Steroid sulfatase (STS) is considered to be one of the key enzymes contributing to the development of breast cancer. It catalyzes the hydrolysis of inactive sulfated steroids such as estrone sulfate (ES) to inorganic sulfate active steroids such as estrone (E1), a precursor to estradiol (E2), a key stimulator for breast cancer development. Inhibitors of STS are currently being pursued in both academia and industry as potential drugs for treating breast cancer. A series of 4-substituted estrone and estradiol derivatives were examined as inhibitors of STS. Inhibition of STS with 4-FE1, an irreversible inhibitor of STS previously studied in the Taylor group, can be enhanced by introducing a hydrophobic benzyl group at the 17-positon of 4-FE1. As with 4-FE1, the inhibition was concentration and time-dependent. Only 14% of the activity could be recovered after extensive dialysis. Introducing substituents at the 2-position of 4-formyl estrogen derivatives resulted in loss of concentration and time-dependent inhibition and a considerable decrease in inhibitor affinity. Studies with estrogen derivatives substituted at the 4-position with groups other than a formyl revealed that a relatively good reversible inhibitor can be obtained simply by introducing an electron withdrawing group at this position. These types of inhibitors are non-competitive inhibitors suggesting an alternative steroid binding site. A series of estrone derivatives were examined as photoaffinity labels of STS. 4-azidoestrone suflate and 4-azidoestrone phosphate exhibited properties that are suitable for photoaffinity labeling studies with STS. These labels may be useful for ascertaining pathways of substrate entry into the STS active site. 16-diazoestrone phosphate was not a photoaffinity label of STS. 2- and 4-azido estrone and 16-diazoestrone all acted as photoaffinity labels of STS. These compounds may be useful for ascertaining pathways of product release from the STS active site.

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Steroid sulfatase (STS) is considered to be one of the key enzymes contributing to the development of breast cancer. It catalyzes the hydrolysis of inactive sulfated steroids such as estrone sulfate (ES) to inorganic sulfate active steroids such as estrone (E1), a precursor to estradiol (E2), a key stimulator for breast cancer development. Inhibitors of STS are currently being pursued in both academia and industry as potential drugs for treating breast cancer. A series of 4-substituted estrone and estradiol derivatives were examined as inhibitors of STS. Inhibition of STS with 4-FE1, an irreversible inhibitor of STS previously studied in the Taylor group, can be enhanced by introducing a hydrophobic benzyl group at the 17-positon of 4-FE1. As with 4-FE1, the inhibition was concentration and time-dependent. Only 14% of the activity could be recovered after extensive dialysis. Introducing substituents at the 2-position of 4-formyl estrogen derivatives resulted in loss of concentration and time-dependent inhibition and a considerable decrease in inhibitor affinity. Studies with estrogen derivatives substituted at the 4-position with groups other than a formyl revealed that a relatively good reversible inhibitor can be obtained simply by introducing an electron withdrawing group at this position. These types of inhibitors are non-competitive inhibitors suggesting an alternative steroid binding site. A series of estrone derivatives were examined as photoaffinity labels of STS. 4-azidoestrone suflate and 4-azidoestrone phosphate exhibited properties that are suitable for photoaffinity labeling studies with STS. These labels may be useful for ascertaining pathways of substrate entry into the STS active site. 16-diazoestrone phosphate was not a photoaffinity label of STS. 2- and 4-azido estrone and 16-diazoestrone all acted as photoaffinity labels of STS. These compounds may be useful for ascertaining pathways of product release from the STS active site.

