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Biochemistry, Biophysics, and Structural Biology Commons™

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Engineering

Series

2010

Articles 1 - 6 of 6

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Negative Dielectrophoretic Capture Of Bacterial Spores In Food Matrices, Mehti Koklu, Seungkyung Park, Suresh D. Pillai, Ali Beskok Sep 2010

Negative Dielectrophoretic Capture Of Bacterial Spores In Food Matrices, Mehti Koklu, Seungkyung Park, Suresh D. Pillai, Ali Beskok

Mechanical & Aerospace Engineering Faculty Publications

A microfluidic device with planar square electrodes is developed for capturing particles from high conductivity media using negative dielectrophoresis (n-DEP). Specifically, Bacillus subtilis and Clostridium sporogenes spores, and polystyrene particles are tested in NaCl solution (0.05 and 0.225 S/m), apple juice (0.225 S/m), and milk (0.525 S/m). Depending on the conductivity of the medium, the Joule heating produces electrothermal flow (ETF), which continuously circulates and transports the particles to the DEP capture sites. Combination of the ETF and n-DEP results in different particle capture efficiencies as a function of the conductivity. Utilizing 20 μm height DEP chambers, “almost complete” and …

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Crystallization Of Community-Acquired Respiratory Distress Syndrome Toxin From Mycoplasma Pneumonia, Olga N. Pakhomova, Alexander B. Taylor, Argentina Becker, Stephen P. Holloway, T. R. Kannan, Joel B. Baseman, P. John Hart Mar 2010

Crystallization Of Community-Acquired Respiratory Distress Syndrome Toxin From Mycoplasma Pneumonia, Olga N. Pakhomova, Alexander B. Taylor, Argentina Becker, Stephen P. Holloway, T. R. Kannan, Joel B. Baseman, P. John Hart

Bioelectrics Publications

Community-acquired respiratory distress syndrome toxin (CARDS TX) is a 591-amino-acid protein with ADP-ribosyltransferase and vacuolating activities that damages the cells lining the respiratory tracts of patients infected with the bacterial pathogen Mycoplasma pneumoniae. Crystals of CARDS TX were grown in space group C2, with unit-cell parameters a = 191.4, b = 107.4, c = 222.1 A, beta = 90.6 degrees. A complete 2.2 A data set was obtained from a single CARDS TX crystal.

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Cytotoxicity Of Bacterial-Derived Toxins To Immortal Lung Epithelial And Macrophage Cells, Dianne E. Peterson, Jayne M. Collier, Matthew E. Katterman, Rachel A. Turner, Mark R. Riley Feb 2010

Cytotoxicity Of Bacterial-Derived Toxins To Immortal Lung Epithelial And Macrophage Cells, Dianne E. Peterson, Jayne M. Collier, Matthew E. Katterman, Rachel A. Turner, Mark R. Riley

Department of Biological Systems Engineering: Papers and Publications

Health risks associated with inhalation and deposition of biological materials have been a topic of great concern due to highly publicized cases of inhalation anthrax, of new regulations on the release of particulate matter, and to increased concerns on the hazards of indoor air pollution. Here, we present an evaluation of the sensitivity of two immortal cell lines (A549, human lung carcinoma epithelia) and NR8383 (rat alveolar macrophages) to a variety of bacterial-derived inhalation hazards and simulants including etoposide, gliotoxin, streptolysin O, and warfarin. The cell response is evaluated through quantification of changes in mitochondrial succinate dehydrogenase activity, release of …

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Electroporation-Mediated Delivery Of A Naked Dna Plasmid Expressing Vegf To The Porcine Heart Enhances Protein Expression, W. G. Marshall Jr., B. A. Boone, J. D. Burgos, S. I. Gografe, M. K. Baldwin, M. L. Danielson, M. J. Larson, D. R. Caretto, Y. Cruz, B. Ferraro, L. C. Heller, K. E. Ugen, M. J. Jaroszeski, R. Heller Jan 2010

Electroporation-Mediated Delivery Of A Naked Dna Plasmid Expressing Vegf To The Porcine Heart Enhances Protein Expression, W. G. Marshall Jr., B. A. Boone, J. D. Burgos, S. I. Gografe, M. K. Baldwin, M. L. Danielson, M. J. Larson, D. R. Caretto, Y. Cruz, B. Ferraro, L. C. Heller, K. E. Ugen, M. J. Jaroszeski, R. Heller

Bioelectrics Publications

Gene therapy is an attractive method for the treatment of cardiovascular disease. However, using current strategies, induction of gene expression at therapeutic levels is often inefficient. In this study, we show a novel electroporation (EP) method to enhance the delivery of a plasmid expressing an angiogenic growth factor (vascular endothelial growth factor, VEGF), which is a molecule previously documented to stimulate revascularization in coronary artery disease. DNA expression plasmids were delivered in vivo to the porcine heart with or without coadministered EP to determine the potential effect of electrically mediated delivery. The results showed that plasmid delivery through EP significantly …

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Dielectrophoretic Choking Phenomenon In A Converging-Diverging Microchannel, Ye Ai, Shizhi Qian, Sheng Liu, Sang W. Joo Jan 2010

Dielectrophoretic Choking Phenomenon In A Converging-Diverging Microchannel, Ye Ai, Shizhi Qian, Sheng Liu, Sang W. Joo

Mechanical & Aerospace Engineering Faculty Publications

Experiments show that particles smaller than the throat size of converging-diverging microchannels can sometimes be trapped near the throat. This critical phenomenon is associated with the negative dc dielectrophoresis arising from nonuniform electric fields in the microchannels. A finite-element model, accounting for the particle-fluid-electric field interactions, is employed to investigate the conditions for this dielectrophoretic (DEP) choking in a converging-diverging microchannel for the first time. It is shown quantitatively that the DEP choking occurs for high nonuniformity of electric fields, high ratio of particle size to throat size, and high ratio of particle's zeta potential to that of microchannel. © …

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Frustrated Drift Of An Anchored Scroll-Wave Filament And The Geodesic Principle, Marcel Wellner, Christian W. Zemlin, Arkady M. Pertsov Jan 2010

Frustrated Drift Of An Anchored Scroll-Wave Filament And The Geodesic Principle, Marcel Wellner, Christian W. Zemlin, Arkady M. Pertsov

Bioelectrics Publications

We investigate anchored scroll-wave filaments in an excitable medium whose diffusivity matrix, including its determinant, is spatially nonuniform. The study is motivated by cardiological applications where scroll-wave behavior in the presence of diffusivity gradients is believed to play an important role in the development of severe arrhythmias. A diffusivity gradient is expected to make the filament drift, unless drift is prevented ("frustrated") by anchoring to localized defects in the propagation medium. The resulting stationary filament is a geodesic curve, as demonstrated here in the case of a nonzero but constant gradient. That is, the diffusivity matrix has a determinant that …

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