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Emergence of avian origin and equine origin canine influenza viruses (CIVs) in Asia and the United States brings important concerns. Humans are in closer and more frequent contact with dogs than other common hosts of influenza. Thus, CIV is a potential threat to human health. However, little is known about the determinants of CIV host tropism or the transmissibility of CIVs to humans. An amino acid change (W222L) was implicated in modifying hemagglutinin receptor binding by CIV. This was tested using reverse genetics, glycan microarray and virus histochemistry. Glycan microarray demonstrated that avian-origin CIV (H3N2-222W) bind predominantly to alpha-2, 3 linked glycans. Virus histochemistry indicated that rH3N2-222L had higher binding affinity with epithelial cilia of canine tracheal tissue and weaker binding with avian tracheal tissue. Ferret infection demonstrated that the avian-origin H3N2 CIV could cause infection and limited to rhinitis, suggesting that CIV could infect humans.

COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID 19 is detected by RT-PCR tests and serological tests. RT-PCR tests detect viral RNA and require trained individuals to run the test as well as a lengthy analysis time. Serological tests detect antibodies produced in response to viral infection. Rapid antigen detection (RAD) tests, such as the at-home COVID test kits, are quick and easy to run. RAD tests detect viral antigen in the test sample binding to the antibody-coated testing device. However, production of antibodies is a long and costly process. Aptamers can replace antibodies with advantages including low-cost, stability, tunable selectivity, and ability to be chemically modified. Aptamers are short single-stranded oligonucleotides selected for specific targets using Systematic Evolution of Ligands by Exponential Enrichment (SELEX). This project aims to characterize the binding of aptamers to SARS-CoV-2 nucleocapsid (N) protein using capillary electrophoresis (CE) and compare with bio-layer interferometry (BLI). DNA aptamers were selected via SELEX and screened using BLI in which protein was immobilized on the BLI sensor tip and dipped into aptamer solution. Three aptamers specific to N protein were selected for further binding affinity (Kd) determination. In CE, the aptamer and protein are free in solution to bind and unbind, providing an alternative approach in characterizing the binding. A greater Kd was observed with CE compared to BLI. Using CE, the apparent Kd of the 3 aptamers was determined to be 18 ± 4 nM, 45 ± 11 nM, and 32 ± 7 nM, respectively. When tested with BLI, the apparent Kd were 4.83 ± 0.63, 4.51 ± 0.87, and 2.91 ± 0.59 nM, respectively. This discrepancy in affinity can be due to steric differences between immobilized (BLI) and in solution (CE) binding, buffer composition and stability of aptamer structures, or buffer pH and difference in electrostatic interactions. All three of these variables will impact binding and the calculated Kd. This work offers insight into aptamer affinity when used in a different system from which they were selected. This work would lead to a better understanding when employing aptamers to different assays and assay mediums.

We hypothesized that estradiol (E2) serves as a neurotrophomodulatory substance for basal forebrain cholinergic neurons thought to be involved in learning and memory. Learning/memory was assessed using the two-way active avoidance paradigm and the Morris water task. Female Sprague-Dawley rats were either ovariectomized (OVX) or OVX for 3 weeks, followed by s.c. implantation of a Silastic pellet containing 17-ß E2 (E2 pellet), resulting in a replacement of E2 to physiological levels. Ovary-intact (INTACT) animals served as our positive control. Active avoidance behavior and choline acetyltransferase (ChAT) activity in the frontal cortex and hippocampus were assessed at 5 and 28 weeks postovariectomy while performance on the Morris water task and high-affinity choline uptake (HACU) were measured only at the 5-week time point. At the 5-week time point, E2 replacement caused a significant elevation in the level of active avoidance performance relative to OVX animals. At the 28-week time point, OVX animals demonstrated a significantly lower number of avoidances relative to controls (61%) whereas E2-pellet animals not only demonstrated superior performance relative to OVX animals but also showed an accelerated rate of learning. Morris water task performance, on the other hand, was not significantly affected by estrogenic milieu despite a trend towards better performance in the E2-pellet group. Neurochemical analyses revealed that 5 weeks of ovariectomy was sufficient to reduce HACU in both the frontal cortex and hippocampus by 24 and 34%, respectively, while E2 replacement was successful in elevating HACU relative to OVX animals in both regions. ChAT activity was decreased in the hippocampus but not the frontal cortex of 5-week OVX animals. E2 replacement resulted in a reversal of this effect. At the 28-week time period, an unexpected decrease in ChAT activity was observed across all treatment groups. Interestingly, E2-pellet animals demonstrated the least severe decline in ChAT. This phenomenon was most evident in the frontal cortex where ChAT decreased by 61 and 56% in INTACT and OVX animals, respectively, whereas the decline in E2-pellet animals was only 16% over the same time period, suggesting a previously unreported cytoprotective effect of E2. Taken together, these findings demonstrate important effects of estrogens on cholinergic neurons and support the potential use of estrogen therapy in treatment of dementias in postmenopausal women.

