5,950 research outputs found

    Subclinical Photoreceptor Disruption in Response to Severe Head Trauma

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    Commotio retinae is a transient opacification of the retina due to outer retinal disruption occurring in a contrecoup fashion after blunt trauma.Histological studies in animals and humans after ocular blunt trauma have revealed that disruption occurs at the level of the photoreceptor outer segments and retinal pigment epithelium.Recent reports using optical coherence tomography (OCT) have shown detectable disruption at the level of the photoreceptor inner segment/outer segment junction and retinal pigment epithelium and that these changes may be reversible over time with restoration of normal outer retinal architecture.However, the resolution of existing OCT technology may not be sensitive enough to detect photoreceptor disruption. Adaptive optics (AO) imaging systems enable cellular-resolution imaging of the human retina, and there is a growing number of cases where deficits have been visible on AO images but not on OCT. Herein, we report a case of subclinical photoreceptor disruption after head trauma as seen by an AO scanning ophthalmoscope (AOSO) but not apparent clinically or on spectral-domain OCT (SD-OCT)

    The ferroelectric Mott-Hubbard phase of organic (TMTTF)2X conductors

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    We present experimental evidences for a ferro-electric transition in the family of quasi one- dimensional conductors (TMTTF)2X. We interpret this new transition in the frame of the combined Mott-Hubbard state taking into account the double action of the spontaneous charge disproportionation on the TMTTF molecular stacks and of the X anionic potentials

    Development and Psychometric Evaluation of a Brief Measure of School and Community Mental Health Supports and Services

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    This study evaluated a self-report survey assessing school professionals’ perceptions of school and community mental health supports and services. Based on responses from 560 school professionals, findings provide support for the measure’s internal structure and ability to distinguish low-poverty and high-poverty schools. Practitioners and researchers may consider using this survey to understand perceptions of the quality and availability of mental health services, informing the selection and adaptation of school-based mental health supports and services

    Limited functional conservation of a global regulator among related bacterial genera: Lrp in Escherichia, Proteus and Vibrio

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    Abstract Background Bacterial genome sequences are being determined rapidly, but few species are physiologically well characterized. Predicting regulation from genome sequences usually involves extrapolation from better-studied bacteria, using the hypothesis that a conserved regulator, conserved target gene, and predicted regulator-binding site in the target promoter imply conserved regulation between the two species. However many compared organisms are ecologically and physiologically diverse, and the limits of extrapolation have not been well tested. In E. coli K-12 the leucine-responsive regulatory protein (Lrp) affects expression of ~400 genes. Proteus mirabilis and Vibrio cholerae have highly-conserved lrp orthologs (98% and 92% identity to E. coli lrp). The functional equivalence of Lrp from these related species was assessed. Results Heterologous Lrp regulated gltB, livK and lrp transcriptional fusions in an E. coli background in the same general way as the native Lrp, though with significant differences in extent. Microarray analysis of these strains revealed that the heterologous Lrp proteins significantly influence only about half of the genes affected by native Lrp. In P. mirabilis, heterologous Lrp restored swarming, though with some pattern differences. P. mirabilis produced substantially more Lrp than E. coli or V. cholerae under some conditions. Lrp regulation of target gene orthologs differed among the three native hosts. Strikingly, while Lrp negatively regulates its own gene in E. coli, and was shown to do so even more strongly in P. mirabilis, Lrp appears to activate its own gene in V. cholerae. Conclusion The overall similarity of regulatory effects of the Lrp orthologs supports the use of extrapolation between related strains for general purposes. However this study also revealed intrinsic differences even between orthologous regulators sharing \u3e90% overall identity, and 100% identity for the DNA-binding helix-turn-helix motif, as well as differences in the amounts of those regulators. These results suggest that predicting regulation of specific target genes based on genome sequence comparisons alone should be done on a conservative basis

    Inhibition of \u3cem\u3eFusarium oxysporum\u3c/em\u3e f. sp. \u3cem\u3enicotianae\u3c/em\u3e Growth by Phenylpropanoid Pathway Intermediates

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    Fusarium wilt in tobacco caused by the fungus Fusarium oxysporum f. sp. nicotianae is a disease‑management challenge worldwide, as there are few effective and environmentally benign chemical agents for its control. This challenge results in substantial losses in both the quality and yield of tobacco products. Based on an in vitro analysis of the effects of different phenylpropanoid intermediates, we found that the early intermediates trans‑cinnamic acid and para‑coumaric acid effectively inhibit the mycelial growth of F. oxysporum f. sp. nicotianae strain FW316F, whereas the downstream intermediates quercetin and caffeic acid exhibit no fungicidal properties. Therefore, our in vitro screen suggests that trans‑cinnamic acid and para‑coumaric acid are promising chemical agents and natural lead compounds for the suppression of F. oxysporum f. sp. nicotianae growth

    DNA Methylation Differs in Bluegill Among Temperate, Anthropogenically Warmed, and Tropical Lakes

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    Epigenetic mechanisms can alter gene expression and phenotypes in organisms responding to environmental changes. Within environmental parameters, temperature changes are notably the most pervasive abiotic factor for ectotherms, directly affecting organismal survival and fitness. The goal of this study was to investigate the scale of DNA methylation in populations of a cosmopolitan freshwater species occupying disparate thermal regimes. DNA methylation levels were compared among bluegill sunfish (Lepomis macrochirus) populations from an ambient temperature, temperate lake (Lake Mattoon), a nearby power plant-cooling lake (Lake Coffeen), and a tropical lake (Lake Lucchetti). We used epiRADseq to screen levels of DNA methylation at 105,811 loci among fish. We found levels of total DNA methylation increased among specimens as water temperature of lakes increased from the ambient temperature, temperate lake to the tropical lake. We identified loci with statistically significant differences in the frequency of DNA methylation among individuals between lakes: 654 loci between Lake Mattoon and Lake Lucchetti fish and 373 loci between Lake Coffeen and Lake Lucchetti fish. Considering that a previous study on the same power plant-cooling reservoirs showed a shorter lifespan, decrease in growth performance, and the populations skewed towards younger fish, this study observed DNA methylation pattern may be an important mechanism contributing to the observed phenotypic variations in bluegill from a anthropogenically-warmed lake compared to an ambient temperature lake. Our study suggests that epigenetic regulation of phenotypic plasticity in aquatic organisms may be a critical factor in understanding the organismal response to environmental stress

    Fast Fourier Optimization: Sparsity Matters

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    Many interesting and fundamentally practical optimization problems, ranging from optics, to signal processing, to radar and acoustics, involve constraints on the Fourier transform of a function. It is well-known that the {\em fast Fourier transform} (fft) is a recursive algorithm that can dramatically improve the efficiency for computing the discrete Fourier transform. However, because it is recursive, it is difficult to embed into a linear optimization problem. In this paper, we explain the main idea behind the fast Fourier transform and show how to adapt it in such a manner as to make it encodable as constraints in an optimization problem. We demonstrate a real-world problem from the field of high-contrast imaging. On this problem, dramatic improvements are translated to an ability to solve problems with a much finer grid of discretized points. As we shall show, in general, the "fast Fourier" version of the optimization constraints produces a larger but sparser constraint matrix and therefore one can think of the fast Fourier transform as a method of sparsifying the constraints in an optimization problem, which is usually a good thing.Comment: 16 pages, 8 figure
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