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General Approaches to Caging Sulfation in Biomolecules:
No full textThesis advisor: Jia NiuO-Sulfation is an important chemical code existing widely in nature, participating in a variety of biological activities including immune response, hemostasis, hormone regulation, cell signaling, and viral invasion. The heterogeneous nature, high polarity with negative charge, and the chemical lability of the sulfate modification have created significant challenges in the synthesis and structure-function studies of O-sulfated biomolecules. It is therefore highly desirable to achieve caging and selective release of the O-sulfated biomolecules. Inspired by sulfur (VI) fluoride exchange reaction, our group developed a series of general approaches to caged O-sulfated biomolecules and their selective deprotection. First, an O-sulfation strategy is developed by coupling aromatic fluorosulfate with silylated target molecules. Scalable synthesis was demonstrated on monosaccharides, disaccharides, amino acid, and steroid. Selective hydrolytic and hydrogenolytic removal of the aryl masking groups yielded the corresponding O-sulfated products in excellent yields. Furthermore, a complete knowledge gap was noted in biocompatible caging of sulfate. With the rational design and systematic optimizations, we discovered that fluorosulfotyrosine in peptides and proteins was an ideal precursor for sulfotyrosine (sY), which can be efficiently converted into the anionic active form by hydroxamic acid activators under physiologically relevant conditions. Photocaging the hydroxamic acid activators further allowed for light-controlled activation of functional sulfopeptides. This system featuring fast kinetics, high selectivity, excellent robustness, and on-demand release provides a valuable tool for probing functional roles of sulfation in the peptides and proteins.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry
Catalytic Transformations Designed to Facilitate Diversity-Oriented Synthesis:
No full textThesis advisor: Amir H. HoveydaThe possibility of accessing altered frameworks wherein the spatial relationship between several organic fragments can be controlled can notably impact drug discovery and development. In this context, we introduce a strategy that can be used for programmable and divergent synthesis of a diverse and otherwise difficult-to-prepare set of cyclic amines and bridged bicyclic enamines wherein up to four exit vectors can be altered accordingly. Central to the approach is a catalytic multicomponent reaction that merges a nitrile, a trisubstituted allenylboronate and a silyl hydride, delivering multifunctional 1,4-aminoboronates that contain a versatile and stereochemically defined trisubstituted alkenyl boronate. We show that the products can be modified to afford an assortment of complex, drug-like, polycyclic amines. What is more, a new cyclization strategy, involving the triflic anhydride-mediated reaction of a trisubstituted alkene and a nearby amide, was developed for synthesis of the corresponding bridged bicyclic scaffolds. These resulting bridged enamines and various derivatives are evocative of the 1-azabicyclo[3.2.1]octane core, found in a variety of bioactive alkaloids.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry
Why Do Managers Interact with Unfavorable Analysts during Earnings Calls?:
No full textThesis advisor: Mark BradshawManagers prioritize questions from favorable analysts during earnings announcement conference calls, reinforcing analysts’ incentives to be optimistic. However, managers also interact with unfavorable analysts on calls, and, when they do, absolute announcement returns are larger. I seek to understand why managers interact with unfavorable analysts. I find that unfavorable analysts attenuate their negative views after these interactions with managers. Additionally, the stock price response is stronger for forecasts from managers who regularly interact with unfavorable analysts, consistent with enhanced credibility of these managers. Finally, I use peer firm restatement announcements as exogenous shocks to investors’ assessment of a firm’s accounting quality, and I find that nonrestating firms with managers who regularly interact with unfavorable analysts experience attenuated negative returns, relative to other nonrestating peers. Overall my findings are consistent with managers’ interactions with unfavorable analysts providing significant benefits to the firm, such as resolving analysts’ concerns and increasing managers’ credibility.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Carroll School of Management.Discipline: Accounting
" They're out to take away your sanity": An ecological investigation of gaslighting in intimate partner violence
