Analytical & Physical
9:00 - 9:20 am
Investigating the patterns of spatial distribution of the Atlantic Bay Nettle (Chrysaora chesapeakei) in the Patuxent River Waterscape
Mya Sharpe
Institution Morgan State University
Faculty Mentor: Dr. Chunlei Fan
Species of the scyphozoan are known for negatively affecting commercial, industrial, recreational enterprises, and ecological structures. Jellyfish blooms damage economically important fisheries, close tourist beaches, disrupt intakes of coastal power and desalination plants. Investigating the patterns of spatial distribution will close the knowledge gap necessary for understanding bloom dynamics, to properly mitigate and predict jellyfish blooms. The focus species is the Atlantic Bay nettle. The objective is to determine its spatial distribution patterns and to understand the distribution dynamics and other factors that are prevalent in the area that bay nettle is abundant. The study area, the Patuxent River Waterscape is a sub-estuary of the larger estuary, the Chesapeake Bay. This estuary does not offer the opportunity for high visibility into the water. To quantify blooms a method that requires low visibility is used. The Adaptive Resolution Imaging Sonar was deployed in the sub-estuary of the waterscape along 5 different transects, smaller region to represent a larger region longitudinally and latitudinally to collect sonar data. The collected data will be compared based on three variables; habitat type, date and transect.
9:20 - 9:40 am
Quantum-chemical study of the adsorption of mercury on ice surface
Logan Vogelsong
Institution: Pennsylvania State University Harrisburg
Faculty Mentor: Abu Asaduzzaman
Elemental mercury emitted by anthropogenic processes is oxidized in the atmosphere by halogens, ozone or nitro species under ultraviolet light. The oxidized mercury then deposits on the surface environment or reduces back to elemental mercury. The aqueous phase atmospheric photoreduction of oxidized mercury also can take place in the clouds. Thus, the oxidation, reduction and surface deposition control the overall mercury budget and distribution in the atmosphere. One possible process is the adsorption of oxidized mercury on the ice surface and subsequent diffusion into the water supply. Density Functional Theory (DFT) was applied to calculate binding energies and to determine if this process is favorable. These mercury-containing compounds can interact with ice sheets in different orientations, parallel or perpendicular to the surface. BrHgXO and BrHgOX (X = Cl, Br, and I) molecules have the highest adsorption to the ice sheet. Molecules placed on larger supercells dissociated, which explain how mercury enters the water supply in the Arctic.
9:40 - 10:00 am
Electronic Paddlewheels in a Solid-State Electrolyte
Rahul Somni
Institution: Rutgers University, New Brunswick
Faculty Mentor: Richard Remsing
Solid-state superionic conductors are promising alternatives to current liquid battery technologies, but the principles governing solid-state conduction is not completely understood. Previous studies suggest the existence of coupled dynamics between mobile ions and the anionic lattice in solid-state superionic conductors. Further characterisation of these dynamics is essential to develop a physical framework to understand this type of conduction. In this study, we investigate the interactions between mobile cations and the anionic lattice of prototypical superionic conductor AgI. For this purpose, we use ab initio molecular dynamics simulations to examine the coupling between cation motion and rotations of iodine lone pairs, using maximally localized Wannier function centers. Short-lived interactions between the silver cation and the iodine lone pairs propel the cation through the lattice in a paddle wheel motion. These insights into AgI will inform further investigations into other promising superionic conductors.
10:00 - 10:20 am
Photophysical Evaluation of Potent Photosensitizers to Improve Photodynamic Therapy
Brianna Maslonka
Institution: Lehigh University
Faculty Mentor: Elizabeth Young
Photodynamic therapy (PDT) is a form of cancer treatment that uses light to kill cancer. In PDT, light irradiation of a photosensitizer (PS) localized in a tumor site leads to the production of singlet oxygen (also known as reactive oxygen species, ROS) within cells. ROS can trigger cancer cell death. The goal of this project is to evaluate several porphyrinoid-based PSs that are more potent than current PSs. Using transient absorption spectroscopy (TAS), the lifetime and triplet quantum yield of the PSs are measured determined to determine if these properties are correlated to the efficiency of the PS with respect to singlet oxygen production. Overall, we aim to determine the triplet lifetimes and quantum yields of the PSs and ultimately correlate that with the efficacy of pHLIP-PS conjugates in triggering cancer cell death.
10:20 - 10:40 am
Transport Properties of Chloroaluminate Ionic Liquids – Developing Structure-Property Relationships
Michael Schnabel
Institution: United States Naval Academy
Faculty Mentor: Paul Trulove
Ionic liquids (ILs) are liquids consisting entirely or almost entirely of ions. Chloroaluminates are a class of ILs prepared by mixing an organic chloride salt with aluminum chloride. Chloroaluminates and other halometallate ILs possess properties with significant promise for energy storage, electrodeposition, and chemical synthesis applications. By varying the concentrations of reactants and changing the chemical structure of the organic cation, a wide range of physical and chemical properties can be achieved. In the present work, we are exploring how viscosity, ionic conductivity, and thermal stability are impacted by systematic variation in reactant concentration and organic cation chemical structure. We employ broadband dielectric spectroscopy, rheology, and differential scanning calorimetry to investigate ion dynamics and charge transport in 1-alkyl-3-methylimidazolium chloroaluminates over broad frequency and temperature ranges. These in-depth studies are focused on developing underlying structure-property relationships critical to realizing the full potential of chloroaluminate ILs as electrolyte systems.
