Natural Sciences

Characterization of Waterpipe Tobacco Smoke (WTS) by Attenuated Total Reflectance (ATR) and On-Line Fouier Transform Infrared Spectroscopy (FTIR)

Waterpipe smoking is becoming an increasingly popular social activity in the US, especially among college-age students. Unlike cigarette smoke, waterpipe tobacco smoke (WTS) is passed through a bowl of “filtration” liquid prior to inhalation and is thus often misperceived as a safer alternative to cigarette smoking. However, little is known about the chemical composition of WTS and its potential toxicity. In this work the gas and particle phases of WTS, its condensate, and shisha tobacco coating are examined using Fourier Transform Infrared Spectroscopy (FTIR) under charcoal and electronic heating conditions. Identified organic aerosols found include: glycerol, carbon monoxide, solvated carbon dioxide, and an unidentified hydroxyl or amine stretch. This work serves as a proof of concept, demonstrating FTIR’s potential for use in WTS analysis, but calls for the development of more specific methods with sensitivities capable of identifying the unknown compound observed and further organic components in WTS.

Physical Properties of Waterpipe Shisha Smoke

The use of waterpipe in the United States is increasing in a largely unregulated market. Little is known about the particulate matter size distributions of waterpipe smoke, though much of this particulate matter is able to penetrate into the lungs. Particulate matter distributions were characterized for trials in which the head contained various components of hookah shisha to determine their contribution to the size and concentration of hookah smoke. Data suggest that glycerol particles peak between 200 and 300 nm in diameter, while flavorants contribute particles peaking between 100 and 200 nm in diameter. Tobacco leaves appear to produce particulate matter in a bimodal distribution peaking below 5 nm in diameter and at about 225 nm in diameter. Further research needs to be conducted to determine the concentration of particles produced below 5.6 nm and above 560 nm in diameter.

Synthesis of multivalent glycooligomers for studying carbohydrate-protein binding

One major limitation in studying carbohydrate-protein interactions is the low binding affinity of individual carbohydrate subunits. Molecular scaffolds that display carbohydrates in a multivalent fashion are useful for studying these processes. However, the lack of methods for the preparation of well-defined molecular scaffolds remains a major limitation. In this poster, we describe how our research aims to overcome this limitation through the synthesis and characterization of a series of well-defined and tunable glycooligomers that can be systematically designed to probe carbohydrate-protein interactions.

Methods Development for Expression of Luminopsin 3 in the Neurons of C. elegans

Optogenetics has emerged as a novel method for investigating neural circuits. This method uses light activated or light emitting molecules that have been integrated in neurons to either stimulate neuron firing or to report neural activity.  In this project, I am using an optogenetic protein called luminopsin 3 to stimulate a subset of neurons in the model organism C. elegans. The crux of luminopsin 3 (LMO3) is a light-activated ion channel called channelrhodopsin. When channelrhodopsin is stimulated with blue light, it propagates action potentials in neurons, making it a valuable optogenetic tool. The LMO3 protein can also act in the absence of external light when a chemical cofactor, called coelantrazine (CTZ), is present. This makes LMO3 a chemical genetic tool as well. While channelrhodopsin has been integrated into C. elegans neurons before, to the best of our knowledge, a dual optogenetic and chemical genetic approach in these animals has not yet been described. Furthermore, no literature exists for the application or introduction of CTZ in C. elegans. Therefore, we are developing a method for the expression of LMO3 in the GABAergic neurons of the model organism C. elegans. Here, we report a transgenic strain of C. elegans containing the construct, preliminary data for the characterization of the construct, and a novel approach for the use of CTZ in a C. elegans system. We hope this tool will open up new pathways for research on effects of short term, chronic, and temporal effects of neuron activation on axon regeneration and neuroplasticity.

Charge Carrier Diffusion in Blue LEDs

Blue light emitting diodes (LEDs) remain subject to widespread research because they exhibit detrimental behavior that LEDs of other colors do not. While most LEDs become more efficient at converting electrical power to light as the drive current increases, blue LEDs only increase in efficiency up to a certain current threshold, at which point they become progressively less efficient. The decrease in efficiency is called droop. Previous research in the Gfroerer lab has shown that when a laser excites a blue LED device, the device emits light from regions that are not directly excited. We investigate this phenomenon by comparing operational conditions under optical and electrical excitation, and constructing a computational model of electron-hole diffusion in the device.

Plotting the flight path of a knuckleball

A knuckleball, or a pitch in baseball that has minimal spin, experiences a small lateral force that depends on its orientation. In this situation, were the ball to be rotating slowly, the lateral force would vary sinusoidally, with period equal to one quarter of the period of spin. Because of this phenomenon, a knuckleball tends to change the direction in which it curves during flight. Any baseball fan knows this, and they also know that even some of the best professional hitters have trouble hitting a knuckleball. This project will use python 3 to code simultaneous differential equations for a knuckleball’s position in three dimensions with respect to time and plot the flight path of the ball from the catcher’s perspective, the third baseman’s perspective, and the overhead perspective, with the goal of visually representing how unorthodox the ball’s flight path is relative to other baseball pitches.