Get PDFThesis advisor: Lisa A. GoodmanThe term “gaslighting” has become increasingly ubiquitous in popular media, from self-help literature to political analysis (Carpenter, 2018; Sarkis, 2018; Stern, 2018). It is also beginning to gain traction in the medical and mental health establishment. For instance, the Centers for Disease Control and Prevention (CDC) now includes gaslighting under its definition of psychological aggression (Breiding, Basile, Smith, Black, & Mahendra, 2015). However, empirical research on this topic lags behind popular discourse. There is desperate need for definition clarity and empirical evidence of this uniquely epistemic form of harm, otherwise the term gaslighting runs the risk of becoming vague, diffuse, and almost meaninglessness. Gaslighting in intimate partner violence (IPV) is the original and paradigmatic case of gaslighting (Cukor, 1944; Hamilton, 2015). A small handful of recent studies have investigated gaslighting in this context, and more general psychological abuse literature has hinted at it by other names (e.g. Bhatti et al., 2021; Ferraro, 2006; Sweet, 2019; Tolman, 1992). However, the present study represents the first systematic, empirical, psychological investigation of gaslighting in IPV. Study aims were to illuminate the tactics, effects, and long-term implications of gaslighting in IPV, as well as ecological factors that may influence survivor experiences. Fifteen IPV survivors were interviewed about their gaslighting experiences, and data were analyzed using qualitative descriptive methods. Three clusters of findings emerged: Survivors described (1) the gaslighting process, (2) their long-term responses to gaslighting, and (3) the influence of ecological factors on self-trust. This study represents a substantial advancement in the literature on gaslighting in IPV, demonstrating the validity of a new two-part model of gaslighting, describing survivors’ subjective experiences of self-doubt, and illuminating how gaslighting fits into broader patterns of power and control in IPV. It also provides the first account of what survivor resistance to gaslighting might look like, and how other factors in survivors’ lives may hinder or promote resistance. Implications for research and practice are discussed in the context of study limitations.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Lynch School of Education.Discipline: Counseling, Developmental and Educational Psychology
Emergency Nurse Efficiency as a Measure of Emergency Nurse Performance:
No full textThesis advisor: Monica O'Reilly-JacobBackground: Emergency department crowding (EDC) is a major issue affecting hospitals in the United States and has devastating consequences, including an increased risk of patient mortality. Solutions to address EDC are traditionally focused on adding resources, including increased nurse staffing ratios. However, these solutions largely ignore the value of the experience and expertise that each nurse possesses and how those attributes can impact patient outcomes. This dissertation uses Benner’s Novice to Expert theory of professional development to describe how individual emergency nurse expertise influences patient length of stay in the emergency department and how it can be part of the strategy in addressing EDC.Purpose: The purpose of this program of research was to identify, articulate, and demonstrate a new approach to emergency nurse performance evaluation that integrates patient outcome data and emergency nurse characteristics.
Methods: First, in a scoping review, we explored the different approaches to measuring nurse performance using patient outcome data and identified common themes. Second, a concept analysis introduced Emergency Nurse Efficiency as a novel framework to understand how emergency nurses can be evaluated using patient outcome data. Finally, a retrospective correlational study established the association between nurse expertise and emergency patient length of stay.
Results: In Chapter Two of this dissertation, the researchers conducted a scoping review of nurse performance metrics and identified twelve articles for inclusion. We identified three themes: the emerging nature of these metrics in the literature, variability in their applications, and performance implications. We further described an opportunity for future researchers to work with nurse leaders and staff nurses to optimize these metrics. In Chapter Three, we performed a concept analysis to introduce a novel metric, called Emergency Nurse Efficiency, that is a measurable attribute that changes as experience is gained and incorporates the positive impact of an individual nurse during a given time while subtracting the negative. Using this measurement to evaluate ED nurse performance could guide staff development, education, and performance improvement initiatives. In Chapter Four, we performed a retrospective correlational analysis and administered an online survey to describe the relationship between individual emergency nurses, and their respective level of expertise, and their patients’ ED LOS. We found that, when accounting for patient-level variables and the influence of the ED physicians, emergency nurses are a statistically significant predictor of their patients’ ED LOS. A higher level of clinical expertise among emergency likely produces a lower ED LOS for their patients, and nurse leaders should seek to better understand these metrics for professional development and quality improvement activities.