This thesis investigates self-tracking practices of users of MyFitnessPal calorie counting app. The thesis researches everyday self-trackers users who have started using the app on their own and are not part of any self-tracking community and focuses on the practices of self-tracking. The thesis responds to the literature on self-tracking that has often neglected everyday self-trackers and practices of self-tracking. First, many studies, whether sociological investigations or human-computer interaction research, focus on members of Quantified Self (QS) community (Choe, Lee, Lee, Pratt, & Kientz, 2014; Li, Dey, & Forlizzi, 2010; Neff & Nafus, 2015; Sharon & Zandbergen, 2016). QS is a community of individuals who are interested in learning more about themselves through, oftentimes unusual and complex, self-tracking, which involves modification of existing technologies or even creation of new ones. Thus, focusing on QS members neglects the individual everyday self-trackers, their experiences and practices. Second, existing studies have mainly focused on health or social implications of self-tracking (Lupton, 2012b, 2013d, 2014a, Swan, 2012b, 2013). These include, but are not limited to, potential of self-tracking to assist diagnosis (Wile, Ranawaya, & Kiss, 2014), or behaviour change (Chiauzzi, Rodarte, & Dasmahapatra, 2015), self-tracking increasing surveillance, public pedagogy (Rich & Miah, 2014) and subjection to neoliberal values and promotion of healthism (Lupton, 2012b, 2013a) or leading to monetisation of exercise (Till, 2014). While these studies have yielded important insights, they do not help us to understand what people actually do when they self-track, i.e. what practices self-tracking involves and how people engaged in self-tracking manage them. Guided by the STS approach that highlights the importance of observing the mundane practices and need to focus on technology users, this thesis explores the practices of everyday self-trackers. The exploration of the practices of self-tracking among the everyday self-trackers is based on 31 interviews with early mid-life individuals, who were mainly recruited from gyms and shared their self-tracking experience of using the MyFitnessPal calorie counting app. The analytical chapters answer three questions: What is self-tracking by calorie counting in the everyday like? How is self-tracking by calorie counting done? What are the practices through which self-tracking affects those engaged in it? To answer the first question, I juxtapose self-tracking goals, use and effects as they are represented in the literature on the QS to those of my participants. Doing this reveals that self-tracking in the everyday is perceived and done quite differently than the QS metaphor would allow us to believe. The goals of the participants are mundane (weight loss), they do not use the sophisticated features of the app and are not interested in the historical data, the effects of the app are not life-changing and temporary closely tied to the use of the app. This stands in contrast to QS metaphor where self-tracking is geared towards continuous self-improvement, driven by intricate data analysis and biohacking. To answer the second question, I focus on self-tracking by calorie counting with MyFitnessPal as a dieting practice. I explore how self-tracking affects the daily practices as well as is incorporated in participants lives. The users, thus, aim to find an approach to temporal aspects of tracking and precision that would fit most conveniently with their other daily practices. They manipulate their use of the app to accommodate any meals that are not in their usual dieting routine. This highlights that dieting through self-tracking is not a straightforward data collection and involves practical strategies and negotiations, and can both influence and be influenced by other everyday practices. The third question focuses on quantification, that is the production and communication of numbers (W. N. Espeland & Stevens, 2008, p. 402). Quantification has usually been discussed at institutional levels, in terms of government, science or, in the case of Espeland and Sauder s (W. N. Espeland & Sauder, 2007) seminal work, in terms of academic rankings. I adopt the insights from these studies to make sense of the quantification at the individual level using MyFitnessPal. I draw out two features of individual quantification that distinguish it from institutional one, mainly that quantification is done for oneself only and it relies on self-governance. Further, I outline how quantification affects such decisions as whether to eat, what to eat and how much to eat. Quantification also works as commensuration as participants compared different foods referring to their calorie value. However, unlike in the case of institutional quantification, individual quantification did not have to be accepted unquestionably and often other values of food would be weighted in relation to calories when participants made choices what to eat. Ultimately, this thesis contributes a new perspective on self-tracking as it explores the mundanity of it. It adds fine-grained insights into the everyday practices of self-tracking by adopting a novel analytical angle that centres on practices and by exploring a neglected user group of everyday self-trackers.

This thesis is focused on adsorption of phthalocyanines on tin and indium passivated silicon Si(111) surfaces with the √3 × √3 reconstruction at room temperature. Scanning tunneling microscopy was used for obtaining atomically resolved surface images. Molecules on these surfaces predominantly adsorb on Si-substitutional defects. Local density of states (LDOS) of strongly adsorbed molecules was obtained by scanning tunneling spectroscopy. The origin of fuzzy imaging of molecules sitting on Si-substitutional double defects was probed. Voltage dependence of mean lifetime of two observed states, between which the "fuzzy" molecule is switching, was measured by analysis of tunneling current fluctuations. We discussed the influence of external parameters on the switching between the two states. We attribute the fuzzy behaviour of the molecule and resulting tunneling current fluctuations to the motion of the molecule in a double-well potential and propose two most likely kinds of the motion which most closely agree with the obtained data.

