349 research outputs found

    Assessing the Awareness of Lead Hazards in the Greater Burlington Area

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    Introduction. Lead is a heavy metal found in and around homes built before 1978, comprising more than 80% of the housing stock in Chittenden County, Vermont. Lead exposure during infancy and childhood can have deleterious effects on development. Our study assessed baseline community understanding of potential household lead hazards in Chittenden County, Vermont. Methods.. 123 paper, 10-question surveys were randomly administered to Chittenden County, VT residents to assess recognition of lead toxicology symptoms and awareness of lead safety programs. Scores were treated as continuous variables, demographically grouped, and analyzed using non-parametric statistical analysis (Mann-Whitney & Kruskal-Wallis). Individual questions were treated as dichotomous variables, demographically grouped and analyzed using chi-squared testing. Results.. 48% of survey participants understood the interaction between ADHD and lead or knew the importance of window maintenance. 54.5% were aware of the Burlington Lead Program\u27s assistance program. Participants earning less than $60,000 and those with less than a graduate degree scored statistically lower (p Conclusion.. Lesser-known lead poisoning symptoms and home interventions that decrease lead exposure should be emphasized to the community. High-risk groups requiring targeted education include those who rent, have lower income and education levels. Primary care providers could serve a larger role in educating patients. Additional efforts should be made to publicize services offered by the Burlington Lead Program.https://scholarworks.uvm.edu/comphp_gallery/1241/thumbnail.jp

    Proposing the Interactivity-Stimulus-Attention Model (ISAM) to Explain and Predict the Enjoyment, Immersion, and Adoption of Purely Hedonic Systems

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    Traditional TAM research primarily focuses on utilitarian systems where extrinsic motivations chiefly explain and predict acceptance. We propose a theoretical model, ISAM, which explains the role of intrinsic motivations in building the user attention that leads to hedonic system acceptance. ISAM combines several theories with TAM to explain how interactivity acts as a stimulus in hedonic contexts—fostering curiosity, enjoyment, and the full immersion of cognitive resources. Two experiments involving over 700 participants validated ISAM as a useful model for explaining and predicting hedonic system acceptance. Immersion and PE are shown to be the primary predictors of behavioral intention to use hedonic systems. Unlike traditional utilitarian adoption research, PEOU does not directly impact BIU, and extrinsic motivations are virtually non-existent. The implications of this study extend beyond hedonic contexts, as users of utilitarian systems continue to demand more hedonic features and enjoyment is often more important than PEOU

    Defect-mediated metastability and carrier lifetimes in polycrystalline (Ag,Cu)(In,Ga)Se-2 absorber materials

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    Using a combination of optical and electrical measurements, we develop a model for metastable defects in Ag-alloyed Cu(In,Ga)Se-2, one of the leading thin film photovoltaic materials. By controlling the pre-selenization conditions of the back contact prior to the growth of polycrystalline (Ag,Cu)(In,Ga)Se-2 absorbers and subsequently exposing them to various stresses (light soaking and dark-heat), we explore the nature and role of metastable defects on the electro-optical and photovoltaic performance of high-efficiency solar cell materials and devices. Positron annihilation spectroscopy indicates that dark-heat exposure results in an increase in the concentration of the selenium-copper divacancy complex (V-Se-V-Cu), attributed to depassivation of donor defects. Deep-level optical spectroscopy finds a corresponding increase of a defect at E-v+0.98eV, and deep-level transient spectroscopy suggests that this increase is accompanied by a decrease in the concentration of mid-bandgap recombination centers. Time-resolved photoluminescence excitation spectroscopy data are consistent with the presence of the V-Se-V-Cu divacancy complex, which may act as a shallow trap for the minority carriers. Light-soaking experiments are consistent with the V-Se-V-Cu optical cycle proposed by Lany and Zunger, resulting in the conversion of shallow traps into recombination states that limit the effective minority carrier recombination time (and the associated carrier diffusion length) and an increase in the doping density that limits carrier extraction in photovoltaic devices.Peer reviewe

