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Relationship between maize and groundnut consumption and aflatoxin levels in Nepalese pregnant women eating a rice-dominated diet.
No full textAmerican Society of Nutrition 2018 presentation on Aflatoxin levels in Nepalese pregnant women eating rice dominated diet
Attentional Strategies in Concurrent Visual Search in Pigeons and Humans
No full textAbstract: The strategic allocation of attention is necessary for everyday survival. In order to study attentional processes in a controlled environment, pigeons and humans were given simultaneously available discrimination "tasks" involving two concurrently available orthogonal dimensions in a 32-item visual search display. An equal number of stimuli in the two-dimensional tasks had reinforced and non-reinforced values so participants were either reinforced for selecting the eight brightest (or darkest) stimuli and the eight most vertical (or horizontal) stimuli. Humans preferentially stayed with one dimension before switching to the other, suggesting they used a sequential dimensional strategy. The pigeons did not preferentially stay or switch between the two dimensions on consecutive choices, ignoring the dimensionality of the stimuli and switching between dimensions depending on which item was most discriminable and likely to yield reward. Computational modeling was conducted to analyze the differences in human and pigeon response behaviors.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Psychology.Advisor: Robert Cook.Committee: Robert Cook, Nathan Ward, and Zarin Machanda.Keyword: Experimental psychology
Environmental Effects on Tea Quality
No full textAbstract: Plant-based products are highly complex samples that contain hundreds of volatile secondary metabolites. These natural products are often used as flavoring agents in foods, beverages, and pharmaceuticals and as odorants in cleaning supply, personal care and other consumer products. Plant secondary metabolites play a vial and important role in plant defense and are thought to be response for sensory and nutritional quality of the plant. The composition of plant volatile extracts is affected by plant species, geographical origin, cultivar, plant organ, maturity, and environmental factors, making identification of individual constituents challenging. The complex nature of plant-based products makes it difficult to identify all of the constituents by gas chromatography/mass spectrometry (GC/MS) alone. The work described herein employs automated sequential, multidimensional gas chromatography/mass spectrometry (GC-GC/MS) to obtain a matrix-specific retention time/index and mass spectrometry database. Once the targeted metabolite database is produced, it can be used with spectral deconvolution and mass spectral subtraction of routine GC/MS data to reveal untargeted metabolites, providing an efficient, reliable, and unambiguous means to identify all constituents. Specifically, metabolites were used to track how climate variations affected teas harvested in Yunnan and Fujian Province in China. Striking differences in concentration were observed in response to elevational, seasonal, and yearly differences. In addition, a field-practical volatile sample collection method was developed to measure plant response to environmental stress in situ.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Chemistry.Advisor: Albert Robbat Jr..Committee: Charles Mace, Samuel Kounaves, and Christopher LaFratta.Keywords: Analytical chemistry, Food science, and Climate change
Neuronal Exosomal miR-124 Regulation of Glutamate Uptake
No full textAbstract: Exosomes have been recently touted as a novel form of intracellular communication, and of great excitement as there may be variability of the types of cells that release exosomes, exosomal contents, and the specificity of the recipient cells, particularly in disease states. This combined with the possibility that exosomes can be secreted from central nervous system tissues into the cerebrospinal fluid or blood in the periphery suggests that exosomes may also be examined for insight into dysregulation of the host tissue. However, from the myriad of studies observing altered exosomal content in disease states, we remain unable to determine the exosomal host cell or the functional implications of their altered cargo. One of the few studies successfully aimed to answer these questions was published prior to my tenure in the Yang Lab, where authors observed that neurons release a high abundance of microRNA-124, of which is capable of upregulating glutamate transporter expression in astrocytes. The purpose of my thesis has been to further investigate this mechanism, and determine if it is altered in a neurological disease state. In my first publication, my colleagues and I have characterized a novel cre-dependent CD63-eGFP transgenic mouse, which allowed us to observe extracellular vesicle behavior for the first time in vivo. We show that neurons release an abundance of exosomes which are internalized into glia, and that these exosomes contain distinct microRNA profiles. Compellingly, we found that blockade of exosome biogenesis led to a reduction of glutamate transporter expression in astrocytes, mediated in part by the loss of neuronally-delivered miR-124. I further characterized a mechanism where miR-124 inhibits the expression of downstream microRNAs miR-132 and miR-218, both of which inhibit GLT1 protein expression. Utilizing our now-characterized CD63-eGFP