Jessica Shott & Monica Flores, GW Chemistry Graduate Students

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GW Chemistry Department is proud to present as our guest speakers, graduate students, Monica Flores and Jessica Shott.

Vertical Profiling of Water and Carbon Dioxide in the Troposphere and Lower Stratosphere

Monica Flores | Graduate Student, Miller Lab

Water vapor is the strongest greenhouse gas in the atmosphere and has a profound effect on weather and climate due to its participation in multiple, interconnected feedback mechanisms. Further, carbon dioxide is the dominant anthropogenic radiative forcer, making detailed vertical profile data on temperature variations and concentration profiles for these gases necessary for weather and climate forecasting.  Because of its relatively low cost and potential for wide global coverage, the development of a new laser heterodyne radiometry technique, Precision Heterodyne Oxygen-Calibration Spectrometry, will fill an important niche for remote sensing of these gas concentrations. The prototype instrument is equipped with two active laser channels for O2 and H2O (~1278 nm) and CO2 (~1572 nm) determinations. O2 measurements provide dry gas corrections and refine temperature and pressure profiles that improve the precision of the CO2 and H2O vertical column retrievals enabled by interrogating the low-noise absorption lines shapes of »0.0067 cm-1 instrument.

Gadolinium Gold Core-Shell Nanoparticles for Molecular MRI Contrast Agents

Jessica L. Shott | Graduate Student, Wagner Lab

MRI has become an increasingly important diagnostic tool due to its ability to perform rapid, high-resolution scans of the body with minimal adverse effects. However, utilization of MRI on a molecular scale requires development of improved contrast agents (CA). MRI CA can be classified as 1) T1 CA (e.g. Gd3+ chelates) which generate positive contrast or “bright” areas in an MRI image and are preferred for medical applications, or 2) T2 CA, such as superparamagnetic iron nanoparticles (SPIONs), which generate negative contrast or “dark” areas in an image. Gold coated-gadolinium nanoparticles have been synthesized in an effort to overcome the limitations associated with current T1 (Gd3+ chelate) CA. The Gd@Au nanoparticles exhibit paramagnetism and per-gadolinium relaxivities of 19.7 (R1) and 21.7 (R2) mM-1s-1, roughly three times higher than commercially available Gd3+ chelate contrast agents. Furthermore, the R2/R1 ratio of 1.1 is close to the theoretical ideal for T1 MRI contrast making these nanoparticles promising candidates for use as MRI contrast agents.