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Transcriptome analysis of pig intestinal cell monolayers infected with Cryptosporidium parvum asexual stages.
No full textBackground: Human cryptosporidiosis is caused primarily by two species of apicomplexan protozoa, Cryptosporidium parvum and C. hominis. In cultured cell monolayers, the parasite undergoes two generations of asexual multiplication (merogony). However, the proportion of parasites completing the life-cycle is low and insufficient to sustain continuous propagation. Due to the intracellular location of meronts and later life-cycle stages, oocyst and sporozoites are the only forms of the parasite that can readily be isolated.Keywords: Transcriptome, Cryptosporidium parvum, Sus scrofa, RNA-Seq.Springer Open
Establishing the Malawian Food Composition database: Where are we?.
No full textThis presentation was given at USAID Administrative Representative visit to Malawi.Original file name: Malawi_foodcomp_Updated _USAID_Rep March 28_SVM_
Environmental Enteric Dysfunction, Aflatoxin Exposure, and Poor Growth Outcomes During the First 1,000 Days in Uganda
No full textAbstract: Background: Stunting remains a pervasive form of undernutrition globally, affecting ~155 million children < 5 years of age. Growth failure frequently begins in utero and continues until at least 24 months of life (called the "first 1,000 days"), after which time its effects are largely irreversible. While inadequate diets and diarrheal disease are commonly cited as immediate determinants, they fail to explain much of the burden. Meanwhile, less is known about the role of chronic, asymptomatic gastrointestinal inflammation (environmental enteric dysfunction, or EED) and/or aflatoxin (AF) exposure during the first 1,000 days and their implications for poor child growth. Objectives: The goal of this PhD thesis was to examine the associations among EED, AF exposure, and poor growth outcomes during the first 1,000 days in Uganda. Specifically, the objective of aim #1 was to examine the associations among poor household drinking water quality, EED, and poor growth outcomes in children 12-16 months of age living in rural southwestern Uganda. The objective of aims #2 and #3 were to examine the association between EED biomarkers (aim #2) and AF exposure (aim #3) in pregnant women aged 18-45 and subsequent adverse birth outcomes in Mukono District, Uganda. Methods: For aim #1, we conducted a cross-sectional, observational study within a longitudinal birth cohort study. A lactulose: mannitol (L:M) test was performed on 385 children ages 12-16 months living in 7 sub-counties of southwestern Uganda. Water quality data were obtained using a compartment bag test, and safe water was defined as water lacking E. coli contamination. Data on child anthropometry and covariates were extracted from an existing birth cohort study. For aims #2 and #3, we conducted a prospective cohort study in Mukono, Uganda with a sample of 258 pregnant women who were enrolled at their first prenatal visit. We measured maternal EED biomarkers, namely L:M ratios and serum anti-flagellin and anti-lipopolysaccharide (LPS) antibodies, as well as maternal aflatoxin B1 (AFB1) concentrations. Data on maternal anthropometry and covariates were obtained at enrollment and 3 weeks prior to participants' estimated date of delivery. For all aims, statistical analyses were conducted using STATA 15 software and results were obtained from multivariate linear regression models. Results: Aim #1: Children from households with safe drinking water had significantly lower mean ln L:M ratios (0.23-point difference, 95% CI: 0.09, 0.38) and significantly higher length-for-age (LAZ) (β: 0.34, 95% CI: 0.07, 0.61) and weight-for-age (WAZ) (β: 0.24, 95% CI: 0.10, 0.38) Z-scores at 12-16 months of age. Additionally, children with higher LAZ at 6 and 9 months had significantly lower ln L:M ratios at 12-16 months of age (β: -0.06, 95% CI: -0.13, 0.00 and β: -0.05, 95% CI: -0.10, -0.001, respectively). Aim #2 and #3: Higher concentrations of maternal anti-flagellin IgG and anti-LPS IgG were significantly associated with shorter length of gestation [(β: -1.35, 95% CI: -2.64, -0.07) and (β: -0.89 [95% CI: -1.52, -0.25)] and with lower length at birth [(β: -0.97, 95% CI: -1.79, -0.14) and (β: -0.45, 95% CI: -0.87, -0.02)] and lower LAZ at in infants at birth [(β -0.52, 95% CI: -0.95, -0.08) and (β: -0.25, 95% CI: -0.48, -0.03)]. Furthermore, elevations in maternal ln AFB1 levels were associated with lower weight (β: -0.07; 95% CI: -0.13, -0.002), lower WAZ (β: -0.16; 95% CI: -0.30, -0.03), smaller head circumference (β: -0.27; 95% CI: -0.51, -0.03), and lower head circumference-for-age Z-score (HCZ) (β: -0.23; 95% CI: -0.41, -0.04) in infants at birth. Conclusions: Maternal and child EED and AF exposure were associated with significant decreases in growth at birth, infancy, and early childhood. Efforts to improve nutrition and reduce stunting may be enhanced by simultaneously addressing EED and AF exposure.