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Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Biochemistry

Old Dominion University

2012

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Identification Of Persistent Long Range Interactions In GA95 And GB95 Through Thermal Unfolding Simulations, Milen Redai Tesfamariam Jul 2012

Identification Of Persistent Long Range Interactions In GA95 And GB95 Through Thermal Unfolding Simulations, Milen Redai Tesfamariam

Chemistry & Biochemistry Theses & Dissertations

For over five decades, different experiments have been performed to research how proteins attain their native three dimensional structures. However, the folding problem continues to be a puzzle in modern science. The design of two proteins that have maximal sequence identity but different folds and functions is one method that is being used to study the relationship between protein structure and amino acid sequence. In particular, mutant proteins of Streptococcus protein G, GA and GB, have 95% sequence identity and a 3a helix fold and β4/a fold, respectively. Molecular dynamics simulations of GA95 …

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Design Of In Vivo Assays For Study Of Transport, Biocompatibility And Toxicity Of Nanoparticles, Kerry Jean Lee Apr 2012

Design Of In Vivo Assays For Study Of Transport, Biocompatibility And Toxicity Of Nanoparticles, Kerry Jean Lee

Theses and Dissertations in Biomedical Sciences

This dissertation focuses on the design of new in vivo assays for study of transport, biocompatibility and toxicity of nanoparticles (NPs) in zebrafish embryos. We synthesized and purified spherical silver (Ag) NPs with diameters, ranging from 12 to 95 nm, that are stable (non-aggregated) in egg-water media. We developed new imaging approaches to characterize the sizes of single Ag NPs in zebrafish embryos at nanometer resolution by measuring their size-dependent plasmonic spectra and scattering intensity using dark-field optical microscopy and spectroscopy (DFOMS). We used single Ag NPs because they exhibit the high quantum yield (QY) of Rayleigh scattering and resist …

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Microfluidic Separation Of Live And Dead Yeast Cells Using Reservoir-Based Dielectrophoresis, Saurin Patel, Daniel Showers, Pallavi Vedantam, Tzuen-Rong Tzeng, Shizhi Qian, Xiangchun Xuan Jan 2012

Microfluidic Separation Of Live And Dead Yeast Cells Using Reservoir-Based Dielectrophoresis, Saurin Patel, Daniel Showers, Pallavi Vedantam, Tzuen-Rong Tzeng, Shizhi Qian, Xiangchun Xuan

Mechanical & Aerospace Engineering Faculty Publications

Separating live and dead cells is critical to the diagnosis of early stage diseases and to the efficacy test of drug screening, etc. This work demonstrates a novel microfluidic approach to dielectrophoretic separation of yeast cells by viability. It exploits the cell dielectrophoresis that is induced by the inherent electric field gradient at the reservoir-microchannel junction to selectively trap dead yeast cells and continuously separate them from live ones right inside the reservoir. This approach is therefore termed reservoir-based dielectrophoresis (rDEP). It has unique advantages as compared to existing dielectrophoretic approaches such as the occupation of zero channel space and …

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Microfluidic Impedance Spectroscopy As A Tool For Quantitative Biology And Biotechnology, Ahmet C. Sabuncu, Jie Zhuang, Juergen F. Kolb, Ali Beskok Jan 2012

Microfluidic Impedance Spectroscopy As A Tool For Quantitative Biology And Biotechnology, Ahmet C. Sabuncu, Jie Zhuang, Juergen F. Kolb, Ali Beskok

Mechanical & Aerospace Engineering Faculty Publications

A microfluidic device that is able to perform dielectric spectroscopy is developed. The device consists of a measurement chamber that is 250 μm thick and 750 μm radius. Around 1000 cells fit inside the chamber assuming average quantities for cell radius and volume fraction. This number is about 1000 folds lower than the capacity of conventional fixtures. A T-cell leukemia cell line Jurkat is tested using the microfluidic device. Measurements of deionized water and salt solutions are utilized to determine parasitic effects and geometric capacitance of the device. Physical models, including Maxwell-Wagner mixture and double shell models, are used to …

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Rapid And Noncontaminating Sampling System For Trace Elements In Global Ocean Surveys, Gregory A. Cutter, Kenneth W. Bruland Jan 2012

Rapid And Noncontaminating Sampling System For Trace Elements In Global Ocean Surveys, Gregory A. Cutter, Kenneth W. Bruland

OES Faculty Publications

A system for the rapid and noncontaminating sampling of trace elements with volumes of up to 36 L per depth and including the dissolved and particulate phases has been developed for ocean sections that are a crucial part of programs such as International GEOTRACES. The system uses commercially available components, including an aluminum Seabird Carousel with all titanium pressure housings for electronics and sensors to eliminate zinc sacrificial anodes and holding twenty-four 12 L GO-FLO bottles, and a 7500 m, 14 mm Vectran conducting cable (passing over an A-frame with nonmetallic sheave) spooled onto a traction winch. The GO-FLO bottles …

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Controls On Dissolved Cobalt In Surface Waters Of The Sargasso Sea: Comparisons With Iron And Aluminum, R. U. Shelley, Peter N. Sedwick, T. S. Bibby, P. Cabedo-Sanz, T. M. Church, R. J. Johnson, A. I. Macey, C. M. Marsay, E. R. Sholkovitz, S. J. Ussher, P. J. Worsfold, M. C. Lohan Jan 2012

Controls On Dissolved Cobalt In Surface Waters Of The Sargasso Sea: Comparisons With Iron And Aluminum, R. U. Shelley, Peter N. Sedwick, T. S. Bibby, P. Cabedo-Sanz, T. M. Church, R. J. Johnson, A. I. Macey, C. M. Marsay, E. R. Sholkovitz, S. J. Ussher, P. J. Worsfold, M. C. Lohan

OES Faculty Publications

Dissolved cobalt (dCo), iron (dFe) and aluminum (dAl) were determined in water column samples along a meridional transect (∼31°N to 24°N) south of Bermuda in June 2008. A general north-to-south increase in surface concentrations of dFe (0.3-1.6 nM) and dAl (14-42 nM) was observed, suggesting that aerosol deposition is a significant source of dFe and dAl, whereas no clear trend was observed. for near-surface dCo concentrations. Shipboard aerosol samples indicate fractional solubility values of 8-100% for aerosol Co, which are significantly higher than corresponding estimates of the solubility of aerosol Fe (0.44-45%). Hydrographic observations and analysis of time series rain …

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