11:00 - 11:20 am
Using Molecular Dynamics to assess the self-assembly of water in hydrocarbon lakes on Saturn's moon Titan
Ryan Nival
Institution: Rutgers University
Faculty Mentor: Rick Remsing
The discovery of methane/ethane lakes on the surface of Saturn's moon Titan has reinvigorated interest in the chemistry of hydrocarbon solutions, especially at the molecular level. Currently, hydrocarbons are modeled by fixed, symmetric charge distributions that do not capture the dielectric response important for solvation and self-assembly. This can lead to incorrect predictions for the assembly of simple molecules in liquid hydrocarbons. We use molecular dynamics simulations to investigate the self-assembly of water in liquid methane. We examine the role of the solvent's dielectric constant by using both the standard OPLS model and a new model with fixed molecular dipoles that gives the proper dielectric constant of liquid methane. Furthermore, we also compare the structure of water clusters formed in both liquid methane models to their structure in the gas phase. Our results demonstrate that the new dielectric-corrected models improve upon the dipole-free models. In future work, we plan to use these new models to investigate solvation and self-assembly of other small molecules relevant to chemistry on Titan.
11:20 - 11:40 am
The Preclinical Pharmacokinetic Analysis of Vem-BisAmide-2
Ahila Moorthy
Institution: University of Delaware
Faculty Mentor: Ronen Marmorstein
Malignant melanoma is a type of cancer that develops from melanocytes. Vemurafenib causes programmed cell death in melanoma cell lines by inhibiting the BRAF/MEK/ERK pathway − if BRAF has the common V600E mutation. One of the challenges with vemurafenib therapy is the development of resistance within a year of the start of treatment through the transactivation of RAF dimers. Studies from our laboratory demonstrate that the BRAF dimer inhibitor, Vem-BisAmide-2, could be used to inhibit melanoma cell growth. An important obstacle to the development of Vem-BisAmide-2 is the paucity of pharmacokinetic and pharmacodynamic data. We developed an ultra-performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) for quantification of Vem-BisAmide-2 in small volumes (25 µL) of mouse plasma. This assay has been implemented successfully for pharmacokinetic analysis of Vem-BisAmide-2 in highly immunodeficient cancer xenograft mouse model (NOD scid gamma, NSG™). The results of the UPLC-MS/MS assay and pharmacokinetic analysis will be presented.
11:40 - 12:00 pm
Profiling Trace Element Contaminants of Toxicological Interest in Commercially Available Hemp Derived CBD Tincture Oils
Marjanii Walton
Institution: Lincoln University of PA
Faculty Mentor: Thomas Gluodenis
Cannabidiol (CBD) is a phytocannabinoid found in hemp which is commonly extracted and used in dietary supplements. CBD tincture oil is designed to be taken orally and contains the extracted CBD typically diluted in medium chain triglycerides (MCT), hemp seed or olive oil. In addition to being a source of CBD, hemp is known for its bioaccumulation properties that allow for the extraction of metals from the soil in which the plants grow. Due to this property, hemp plants have been used to decontaminate soils. This ability to accumulate metals raises questions about the concentration of potentially toxic metals in CBD based products. In this study, several CBD oils purchased from local smoke shops were screened for all metals in the periodic table using microwave digestion followed by ICP-MS analysis. Elements present at concentrations above the limit for oral permitted daily exposure were reported.
12:00 - 12:20 pm
Shining Organic Radicals
Yue (Ice) Hu
Institution: Lehigh University
Faculty Mentor: Lisa Fredin
Understanding what happens to molecules when they are excited with light is critical to being able to use their chemistry for particular applications, like in light emitting diodes and solar light harvesting. Organic molecules that have unpaired spins have particularly interesting light responses. However, calculating the properties of unpaired electrons in large molecules is not easy. We have calculated the light response of a range of organic radicals with different levels of quantum mechanics including configuration interaction (CI) methods, and time-dependent extensions of density functional theory (TDDFT). From our findings, TDDFT best matches CI singles (CIS) for non-flat highly conjugated organic molecules, but it is not accurate enough for smaller radicals. Therefore, CI level of theory is needed for radical molecules to correctly predict their excited state properties. However, calculating double excitations (CISD) is not essential for radicals as most excitations are single electron excitations (captured by CIS). By thorough benchmarking of methods, this work has shown that CIS can predict the excited state properties of organic radicals, allowing computational chemists to explore new organic radical structures and provide experimental targets for important applications like light harvesting.