1,259 research outputs found

    Functional Role of Zebrafish TLR Proteins

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    Project summary. Influenza virus infections lead to significant illness, mortality, and social disruption worldwide. Herein, the first studies establishing the zebrafish as a model for human influenza infection are presented and it is shown that influenza infection proceeds and can be resolved through similar mechanisms in zebrafish and humans (Gabor, et al.). Our laboratory has previously characterized a fish rhabdovirus infection model in the zebrafish (Phelan, et al.)

    Technology and Aging: An Emerging Research and Development Sector in Maine

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    The authors discuss the importance of research for developing products and services that cater to the needs of a rapidly growing aging population and provide examples of projects underway at the University of Maine. Products designed to improve and protect older adult health and well-being represent a significant opportunity for economic growth in Maine

    Tracking the prelude of the electroreduction of carbon monoxide via its interaction with Cu(100): Studies by operando scanning tunneling microscopy and infrared spectroscopy

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    The first isolable intermediate in the electrochemical reduction of carbon dioxide is carbon monoxide. This species, or its hydrated form, formic acid, is also the primary end product from all but a handful of metallic electrodes; with the latter, hydrogen gas is generated, but it emanates from the reduction of water and not from COâ‚‚. Only one electrode material, zerovalent copper, can spawn, in greater-than-trace quantities, a variety of species that are more highly reduced than CO. Hence, if the aim is to pursue a reaction trail of the reduction of COâ‚‚ to products other than CO, it would be both logical and expedient to track the electrocatalytic reaction of CO itself. Heterogeneous electrocatalysis is a surface phenomenon; it transpires only when the reactant, CO in this case, chemisorbs on, or chemically interacts with, the Cu electrode surface. There is no electrocatalytic reaction if there is no CO adsorption. In ultrahigh vacuum, no CO resides on the Cu(100) surface at temperatures higher than 200 K. However, under electrochemical conditions, CO is chemisorbed on Cu at ambient temperatures at a given potential. We thus paired, in seriatim fashion, scanning tunneling microscopy (STM) and polarization-modulation IR reflection-absorption spectroscopy (PMIRS) to document the influence of applied potential on the coverage, the molecular orientation, and the adlattice structure of CO adsorbed on Cu(100) in alkaline solutions; the results are described in this paper

    Acquisition of Laser Scanning Confocal Microscope for Biological and Materials Research

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    Biological and Materials research at the University of Maine will be strongly impacted by the acquisition of a Laser Scanning Electron Microscope as a result of this NSF-MRI award. The Leica confocal unit, along with an upright and inverted microscope and digital camera will form a multi-user facility for campus researchers working with a range of biological and materials problems. Initially, 13 faculty members from 8 academic departments have projects planned for the instrument. The microscope will be the first of its kind on the University of Maine campus. A wide range of research problems will be attacked through use of this instrument in conjunction with existing instrumentation. Examples include: Biological research projects involve understanding the maintenance of bone structure through mapping of the distribution of proteins, the reproduction of algae in troubled marine ecosystems, and bacterial or viral diseases of fish. Additionally, improved understanding of fundamental microbe-plant symbiosis and wood decay processes will allow for future applied research to attack economically and socially important problems. The development of biofilms for sensors of biological and chemical warfare agents will be aided through film characterization using this instrument. This $10 million effort is a University/private industry/Department of Defense partnership. Materials-related research includes determination of morphology and fracture of wood-based composite material, microfracture characterization of cement-based materials, and characterization of paper roughness. This work, along with environmental scanning electron microscopy and X-ray microtomography, is focused on the measurement of microstructural mechanisms of material behavior and its improvement through subsequent processing changes. The ultimate benefit will include more efficient use of natural resources, better performance and lowered product costs

    Sestrins are evolutionarily conserved mediators of exercise benefits.

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    Exercise is among the most effective interventions for age-associated mobility decline and metabolic dysregulation. Although long-term endurance exercise promotes insulin sensitivity and expands respiratory capacity, genetic components and pathways mediating the metabolic benefits of exercise have remained elusive. Here, we show that Sestrins, a family of evolutionarily conserved exercise-inducible proteins, are critical mediators of exercise benefits. In both fly and mouse models, genetic ablation of Sestrins prevents organisms from acquiring metabolic benefits of exercise and improving their endurance through training. Conversely, Sestrin upregulation mimics both molecular and physiological effects of exercise, suggesting that it could be a major effector of exercise metabolism. Among the various targets modulated by Sestrin in response to exercise, AKT and PGC1α are critical for the Sestrin effects in extending endurance. These results indicate that Sestrin is a key integrating factor that drives the benefits of chronic exercise to metabolism and physical endurance

    Testing Multiple Hypotheses through IMP weighted FDR Based on a Genetic Functional Network with Application to a New Zebrafish Transcriptome Study

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    In genome-wide studies, hundreds of thousands of hypothesis tests are performed simultaneously. Bonferroni correction and False Discovery Rate (FDR) can effectively control type I error but often yield a high false negative rate. We aim to develop a more powerful method to detect differentially expressed genes. We present a Weighted False Discovery Rate (WFDR) method that incorporate biological knowledge from genetic networks. We first identify weights using Integrative Multi-species Prediction (IMP) and then apply the weights in WFDR to identify differentially expressed genes through an IMP-WFDR algorithm. We performed a gene expression experiment to identify zebrafish genes that change expression in the presence of arsenic during a systemic Pseudomonas aeruginosa infection. Zebrafish were exposed to arsenic at 10 parts per billion and/or infected with P. aeruginosa. Appropriate controls were included. We then applied IMP-WFDR during the analysis of differentially expressed genes. We compared the mRNA expression for each group and found over 200 differentially expressed genes and several enriched pathways including defense response pathways, arsenic response pathways, and the Notch signaling pathway

    Design of stiffened panels for stress and buckling via topology optimization

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    This paper investigates the weight minimization of stiffened panels simultaneously optimizing sizing, layout, and topology under stress and buckling constraints. An effective topology optimization parameterization is presented using multiple level-set functions. Plate elements are employed to model the stiffened panels. The stiffeners are parametrized by implicit level-set functions. The internal topologies of the stiffeners are optimized as well as their layout. A free-form mesh deformation approach is improved to adjust the finite element mesh. Sizing optimization is also included. The thicknesses of the skin and stiffeners are optimized. Bending, shear, and membrane stresses are evaluated at the bottom, middle, and top surfaces of the elements. A p-norm function is used to aggregate these stresses in a single constraint. To solve the optimization problem, a semi-analytical sensitivity analysis is performed, and the optimization algorithm is outlined. Numerical investigations demonstrate and validate the proposed method
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