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Full-Text Articles in Biomedical Engineering and Bioengineering

Effect Of Fa Chain Length On Normal- And Reversed-Phase Hplc Of Phospholipids, Dongmei Zhai, Peter J. Reilly Dec 2002

Effect Of Fa Chain Length On Normal- And Reversed-Phase Hplc Of Phospholipids, Dongmei Zhai, Peter J. Reilly

Chemical and Biological Engineering Publications

Forty-seven saturated synthetic diacyl PA, PC, PE, PG, and PS and five unsaturated diacyl phospholipids (PL) underwent normal- and reversed-phase (RP) HPLC with isocratic isopropanol/hexane/water (5∶4∶1) and methanol/chloroform/acetonitrile/water (79.5∶9∶8∶3.5) mobile phases, respectively. For normal-phase HPLC, capacity factors (k′ i ) decrease with chain length (n) of the two identical PL FA residues, whereas the opposite occurs with RP (C18)-HPLC. Plots of In k′ i vs. n for individual PL classes are in general curved, violating the linear free-energy relationship. For PL of the same n but with ...


Accurate Quantification Of Steady And Pulsatile Flow With Segmented K-Space Magnetic Resonance Velocimetry, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando P. Simonetti, Paulo R. Schvartzman, Richard D. White, George P. Chatzimavroudis Sep 2002

Accurate Quantification Of Steady And Pulsatile Flow With Segmented K-Space Magnetic Resonance Velocimetry, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando P. Simonetti, Paulo R. Schvartzman, Richard D. White, George P. Chatzimavroudis

Chemical & Biomedical Engineering Faculty Publications

Conventional non-segmented magnetic resonance phase velocity mapping (MRPVM) is an accurate but relatively slow velocimetric technique. Therefore, the aim of this study was to evaluate the accuracy of the much faster segmented k-space MRPVM in quantifying flow. The axial velocity was measured in four straight tubes (inner diameter: 5.6–26.2 mm), using a segmented MRPVM sequence with seven lines of k-space per segment. The flow rate and flow volume were accurately quantified (errorssteady (r2=0.99) and pulsatile flow (r2=0.98), respectively. The measured velocity profiles and flow rates from the segmented ...


Fermentation Of Cottonseed And Other Feedstuffs In Cattle Rumen Fluid, Ian C. Schneider, Michael L. Ames, Mark A. Rasmussen, Peter J. Reilly Mar 2002

Fermentation Of Cottonseed And Other Feedstuffs In Cattle Rumen Fluid, Ian C. Schneider, Michael L. Ames, Mark A. Rasmussen, Peter J. Reilly

Chemical and Biological Engineering Publications

Bovine rumen fluid was fermented anaerobically over 48 h with cottonseed, corn, alfalfa, or a mixture of these substrates in anaerobic mineral buffer. Samples taken at different incubation times were derivatized with n-butanol and subjected to gas chromatography and mass spectroscopy. No unusual fermentation end-products from the cottonseed substrate were detected. Cottonseed supported rumen fermentation at levels comparable to those of the other substrates. Major components were usually found in the decreasing order of acetate, propionate, butyrate, and valerate, although acetate and propionate concentrations decreased late in the alfalfa and mixed-feed fermentations, eventually allowing butyrate concentrations to exceed those ...


Ultrafast Flow Quantification With Segmented K-Space Magnetic Resonance Phase Velocity Mapping, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando P. Simonetti, Paulo R. Schvartzman, Richard D. White, George P. Chatzimavroudis Jan 2002

Ultrafast Flow Quantification With Segmented K-Space Magnetic Resonance Phase Velocity Mapping, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando P. Simonetti, Paulo R. Schvartzman, Richard D. White, George P. Chatzimavroudis

Chemical & Biomedical Engineering Faculty Publications

Magnetic resonance (MR) phase-velocity mapping (PVM) is routinely being used clinically to measure blood flow velocity. Conventional nonsegmented PVM is accurate but relatively slow (3–5 min per measurement). Ultrafast k-space segmented PVM offers much shorter acquisitions (on the order of seconds instead of minutes). The aim of this study was to evaluate the accuracy of segmented PVM in quantifying flow from through-plane velocity measurements. Experiments were performed using four straight tubes (inner diameter of 5.6–26.2 mm), under a variety of steady (1.7–200 ml/s) and pulsatile (6–90 ml/cycle) flow conditions ...


