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

Physiologically-Based Pharmacokinetic Modeling For Predicting Drug-Drug Interactions, David M. Ng, Ali Navid Aug 2011

Physiologically-Based Pharmacokinetic Modeling For Predicting Drug-Drug Interactions, David M. Ng, Ali Navid

STAR Program Research Presentations

Dynamics of interactions between the drugs caffeine and ciprofloxacin are predicted using physiologically-based pharmacokinetic (PBPK) modeling. Pharmacokinetic means the model determines where the drugs are distributed in the body over time. Physiologically-based means the anatomy and physiology of the human body is reflected in the structure and functioning of the model. Multiple drugs can interact to increase or decrease their beneficial and/or undesired effects. This is important because some common substances, such as caffeine in coffee and soft drinks, are actually drugs that affect the body. By implementing the model as a computer program, it is relatively straightforward to perform …


Discovery Of An Apoptosis Inducing Ligand For Burkitt Lymphoma, Carolyn Laymon, Kyla Bradylong, Mary Saunders, David Olivos, Kit Lam Aug 2011

Discovery Of An Apoptosis Inducing Ligand For Burkitt Lymphoma, Carolyn Laymon, Kyla Bradylong, Mary Saunders, David Olivos, Kit Lam

STAR Program Research Presentations

One-bead two-compound (OB2C) combinatorial chemistry libraries enable the discovery of novel synthetic compounds which can be used to evoke specific signaling response in cells. The library configuration is composed of a fixed known cell adhesion ligand and a random chemical library displayed on the surface of Tentagel beads. The cell adhesion ligand binds to specific receptors located on the surface of cells enabling the random immobilized chemical molecules on each bead resin bead to evoke specific cellular responses such as apoptosis or cell death. To validate this concept, a OB2C combinatorial library comprised of an α4β1 integrin targeting ligand, LLP2A, …


Forward Osmosis Bag: Ground Testing The Prospect Of Using Alternative Water Sources For Drinking Water, Michaela Marie Brant, Ariella Yendler, Mona Hammoudeh, Michael T. Flynn Aug 2011

Forward Osmosis Bag: Ground Testing The Prospect Of Using Alternative Water Sources For Drinking Water, Michaela Marie Brant, Ariella Yendler, Mona Hammoudeh, Michael T. Flynn

STAR Program Research Presentations

On the STS-135 Space Shuttle mission, to be launched July 8, 2011, a forward osmosis bag (FOB) study will be conducted. At NASA Ames this summer, the ground truth testing is being conducted for results comparisons. The FOB technology is derived from a commercial product, the X-Pack water filter. Forward osmosis operates by utilizing an established concentration gradient across a semi-permeable membrane to move water molecules from one side of the membrane to the other. This concept is exploited to harvest drinking water from grey water sources such as urine, sea water, or vehicle water. In this experiment, potassium chloride …


Thermal-Initiated Hydroxyethyl Methacrylate Functionalization Of Multiwalled Carbon Nanotubes, Greg Curtzwiler, Philip Costanzo, Ray Fernando, Jeffrey E. Danes, Keith Vorst Jul 2011

Thermal-Initiated Hydroxyethyl Methacrylate Functionalization Of Multiwalled Carbon Nanotubes, Greg Curtzwiler, Philip Costanzo, Ray Fernando, Jeffrey E. Danes, Keith Vorst

Chemistry and Biochemistry

Multiwalled-carbon nanotubes (MWCNTs) were functionalized via thermoinitiated free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) using benzoyl peroxide. Tip sonication was used during the polymerization reaction to separate agglomerated nanotubes. The functionalization was confirmed by control experiments and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Differential scanning calorimetry indicated that the addition of poly(HEMA)-MWCNTs to a two-component polyurethane coating will have little effect on the glass transition temperature of the coating. The poly(HEMA)-functionalized MWCNTs formed large colloidal structures of highly dispersed nanotubes in both the nonsheared and sheared coatings as determined by atomic force microscopy. This study determined a quick …


Direct Imaging Of Two-State Dynamics On The Amorphous Silicon Surface, S. Ashtekar, Gregory E. Scott, J. Lyding, M. Gruebele Jun 2011

Direct Imaging Of Two-State Dynamics On The Amorphous Silicon Surface, S. Ashtekar, Gregory E. Scott, J. Lyding, M. Gruebele

Chemistry and Biochemistry

Amorphous silicon is an important material, amidst a debate whether or not it is a glass. We produce amorphous Si surfaces by ion bombardment and vapor growth, and image discrete Si clusters which hop by two-state dynamics at 295 K. Independent of surface preparation, these clusters have an average diameter of ~5 atoms. Given prior results for metallic glasses, we suggest that this cluster size is a universal feature. The hopping activation free energy of 0.93 ± 0.15 eV is rather small, in agreement with a previously untested surface glass model. Hydrogenation quenches the two-state dynamics, apparently by increasing surface …