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Food Policy & Applied Nutrition.Advisor: Shibani Ghosh.Committee: Lynne Ausman, Christopher Duggan, Jeffrey Griffiths, and Patrick Webb.Keywords: Nutrition, and Public health
Treatment of Recessions with Acellular Dermal Matrix in Thick and Thin Biotype Populations
No full textAbstract: ABSTRACT Aim and Hypothesis: Gingival recession is a common periodontal defect where lost gingival attachment on tooth surface results in exposed dentin and predisposes patients to dentin sensitivity, esthetic concerns and root caries. Recession repair is often treated using connective tissue graft (CTG), however availability of donor tissue may limit the number of teeth treated with CTG during surgery. To bypass limitations of donor tissue availability, acellular dermal matrix (ADM) is introduced as a substitute. Literature shows predictable root coverage in using ADM as a substitute for CTG in recession therapy. However, literature reporting long-term outcome is scarce. The present controlled clinical trial aims to investigate the impact of periodontal biotypes on the healing of root coverage procedures performed with ADM H: Level of root coverage in Miller class I or class II defects using CAF + ADM is different in patients with thick biotype compared to patients with thin biotype. Materials and Methods: 10 patients with thick (gingival thickness ≥0.8mm) and 9 with thin biotypes (gingival thickness <0.8mm), each with Miller class I or II defects involving two adjacent teeth. Coronally positioned flaps were advanced over ADM and exposed roots. Stents were made to standardize reference points for measuring recession height (RH) and width (RW), keratinized tissue width (KTW), probing depth (PD), gingival thickness (GT) and clinical attachment level (CAL) at baseline, three, six, and twelve month follow-up visits (FUVs). Repeated measures ANOVA and Friedman's test were used to detect within-group changes, whereas independent samples t-test and Mann-Whitney U test were used for between-group comparisons. Results: Both groups achieved statistically significant reduction in RH from baseline to 3, 6 and 12 month follow (TkB: RHBL=2.68±0.49mm, RH3MO= -0.14±1.63mm, RH6MO=-0.13±1.95mm, RH12MO=0.10±0.99mm; TnB: RHBL=2.63±0.41mm, RH3MO=0.16±1.25, RH6MO=0.79±1.13mm, RH12MO=0.39±0.83mm, p<0.01), but no statistically significant change is observed in between the FUVs during the healing period. Similar reduction in CAL and RW from baseline to all FUVs is observed in both biotypes, but no statistically significant change is observed in between each FUVs. %RC (TkB: %RC6MO=106.46±42.75%, %RC12MO=97.11±33.2%; TnB: %RC6MO=68.18±44.93%, %RC12MO=85.01±28.83%), RH reduction and KTW among the FUVs were statistically not significant. Between group comparison revealed that differences in RH, %RC, CAL, RW and PD were statistically not significant. Increase in GT were statistically significant at the 3-month FUV (p<0.0083) for both groups (TkB: GTBL= 0.96±0.08mm, GT3MO=1.66±0.28mm, GT6MO=1.27±0.16mm, GT12MO=1.12±0.49mm; TnB: GTBL=0.57±0.12mm, GT3MO=1.13±0.28mm, GT6MO=0.91±0.15mm, GT3MO=1.02±0.44mm). At the following FUVs, significant reduction in GT was detected in the TkB group from baseline to 3 month and 6 month FUV (p=0.01). Between thick and thin biotype, statistically significant differences were found for GT at all time points except at 12-month. Conclusions: At 12 month follow up, clinical measurements suggest that no significant difference in outcome is present in between thick and thin biotype treated with CAF + ADM. Both groups achieved statistically significant reduction in recession height, recession width and percent root coverage with no statistically significant difference between the two biotypes. RES assessment confirms similar aesthetic outcome in both groups at 12 month follow up, further confirming the results of from clinical measurement.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Periodontology.Advisor: Wai Cheung.Keyword: Dentistry
DSMB Training Manual.