This dissertation will have three chapters. In chapter one, a comprehensive review on defects in two dimensional materials will be presented. The aim of this review is to elaborate on different types of defects in two dimensional (2D) materials like graphene and transition metal dichalcogenides (TMDs). First, different types of point and line defects, e.g. vacancies, anti-sites, guest elements, adatoms, vacancy clusters, grain boundaries, and edges, in these materials are categorized in terms of structure. Second, interactions among defects are discussed in terms of their rearrangement for low-energy configurations. Before studying the electronic and magnetic properties of defective 2D materials, some of the structures are considered in order to see how defect structure evolves to a stable defect configuration. Next, the influence of defects on electronic and magnetic properties of 2D materials is discussed. Finally, the dynamic behavior of defects and 2D structures under conditions such as electron beam irradiation, heat treatment, and ambient conditions, is discussed. Later as a case study, defects in a two dimensional transition metal dichalcogenide will be presented. Among two-dimensional (2D) transition metal dichalcogenides (TMDs), platinum diselenide (PtSe2) stands at a unique place in the sense that it undergoes a phase transition from type-II Dirac semimetal to indirect-gap semiconductor as thickness decreases. Defects in 2D TMDs are ubiquitous and play crucial roles in understanding and tuning electronic, optical, and magnetic properties. Here intrinsic point defects in ultrathin 1T-PtSe2 layers grown on mica were investigated through the chemical vapor transport (CVT) method, using scanning tunneling microscopy and spectroscopy (STM/STS) and first-principles calculations. Five types of distinct defects were observed from STM topography images and the local density of states of the defects were obtained. By combining the STM results with first-principles calculations, the types and characteristics of these defects were identified, which are Pt vacancies at the topmost and next monolayers, Se vacancies in the topmost monolayer, and Se antisites at Pt sites within the topmost monolayer. Our study shows that the Se antisite defects are the most abundant with the lowest formation energy in a Se-rich growth condition, in contrast to cases of 2D molybdenum disulfide (MoS2) family. Our findings would provide critical insight into tuning of carrier mobility, charge carrier relaxation, and electron-hole recombination rates by defect engineering or varying growth condition in few-layer 1T-PtSe2 and other related 2D materials. Also, in order to investigate the layer dependency of vibrational and electronic properties of two dimensional materials, 2M-WS2 material was selected. Raman spectroscopy and DFT calculation proved that all Raman active modes have a downshift when material is thinned to few layers (less than 5 layers). It was proven that there is a strong interaction between layers such that by decreasing the number of layers, the downshift in Raman active modes is mostly for the ones which belong to out-of-plane atomic movements and the most downshift is for the Ag2 Raman active mode. Also, I investigated the effect of number of layers on the band structure and electronic properties of this material. As the number of layers decreases, band gap does not change until the materials is thinned down to only a single monolayer. For a single monolayer of 2M-WS2, there is an indirect band gap of 0.05eV; however, with applying in-plane strain to this monolayer, the material takes a metallic behavior as the strain goes beyond ±1%. / Doctor of Philosophy / Graphite (consisting of graphene as building blocks) and TMDS in bulk form are layered and with exfoliation one can reach to few layers which is called two-dimension. Two dimensional materials like graphene have been used in researches vastly due to their unique properties, e.g. high carrier mobility, and tunable electronic properties. Transition metal dichalcogenides (TMDs) with a general formula of MX2, where M represents transition metal elements (groups 4-10) and X represents chalcogen elements (S, Se or Te), are another family of two-dimensional materials which have been extensively studied in the past few years. Besides exfoliation, there are also synthesis methods to produce two dimensional materials, e.g. chemical vapor deposition and chemical vapor transport. Normally, after synthesizing these materials, researchers investigate structure and electronic properties of these materials. There might be some atoms which no longer exist in the structure; hence, those are replaced by either vacancies or other elements which all of them are called defects. In chapter 1, defects in graphene and transition metal dichacolgenides were investigated, carefully. Later, dynamic behavior of defects in these materials were investigated and finally, the effect of defects on the electronic properties of the two dimensional materials were investigated. Chapter two talks about a case study which is two dimensional 1T-PtSe2. In this chapter, 5 different kinds of defects were studied using scanning tunneling microscopy and spectroscopy investigations and density functional theory was used to prove our assumptions of the origin of defects. Also, another thing which is investigated by researcher is that how atoms in two dimensional materials vibrate and how the number of layers in the two dimensional material influences vibrations of atoms. Other than this, electronic properties of these materials is dependent upon the number of layers. When these materials are synthesized, there is a stress applied to the material due the mismatch between the material and its substrate, so it is worth investigating the effect of stress (strain) on the structure, and electronic properties of the material of interest. For this purpose, 2M-WS2 was exfoliated on Si/SiO2 substrate and the layer dependency of its vibrational modes was investigated using Raman spectroscopy and density functional theory calculation. Also, in order to investigate the influence of stress (strain) on the electronic properties of two dimensional 2M-WS2, a single monolayer of this materials underwent a series of strains in density functional theory calculations and the effect of strain on the electronic properties of this material was investigated.

