3948 research outputs found
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Development and applications of noncanonical amino acid-targeted click chemistries:
No full textThesis advisor: Abhishek ChatterjeeThis dissertation explores the development and applications of bioorthogonal chemistries, particularly focusing on genetically encoded methods for site-specific protein modification. Advances in genetic code expansion (GCE), such as the development of efficient aminoacyl tRNA synthetase (aaRS) enzymes, enable the incorporation of noncanonical amino acids (ncAAs) with bioorthogonal handles into proteins, allowing precise chemical modifications with diverse applications in basic biological research and therapeutic development. Here, I present new methodologies for chemoselective modification at encoded 5-hydroxytryptophan (5HTP) residues under mild oxidative conditions. I demonstrate that such reactions allow up to three distinct modifications at a single protein residue, facilitating the creation of functional multicomponent bioconjugates. This work also explores the use of our aaRS enzymes in nascent proteome tracking, allowing cell-type-specific labeling and time-resolved tracking of newly synthesized proteins in complex biological systems. Further, I demonstrate that genetically encoded biosynthesis and proteome-wide incorporation of 5HTP allows selective enrichment from mixed bacterial and mammalian environments when using our mild oxidative conditions to label the residues. These new bioorthogonal chemistries and enzymes for their proteomic incorporation enable the creation of antibody-drug conjugates, protein-protein conjugates, and enable access to new methods of nascent proteome labelling and enrichment.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry
Thyroid hormone-informed patterning and remembered positional identity direct zebrafish fin ray morphology:
No full textThesis advisor: Sarah K. McMenaminThesis advisor: Eric FolkerResolving the mechanisms that orchestrate patterning in complex tissues – particularly how positional identity is instantiated, remembered, and directed – is imperative to understanding the morphogenesis of appendages. The zebrafish (Danio rerio) caudal fin skeleton is a powerful model to investigate these questions, as its precisely patterned bony fin rays are restored through regeneration. My aims in this thesis were to investigate the role of endocrine metabolic regulator thyroid hormone (TH) signaling during fin ray morphogenesis and how spatial identity is retained and redeployed during regeneration. I began my work by resolving TH signaling effects on the fin skeleton. Through nuclear receptor Thrab, TH acutely induces distal features in both development and regeneration (Chapter 2). To better understand how distal features are remembered, I established novel microsurgery techniques that would discriminate autonomous versus environmental components of ray patterning. While the rate of regeneration does appear to retain positional memory, I found ray patterning is instead informed by extrinsic cues (Chapter 3). During my investigation of TH activity in Chapter 2, I noted robust TH signaling in peripheral rays. Repurposing the microsurgeries developed in Chapter 3, I discovered this TH signaling is an inherent feature of peripheral rays, and this activity regulates local Notch pathway signaling (Chapter 4). My research has revealed many mechanisms—both dependent and independent of TH—that regulate fin ray patterning and how this positional identity is retained and redeployed during regeneration.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Biology
TheLaw Is a Shadow: The Anti-Marcionite Tradition of Reading Psalm 118
No full textThesis advisor: Brian P. DunkleThe reception of the Mosaic Law was a source of perplexity for ancient Christians. The New Testament cites several of the laws set forth in the Books of Exodus, Leviticus, Numbers, and Deuteronomy (Mt 5:27, Lk 10:25-27, and 1 Cor 9:9-10). Yet the New Testament also suggests that the Mosaic legislation has been mitigated or abrogated (Acts 10, Rom 7:14, and Heb 10:1). Justin Martyr and Irenaeus of Lyon recount second century debates with Marcionites and Valentinians concerning the status of the Mosaic Law in ancient Christianity. This dissertation analyzes how similar debates played out in third and fourth-century interpretations of Psalm 118, an alphabetical acrostic whose 176 verses praise God’s laws (νόμος), commandments (ἐντολή), ordinances (δικαίωμα), testimonies (μαρτύριον), and judgments (κρίμα). Judith Lieu’s question – “Whose Marcion?” – provides a critical point of departure for this study, which focuses on how patristic authors conceptualized and attacked their own conceptions of “Marcion,” rather than on Marcion as an historical figure. Thus, Origen’s extant fragments from his commentary on Psalm 118, the earliest that survives, should be read within the context of his anti-Marcionite, Caesarean, exegetical homilies on the Books of Exodus, Leviticus, and Numbers. Using hermeneutical methods that systematize his attacks on Marcion, Origen inaugurated the anti- Marcionite tradition of interpretating Psalm 118 by emphasizing the figurative interpretation of the Mosaic Law, God’s role in teaching it, and the possibility of spiritual progress through understanding and acting on it. Origen, drawing on Philo