    Characterization of SuperCDMS 1-inch Ge Detectors

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    The newly commissioned SuperCDMS Soudan experiment aims to search for WIMP dark matter with a sensitivity to cross sections of 5×10^(−45)cm^2 and larger (90% CL upper limit). This goal is facilitated by a new set of germanium detectors, 2.5 times more massive than the ones used in the CDMS-II experiment, and with a different athermal phonon sensor layout that eliminates radial degeneracy in position reconstruction of high radius events. We present characterization data on these detectors, as well as improved techniques for correcting position-dependent variations in pulse shape across the detector. These improvements provide surface-event discrimination sufficient for a reach of 5×10^(−45)cm^2

    Potential opportunities and challenges of deploying next generation sequencing and CRISPR-cas systems to support diagnostics and surveillance towards malaria control and elimination in Africa

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    Recent developments in molecular biology and genomics have revolutionized biology and medicine mainly in the developed world. The application of next generation sequencing (NGS) and CRISPR-Cas tools is now poised to support endemic countries in the detection, monitoring and control of endemic diseases and future epidemics, as well as with emerging and re-emerging pathogens. Most low and middle income countries (LMICs) with the highest burden of infectious diseases still largely lack the capacity to generate and perform bioinformatic analysis of genomic data. These countries have also not deployed tools based on CRISPR-Cas technologies. For LMICs including Tanzania, it is critical to focus not only on the process of generation and analysis of data generated using such tools, but also on the utilization of the findings for policy and decision making. Here we discuss the promise and challenges of NGS and CRISPR-Cas in the context of malaria as Africa moves towards malaria elimination. These innovative tools are urgently needed to strengthen the current diagnostic and surveillance systems. We discuss ongoing efforts to deploy these tools for malaria detection and molecular surveillance highlighting potential opportunities presented by these innovative technologies as well as challenges in adopting them. Their deployment will also offer an opportunity to broadly build in-country capacity in pathogen genomics and bioinformatics, and to effectively engage with multiple stakeholders as well as policy makers, overcoming current workforce and infrastructure challenges. Overall, these ongoing initiatives will build the malaria molecular surveillance capacity of African researchers and their institutions, and allow them to generate genomics data and perform bioinformatics analysis in-country in order to provide critical information that will be used for real-time policy and decision-making to support malaria elimination on the continent

    Plug-and-play inference for disease dynamics: measles in large and small populations as a case study

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    Statistical inference for mechanistic models of partially observed dynamic systems is an active area of research. Most existing inference methods place substantial restrictions upon the form of models that can be fitted and hence upon the nature of the scientific hypotheses that can be entertained and the data that can be used to evaluate them. In contrast, the so-called plug-and-play methods require only simulations from a model and are thus free of such restrictions. We show the utility of the plug-and-play approach in the context of an investigation of measles transmission dynamics. Our novel methodology enables us to ask and answer questions that previous analyses have been unable to address. Specifically, we demonstrate that plug-and-play methods permit the development of a modelling and inference framework applicable to data from both large and small populations. We thereby obtain novel insights into the nature of heterogeneity in mixing and comment on the importance of including extra-demographic stochasticity as a means of dealing with environmental stochasticity and model misspecification. Our approach is readily applicable to many other epidemiological and ecological systems

    Origins of the Greenland shark (Somniosus microcephalus): Impacts of ice-olation and introgression

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    Herein, we use genetic data from 277 sleeper sharks to perform coalescent-based modeling to test the hypothesis of early Quaternary emergence of the Greenland shark (Somniosus microcephalus) from ancestral sleeper sharks in the Canadian Arctic-Subarctic region. Our results show that morphologically cryptic somniosids S. microcephalus and Somniosus pacificus can be genetically distinguished using combined mitochondrial and nuclear DNA markers. Our data confirm the presence of genetically admixed individuals in the Canadian Arctic and sub-Arctic, and temperate Eastern Atlantic regions, suggesting introgressive hybridization upon secondary contact following the initial species divergence. Conservative substitution rates fitted to an Isolation with Migration (IM) model indicate a likely species divergence time of 2.34 Ma, using the mitochondrial sequence DNA, which in conjunction with the geographic distribution of admixtures and Pacific signatures likely indicates speciation associated with processes other than the closing of the Isthmus of Panama. This time span coincides with further planetary cooling in the early Quaternary period followed by the onset of oscillating glacial-interglacial cycles. We propose that the initial S. microcephalus–S. pacificus split, and subsequent hybridization events, were likely associated with the onset of Pleistocene glacial oscillations, whereby fluctuating sea levels constrained connectivity among Arctic oceanic basins, Arctic marginal seas, and the North Atlantic Ocean. Our data demonstrates support for the evolutionary consequences of oscillatory vicariance via transient oceanic isolation with subsequent secondary contact associated with fluctuating sea levels throughout the Quaternary period—which may serve as a model for the origins of Arctic marine fauna on a broad taxonomic scale