No full textKeywords: Clinical Trials Data Monitoring Committees, Clinical Trials as Topic, Data and Safety Monitoring Board, Data and Safety Monitoring Committee, Data Monitoring Committee, DSMB, DSMC, Manuals as Topic, SafetyVersion 1.0Editors: M.E. Blair Holbein, Barbara N. Hammack, Tamsin A. Knox, Laurel Yasko.Reviewers: Paul Beninger, Lori Carter-Edwards
Measuring the Impacts of Cooperative Participation on Vanilla Farmers in Madagascar
No full textAbstract: This paper examines the effects of cooperative participation, and the bundle of benefits the cooperative offers, on various household indicators for vanilla farmers in rural Madagascar. The primary benefits of the cooperative are access to zero interest seasonal credit, collective price bargaining, increased security from crop theft, environmental education, and a bonus payment made after the conclusion of the vanilla market. Using a difference in differences approach to compare vanilla farmers who chose to participate in the cooperative to vanilla farmers who chose not to participate, I find that take up of high interest informal loans is significantly reduced for cooperative participants. Similarly, I find that cooperative participants receive higher vanilla prices on average and see a significant reduction in price dispersion. Some of this price increase can be attributed to the fact that farmers no longer accept high interest informal seasonal loans but collective bargaining and transparent markets cannot be ruled out. Surprisingly however, I find a decrease in vanilla production, a decrease in total cash crop income, and a decrease in coffee production for farmers who enter the cooperative. Based on focus groups held during the data collection phase of this study, these decreases could be driven by cooperative members increased entrepreneurial investments in the non-agricultural sectors or side selling to buyers outside of the cooperative, but more research is required to confirm this hypothesis. Most interestingly however, I find differential treatment effects for women for almost all outcome variables with most negative results coming from male cooperative members. Similarly, differential effects were found for different age groups, and across different villages, which suggests cooperative programs could be modified to meet specific needs.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Urban and Environmental Policy and Planning.Advisors: Kyle Emerick, and Mary Davis.Keywords: Environmental economics, and Economics
A Gap Analysis of an Internet of Things Education Toolkit for Undergraduate Students
No full textAbstract: National Instruments (NI), a company that produces automated test equipment and virtual instrumentation software, and PTC, a computer and software technology company, partnered with Tufts University to develop an Internet of Things (IoT) platform for undergraduate engineering students. Through interviews with five engineering students, interviews with two developers of the platform, and usability tests with eight other participants in Tufts University's College of Engineering, I use a gap analysis approach to outline the shortcomings in five aspects of the platform that prevented novice users from quickly developing and/or understanding the IoT data systems. These areas include how students approached the getting started process, using the online dashboard, debugging, adding complexity, and sharing data. Errors, mistakes, and misunderstandings from the usability tests largely revolved around the amount of LabVIEW experience the users had. My analysis suggests future iterations of this toolkit so students can develop solutions more successfully and efficiently.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Mechanical Engineering.Advisor: Chris Rogers.Committee: Daniel Hannon, Fred Visser, and Chris Rogers.Keyword: Mechanical engineering
Novel X-Ray Imaging Techniques for Ex-Situ and Operando Study of Polymer Electrolyte Fuel Cells
No full textAbstract: Polymer electrolyte fuel cells are a promising clean alternative to conventional internal combustion engines for transportation applications. Among the issues preventing full-scale commercialization are the high cost of platinum (Pt), transport losses associated with ionomer distribution in the catalyst layer, and management of the water which is produced as a by-product of the fuel cell reaction. The morphology of the catalyst layer plays an important role in the aforementioned challenges. X-ray computed tomography (CT) is an ideal way to study this morphology as it is non-destructive and can resolve structures on both the micro- and nano-scales. Presented here is a novel way to image Pt and ionomer in catalyst layers using cesium staining and x-ray absorption near edge spectroscopy (XANES). Additionally, this work focuses on overcoming barriers in operando hardware design for synchrotron x-ray imaging, focusing on both micro- and nano-scales, which will help explain the interplay between morphology and transport processes, as well as water management. The fuel cells presented here show significant promise, as they can combine the study of electrochemical performance with that of water distribution in fuel cell components during operation.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Mechanical Engineering.Advisor: Iryna Zenyuk.Committee: Marc Hodes, and Matthew Panzer.Keywords: Mechanical engineering, and Energy