This dissertation is a study of groundwork in Engaged Science, Technology, and Society (STS) research. Engaged STS scholars reframe STS knowledge and move it beyond the traditional scope and boundaries of the field. They use various methods such as critical participation, making and doing, situated interventions, and experimentation to critically engage with their fields of study. These scholars have evaluated their work within the context of the disciplinary outsider, described their use of high-level pragmatic frameworks, and used the arts to bring critical social issues to the public eye. Yet, when I decided to use STS engagement methods to bring visibility to the lesser-known communities in the Bradley Department of Electrical and Computer Engineering (ECE) at Virginia Tech, I found a lack of work documenting the groundwork and experience of engagement. I could not locate groundwork regarding negotiation, designing the most appropriate intervention, collaboration strategies, or confronting my fears and doubts about being in the field. Therefore, in this dissertation, I identify and examine my engagement experience in three interventions within the ECE department to bring visibility to the groundwork of STS engagement. The limited-series podcast Engineering Visibility was a platform to bring visibility to the less dominant communities in the ECE department. Highlighting the experiences of women in engineering, the first-generation student, inclusion and diversity, and the non-traditional student fostered a shared identity and sense of belonging within the ECE department. On the ground, this project examined the need to protect participants' visibility through invisibility. Interventionist Protectivity conceptualizes how I combined trust, accountability, and social awareness to protect my participants' from social scrutiny. The second project was a seminar titled "Expand Your ECE Career." The seminar exposed students to a "broader range of careers" by challenging the traditional ideas of success. The seminar featured four ECE alumni with successful careers in law, finance, and fashion entrepreneurship. Additionally, this intervention pointed out the inadequacies of traditional forms of project assessment. I describe how I measured intervention success through other assessment methods such as "assessment per mobility." The last project was a data-driven white paper that translated the care work of the undergraduate academic career advisors and framed it to be understood by the ECE faculty. The care work done by the academic advisors was underappreciated in its connection to undergraduate student success. On the ground, I discussed the importance of identifying the advisors and the faculty's social construction to create an intervention that translated the advisors' work to be valued by the faculty. Lastly, I conclude with a discussion summarizing the overall lessons learned from the three interventions and discussing my experience of engagement. My engaged STS experience is discussed through my framing of the concept of self-confrontation and the work of avoiding the term of STS being deemed as useful. / Doctor of Philosophy / This dissertation is a study of groundwork in engaged Science, Technology, and Society (STS) research. Recent advances such as critical participation, making and doing, and situated intervention are reframing boundaries between knowledge and action in STS, offering scholars new approaches for improving scientific and technological communities. When I attempted to utilize these theories and methods in a culture change project, however, I found a lack of scholarship documenting the experience of engagement. How does one design the most appropriate intervention? What strategies are required to collaborate and negotiate? How do engaged scholars confront their fears and doubts in their communities and concerning the knowledge they bring back to STS? These groundwork questions confront both novice and seasoned STS scholars and are crucial to successful engaged scholarship, but they rarely are documented and analyzed. Utilizing a matters-of-care framework and self-reflective methods, I describe how and why I sought to change the culture of a large engineering department by making visible unseen and sometimes under-appreciated stakeholders. To do so, I created three interventions: a limited-series podcast to showcase the diversity of experiences in the department, an alternative-career seminar to redefine what counted as success in engineering, and a data-driven white paper to showcase the indispensable care work of academic advisors. I analyzed these projects' construction, application, and outcomes to highlight the complexities and significance of groundwork for STS engagement.