Conclusions: This dissertation made substantial knowledge contributions to the literature regarding the evaluation of individual emergency nurses and the influence that they have on patient outcomes. It established, first, that the measurement of individual nurse performance is varied and inconsistent; second, that considering emergency nursing as a team activity similar to professional sports results in a conceptual framework that can evaluate individual performance within a group context; and, third, that there is a relationship between the individual emergency nurse and their patients’ ED LOS, and that relationship can be further understood within Benner’s Novice to Expert theoretical model. We recommend that nurse leaders use these data as part of their strategy to decrease EDC.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Connell School of Nursing.Discipline: Nursing
Using the HVSR, MASW, and Seismic Refraction Analysis Methods to Estimate the Subsurface Seismic Structures of Two Earth Embankment Dams
Get PDFThesis advisor: John E. EbelDegradation within an earth embankment structure is often unobservable from the surface. In order to evaluate the structural integrity of earth embankment dams and levees and identify subsurface zones of weakness that may result in future failures, various geophysical methods have been proposed as effective subsurface imaging tools. This study presents the results of using the horizontal-to-vertical spectral ratio (HVSR), seismic refraction analysis, and multi-channel analysis of surface waves (MASW) methods to estimate subsurface seismic structures for two earth embankment dams located in Chestnut Hill, MA, and Franklin Falls, NH. The estimated seismic velocity structures from the seismic refraction analysis and MASW performed in this study confirm the HVSR method is able to effectively estimate depth to bedrock at sites atop earth embankments using estimated fundamental frequencies. The MASW was found to resolve a low-velocity zone in the subsurface at the Chestnut Hill reservoir embankment that the seismic refraction method was unable to image, and this low-velocity zone is required to best fit a theoretical HVSR to an observed spectrum. Furthermore, the variation and uncertainty in fundamental frequency estimation were investigated by making repeated HVSR measurements at the Chestnut Hill embankment.Thesis (BS) — Boston College, 2023.Submitted to: Boston College. College of Arts and Sciences..Discipline: Departmental Honors.Discipline: Earth and Environmental Sciences
Phenotypic characterization and genetic requirements of Streptococcus pneumoniae biofilms:
No full textThesis advisor: Tim van OpijnenThesis advisor: Michelle MeyerAlthough bacteria are often studied as planktonic or free-living organisms, they frequently grow in complex surface-attached communities known as biofilms. Biofilms are communities of microorganisms attached to surfaces and embedded in a self-produced extracellular matrix. Biofilms are dynamic structures analogous to human settlements shaped by space and environment. These microbial communities fulfill critical roles in multiple infections in the human body. Streptococcuspneumoniae is a human pathogen that can cause biofilm-associated infections in various tissues and organs. This thesis offers a unique outlook for the study of S. pneumoniae biofilms by combining in vitro, genome-wide, and in vivo experiments to elucidate the complex population dynamics of S. pneumoniae biofilms. Existing methods to cultivate S. pneumoniae biofilms fail to fully capture the complexity of these communities, and most studies are limited to short periods of time. We developed a robust in vitro assay to grow S. pneumoniae biofilms. This assay can be maintained forever rather than days. We then use this robust assay to study their behavior in vivo and monitor disease outcomes. After establishing clear differences in biofilm and dispersal samples, we monitor population dynamics using genome-wide techniques (Tn-seq, RNA-seq and WGS) to provide some insights into this complex mode of growth. This work includes the first global identification of genetic requirements during biofilm establishment in two different S. pneumoniae strains using Tn-Seq. Coupled with our transcriptomic analysis, we found that genes involved in multiple pathways, such as capsule biosynthesis, nucleotide metabolism, and stress response, contributed to biofilm growth. Lastly, we studied the development of antibiotic resistance to three different types of antibiotics under S. pneumoniae biofilm conditions. We revealed common adaptive pathways to achieve biofilm growth and antibiotic resistance (antibiotic target genes), as well as novel routes of adaptation to develop resistance. Our findings add to the growing body of knowledge in the field of bacterial genetics and antimicrobial resistance, paving the way for future research and therapeutic advancement.Thesis (PhD) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Biology
Suspended-Sediment Transport in a New Jersey Salt Marsh Tidal Channel:
Get PDFThesis advisor: Noah P. SnyderSalt marshes are hotspots for biodiversity, important carbon sinks, pollutant filtration systems, and buffers which strengthen coastal resiliency. Detailed geomorphic and sedimentary observations are vital to understanding the stability and sustainability of salt marshes in response to sediment placement restoration projects. Marsh stability is dependent on the suspended sediment and nutrients that are delivered to the marsh platform by meandering tidal channels. This study observed suspended-sediment fluxes at the mouth of Southeast Creek on Gull Island at Seven Mile Island Innovation Lab in coastal, southern New Jersey. The mesotidal, almost entirely low marsh, southern Gull Island received a recent dredge placement in fall 2020 of approximately 30,600 cubic meters of sediment from the adjacent New Jersey Intracoastal Waterway. Wetland instrumentation platforms to monitor post-dredge conditions were deployed summer 2021 and were removed in summer 2022. This instrumentation measured current velocity and depth time series at all platforms and suspended-sediment concentration using acoustic backscatter techniques at the mouth of Southeast Creek. This study is motivated by understanding the ongoing transport and deposition of dredged material placed on the marsh island. I found that velocities were ebb-dominant during all conditions. Concentrations on the flood phase of the tide were approximately half the magnitude of those seen on the ebb phases of the tide for normal circumstances while elevated concentrations were observed on ebbing and flooding currents for storms. A net export of 6.27 x 105 kg suspended sediment was observed through the tidal channel for all timescales throughout the deployment period.Thesis (MS) — Boston College, 2023.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Earth and Environmental Sciences
Fihavanana-Friendship: A Norm of Christian Ethics for Life in Madagascar
Get PDFThesis advisor: Daniel J. DalyThesis advisor: James F. KeenanThis thesis examines the concept of Fihavanana in Malagasy morality, characterized by the promotion of life in its fullness. Currently, global and local socio-political crises have resulted in significantly increased violence in Malagasy society. It reviews and examines the concept of Fihavanana through the lens of Christian friendship as expressed in scriptural and Christian tradition. The thesis endeavors to assess and guide the Malagasy response to the loss of social friendship and increase in deadly violence in the nation. It interprets Fihavanana through Christian friendship rooted in charity to arrive at a principle that can be embraced at the national level. Fihavanana thus interpreted is a norm of Christian ethics for life that can shape and guide Malagasy morality to build (re-build) a peaceful and harmonious society.Thesis (STL) — Boston College, 2023.Submitted to: Boston College. School of Theology and Ministry.Discipline: Sacred Theology
The Assurance of Solidarity in the Midst of Suffering and Death: The Theological and Pastoral Significance of the Messages of Kibeho for Healing, Reconciliation and Peacebuilding in Rwanda Today
Get PDFThesis advisor: Margaret Eletta GuiderThesis advisor: O. Ernesto ValienteBeginning in 1990 and lasting for one decade, in Rwanda and the subregion of Africa where Rwanda is located, violence, wars, genocide, and migrations caused various expressions of suffering. It is said that the Blessed Virgin Mary appeared at Kibeho in a sorrowful state almost ten years before and foretold such atrocities and suggested a way out. Failing to pay heed to her prophetic voice, the consequences are devastating and challenging. In the effort to confront such challenges, the Church looks for ways in which she can channel the healing graces needed in the aftermath. Can we talk of the God who heals the broken-hearted in the context of bitter sufferings subsequent to Genocide against the Tutsi? The answer is ‘yes’ and in Rwanda, particularly the Sorrowful Mother and Jesus Christ, give a hint for that possibility. The solidarity shown by them to the suffering people of Rwanda is key to receiving God’s healing and hope in the promises of his Kingdom despite the bitterness of the suffering. Assured of the solidarity of both the Sorrowful Mother and of Jesus Christ, Rwandans can embark on the long yet necessary journey of healing and reconciliation. The Church in Rwanda ought to lead this urgent imperative with an innovative pastoral approach and at the same time propose a preventative endeavor to deter violence and instill harmonious relationships. This process of healing and reconciliation is informed by God’s example who reconciled humanity through the passion, death, and resurrection of his Son. Practices of solidarity, especially wherever sufferings are still felt, should be a priority. Moreover, a peacebuilding project should be an ecclesial initiative and priority for the sake of generations to come.Thesis (STL) — Boston College, 2023.Submitted to: Boston College. School of Theology and Ministry.Discipline: Sacred Theology