mouse, I was then able to explore this miR-124-mediated mechanism in a mouse model for amyotrophic lateral sclerosis (ALS), SOD1G93A for my second publication. I found increased association of miR-124 with CD63-eGFP, suggesting that miR-124 is increasingly packaged into extracellular vesicles released from diseased SOD1G93A motor neurons. I found that indeed, there is also a loss of miR-124 expression from diseased motor neurons, as well as increased secretion of miR-124 into astrocytes. However, examination of SOD1G93A astrocytes treated with a miR-124 mimic revealed that while there is increased internalization of miR-124 into astrocytes in vivo, miR-124 is incapable of restoring GLT1 protein expression. Taken together, these two bodies of work provide ample characterization of our CD63-eGFP transgenic mouse, which will allow the scientific community to further investigate the role of extracellular vesicles in vivo. I have also shown that neuronal exosomal miR-124 is necessary for maintaining appropriate levels of GLT1 in non-diseased tissue, as well as that this mechanism is perturbed in an ALS disease state, potentially participating in ALS disease pathology.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Cell, Molecular & Developmental Biology.Advisor: Yongjie Yang.Committee: Rob Jackson, Peter Juo, and Larry Feig.Keywords: Neurosciences, Molecular biology, and Developmental biology
“Here, You Try Something”: Shifting Positioning and Engineering Engagement in a Fifth-Grade Classroom.
No full textA qualifying paper submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Education. Abstract: Students’ interactional positions entwine with their learning and engagement in engineering. Classroom studies suggest that students’ positions influence their engagement and opportunities to learn in a variety of disciplines. This study explores the intersections of students’ positions with their engineering engagement. Within the context of a university-led outreach program in a fifth-grade classroom, I consider shifts in two students’ engineering positions and corresponding shifts in their engineering engagement. Positioning can impact students’ learning by influencing their enactment of practices of a discipline; students’ positions shape what students expect and are expected to do in their classrooms and thus influence what students will do in learning activities. In the case presented in this paper, as one student shifted from spectator to contributor positions, she began to engage in engineering; conversely, as she shifted from contributor to spectator positions, no engagement was perceptible. This study contributes to understandings of the ways in which students are positioned and position themselves in classroom engineering activities and the affordances and limitations of this positioning. This work reinforces findings in mathematics and science education that positioning corresponds with disciplinary engagement and suggests that positioning within engineering could impact engineering learning
Effect of exercise and nutritional supplementation on health-related quality of life and mood in older adults: the VIVE2 randomized controlled trial.
No full textBackground: Health-related quality of life (HRQoL) and absence of depressive symptoms are of great importance for older people, which may be achieved through lifestyle interventions, e.g., exercise and nutrition interventions. The aim of this investigation was to analyze the effects of a physical activity program in combination with protein supplementation on HRQoL and depressive symptoms in community-dwelling, mobility-limited older adults.Keywords: Physical activity, Nutritional supplementation, Health-related quality of life, Depressive symptoms.Springer Open
RETRACTED ARTICLE: Detangling PPI networks to uncover functionally meaningful clusters.
No full textBackground: Decomposing a protein-protein interaction network (PPI network) into non-overlapping clusters or communities, sometimes called "network modules," is an important way to explore functional roles of sets of genes. When the method to accomplish this decomposition is solely based on purely graph-theoretic measures of the interconnection structure of the network, this is often called unsupervised clustering or community detection. In this study, we compare unsupervised computational methods for decomposing a PPI network into non-overlapping modules. A method is preferred if it results in a large proportion of nodes being assigned to functionally meaningful modules, as measured by functional enrichment over terms from the Gene Ontology (GO).Keywords: PPI networks, Protein function prediction, Community detection, Diffusion state distance.Springer Open
Performance Analysis of Key Facial Recognition Algorithm.
No full textThis project seeks to analyze the performance of modern day facial recognition algorithms on non-conventional images, such as sketches and thermal. Submitted in partial fulfillment of the grant requirement of the Tufts Summer Scholars Program
Pilot testing of agricultural technologies: uptake and impacts on diet diversity in Bangladesh.
No full textThis presentation was from 6th Annual scientific Symposium in Nepal
Real Time Information Management of Nutrition Intervention in earthquake affected 14 priority districts of Nepal including data collection with customized REMO system.
No full textThis poster shows the support real time data collection and visualization through dashboard, of emergency nutrition interventions