Damming is one of the most high-profile forms of human intervention in the environment, and it is commonly found across the modern Korean landscape. Since the 1960s, under the name of "Comprehensive Water Resources Development," South Korean state engineers have constructed more than a dozen large multi-purpose dams on rivers in the nation. The prevailing Korean narrative tends to regard the surge of large dam-building as the outcome of modern state authority. Rather than granting all agency to the state, this dissertation shifts focus to newly emerged water experts who rationalized the damming of the nation. These new experts with backgrounds in civil engineering embraced hydrology as part of their research agenda to lead a comprehensive dam construction plan from a perspective of national water circulation. By examining the work of these experts, I demonstrate that river engineering became crucial for Korean engineers to position themselves in the developing nation that stood between the colonial legacy on the one side and American hegemony on the other. By utilizing both colonial data and Western development models, hydrological engineers quantified rivers, a process that compressed complex understandings of and interactions with unruly rivers into a singular vision—rivers as a manageable national resource. This conceptual and physical infrastructure naturalized a form of life dedicated to industrial South Korea while marginalizing social and cultural lives in rural areas. I ultimately argue that the modern dammed riverscape of the nation is the product of engineers' precarious and contested efforts to build their own professional identities and research programs in developing South Korea. This contextualization of river engineering allows us to examine the violence of river engineering not just from a lens of top-down state authority but from compromises, contestations, and negotiations over the legitimate forms of rivers, modern South Korea, and how they are related. / Doctor of Philosophy / Damming is one of the most visible forms of human intervention in the environment, and it is commonly found across the modern Korean landscape. Since the 1960s, under the name of "Comprehensive Water Resources Development," South Korean state engineers have constructed more than a dozen large multi-purpose dams on rivers in the nation. The prevailing Korean narrative tends to regard the surge of large dam-building as the outcome of modern state authority. Rather than granting all agency to the state, this dissertation shifts focus to newly emerged water experts who rationalized the damming of the nation. These new experts with backgrounds in civil engineering embraced hydrology as part of their research agenda to lead a comprehensive dam construction plan from a perspective of national water circulation. By examining the work of these experts, I demonstrate that river engineering became crucial for Korean engineers to position themselves in the developing nation that stood between the colonial legacy on the one side and American hegemony on the other. By utilizing both colonial data and Western development models, hydrological engineers quantified rivers, a process that compressed complex understandings of and interactions with unruly rivers into a singular vision—rivers as a manageable national resource. This conceptual and physical infrastructure naturalized a form of life dedicated to industrial South Korea while marginalizing social and cultural lives in rural areas. This historical investigation of river engineering shows that the current riverscape and its violence in modern South Korea are the products of compromises, contestations, and negotiations over the legitimate forms of rivers, modern South Korea, and how they are related.

Culture frames what an institution values, reveres, and rewards. It emerges over an extended period, sometimes deliberately, often indirectly. As a subset of organizational culture, a common understanding of both data and culture is needed in order to build the data culture the Army desires. This study examines data culture within the context of the US Army and its interactions with data science over the past six decades. It uses Science and Technology Studies (STS) scholarship to analyze Army data culture from the perspectives of leadership, expertise, technology, and structure and practices to better understand how it can be shaped to better support the Army's goals. This study posits that rather than adopting a data culture as something entirely new, the Army would be better served by an understanding of the data culture it already has, made up of entrenched policy and operational approaches perpetuated over decades, some of which are unsuitable for the current and future environment. A second posit is that Army data culture is situated within a broader context and cannot be understood independently of the external cultures and social systems with which it interacts. And third, STS scholarship is uniquely suited to inform this type of analysis. I conclude that the Army should focus resources on educating leaders on how to assess, build and sustain positive data cultures in their organizations. / Doctor of Philosophy / Culture frames what an institution values, reveres, and rewards. It emerges over an extended period, sometimes deliberately, often indirectly. As a subset of organizational culture, a common understanding of both data and culture is needed in order to build the data culture the Army desires. This study examines data culture within the context of the US Army and its interactions with data science over the past six decades. It uses Science and Technology Studies (STS) scholarship to analyze Army data culture from the perspectives of leadership, expertise, technology, and structure and practices to better understand how it can be shaped to better support the Army's goals. This study posits that rather than adopting a data culture as something entirely new, the Army would be better served by an understanding of the data culture it already has, made up of entrenched policy and operational approaches perpetuated over decades, some of which are unsuitable for the current and future environment. A second posit is that Army data culture is situated within a broader context and cannot be understood independently of the external cultures and social systems with which it interacts. And third, STS scholarship is uniquely suited to inform this type of analysis. I conclude that the Army should focus resources on educating leaders on how to assess, build and sustain positive data cultures in their organizations.