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The Nuclear Crisis: A North Korean Conflict Map.
No full textStudents in Tufts PJS150-5 Conflict Resolution (Spring 2018, Professor Amanda Donahoe) worked in small groups write a collaborative research paper, called a 'conflict map' in which they select and analyze a current world conflict and make an argument for a course of resolution. This conflict map analyzes the North Korean nuclear conflict
Ethical and Institutional Review Boards.
No full textThis presentation was given at First National Workshop in Nepal
Development and testing of a novel survey to assess Stakeholder-driven Community Diffusion of childhood obesity prevention efforts.
No full textBackground: Involving groups of community stakeholders (e.g., steering committees) to lead community-wide health interventions appears to support multiple outcomes ranging from policy and systems change to individual biology. While numerous tools are available to measure stakeholder characteristics, many lack detail on reliability and validity, are not context specific, and may not be sensitive enough to capture change over time. This study describes the development and reliability of a novel survey to measure Stakeholder-driven Community Diffusion via assessment of stakeholders' social networks, knowledge, and engagement about childhood obesity prevention.Keywords: Community-based interventions, Community engagement, Childhood obesity prevention, Survey development.Springer Open
The Development of Novel Model Systems and Imaging Techniques to Advance the Understanding of Calcific Aortic Valve Disease
No full textAbstract: As a leading cause of cardiovascular morbidity and mortality, calcific aortic valve disease (CAVD) is responsible for significant health and cost burden around the world. While valve replacement surgery can improve quality of life and increase life expectancy, it is not without risks and costs. However, this is currently the only method available to treat CAVD since a lack of understanding surrounding the disease mechanisms has hindered the development of pharmaceutical interventions. In order to improve our understanding of valve stenosis and calcification, in the hopes of expanding the range of treatment methods for CAVD, we study several aspects of the disease and have developed an imaging method that non-destructively captures mineralization in tissues and in vitro culture. Stenosis and calcification of valve tissue is accompanied by significant changes to the extracellular matrix (ECM) structure and composition. To discern how these variations in ECM could affect valve interstitial cells (VICs) - the most abundant cell type in valve tissue - we developed both in vitro and in vivo model systems. A 2D, polyacrylamide (PAAM) gel-based cell culture platform showed that hyaluronic acid (HA), an ECM protein found in large abundance in the aortic valve, increased VIC mineralization, but that effect could be mitigated through siRNA knockdown of the HA binding protein CD44. We also developed a Tie2-cre mediated conditional knockout (cKO) of the retinoblastoma protein (pRb) in a mouse model which, compared to control mice, showed increased aortic valve stenosis with age. Significant alterations to the valve leaflet ECM organization and protein composition (as measured by proteomics analysis) were also seen in cKO pRb mice leading to the conclusion that this mouse model may be a useful system for studying CAVD. To further visualize changes to aortic valve tissue, we also developed a novel imaging technique that used endogenous two-photon excited fluorescence signal from calcific nodules to measure mineralization content. We termed this the mineralization associated fluorescence (MAF). MAF as a quantitative measure of calcification was confirmed using human and mouse valve tissue, rat bone, and the 2D PAAM gel in vitro model system. Interestingly, time lapse imaging of our in vitro cell culture platform allowed us to measure calcific nodule growth in real time. During the course of the experiment, we noted varying rates of development and growth rates of mineralization which further emphasizes the variability that can occur during valve calcification. Lastly, to further the understanding of the effect ECM proteins can have on valve mineralization, we created a methacrylated hyaluronic acid (MeHA)-based 3D model. To investigate cell response, we can incorporate ECM proteins, identified through the transcriptomic approach of RNA sequencing, into the MeHA gels. Utilizing VICs, we can evaluate the effect of MeHA gel composition on mineralization over time. Using the non-destructive imaging approach that we developed, as well as other nonlinear microscopy techniques, we can track calcification and cell response. Overall, the research described in this thesis highlights the importance of taking a multipronged approach to further the understanding of CAVD with the goal of developing more effective treatment methods.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Biomedical Engineering.Advisor: Lauren Black.Committee: Elena Aikawa, Irene Georgakoudi, Philip Hinds, and Gordon Huggins.Keyword: Biomedical engineering
Brief Deceptive Rainbows: Cultural Memory in Productions of Tennessee Williams's The Glass Menagerie, A Streetcar Named Desire, and Cat on a Hot Tin Roof