Beta Zeolite Supported On A Macroscopic Pre-Shaped Sic As A High Performance Catalyst For Liquid-Phase Benzoylation, G. Wine, Jean-Philippe Tessonnier, C. Pham-Huu, M. J. Ledoux Jan 2002

Beta Zeolite Supported On A Macroscopic Pre-Shaped Sic As A High Performance Catalyst For Liquid-Phase Benzoylation, G. Wine, Jean-Philippe Tessonnier, C. Pham-Huu, M. J. Ledoux

Jean-Philippe Tessonnier

Preparation and characterisation of a highly active and stable beta zeolite supported on a pre-shaped silicon carbide catalyst for the benzoylation reaction in liquid phase.


Development Of Novel Polymeric Materials For Gene Therapy And Ph-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, And Analysis , Brian Curtis Anderson Jan 2002

Development Of Novel Polymeric Materials For Gene Therapy And Ph-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, And Analysis , Brian Curtis Anderson

Retrospective Theses and Dissertations

The aim of this work was to obtain a fundamental understanding of drug release mechanisms from polymers that undergo thermoreversible gelation and to synthesize new polymers based on these that exhibit both pH and temperature sensitivity. Novel block and random copolymers with cationic character have been developed for drug delivery and gene therapy applications. The development of these materials began with a study of the mechanism of drug release from poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) block copolymers. This study revealed the release rates of drugs from water-soluble hydrogels composed of the PEO-PPO-PEO block copolymer PluronicRTM F127 ...


Mm# Modeling Of Aldopentose Pyranose Rings, Michael K. Dowd, William M. Rockey, Alfred D. French, Peter J. Reilly Jan 2002

Mm# Modeling Of Aldopentose Pyranose Rings, Michael K. Dowd, William M. Rockey, Alfred D. French, Peter J. Reilly

Chemical and Biological Engineering Publications

MM3 (version 1992, ϵ=3.0) was used to study the ring conformations of d-xylopyranose, d-lyxopyranose and d-arabinopyranose. The energy surfaces exhibit low-energy regions corresponding to chair and skew forms with high-energy barriers between these regions corresponding to envelope and half-chair forms. The lowest energy conformer is 4 C 1 for α- and β-xylopyranose and α- and β-lyxopyranose, and the lowest energy conformer is 1 C 4 for α- and β-arabinopyranose. Only α-lyxopyranose exhibits a secondary low-energy region (1 C 4) within 1 kcal/mol of its global minimum. Overall, the results are in good agreement with NMR and crystallographic ...


Synergistic Effects Of Physical And Chemical Guidance Cues On Neurite Alignment And Outgrowth On Biodegradable Polymer Substrates, Cheryl Miller, Srdija Jeftinija, Surya K. Mallapragada Jan 2002

Synergistic Effects Of Physical And Chemical Guidance Cues On Neurite Alignment And Outgrowth On Biodegradable Polymer Substrates, Cheryl Miller, Srdija Jeftinija, Surya K. Mallapragada

Chemical and Biological Engineering Publications

This article demonstrates that directional outgrowth of neurites is promoted by applying a combination of physical and chemical cues to biodegradable polymer substrates. Films of poly-D,L-lactic acid and poly(lactide-co-glycolide) were micropatterned to form grooves on substrate surfaces, using novel indirect transfer techniques developed specifically for biodegradable polymers that cannot be micropatterned directly. Laminin was selectively adsorbed in the grooves. Whole and dissociated dorsal root ganglia were seeded on the substrates and neurite outgrowth and alignment along the microgrooves were measured. The microgrooves provide physical guidance, whereas laminin provides chemical cues to the neurons. The groove depth and spacing ...