of Alexandria’s figurative interpretations of the Pentateuch, responds to the Marcionite challenge by describing the contemplation of the Mosaic Law as a foundation for Christian ethics. During the fourth century, two western bishops – Hilary of Poitiers and Ambrose of Milan – received and developed Origen’s anti-Marcionite interpretation of Psalm 118. This study argues that both Hilary and Ambrose retain the anti-Marcionite orientation of Origen’s commentary and respond to the emergent threat posed by the Manichaeans, who in turn received and developed the Marcionites’ antinomian challenge. Hilary builds on Origen’s exegesis of Psalm 118 by describing divine law as a remedy for infirmitas. Hilary’s Tractatus on Psalm 118 recapitulates the main themes of Origen’s interpretation while giving greater emphasis to themes of theological anthropology. Rather than contemplation, Hilary calls for “exercise” (μελέτη/exercitiō) in the law as a means of Christian formation. Unlike his predecessors, Ambrose explicitly attacks Marcion in his Expositio on Psalm 118, unveiling the anti-heretical bearings of the tradition inaugurated by Origen. Ambrose comments on Psalm 118 within the liturgical context of offering post-baptismal catechesis to neophytes. Ambrose builds on Origen’s exegesis of Psalm 118 by describing David – the author of the Psalter – as an exemplary exegete of the figurative sense of the Mosaic Law. For the benefit of the neophytes, Ambrose contrasts David’s understanding of the Mosaic Law with the misunderstandings of the Marcionites, Manichaeans, and Jews. This study shows that the anti-Marcionite tradition of commenting on Psalm 118 was ultimately overshadowed in the fifth century and afterwards by Augustine’s anti-Pelagian Enarratio in Psalmum 118. Yet the anti- Marcionite tradition – which teaches Christians to read and profit spiritually from the Mosaic Law – is worthy of recovery.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Theology
Speaking of Sisterhood: An Intersectional Exploration of College Students' Perceptions of Women's Health Discussions as Acts of Feminist Solidarity
No full textThesis advisor: C. Shawn McGuffeyThis study examines the conversations female college students have surrounding women’s health and how these interactions may be perceived as a form of feminist solidarity. Previous research has provided many definitions to the term “feminist solidarity” and has shown the effectiveness of friendships in accessing sexual and reproductive healthcare. For this study, 17 undergraduate students at a Jesuit university were interviewed and asked questions relating to feminist solidarity, peer interactions, and experiences surrounding conversations about birth control, abortion, and menstruation. To allow for the analysis of how feminist discourse differs between women of different races, the women were separated into focus groups by race (White, Black, and Asian). The findings supported literature about a feminist solidarity which is rooted in collective action and literature which has shown how friendships are important sources of reproductive and sexual health advice. Moreover, the identity of Asian and Black women were found to be key factors in how they engaged with and perceived feminism. In particular, the experiences of Asian women in this study have contributed to filling the information gap regarding the navigation of feminism and women’s health by women of Asian descent.Thesis (BA) — Boston College, 2024.Submitted to: Boston College. Morrissey School of Arts and Sciences.Discipline: Sociology.Discipline: Departmental Honors
Between Silence and Cheer: Illuminating the Freedoms and Frictions of Youth Reading Across Difference in a Middle Grade Classroom
No full textThesis advisor: Jon M. WargoThesis advisor: Patrick ProctorBook banning has exploded in recent years. Conflicts over what texts belong in schools have caused rifts in communities around the nation. Within English language arts (ELA) classrooms specifically, many teachers have been under scrutiny with local groups and national organizations demanding that some teachers be monitored, fired, or even arrested. Backdropped by this socio-historical moment wherein calls for book censorship and attacks against school teachers are commonplace, this three-article dissertation joins the growing scholarship that explores the challenges that arise when teachers and students dare to address topics of race, racism, gender, and sexuality in the ELA classroom. Designed as an ethnographic case study, this dissertation explores how one White ELA teacher and her sixth-grade students engaged with two regularly banned novels in a racially, culturally, and linguistically diverse classroom. The first paper employs critical Whiteness theory to examine the challenges, opportunities, and contextual factors that one White novice teacher encountered as she employed an antiracist approach to literature instruction. It offers a structural understanding of why so many White teachers attempt but fall short of delivering antiracist pedagogy effectively. The second paper traces how three students of Color in the class negotiated their emotions during conversations about race as it emerged within a literature unit. Using critical discourse analysis, I examine how language was mobilized to invite some emotions (e.g., surprise) and inhibit others (e.g., anger), manifesting as “emotional rules” that regulated students' responses to texts. The third paper examines how two LGBTQ+ youths engaged in literacy not only as a medium for identity work, but as a way to speak back to the social, political, and institutional contexts of their schooling. Placing the theatrical performances that queer youth wrote and directed at the center of my analysis, I submit that these literacy activities are a means of understanding how youth see themselves in the world. Taken together, these articles extend the scholarship on how teachers engage their students on issues of difference through literature, raising important questions about how sociopolitical tensions take shape through moments of silence and cheer in the ELA classroom.