No full textAbstract: My dissertation offers an interdisciplinary framework to rethink production histories of The Glass Menagerie, A Streetcar Named Desire, and Cat on a Hot Tin Roof. I focus my study on twelve productions, four of each play, that demonstrate the gap between embodied memories from the productions and normative evaluation, to recover the role of minoritarian identity ignored and erased by traditional criticism and scholarship. To foster this questioning, I develop the term production counter-history. In these production counter-histories, I adapt concepts from memory studies in order to rethink the normative form of production histories by integrating overlooked evidence about oppressed identity. By adapting concepts from memory studies, I foreground the role of memory in shaping the differences in how theatrical practitioners and scholars remember productions of Tennessee Williams's most popular plays.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Drama.Advisor: Noe Montez.Committee: Heather Nathans, Kareem Khubchandani, and Annette Saddik.Keywords: Theater, Gender studies, and Theater history
Characterization of the Influence of Thermal Profile on Microstructural Development in a Eutectic Cobalt Silicon Alloy
No full textAbstract: The purpose of this study is to develop a new image processing technique to evaluate decanted structures of undercooled alloys. Dendrite growth theory reveals a trend of decreasing dendrite radii as undercooling levels increases and a similar decreasing trend with increasing convection rates at lower undercoolings. Experiments were performed to evaluate if optical microscopy could be used to quantify decanted surface structures following rapid solidification of eutectic CoSi62 at% alloys. Dendrite diameters decrease with increasing undercooling except for tests conducted with applied stirring at low undercoolings. The higher the convection, the greater the deviation. Marangoni stirring was induced by irradiating a small target area on the surface of levitated molten samples. For a 0.5W laser input, the characteristic diameter was half the unstirred value. For 2.4 W laser input this factor drops to one third. The developed imaging technique was able to produce these trends when identifying the primary phases.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Mechanical Engineering.Advisor: Douglas Matson.Committee: Luisa Chiesa, and Darryl Williams.Keyword: Mechanical engineering
Novel Methods for Assessing Exposures and Health Effects of Ultrafine Particles and Nitrogen Oxides
No full textAbstract: Long-term exposure to traffic-related air pollution (TRAP) is associated with cardiovascular morbidity and mortality. The impact of the smallest size fraction of particulate matter, ultrafine particulate matter (UFP, measured as particle number concentration or PNC) is less well-established. Only one study examined the joint effects of PNC and gaseous components of TRAP. We considered these effects within the prospective Boston Puerto Rican Health Study (BPRHS; n=902 participants in Chelsea and Boston, Massachusetts). We assessed spatial and temporal factors affecting the distribution and covariation of PNC and nitrogen oxides (NOx). We found higher correlations in times and locations where traffic-related sources have greater impact. We developed a land use regression model to predict NOx concentrations at <200-m and 1-h resolution in Chelsea and Boston for 2003-2015 using data from a mobile platform and a fixed site. The model was stable with two cross-validation methods and predicted concentrations at three validation sites (adjusted-R2=0.53-0.62). Using the NOx model and a previously developed PNC model, we estimated participants' annual average exposures to both pollutants. We tested the independent and joint effects of long-term exposure to PNC and NOx on blood pressure and a biomarker of systemic inflammation (C-reactive protein). We found limited evidence that the pollutants affect diastolic blood pressure but the associations with each of the outcomes were inconsistent. Effect modification was observed by sex, smoking, and baseline hypertension status. To understand how PNC affects cardiovascular outcomes, we investigated the use of an instrument for a mediator to test mechanistic hypotheses within observational studies. We tested the impact of violations of the strong assumptions of this method in a simulation study. The method was more robust against confounding of the instrument-outcome relationship than the presence of instrument-outcome paths independent of the mediator. To improve exposure assessment of PNC, we measured the population-specific age-, sex-, weight-, and physical activity-adjusted minute respiratory volumes for a population like the BPRHS population. These values were applied to our previously developed exposure metric, the particle inhalation rate (PIR). The population-specific values did not change the PIR or health effect estimates. Our PIR algorithm is generalizable to diverse populations.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Civil Engineering.Advisor: David Gute.Committee: Doug Brugge, John Durant, Jon Levy, and Mark Woodin.Keywords: Environmental health, Epidemiology, and Environmental science
Novel Approaches to Manufacturing Membranes with Controlled Selectivity
