Airway mucus gel plays a vital role in maintaining the integrity of mucosal epithelia and protecting respiratory health. Such defensive mechanism stems primarily from a constant clearance of mucus-entrapped inhaled pathogens and particulates by mucociliary transport. The success in removing mucus-entrapped harmful substances relies heavily on proper mucus rheology. It is well established that hydration is the single most important determinant of mucus rheological properties. In a healthy condition, the body precisely controls the degree of mucus hydration through modulating physiological parameters of various ionic concentrations in the nascent microenvironment which bathe the mucus. On the contrary, inadequate mucus hydration and abnormal mucus hypersecretion seem to be the major causal factors underlying pathological states involving the accumulation of highly viscous mucus plugs, obstructive airflow, chronic infection and inflammation. These symptoms are characteristic of pulmonary diseases including, but not limited to, chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis (CF).

My research focused on the mechanisms of how (i) environmental and (ii) physiologicalfactors affect mucus secretion and rheological properties. My first project tested whether titanium dioxide nanoparticles (TiO2NPs), a common air pollutant that constitutes airborne particulate matter, can induce mucin hypersecretion from airway epithelial cells via a Ca2+-mediated pathway. Aside from being an airborne pollutant, many engineered NPs are utilized in the nanoindustry and have acquired secondary surface modifications. The question of functionalized NPs with surface charges being able to alter mucus rheological properties is the focal point of the second project. The third study aimed at understanding how physiological parameters involving bicarbonate ion concentrations regulate mucus rheological characteristics. Abnormal bicarbonate levels in humans have recently been suggested to instigate a devastating Caucasian disease, cystic fibrosis.

A more in-depth comprehension of how both environmental and physiological factors disturb mucus rheology and over-secretion facilitate the design of future therapies to counteract the concomitant pathologies.

Secretory protein neural EGFL like 1 (Nell-1) has been shown to exert potent osteogenic effects in multiple small and large animal models. Here, we identified and validated contactin-associated protein-like 4 (Cntnap4) as the first Nell-1 specific cell surface receptor. Cntnap4, a transmembrane neurexin superfamily protein member, has critical functions in neurodevelopment but no known function in osteogenesis. In the present study, we demonstrate that: 1) Nell-1 and Cntnap4 co-localize on the surface of osteogenic-committed cells, 2) Nell-1 and Cntnap4 exhibit high-affinity interactions, 3) Cntnap4 knockdown reduces Nell-1-responsive osteogenesis, and 4) Cntnap4 mediates Nell-1-activated MAPK and Wnt signaling in osteogenic-committed cells. Taken together, these findings and recent literature further the notion of potential neuroskeletal interplay. This unanticipated discovery connecting Cntnap4 to Nell-1 during osteogenesis provides a foundational framework for further exploration of a novel functional axis as it relates to skeletal and potential neuronal function.

Airway mucus gel plays a vital role in maintaining the integrity of mucosal epithelia and protecting respiratory health. Such defensive mechanism stems primarily from a constant clearance of mucus-entrapped inhaled pathogens and particulates by mucociliary transport. The success in removing mucus-entrapped harmful substances relies heavily on proper mucus rheology. It is well established that hydration is the single most important determinant of mucus rheological properties. In a healthy condition, the body precisely controls the degree of mucus hydration through modulating physiological parameters of various ionic concentrations in the nascent microenvironment which bathe the mucus. On the contrary, inadequate mucus hydration and abnormal mucus hypersecretion seem to be the major causal factors underlying pathological states involving the accumulation of highly viscous mucus plugs, obstructive airflow, chronic infection and inflammation. These symptoms are characteristic of pulmonary diseases including, but not limited to, chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis (CF). My research focused on the mechanisms of how (i) environmental and (ii) physiological factors affect mucus secretion and rheological properties. My first project tested whether titanium dioxide nanoparticles (TiO₂ NPs), a common air pollutant that constitutes airborne particulate matter, can induce mucin hypersecretion from airway epithelial cells via a Ca²⁺-mediated pathway. Aside from being an airborne pollutant, many engineered NPs are utilized in the nanoindustry and have acquired secondary surface modifications. The question of functionalized NPs with surface charges being able to alter mucus rheological properties is the focal point of the second project. The third study aimed at understanding how physiological parameters involving bicarbonate ion concentrations regulate mucus rheological characteristics. Abnormal bicarbonate levels in humans have recently been suggested to instigate a devastating Caucasian disease, cystic fibrosis. A more in-depth comprehension of how both environmental and physiological factors disturb mucus rheology and over-secretion facilitate the design of future therapies to counteract the concomitant pathologies.

Although ideology is widely studied, less is known about how it varies across sociocultural contexts. Ideology is an organizing structure for political attitudes in that positions on a core set of political attitudes have been found to be aligned along a liberal-conservative ideological dimension. Some personality-based approaches to political psychology suggest that, because ideology arises from low-level psychological features, the political attitudinal structure of ideology is likely to be consistent across sociocultural contexts. However, the cultural psychology perspective suggests that both low-level psychological features and their higher-level political attitudinal manifestations may differ across cultures. The five studies in this dissertation examined this tension using eight datasets from the General Social Survey, applying linear and logistic regression and lasso regression, and the machine learning techniques of random forest classification and regression and support vector machine classification. Across these studies, the importance of ideology as an organizing structure varied across sociocultural contexts, especially across race, education, and income lines. The associations between ideological self-placement and measures of political attitudes were weaker for those with lower incomes and with no college education, and the associations were almost entirely absent for Black Americans. In addition, this dissertation examined other ways that political concerns are prioritized, beyond ideology.