5,562 research outputs found

    Microtubule binding by dynactin is required for microtubule organization but not cargo transport

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    Dynactin links cytoplasmic dynein and other motors to cargo and is involved in organizing radial microtubule arrays. The largest subunit of dynactin, p150glued, binds the dynein intermediate chain and has an N-terminal microtubule-binding domain. To examine the role of microtubule binding by p150glued, we replaced the wild-type p150glued in Drosophila melanogaster S2 cells with mutant ΔN-p150 lacking residues 1–200, which is unable to bind microtubules. Cells treated with cytochalasin D were used for analysis of cargo movement along microtubules. Strikingly, although the movement of both membranous organelles and messenger ribonucleoprotein complexes by dynein and kinesin-1 requires dynactin, the substitution of full-length p150glued with ΔN-p150glued has no effect on the rate, processivity, or step size of transport. However, truncation of the microtubule-binding domain of p150glued has a dramatic effect on cell division, resulting in the generation of multipolar spindles and free microtubule-organizing centers. Thus, dynactin binding to microtubules is required for organizing spindle microtubule arrays but not cargo motility in vivo

    Semi-supervised prediction of protein interaction sentences exploiting semantically encoded metrics

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    Protein-protein interaction (PPI) identification is an integral component of many biomedical research and database curation tools. Automation of this task through classification is one of the key goals of text mining (TM). However, labelled PPI corpora required to train classifiers are generally small. In order to overcome this sparsity in the training data, we propose a novel method of integrating corpora that do not contain relevance judgements. Our approach uses a semantic language model to gather word similarity from a large unlabelled corpus. This additional information is integrated into the sentence classification process using kernel transformations and has a re-weighting effect on the training features that leads to an 8% improvement in F-score over the baseline results. Furthermore, we discover that some words which are generally considered indicative of interactions are actually neutralised by this process

    Coloring translates and homothets of a convex body

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    We obtain improved upper bounds and new lower bounds on the chromatic number as a linear function of the clique number, for the intersection graphs (and their complements) of finite families of translates and homothets of a convex body in \RR^n.Comment: 11 pages, 2 figure

    Vortex Fluctuations in High-Tc Films: Flux Noise Spectrum and Complex Impedance

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    The flux noise spectrum and complex impedance for a 500 {\AA} thick YBCO film are measured and compared with predictions for two dimensional vortex fluctuations. It is verified that the complex impedance and the flux noise spectra are proportional to each other, that the logarithm of the flux noise spectra for different temperatures has a common tangent with slope ≈−1\approx -1, and that the amplitude of the noise decreases as d−3d^{-3}, where dd is the height above the film at which the magnetic flux is measured. A crossover from normal to anomalous vortex diffusion is indicated by the measurements and is discussed in terms of a two-dimensional decoupling.Comment: 5 pages including 4 figures in two columns, to appear in Phys. Rev. Let

    Sustainable Practices Within a School‐Based Intervention: A Report from Project Healthy Schools

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    Over the past three decades the proportion of students classified as overweight has almost tripled. This trend in childhood obesity is a cause for concern. Stakeholders have come together to stem growth and implement healthy habits in childhood to not only prevent obesity, but also future cardiovascular risk. School‐based health interventions have proven to be an effective medium to reach youth. Sustainable practices remain the largest determinant of long‐term success of these programs. Project Healthy Schools, a community–university collaborative school‐based health intervention program, sustainable practices have led to positive changes in participating middle schools. This collaborative has provided important insight on key factors needed for long‐term sustainability for a school‐based wellness program. These key factors are described under leadership, policy, finances, and reproducibility. Future school‐based programs may plan for success with sustainability while drawing from our experience.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96375/1/wmh36.pd

    Spatiotemporal dynamics of discrete sine-Gordon lattices with sinusoidal couplings

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    The spatiotemporal dynamics of a damped sine-Gordon chain with sinusoidal nearest-neighbor couplings driven by a constant uniform force are discussed. The velocity characteristics of the chain versus the external force is shown. Dynamics in the high- and low-velocity regimes are investigated. It is found that in the high-velocity regime, the dynamics is dominated by rotating modes, the velocity shows a branching bifurcation feature, while in the low-velocity regime, the velocity exhibits step-like dynamical transitions, broken by the destruction of strong resonances.Comment: 10 Revtex pages, 8 Eps figures, to appear in Phys. Rev.E 57(1998

    Roadmap on semiconductor-cell biointerfaces.

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    This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world

    Elucidating glycosaminoglycan–protein–protein interactions using carbohydrate microarray and computational approaches

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    Glycosaminoglycan polysaccharides play critical roles in many cellular processes, ranging from viral invasion and angiogenesis to spinal cord injury. Their diverse biological activities are derived from an ability to regulate a remarkable number of proteins. However, few methods exist for the rapid identification of glycosaminoglycan–protein interactions and for studying the potential of glycosaminoglycans to assemble multimeric protein complexes. Here, we report a multidisciplinary approach that combines new carbohydrate microarray and computational modeling methodologies to elucidate glycosaminoglycan–protein interactions. The approach was validated through the study of known protein partners for heparan and chondroitin sulfate, including fibroblast growth factor 2 (FGF2) and its receptor FGFR1, the malarial protein VAR2CSA, and tumor necrosis factor-α (TNF-α). We also applied the approach to identify previously undescribed interactions between a specific sulfated epitope on chondroitin sulfate, CS-E, and the neurotrophins, a critical family of growth factors involved in the development, maintenance, and survival of the vertebrate nervous system. Our studies show for the first time that CS is capable of assembling multimeric signaling complexes and modulating neurotrophin signaling pathways. In addition, we identify a contiguous CS-E-binding site by computational modeling that suggests a potential mechanism to explain how CS may promote neurotrophin-tyrosine receptor kinase (Trk) complex formation and neurotrophin signaling. Together, our combined microarray and computational modeling methodologies provide a general, facile means to identify new glycosaminoglycan–protein–protein interactions, as well as a molecular-level understanding of those complexes

    A Nightingale-Based Model for Dementia Care and its Relevance for Korean Nursing

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    This article addresses the synchrony between a Western middle-range theory of care for persons with dementia and traditional Korean nursing care. The Western theory is called a need-driven, dementia-compromised behavior model and is heavily influenced by the assessment categories outlined in Nightingale’s work. This model is presented as congruent with Nightingale’s work and then viewed from the perspective of traditional Korean nursing. Several congruencies and a few incongruencies are found between these Western and Eastern views, and suggestions are made for greater consistency between these views.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68880/2/10.1177_08943189922107043.pd
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