The Massachusetts Commercial Food Waste Disposal Ban: A Case Study of the Effectiveness and Implementation of the Ban and the Waste Stream for Colleges and Universities
No full textAbstract: This thesis assesses the effectiveness and implementation process of Massachusetts' Commercial Food Waste Ban, with particular emphasis on the influence of the ban on the waste generated by colleges and universities. This thesis considers the ban's overall effectiveness in increasing food waste diversion, the large-scale benefits to society as a result of the ban, and its influence on a particular category of waste generation. It reviews academic literature as well as government and nonprofit reports on food waste, data on waste generation and diversion in Massachusetts, and analyzes stakeholder interviews. The waste stream for colleges and universities is highlighted through four case studies with colleges and universities of different sizes, locations, and management of dining operations. Since the implementation of the ban, the amount of food waste diverted in the state has increased, as has the infrastructure to support diversion, successes that can partly be attributed to the long stakeholder process as part of developing the ban. Colleges and universities throughout Massachusetts have not necessarily adopted food waste diversion practices since 2014, when the ban was made effective, as many institutions throughout Massachusetts began implementing diversion practices well before the ban was officially enacted. The results of the ban have however provided resources to support further development of food waste reduction and diversion goals at the college and university level and have benefited some stakeholders in the processing of food waste. The main areas for improvement are to increase resources for enforcement of the ban to ensure that generators out of compliance are aware of their behavior and can take the steps to rectify their actions, better understand the impact of the ban on other categories of food waste generators, particularly those in the food processing, manufacturing, and distribution sectors, and to assess the role of source reduction in complying with the ban.Thesis (M.A.)--Tufts University, 2018.Submitted to the Dept. of Urban and Environmental Policy and Planning.Advisor: Penn Loh.Committee: Timothy Griffin.Keywords: Public policy, and Agriculture
Against Form: Figural Excess and the Negative Democratic Impulse in American Literature
No full textAbstract: Against Form addresses the necessity of form as well as form's inevitable exclusions and violence. Moving between art and politics, Against Form shows how both literature and democracy depend on acts of representation through which various "parts" are organized to appear as a whole, whether a political community or a narrative structure. Yet the figures—bodies, tropes—on which representation depends are more dynamic than any configuration deems possible, for any represented form necessarily fixes and regulates their movements in a particular way. "Figurality" names the excess and lack that haunt every act of representation, and by following figural excess, I foreground the democratic potential of literature's egalitarian aesthetics, through which voices, bodies, or scenes excluded from official representation are able to appear in a way that disturbs the order of things. Of course, exclusions and instabilities manifest in any political or aesthetic system of representation—even those aiming for equality. In politics as in art, you always leave something (or someone) out, and you always say more than you intend. Both politics and art can therefore stage a misunderstanding or disagreement between two parts: the part that counts and the part that does not. The texts in Against Form always force a confrontation—and a misunderstanding—between incommensurable regimes. Drawing on the work of Jacques Rancière and Jacques Lacan, I show how the democratic operation in politics and art disturbs the fantasy of a seamless totality.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of English.Advisor: Lee Edelman.Committee: Lisa Lowe, Priscilla Wald, and Nathan Woolf.Keywords: American literature, and Literature