TITLES, ABSTRACTS and PDF's of SENIOR THESES, May 2007
Eric Kuo “Determining the Velocity Dependence of the Magnus Force on a Baseball” (advisor: Prof Fell)
Abstract: The Magnus Force is responsible for the deflection of a rapidly spinning baseball traveling through air and is the reason pitches, such as the curveball and the slider, deviate from a trajectory affected only by gravity. It is widely believed that the Magnus Force is directly proportional to the square of the translational speed V and a dimensionless quantity known as the lift coefficient, CL, which is also a function of velocity. However, the principles of fluid dynamics along with recent, low speed experiments predict the Magnus Force goes as V for low speeds (implying that CL goes as 1/V ). The goal of this experiment is to see if this prediction is valid for higher speeds which are more representative of those common in baseball.
Click here to see a PDF version of Eric Kuo's presentation.
Jennifer Makridakis "Quantifying the Repair Process In Vivo in Saccharmyces Cerevisiae through Single Cell Long-term Microscopy" (advisor: Prof. Samadani)
Abstract: Most research done in the study of the cellular mechanisms in Saccharmyces cerevisiae has been done at the population level, but little is known of the cell-to-cell variability at the single cell level. In order to quantify the repair process of budding yeast at the individual level, I developed a device that combines an agarose pad with a microscope. This device enables the imaging of cells for more than 10 hours through long-term microscopy. It was found that this device replicated the conditions of liquid media by keeping the cells supplied with a constant supply of nutrients. In addition, the cells had similar doubling times under the agarose pad that they do when growing in a liquid media. Through long-term microscopy, you can visually track the progeny of a mother cell for over four generations. Using a strain of yeast containing a fluorescently tagged protein, Rad52, which is present at the site of the double strand break during the recombination process, the timing of the start and finish of the recombination event can be quantified by tracking the localized dot in the nucleus. The experiments showed that the dot formation, disappearance, and cell division took on average 150 minutes.
Click here to see a PDF version of Jennifer Macredakis' presentation.
Jonathan Mizrahi “A Model for the Magnetic Field in the Jet of the Quasar 3C 273” (advisor: Prof Wardle)
Abstract: The purpose of this study was to develop a three dimensional model for the magnetic field in the jet of 3C273. Using this model, the fractional polarization of synchrotron radiation from such a jet could then be calculated, and compared to observation. After fitting the theoretical model to observation, the current running down the jet then follows from Ampère’s law.
Click here to see a PDF version of Jonathan Mizrahi's presentation.
Katie Piattelli “Computational Applications Used in Microfluidics” (advisor: Prof Fraden)
Abstract: In this paper, several topics in both pure microfluidics and computer applications used in microfluidics are explored. One of the main objectives was to develop a microfluidics device capable of producing consistently sized and spaced drops. To achieve this, two designs were made. One created drops through the use of flow focusing and the other through use of pumps at a T-junction. Reasonably good results were obtained through the flow focusing method, when used with a variety of oils. However, we encountered a range of problems with the T-junction design, although eventually these problems were corrected to obtain uniform drops. In addition, a computer program was developed to do image processing on drops in order to determine their area as a function of time. A second computer program was also written to plot experimental data against theory and thus extract two physical parameters."
Click here to see a PDF version of Katie Piattelli's presentation.
Samuel Rauhala “D. Discoideum. The Not-So-Black Box” (advisor: Prof Samadani)
Abstract: Chemotaxis in cells is a complex process that spans several realms of cellular activity from biochemical motion, through the actin network resulting ultimately in some net cellular motion. Using Dictyostelium as a model system we explore a few models for describing chemotaxis and what experimental predictions they make. We then present an experimental setup designed to test those predictions and additionally provide calibration data for it.
Click here to see a PDF version of Samuel Rauhala's presentation.
Michael DeSantis “Probing the Not-So-Black Box Using a Homemade Flow Chamber” (advisor: Prof Samadani)
Abstract: Dictyostelium is a social amoeba capable of chemotaxis, directed cellular movement towards an increasing concentration of chemoattractant. The present view of this organism’s biological system with respect to its directional sensing ability is limited; accordingly, the purpose of this research is to further our understanding of this mechanism by studying cell responses to repeated chemical signals of varying frequency and duration. To ‘pulse’ these cells, an experimental system comprising a homemade flow chamber and actuator was assembled and characterized with fluorescein for different flow rates. Using a modified strain expressing the green fluorescent protein (GFP) bound to CRAC, a molecule involved in chemotaxis, we are able to quantitatively measure the response by visualizing this CRC-GFP fusion construct which preferentially accumulates at the cell’s leading edge and subsequently extracting the intensities with image analysis codes I have written.