Tag: Poster 79

Vascular Endothelial Growth Factor (VEGF) Signaling Contributions to Heart Ventricle Development

Presenter: Justine Nguyen

Faculty Mentor: Kryn Stankunas, Kate Karfilis

Presentation Type: Poster 79

Primary Research Area: Science

Major: Human Physiology

Cardiomyopathies are congenital heart diseases that affect the heart musculature, which could cause the heart to become weaker and pump less blood efficiently. The purpose of my research is to study the developmental programs that underlie ventricular trabeculation and the role vascular endothelial growth factor (VEGF) plays in regulating this process. VEGF plays a distinct role in direct signaling of angiogenesis along with the cardiac muscle formation and trabeculation in the ventricles. If the gene pathways for the development of trabeculation in the heart are understood, then in a disease state, appropriate remedies could be determined based on where the genes are expressed incorrectly. Currently, two possible hypotheses could explain VEGF signaling and its role in trabecular development. One hypothesis is that VEGF signaling is directly turning on a gene that directs VEGF signaling while the other hypothesis is that the two cell types (endocardial and myocardial cells) are directly interacting with each other due to VEGF signaling. In order to study trabecular development, pregnant mice are dissected when the embryos are developing the trabeculations. Embryos are processed so that their hearts are examined through various cellular biology techniques. A specific small molecule inhibitor, Cabozantinib is used in order to inhibit VEGF signaling, disrupting the formation of the trabeculae. A VEGF inhibited sample can be compared to an untreated wildtype sample to compare the differences in the trabeculation development.

Quantitative Analysis of Thin Films via X-ray Fluorescence Spectroscopy

Presenter(s): Dylan Bardgett − Chemistry

Faculty Mentor(s): David Johnson

Poster 79

Research Area: Natural/Physical Science

From photovoltaics and semiconductors to optical and protective coatings, thin films have made their way into every facet of daily life. Driven by the significance of these materials, the scientific community has embarked on a global quest for cheap, nondestructive, and precise analytical techniques for determining the elemental composition and structure of thin films. One technique, known as X-Ray Fluorescence spectroscopy (XRF), uses the characteristic energies of photons fluoresced by an incident beam of X-rays to determine the relative amounts of different elements in a material. This study set out to take XRF a step further by measuring not only the relative quantity, but the exact quantity, directly proportional to the number of atoms, of each element in a film. Using a solid-state material synthesis method known as physical vapor deposition, thin films were deposited onto silicon substrates and heated to produce a wide range of crystalline compounds such as TiSe2, Bi2Se3, and MoSe2. Crystalline diffraction techniques were used to identify and confirm the structures of the films as well as their total thicknesses. These films were then scanned on an XRF spectrometer, and background signals were subtracted manually by measuring a fragment of the non-deposited silicon substrate set aside before the film deposition process. Data indicates that the intensity of fluoresced photons of a given energy characteristic of an atomic element scales linearly with the number of atoms of the corresponding element, so long as the total film thickness is less than roughly 100 nm. This study concludes that, when calibrated properly, XRF can be used to directly measure the quantities of specific elements in a film. These findings greatly bolster the viability of XRF spectroscopy as suitable analytical technique for the characterization of thin films.