    Tourist Photographers and the Promotion of Travel: the Polytechnic Touring Association, 1888–1939

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    The Polytechnic Touring Association (PTA) was a London-based, originally philanthropic turned commercial travel firm whose historical origins coincided with the arrival of the Kodak camera in 1888 – thus, of popular (tourist) photography. This article examines the PTA’s changing relationship with tourist photographers, and how this influenced the company’s understanding of what role photography could play in promoting the tours, in the late nineteenth and early twenty century. This inquiry is advanced on the basis of the observation that, during this time, the PTA’s passage from viewing tourists as citizens to educate, to customers to please, paralleled the move from using photography-based images to mixed media. Such a development was certainly a response to unprecedented market demands; this article argues that it should also be considered in relation to the widening of photographic perceptions engendered by the democratization of the medium, to which the PTA responded, first as educator, then as service provider. In doing so, the article raises several questions about the shifting relationship between “high”, or established, and “low”, or emerging, forms of culture, as mass photography and the mass marketing of tourism developed

    Small RNA changes en route to distinct cellular states of induced pluripotency

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    MicroRNAs (miRNAs) are critical to somatic cell reprogramming into induced pluripotent stem cells (iPSCs), however, exactly how miRNA expression changes support the transition to pluripotency requires further investigation. Here we use a murine secondary reprogramming system to sample cellular trajectories towards iPSCs or a novel pluripotent ‘F-class’ state and perform small RNA sequencing. We detect sweeping changes in an early and a late wave, revealing that distinct miRNA milieus characterize alternate states of pluripotency. miRNA isoform expression is common but surprisingly varies little between cell states. Referencing other omic data sets generated in parallel, we find that miRNA expression is changed through transcriptional and post-transcriptional mechanisms. miRNA transcription is commonly regulated by dynamic histone modification, while DNA methylation/demethylation consolidates these changes at multiple loci. Importantly, our results suggest that a novel subset of distinctly expressed miRNAs supports pluripotency in the F-class state, substituting for miRNAs that serve such roles in iPSCs

    Combination therapy in a xenograft model of glioblastoma: enhancement of the antitumor activity of temozolomide by an MDM2 antagonist

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    OBJECTIVE Improvement in treatment outcome for patients with glioblastoma multiforme (GBM) requires a multifaceted approach due to dysregulation of numerous signaling pathways. The murine double minute 2 (MDM2) protein may fulfill this requirement because it is involved in the regulation of growth, survival, and invasion. The objective of this study was to investigate the impact of modulating MDM2 function in combination with front-line temozolomide (TMZ) therapy in GBM. METHODS The combination of TMZ with the MDM2 protein-protein interaction inhibitor nutlin3a was evaluated for effects on cell growth, p53 pathway activation, expression of DNA repair proteins, and invasive properties. In vivo efficacy was assessed in xenograft models of human GBM. RESULTS In combination, TMZ/nutlin3a was additive to synergistic in decreasing growth of wild-type p53 GBM cells. Pharmacodynamic studies demonstrated that inhibition of cell growth following exposure to TMZ/nutlin3a correlated with: 1) activation of the p53 pathway, 2) downregulation of DNA repair proteins, 3) persistence of DNA damage, and 4) decreased invasion. Pharmacokinetic studies indicated that nutlin3a was detected in human intracranial tumor xenografts. To assess therapeutic potential, efficacy studies were conducted in a xenograft model of intracranial GBM by using GBM cells derived from a recurrent wild-type p53 GBM that is highly TMZ resistant (GBM10). Three 5-day cycles of TMZ/nutlin3a resulted in a significant increase in the survival of mice with GBM10 intracranial tumors compared with single-agent therapy. CONCLUSIONS Modulation of MDM2/p53-associated signaling pathways is a novel approach for decreasing TMZ resistance in GBM. To the authors' knowledge, this is the first study in a humanized intracranial patient-derived xenograft model to demonstrate the efficacy of combining front-line TMZ therapy and an inhibitor of MDM2 protein-protein interactions
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