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This study investigated the frequency of distortion that occurs when raw score patterns of Affinity 2.0, a viewing time measure designed to assess sexual interest, are converted to ipsative scores. Eighty-eight percent of a sample of ninety-nine non-pedophilic, exclusively heterosexual males' profiles sustained some degree of distortion. The study also applied Brown's (2005) approach to predicting distortion with this sample of males' responses. Brown's techniques were largely ineffective in predicting males' distortion scores.

This thesis tests the relative efficiency of Fischer's approach of Chi-square on Affinity viewing time profiles to the more commonly used deviance differential approach. Through his use of a Chi-square approach, Fischer has attempted to make a norm-referenced, comparison of ipsative scores generated using Affinity. His goal has been to create an ethically acceptable approach to identifying sexual interest without losing the efficiency generated through the use of the commonly used deviance differential. A Receiver Operating Characteristic (ROC) curve is used to generate the efficiency of each approach and provide results for comparison. These results lead to a discussion of their implications for Fischer's approach of Chi-square, the deviance differential approach, and to the general use of data generated by Affinity.

In this dissertation, microfluidic systems that integrate antibody-based sample preparation methods with electrophoretic separation are developed to analyze multiple biomarkers in a point-of-care setting. To form an affinity column, both monolith materials and wall-coated channels were explored. I successfully demonstrated that monolith columns can be prepared in microfluidic devices via photopolymerization. The selectivity of monolith columns was improved by immobilizing antibodies on the surface. These affinity columns can selectively enrich target analytes and reduce the signal of contaminant proteins up to 25,000 fold after immunoaffinity extraction. These results clearly demonstrate that microchip affinity monoliths can selectively concentrate and purify target analytes through specific antibody-antigen interactions. These monolith columns operated well for simple systems such as buffered solution, but suffered from clogging with real biological samples such as human serum. Therefore, I developed new affinity columns using a wall coating protocol. To form the affinity columns, a thin film of a reactive polymer was UV polymerized in a microchannel. Antibodies were attached by reaction between the polymer epoxy groups and antibody amine groups. All steps, including loading, washing, and elution for affinity extraction, as well as capillary electrophoresis analysis, were achieved simply via applying voltages to reservoirs on the microdevice. By adding reservoirs containing alpha-fetoprotein (AFP) standard into the same device, a quantitative method, either standard addition or calibration curve, can also be performed on-chip. These polymer microdevices have been applied in determining AFP levels in spiked serum samples, and the results are comparable with the values measured using a commercial enzyme linked immunosorbent assay kit. These microchips have also been adapted for detection of multiple biomarkers by immobilizing different antibodies on the affinity column. Four kinds of antibodies were attached to microchip columns, and the amounts of immobilized antibodies were characterized. The fluorescence signals of all four protein antigens were in the same range after rinsing, indicating that the derivatization reaction had little bias toward any of the four antibodies. With spiked human blood serum samples, four proteins in the ng/mL range were simultaneously quantified using both calibration curves and standard addition. In general, the calibration curve and standard addition results were close to the known spiked concentrations. These results indicate that my integrated microdevices can selectively retain and analyze targeted compounds in clinical samples. Moreover, my platform is generalizable and applicable for the simultaneous quantification of multiple biomarkers in complex matrices.

