Electrophoretic displays, such as the Kindle®, currently employ electrostatic effects in apolar media to create a paper-like display. In an electrophoretic display, images are comprised of black and white pixels generated by applying an electric field to reposition charged pigment particles. The optimization of this technology is limited due to the incomplete knowledge of the mechanism(s) by which particles acquire charge in these systems. My project explores the charging behavior of carbon black pigments dispersed in apolar media. Previous studies of mineral oxide particles have provided support for the theory of an acid-base charging mechanism for particles dispersed in apolar media with various charge stabilizing surfactants. My current work looks at the possible extension of the theory of an acid-base charging mechanism to carbon black pigments in apolar systems. I have investigated the charging behavior of four different carbon black pigments by measuring the electrophoretic mobility of each pigment dispersed in solutions of heptane, and a charge stabilizing surfactant at varying weight percentages. Three surfactants were used for charge stabilization: Aerosol OT, SPAN 80 and OLOA 11000. Aerosol OT is a neutral surfactant in water, whereas SPAN 80 is acidic and OLOA 11000 is basic. The surface characteristics of each carbon black pigment were studied by Inverse Gas Chromatography (IGC) and X-ray Photoelectron Spectroscopy (XPS). The preliminary findings of my investigation show the sign of the charge for the carbon black pigments to be dependent on the charge stabilizing surfactant used.

The primary cilium is a sensory organelle found on most cells. In the brain, most or all neurons contain a single primary cilium, yet its function is not entirely understood. Ciliopathies are defined as a group of disorders physiologically characterized by malformation or dysfunction of primary cilia, which in turn result in a variety of symptoms including cognitive deficits, retinal blindness, situs inversus and polydactyly. The serotonin 6 receptor (5-HT6) is the only 5-HT receptor that localizes to neuronal primary cilia, and previous research has implemented the receptor in learning, memory, and drug addiction. Our experiment will investigate the link between neuronal primary cilia and 5-HT6 in an attempt to better understand the significance of this unique localization. Using an immortalized line of rat adrenal cells (PC12), we will express the 5-HT6 receptor using viral vectors, and then pharmacologically manipulate the activity of the receptors with either an agonist (WAY 399885) or an antagonist (SB 208466). We will first stain the cells using immunohistochemistry, then image using florescence microscopy, and lastly quantify the morphological change in primary cilia length. We expect to see a shortening of primary cilium in response to the introduction of an antagonist, and an increase in length with an agonist. Since the 5-HT6 receptor has been shown to be homologous between rats and humans, a practical application of this research could eventually result in a pharmaceutical solutions to some of the cognitive symptoms associated with ciliopathies like congenital cerebellar ataxia or Joubert syndrome.

Protein kinases are enzymes that take phosphate groups from adenosine triphosphate (ATP) molecules, the energy in your body, and add them to other specific molecules inside the cell. This transfer of the phosphate group can activate or deactivate the target molecule, thus regulating cellular activities such as growth, replication, and respiration. The kinases studied here are hemopoietic cell kinases (Hck kinases) under the class of Scr kinases. Hck kinases are present in bone marrow and are often associated with myeloid leukemias and myeloproliferative disorders. Studies have shown that in the active conformation, the Hck kinase detaches two of its domains, SH2 and SH3, resulting in a more extended conformation. Using a Waters Synapt G2 HDMS, ion mobility mass spectrometry (IM-MS) techniques were used to probe the size of inactive and active Hck kinases by measuring drift times of their gas-phase ions traveling through a neutral background gas under the presence of a weak electric field. Drift times were then converted into collision cross section (CCS) values, which depend on the size and shape of the ion of interest. Eight different small molecules (< 500 Da) were used to inhibit Hck kinases, and changes in conformation were investigated using IM-MS. Preliminary data shows no significant changes in global conformation or size, conflicting with the previous studies. To investigate more subtle changes in conformation, collision induced unfolding (CIU) methods are used. By selecting an ion of interest using a quadrupole mass filter, protein unfolding is monitored using ion mobility as a function of ion activation prior to ion mobility analysis. This process allows an investigation of the subtle conformational changes in the Hck kinase upon the binding of small inhibitor molecules.

Electrospray ionization (ESI) is a powerful tool for transferring intact protein complexes from solution to the gas phase. ESI creates multiply charged ions with a net positive (cation) or negative (anion) charge. Although the structures of gas-phase protein cations have been investigated extensively, relatively little research addressing the structures of negatively charged protein ions exists in the literature. In my research, I use ion mobility (IM) to measure drift times, or the time an ion takes to traverse a gas-filled drift tube in the presence of a weak electric field. The drift times for ions depend on their charge and collision cross section (CCS), which to a first approximation, is the orientationally averaged projected cross section of its structure. Therefore, the drift times of ions depend on their structure. Preliminary CCS values that I have measured for protein complex anions are slightly smaller than values in the literature for the analogous protein complex cations, which suggests that the anions are more compact than the cations. One challenge in interpreting those results is the anions had a lower absolute number of charges than the analogous cations, so the results may not be directly comparable. The focus of my research is to make more direct comparisons between the structures of protein complex cations and anions. To this end, I am developing methods to reduce the number of charges on protein complex cations to values equal to those observed previously for the anions. CCS values determined for these charge-reduced cations will be directly comparable to those measured for the anions, and should reveal any structural differences between protein complex cations and anions. These results will also be useful for calibrating other IM experiments and determining how best to use IM to characterize the native structures of protein complexes.

This action-research project describes a particular student-lead model created to foster community and awareness of global health across campus. We, the student leaders, who form the Global Health Undergraduate Leadership Committee (GHULC), have shaped this model to best respond to an ongoing challenge of engaging all undergraduates in awareness and community building around global health issues. The model for this approach involves bimonthly meetings with the committee and two advisors in addition to attending events planned by the GHULC and the Department of Global Health. Methods we have taken to increase undergraduate involvement in the minor include regular information sessions about the minor, monthly student-planned Community Connections events on critical issues, a joint student- and faculty-run journal club, peer advising, walking tours of Global Health organizations in Seattle, and a GHULC blog. Preliminary quantitative data suggests that there has already been an increase in the number of students enrolled in the minor this year as well as an increase in the academic diversity of participating students. Our next step will be to develop a qualitative assessment of the GHULC’s impact by administering a feedback form to all Global Health minor students regarding their perception of and involvement in the minor. We intend to gather this information on a yearly basis in order to improve the minor as well as the GHULC’s role with the goal of continuing to increase diversity, engagement, and mentorship.