No full textAbstract: Membrane separation processes are energy-efficient, green and easy to implement. They are used in a wide array of applications from waste water treatment to pharmaceuticals to food industries. However, these established applications are mostly constrained to separations based on a size sieving mechanism. Moreover, there are only a handful of membrane chemistries on the market, further limiting their applications. In this dissertation, these two problems are addressed by utilizing new approaches. First, chemoselective membranes are fabricated by self-assembly of random copolymer micelles, a simple and scalable method. This copolymer self-assembles during coating to form a structure with interconnected 1-2 nm nanochannels, lined with functional groups. The nanoconfinement along with chemical functionality leads to high separation efficiency of small organic molecules. In addition, the high porosity of the membrane selective layer leads to high permeability. Initially, this approach was used to prepare membranes to separate a mixture of two solute with similar size, but different charge in both diffusion and pressure-driven filtration experiments. The membranes exhibited unprecedented charge-based selectivity for small molecules that was further enhanced in competitive experiments. This effect is similar to that observed in biological pores such as ion channels, implying novel selective transport mechanisms. Next, these membranes were modified to address a more complex separation of small molecules based on their aromaticity. A simple and straightforward conjugation chemistry was used to convert the carboxylate groups in the pores to aromatic groups. The permeation selectivity of these membranes for separation of two steroid hormones of similar size and charge was examined. Selectivity was linked with the interactions of these solutes with functional groups on the membrane surface, measured using quartz crystal microbalance with dissipation (QCM-D), which provides a significant insight into separation mechanism. The functionalized membrane showed exceptionally high selectivity for the aromatic solute in competitive diffusion experiments. This, in combination with additional results, imply a hopping transport mechanism. In another direction, a novel method to fabricate of membranes with a wide range of monomer chemistries in a simple and scalable manner, interfacially initiated free radical polymerization (IIFRP), is presented. We developed this method and exploited the applicability of this method for fabrication of ultrathin hydrogel selective layers and its application for protein purification. Membrane performance can be tuned by experimental parameters such as UV irradiation time, monomer concentration, and the addition of porogen or functional comonomers. The results illustrate successful fabrication of uniform, defect-free and ultrathin hydrogel layers whose dry thickness varies by UV irradiation time. The hydrogel membranes are efficient and stable with excellent antifouling properties, and suitable for protein purification. Overall, the results presented in this dissertation illustrate simple, robust and scalable approaches for fabrication of selective membranes for various targeted separations. Both methods can have a broad impact in various areas from pharmaceuticals, drug delivery, sensors, barrier materials to water filtration or gas purification.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Chemical and Biological Engineering.Advisor: Ayse Asatekin.Committee: Hyunmin Yi, Iryna Zenyuk, and William Phillip.Keywords: Polymer chemistry, Nanoscience, and Materials Science
Near-infrared spectroscopy and mathematical modeling for the characterization of human cerebral hemodynamics in the microvasculature
No full textAbstract: Near-infrared spectroscopy (NIRS), in combination with coherent hemodynamics spectroscopy (CHS), provides information about the cerebral microvasculature in terms of cerebral blood flow, cerebral blood volume, and the cerebral metabolic rate of oxygen. We characterize the frequency-dependent relationship between tissue concentrations of oxyhemoglobin and deoxyhemoglobin, measured with NIRS, as well as the relationship between total hemoglobin concentration and arterial blood pressure in healthy subjects. We use the hemodynamic model of CHS for the analysis of the results to yield physiologic parameters such as absolute cerebral blood flow and cerebral autoregulation. Further, we demonstrate the application of NIRS-CHS in the clinical setting of the neurocritical care unit.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Biomedical Engineering.Advisor: Sergio Fantini.Committee: Irene Georgakoudi, Brian Tracey, and Joshua Kornbluth.Keyword: Biomedical engineering
Zambian Luvale Ngoma: Timbre, Voice, and Rhythm
No full textAbstract: This thesis aims to introduce the music and instruments of the Zambian Luvale percussion ensemble through an analysis of timbre, vocal behavior, and rhythm. I hope to address a lacuna in academia as little scholarship has been dedicated to Luvale drumming and the music of Zambia. I situate Luvale percussion in its larger contextual setting and begin to explain how it is musically organized and performed. My ethnographically informed approach reveals how an emic attention to timbre helps shape the music and explains choices in technique and tuning, layering, and rhythmic play. My organization of vocal behavior demonstrates how both intensity and dance are vocally manipulated. In my analysis of rhythm in one item of repertory, Chiyanda, I examine how motility is rhythmically generated and uncover the complexity of supporting instruments' parts. Ultimately I provide an account that reveals both the breadth and depth of Luvale percussion while simultaneously providing a case study for the interrelatedness of different musical elements.Thesis (M.A.)--Tufts University, 2018.Submitted to the Dept. of Music.Advisor: David Locke.Committee: David Locke, Jeffrey Summit, and Steven Friedson.Keywords: Music, Music theory, and African studies