Oxidation Kinetics Of Silver Thin Films For Antimicrobial Applications In The Health Care Industry, Sean D. Morham Jun 2011

Oxidation Kinetics Of Silver Thin Films For Antimicrobial Applications In The Health Care Industry, Sean D. Morham

Materials Engineering

To determine if varying city water qualities from around the United States can support a developing “oxidation corrosion of silver thin films” method of creating aqueous ionic silver solutions for the anti-microbial treatment of healthcare linens, a test was devised holding all variables constant with the exception of water quality parameters. This corrosion style test was done in order to assess a pass/fail criteria of 25 ppb ionic silver concentration in the aqueous solutions which resulted from the corrosion of silver thin film coated substrates. Above 25 ppb being a pass, below 25 ppb being a fail. While varying the …


Determining A Method For Rendering Low Cost Cdse(Zns) Core(Shell) Quantum Dots Aqueous Soluble Via Amphiphilic Polymer Wrapping, Patrick Mcbride Jun 2011

Determining A Method For Rendering Low Cost Cdse(Zns) Core(Shell) Quantum Dots Aqueous Soluble Via Amphiphilic Polymer Wrapping, Patrick Mcbride

Materials Engineering

Herein is described the procedure of two amphiphilic polymer wrapping techniques that may be employed for obtaining aqueous soluble quantum dots (QDs) for use in biological fluorescent imaging applications. The advent of QDs has led to new nanoscale fluorescent materials that exhibit unparalleled quantum yields (QYs), high resistance to photobleaching, tunable emissions, and
absorption over a large optical range. However, the QD synthesis employed here at Cal Poly to obtain bright, photostable CdSe(ZnS) core(shell) QDs involves the use of organic solvents and surfactants, leading to hydrophobic QDs. Since all of biology relies on aqueous solubility, this hydrophobicity creates a major …


Caffeine Metabolism And Cytochrome P450 Enzyme Mrna Expression Levels Of Genetically Diverse Inbred Mouse Strains, Neal Addicott, Michael Malfatti, Gabriela G. Loots Jan 2011

Caffeine Metabolism And Cytochrome P450 Enzyme Mrna Expression Levels Of Genetically Diverse Inbred Mouse Strains, Neal Addicott, Michael Malfatti, Gabriela G. Loots

STAR Program Research Presentations

Cytochrome P450 (CYP) enzymes activate or eliminate medications and other xenobiotics, and Caffeine has been used as an indicator of activity for some CYPs. The natural genetic variation in the human population for caffeine metabolizing CYPs does not yet have an established animal model for comparison, but the natural variation in inbred mouse strains presents an attractive starting point. The project gave four different strains of mice a 40mg/kg dose of caffeine and sampled blood and liver tissue after 30 minutes. Samples were analyzed using High Performance Liquid Chromatography (HPLC), reverse transcription PCR (rtPCR), and quantitative PCR (qPCR). The DBA/2J …


Better Biomolecule Thermodynamics From Kinetics, Kiran Girdhar, Gregory Scott, Yann R. Chemla, Martin Gruebele Jan 2011

Better Biomolecule Thermodynamics From Kinetics, Kiran Girdhar, Gregory Scott, Yann R. Chemla, Martin Gruebele

Chemistry and Biochemistry

Protein stability is measured by denaturation: When solvent conditions are changed (e.g., temperature, denaturant concentration, or pH) the protein population switches between thermodynamic states. The resulting denaturation curves have baselines. If the baselines are steep, nonlinear, or incomplete, it becomes difficult to characterize protein denaturation. Baselines arise because the chromophore probing denaturation is sensitive to solvent conditions, or because the thermodynamic states evolve structurally when solvent conditions are changed, or because the barriers are very low (downhill folding). Kinetics can largely eliminate such baselines: Relaxation of chromophores, or within thermodynamic states, is much faster than the transition over activation …


Microfluidic Paper-Based Analytical Devices: From Pocket To Paper-Based Elisa, Andres W. Martinez Jan 2011

Microfluidic Paper-Based Analytical Devices: From Pocket To Paper-Based Elisa, Andres W. Martinez

Chemistry and Biochemistry

Microfluidic paper-based analytical devices (microPADs) began as a simple idea with an ambitious goal. The idea was to make microfluidic devices out of paper instead of plastic or glass. The goal was to develop low-cost and portable paper-based diagnostic devices to improve healthcare in developing countries. Over the past 6 years, many developments have been made in the emerging field of paper-based microfluidic devices. Reviewing the development of these devices in the Whitesides group at Harvard University (Cambridge, MA, USA) can provide some insight into the future of the field and encourage scientists from a variety of backgrounds to contribute …