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Lynch School of Education.Discipline: Teaching, Curriculum, and Society
Political Theology in Origen of Alexandria:
No full textThesis advisor: David G. HunterThesis advisor: Samuel FernándezOrigen of Alexandria (ca. 185–253) produced a comprehensive theological narrative of salvation history, from protology to eschatology, based on his interpretation of Scripture. More than one “plotline” is being developed throughout Origen’s unique rendition or performance of the Christian drama of salvation history. The primary goal of this dissertation is to bring the political dimension of Origen’s theological narrative into focus. To this end, it examines the constitutive elements of political thought in Late Antiquity—community, justice, and rulership—as thematic loci within Origen’s theological narrative. By tracking Origen’s development of this political plotline, from beginning to end, this dissertation provides the first systematic treatment of what may be called Origen’s “political theology.” This dissertation also provides an original study of how the political language, models, and themes of Scripture were received into Origen’s theology (e.g., the “Kingdom” and “City” of God, as well as the Pauline “rulers, powers, and authorities”). Within this political framework, Origen discusses the following: (1) the form and method of God’s rulership, (2) the compatibility of the creation’s freedom and its subjection to God’s rulership, (3) the arrangement of creatures into a cosmic hierarchy of rulers and ruled, (4) the justice of God’s rulership, (5) Christ as the form or archetype of Justice, (6) Christ’s restoration of both ruling and obedience within the created order, and (7) the realization of a divine πολιτεία. These are the main topics considered in this study.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Theology
Towards Holistic Evaluation of Education Systems: Using TIMSS 2023 Context Data to Classify Schools by School Climate Health
No full textThesis advisor: Matthias von DavierChildren internationally are entitled to quality education. International education initiatives monitor education system quality through complex evaluations, historically relying on academic benchmarks operationalized by robust comparative achievement data. However, quality in schooling is evolving to comprise development beyond academic abilities – it should support emotional, social, and psychological development. Valid systems-level evaluations of these features internationally require well-defined benchmarks for school conditions suitably supportive of this development. Emerging international initiatives, such as UNESCO’s Happy Schools Framework, define frameworks for non-academic facets but have not been empirically tested. This study defines school climate health as the intersection of the Happy Schools Framework, existing literature on school climate and wellbeing, and the Trends in International Mathematics and Science (TIMSS) Context Questionnaire. This research aims to provide a first step towards defining benchmarks by exploring an international dataset to define existing patterns of interrelated school context variables. This study is responsive to empirical literature and relevant theoretical frameworks for evaluating social systems (systems evaluation, ecological systems theories). An exploratory multilevel latent class analysis (MLCA) of 22 variables is conducted for the 58 participating countries to define four school clusters and three country classes defining the composition and distribution of school climate health internationally. Combining response variables from students, teachers, principals, and parents is a novel application. Characteristics of each school cluster and country class are described. Secondary analyses investigate possible confoundedness of school demographics and possible relationships between school-level average achievement.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Lynch School of Education.Discipline: Education
Development of 1,4-Azaborine-Derived Biaryl Phosphine Ligands with P-central and Axial Chirality:
No full textThesis advisor: Shih-Yuan LiuNew P-central and axially chiral 1,4-azaborine-derived biaryl phosphine Senphos ligand were designed and synthesized. The separation of diastereomers and enantiomers of those ligands was achieved through preparative recycling HPLC, and the separation efficiency was increased via the use of a borane protecting group. The effect of solvents and diamine ligands in enantioselective ligand synthesis was examined. The absolute configuration of the key enantiomer was confirmed via X-ray crystallography analysis. The catalytic performance of these newly synthesized ligands was evaluated through several benchmark reactions, demonstrating their potential in enantioselective catalysis.Thesis (MS) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry
Particulate Organic Carbon Flux in the Subpolar North Atlantic as Informed by Bio-Optical Data from the Ocean Observatories Initiative:
No full textThesis advisor: Hilary I. PalevskyThe biological carbon pump in the North Atlantic Ocean is powered by the annual spring phytoplankton bloom. These primary producers use inorganic carbon in the surface oceans and convert it into organic carbon, a fraction of which is exported out of the surface mixed layer and sequestered at depth. Determining the rate of carbon flux below the maximum winter mixed layer depth, driving sequestration on annual or longer timescales, is critical to understanding the North Atlantic carbon cycle.To constrain daily-to-annual scale changes in carbon export in the subpolar North Atlantic, I analyzed seven years of daily optical backscatter depth profiles (200-2600 m) collected from the subsurface profiler mooring at the Ocean Observatories Initiative (OOI)’s Global Irminger Sea Array from September 2014 to May 2021. This is the longest-running time series of daily, year-round optical backscatter profiles that has been collected in this region, providing novel opportunities to assess seasonal and interannual variations in particulate organic carbon (POC) flux to depth. This analysis, focused on large particles and aggregates identified from optical backscatter spikes, shows annual pulses of sinking particles initiating in May to June during each year of our seven-year time series, consistent with these export pulses being driven by organic matter production during the spring
phytoplankton bloom. These pulses of particles sink through the water column at rates ranging from 10 and 30 meters per day, and though particle concentration attenuates through the water column due to remineralization, coherent large particle pulses generally extend deeper than 1500 m, the deepest maximum annual mixed layer depth over this period. Although deep winter mixing in this region requires sinking particles to penetrate much deeper than in other parts of the ocean to be sequestered long-term, pulses of large particles consistently penetrate to below even the deepest annual mixed layer depths in the region, highlighting the importance of these large particle pulses to carbon sequestration at depth in the subpolar North Atlantic.Thesis (MS) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Earth and Environmental Sciences
Situating Freedom: A Study of Hegel's Philosophy of History and Theory of the State
No full textThesis advisor: Paul T. WilfordThis dissertation is an inquiry into Hegel’s account of the modern constitutional state. In particular, it traces Hegel’s understanding of its historical genesis, theoretical foundations, and sustaining conditions. Chapter one begins with an examination of the presuppositions, method, and structure of Hegel’s philosophy of history, which provides the anthropological and historical framework that underpins his political thought. Hegel argues that the human is a rationally reflective, socially embedded, historically self-transformative being, whose nature can only be fully realized through intersubjective recognition under norms that affirm the inherent dignity and equality of human beings. Seeking to uncover the logic that has been at work within history, he portrays it as a “progress in the consciousness of freedom” that is driven by the search for a form of intelligibility and a corresponding socio-political order in which the human being can be fully at home in the world. Chapters two and three reconstruct Hegel’s account of this historical development, which proceeds through a series of ethical-political orders that each instantiate a distinct image of the human and the divine. This development culminates in the production of institutional conditions that allow for the full recognition of human freedom: the emergence of a universal notion of right, the affirmation of individual moral autonomy, and the creation of modern constitutional nation-states. Chapter four turns to Hegel’s conception of the political order that best realizes modern notions of justice and freedom. While Hegel fully affirms and embraces a notion of the individual as a rights-bearing and morally autonomous agent, he contends that a philosophically adequate conception of freedom must account for the historically-formed institutions that realize freedom by making it concrete. His conception of ethical life portrays the modern individual as the creation of specific institutional configurations, shared normative commitments, habits, and mores that bind a community together and produce a "second nature.” Hegel thereby provides a conception of political community that integrates the historical, social, and cultural conditions that nourish and sustain modern liberal institutions and their underlying aspirations. The dissertation concludes with a critical juxtaposition between Hegel’s and Carl Schmitt’s judgements of liberalism in an attempt to reflect upon the enduring tensions within the modern constitutional state.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Political Science