Social capital is the value of the relationships we create and maintain within our social networks to gain access to and mobilize needed resources (e.g., jobs, moral support). Quantifying, and subsequently leveraging, social capital are challenging problems in the social sciences. Most work so far has focused on analyses from static surveys of limited numbers of participants. The explosion of online social media means that it is now possible to collect rich data about people's connections and interactions, in a completely ubiquitous, non-intrusive manner. Such dynamic social data opens the door to the more accurate measuring and tracking of social capital. Similarly, online data is replete with additional personal data, such as topics discussed in blogs or hobbies listed in personal profiles, that is difficult to obtain through standard surveys. Such information can be used to discover similarities, or implicit affinities, among individuals, which in turn leads to finer measures of social capital, including the often useful distinction between bonding and bridging social capital. In this work, we exploit these opportunities and propose a computational framework for quantifying and leveraging social capital in online communities. In addition to being dynamic and formalizing the notion of implicit affinities, our framework significantly extends current social network analysis research by modeling access and mobilization of resources, the essence of social capital. The main contributions of our framework include 1) hybrid networks that provide a way for potential and realized social capital to be distinguished; 2) the decoupling of bonding and bridging social capital, a formulation previously overlooked which coincides with empirical evidence; 3) the unification of multiple views on social capital, in particular, the seamless integration of resources. We demonstrate the broad applicability of our framework through a number of representative, real-world case studies to test relevant social science hypotheses. Assuming that the extraction of implicit affinities may be useful for community building, we built a large social network of blogs from an active, tech-oriented segment of the Blogosphere, using cross-references among blogs. We then used topic modeling techniques to extract an implicit affinity network based on the content of the blogs, and showed that potential sub-communities could be formed through increased bonding. A widespread assumption in sociology is that bonding is more likely than bridging in social networks. In other words, people are more likely to seek out others who are like them than attempt to link to those they share little or nothing with. We wanted to test that hypothesis, particularly in the context of online communities. Using Twitter, we created an experiment where hand-crafted accounts would tweet at regular intervals and use varied following strategies, including following only those with maximum affinity, following only those with no affinity, following random users, etc. Using the number of follow-backs as a surrogate for social capital, we showed that the assumed physical social behavior is also prevalent online, p < 0.01. There is much interest in computational social science to compare physical and cyber behaviors, test existing hypotheses on a large scale and design novel experiments. The advent of social media is also impacting public health, with growing evidence that some global health issues (e.g., H1N1 outbreak) may be discovered and tracked more efficiently by monitoring the content of social exchanges (e.g., blogs, tweets). In collaboration with colleagues from Health Sciences, we wanted to test whether broadly applicable health topics were discussed on Twitter, and to design and guide the process of discovering such themes. We gathered a large number of tweets over several regions of the United States over a one-month period, and analyzed their content using topic modeling techniques. We found that while clearly not a mainstream topic, health concerns were non-negligible on Twitter. By further focusing on tobacco, we discovered several subtopics related to tobacco (e.g., tobacco use promotion, addiction recovery), which indicate that analysis of the Twitter social network may help researchers better understand how Twitter promotes both positive and negative health behaviors. Finally, in collaboration with colleagues from Linguistics, we wanted to quantify the effect of social capital on second language acquisition in study abroad. Using questionnaire data collected from about 200 study abroad participants, we found that students participating in bridging relationships had significantly higher levels of language improvement than their counterparts, F(1,201) = 12.53, p < .0001.

Chromatography units, used in the production of pharmaceuticals, degrade with use and need to be changed or repackaged. This study investigates the effectiveness of two statistical methods, principal component analysis and simple and one-point multiparameter technique, for determining degradation in the Fibro chromatography unit. The methods have been shown to be effective on resin chromatography columns but not before tested on the relatively new Fibro chromatography unit. The statistical methods are implemented in an unreleased version of the monitoring and control software Unicorn. This implementation aims to be a proof of concept for including more complex methods for monitoring runs directly in the software, easing the workflow of operators by removing the need to export measurements to a third-party program. The methods were tested on measurements of absorbance, conductivity, and pressure from two series of chromatograms performed on two Fibro chromatography units. One of the units was defective and broke down halfway through the series. Principle component analysis could clearly visualize a difference between early and late runs on the defective unit. The same could only be achieved for the non-defective unit by excluding measurements of pressure. Simple and one-point multiparameter technique visualized trends from early to late in the series which were much clearer for the defective unit. Both methods showed signs of predicting degradation in a Fibro chromatograpy unit but require validation on chromatogram series with more direct measurements of performance and a wider range of failure causes.