-Mannopyranose After Its Formation By Endoplasmic Reticulum Α-(1→2)-Mannosidase I Catalysis, Chandrika Mulakala, Wim Nerinckx, Peter J. Reilly Feb 2007

The Fate Of Β-D-Mannopyranose After Its Formation By Endoplasmic Reticulum Α-(1→2)-Mannosidase I Catalysis, Chandrika Mulakala, Wim Nerinckx, Peter J. Reilly

Chemical and Biological Engineering Publications

The automated docking program AutoDock was used to dock all 38 characteristic β-d-mannopyranose ring conformers into the active site of the yeast endoplasmic reticulum α-(1→2)-mannosidase I, a Family 47 glycoside hydrolase that converts Man9GlcNAc2 to Man8GlcNAc2. The subject of this work is to establish the conformational pathway that allows the cleaved glycon product to leave the enzyme active site and eventually reach the ground-state conformation. Twelve of the 38 conformers optimally dock in the active site where the inhibitors 1-deoxymannonojirimycin and kifunensine are found in enzyme crystal structures. A further 23 ...


A Term-By-Term Direct Numerical Simulation Validation Study Of The Multi-Environment Conditional Probability-Density-Function Model For Turbulent Reacting Flows, S. T. Smith, Rodney O. Fox Jan 2007

A Term-By-Term Direct Numerical Simulation Validation Study Of The Multi-Environment Conditional Probability-Density-Function Model For Turbulent Reacting Flows, S. T. Smith, Rodney O. Fox

Chemical and Biological Engineering Publications

The multi-environment conditional probability-density-function (MECPDF) approach for modeling extinction and re-ignition in turbulent nonpremixed reacting flows in analyzed. A unique derivation of the model is given, which makes use of numerical Gaussian quadrature in addition to physical assumptions. The new derivation offers insight into the physical meaning of model terms and offers a more rigorous method for model validation. The assumptions required to close the dissipation terms are validated term by term using data from direct numerical simulations of an inert and a reacting scalar in decaying isotropic turbulence. Results show convergence of the numerical quadrature with an increasing number ...


Theoretical Study Of The Pyrolysis Of Methyltrichlorosilane In The Gas Phase. 2. Reaction Paths And Transition States, Yingbin Ge, Mark S. Gordon, Francine Battaglia, Rodney O. Fox Jan 2007

Theoretical Study Of The Pyrolysis Of Methyltrichlorosilane In The Gas Phase. 2. Reaction Paths And Transition States, Yingbin Ge, Mark S. Gordon, Francine Battaglia, Rodney O. Fox

Chemical and Biological Engineering Publications

The kinetics for the previously proposed 114-reaction mechanism for the chemical vapor deposition (CVD) process that leads from methyltrichlorosilane (MTS) to silicon carbide (SiC) are examined. Among the 114 reactions, 41 are predicted to proceed with no intervening barrier. For the remaining 73 reactions, transition states and their corresponding barrier heights have been explored using second-order perturbation theory (MP2) with the aug-cc-pVDZ basis set. Final energies for the reaction barriers were obtained using both MP2 with the aug-cc-pVTZ basis set and coupled cluster theory (CCSD(T)) with the aug-cc-pVDZ basis set. CCSD(T)/aug-cc-pVTZ energies were estimated by assuming additivity ...


A Combined Catalyst And Sorbent For Enhancing Hydrogen Production From Coal Or Biomass, Justinus A. Satrio, Brent H. Shanks, Thomas D. Wheelock Jan 2007

A Combined Catalyst And Sorbent For Enhancing Hydrogen Production From Coal Or Biomass, Justinus A. Satrio, Brent H. Shanks, Thomas D. Wheelock

Chemical and Biological Engineering Publications

Future large-scale production of H2 for use as a clean fuel will likely depend upon gasifying coal or biomass followed by steam reforming the resulting gas mixture and separating the CO2 byproduct. The process of steam reforming and CO2 separation can be greatly simplified by utilizing a new material that combines a reforming catalyst with a sorbent for CO2. Such a material was prepared in the form of small pellets with cores made of calcium and magnesium oxides and shells made largely of alumina impregnated with a nickel catalyst. Subsequent laboratory performance tests of the material showed that CO, CH4 ...


Unleashing Biocatalysis/Chemical Catalysis Synergies For Efficient Biomass Conversion, Brent H. Shanks Jan 2007

Unleashing Biocatalysis/Chemical Catalysis Synergies For Efficient Biomass Conversion, Brent H. Shanks

Chemical and Biological Engineering Publications

The goal of incorporating renewable carbon into the fuel and chemical enterprise will most likely be successful when combined systems of biocatalysts and chemical catalysts are exploited. Significant efforts in the biocatalytic release of sugars from biomass are being pursued for subsequent use in fermentation. Two recent papers demonstrate an alternative approach to converting these sugars to a liquid fuel by using chemical catalysts.


Conditional Statistics For Passive-Scalar Mixing In A Confined Rectangular Turbulent Jet, H. Feng, Michael G. Olsen, Rodney O. Fox, James C. Hill Jan 2007

Conditional Statistics For Passive-Scalar Mixing In A Confined Rectangular Turbulent Jet, H. Feng, Michael G. Olsen, Rodney O. Fox, James C. Hill

Chemical and Biological Engineering Publications

Experimental results for the conditional statistics, such as the velocity conditioned on a conserved scalar and the scalar conditioned on velocity, in a confined liquid-phase rectangular jet are presented and analyzed for a data set collected using simultaneous particle image velocimetry and planar laser-induced fluorescence. The joint velocity-scalar probability density function (PDF) is not joint Gaussian in this flow, as the PDF of the conserved scalar is accurately described by a beta-PDF. The conditional mean velocity is found to agree with a linear model when the scalar is close to its local mean value. A gradient PDF model is found ...


Theoretical Study Of The Pyrolysis Of Methyltrichlorosilane In The Gas Phase. 1. Thermodynamics, Yingbin Ge, Mark S. Gordon, Francine Battaglia, Rodney O. Fox Jan 2007

Theoretical Study Of The Pyrolysis Of Methyltrichlorosilane In The Gas Phase. 1. Thermodynamics, Yingbin Ge, Mark S. Gordon, Francine Battaglia, Rodney O. Fox

Chemical and Biological Engineering Publications

Structures and energies of the gas-phase species produced during and after the various unimolecular decomposition reactions of methyltrichlorosilane (MTS) with the presence of H2 carrier gas were determined using second-order perturbation theory (MP2). Single point energies were obtained using singles + doubles coupled cluster theory, augmented by perturbative triples, CCSD(T). Partition functions were obtained using the harmonic oscillator-rigid rotor approximation. A 114-reaction mechanism is proposed to account for the gas-phase chemistry of MTS decompositions. Reaction enthalpies, entropies, and Gibbs free energies for these reactions were obtained at 11 temperatures ranging from 0 to 2000 K including room temperature and typical ...